1 I E> HAHY 
 
 OF THE 
 U N IVLRSITY 
 Of ILLINOIS 
 
 510.84 
 
 I46r 
 
 no. 265-270 
 
 cop. 2 
 
The person charging this material is re- 
 sponsible for its return to the library from 
 which it was withdrawn on or before the 
 Latest Date stamped below. 
 
 Theft, mutilation, and underlining of books 
 are reasons for disciplinary action and may 
 result in dismissal from the University. 
 
 UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN 
 
 MAY 1 1974 
 
 MAY 31\m 
 
 WAY 3 fit 
 
 
 ,■ 
 
 L161 — O-1096 
 
if Report No. 268 
 
 hnuXjw 
 
 STORAGE OF ANALOG VARIABLES IN DELAY LINES 
 
 by 
 
 LAWRENCE H. WALLMAN 
 
 June, 1968 
 
 DEPARTMENT OF COMPUTER SCIENCE • UNIVERSITY OP ILLINOIS • URBANA, ILLINOIS 
 
Digitized by the Internet Archive 
 in 2013 
 
 http://archive.org/details/storageofanalogv268wall 
 
Report No. 268 
 
 STORAGE OF ANALOG VARIABLES IN DELAY LINES 
 
 by 
 
 LAWRENCE H. WALLMAN 
 
 June , I968 
 
 Department of Computer Science 
 University of Illinois 
 Urbana, Illinois 6l801 
 
Ill 
 ACKNOWLEDGEMENT 
 
 The author wishes to express his appreciation to his 
 thesis advisor, Professor W, J. Poppelbaum, whose support and good 
 counsel have made this thesis project possible. Thanks are also 
 extended to Professor Louis Van Biljon, whose suggestions and 
 encouragement were very helpful. 
 
 The author is further grateful to the many members of 
 the research group who gave freely of their time and experience. 
 Finally, the author thanks Mrs. Jonnie Hudspath, Mrs. Gayle Osterberj; 
 and Mrs. Ruth Batley for their excellent typing of the thesis. 
 
IV 
 
 TABLE OF CONTENTS 
 
 Page 
 
 ACKNOWLEDGEMENT iii 
 
 LIST OF FIGURES vi 
 
 1. INTRODUCTION ..... 1 
 
 2. OPERATION OF PHASTOR SYSTEM 5 
 
 2.1 Oscillator 10 
 
 2.2 Modulo 125 Counter 10 
 
 2.3 Ramp Generator and Analog-to-Phase Converter lk 
 
 2.U Control Circuit 17 
 
 2.5 Storage Cell Delay Line 20 
 
 2.6 Calculation of the Period of the Emitter Coupled 
 
 Mono stable Multivibrator 2k 
 
 2.7 Calculation of the Circuit Parameters of the Emitter- 
 Coupled Monostable Multivibrator 26 
 
 2.8 Theoretical Calculation of Change of Period of 
 Emitter-Coupled Monostable Corresponding to Small 
 Variations of Supply Voltages. 33 
 
 2.9 Calculation F!rom Experimental Results of the Change 
 of Period of the Emitter-Coupled Monostable 
 Multivibrator Corresponding to Small Variations of 
 Supply Voltages 30 
 
 2.10 Write Select Gate ^3 
 
 2.11 Readout Select Gate 45 
 
 2.12 Sample and Hold ^5 
 
 2.13 Phastor Model and Description ... .... 50 
 
 3. OPERATION OF COLLECTOR-BASE COUPLED MONOSTABLE MULTIVIBRATOR 52 
 
 3.1 Calculation of the Period of the Collector-Base Coupled 
 Monostable Multivibrator 5U 
 
 3.2 Calculation of the Circuit Parameters of the 
 Collector-Base Coupled Monostable Multivibrator ... 56 
 
 3.3 Theoretical Calculation of the Change of Period of 
 the Collector-Base Coupled Monostable Corresponding 
 
 to Small Variations of Supply Voltage ... 60 
 
 3.^ Calculation from Experimental Results of the Change 
 of Period of the Collector-Base Coupled Monostable 
 Corresponding to Small Variations of Supply Voltages . 68 
 
V 
 
 Page 
 
 k. OPERATION OF COMPLEMENTARY TRANSISTOR MONOSTABLE MULTIVIBRATOR 71 
 
 k.l Calculation of the Period of the Complementary Transistor 
 
 Monostable Multivibrator 73 
 
 k.2 Calculation of the Circuit Parameters of the 
 
 Complementary Transistor Monostable Multivibrator. ... 76 
 
 U.3 Theoretical Calculation of the Change of Period of the 
 Complementary Transistor Monostable Corresponding to 
 Small Variations of Supply Voltage 8l 
 
 k.h Calculation from Experimental Results of the Change of 
 Period of the Complementary Transistor Monostable 
 Corresponding to Small Variations of Supply Voltages . . gU 
 
 5. OPERATION OF EMITTER COUPLED ASTABLE MULTIVIBRATOR 87 
 
 5.1 Calculation of the Period of the Emitter Coupled 
 
 Astable Multivibrator go 
 
 5.2 Calculation of the Circuit Parameters of the Emitter 
 Coupled Astable Multivibrator q^ 
 
 5.3 Theoretical Calculation of the Change of Period of the 
 Emitter Coupled Astable Multivibrator Corresponding 
 
 to Small Variations of Supply Voltages 100 
 
 5.^ Calculation from Experimental Results of the Change 
 of Period of the Collector-Base Coupled Monostable 
 Corresponding to Small Variations of Supply Voltages . . 110 
 
 6. OPERATION OF INTEGRATED CIRCUIT MONOSTABLE MULTIVIBRATOR . . llU 
 
 6.1 Calculation of the Period of the Integrated Circuit 
 Monostable Multivibrator 116 
 
 6.2 Calculation from Experimental Results of the Change of 
 Period of the Integrated-Circuit Monostable 
 Corresponding to Small Variations of Supply Voltages . . 117 
 
 7. CONCLUSION 121 
 
 REFERENCES' " 122 
 
VI 
 
 LIST OF FIGURES 
 
 Figure Page 
 
 1. Storage by Reciprocating Delay Line 2 
 
 2. Block Diagram 6 
 
 3. Phastor Waveforms 7 
 h. Oscillator 11 
 
 5. Modulo 5 Counter •■ 13 
 
 6. Ramp Generator and Amplitude -to-Phase Converter 15 
 
 7. Control Circuit 18 
 
 8. Flip-Flop 19 
 9- Emitter Coupled Monostable Multivibrator 21 
 
 10. Storage Cell 22 
 
 11. Experimental Waveforms of the Emitter Coupled 
 
 Monostable Multivibrator ' • 31 
 
 12. Select Circuit kk 
 
 13. Push Button Connection Diagram 4 5 
 lU. Readout Circuit kj 
 
 15. Sample -and-Ho Id Circuit 48 
 
 16. Panel Photographs 4 9 
 
 17. Collector-Base Coupled Monostable Multivibrator 53 
 
 18. Experimental Waveforms of Collector-Base Coupled 
 Monostable Multivibrator '1 °1 
 
 19. Complementary Transistor Monostable Multivibrator 72 
 
VI 1 
 
 Figure Page 
 
 20. Experimental Waveforms of Complementary 
 
 Transistor Monostable Multivibrator 79 
 
 2.1. Emitter Coupled Astable Multivibrator 88 
 
 22. Experimental Waveforms of the Emitter Coupled 
 
 Astable Multivibrator 98 
 
 23- Integrated Circuit Monostable Multivibrator 115 
 
 2U. Experimental Waveforms of the Integrated 
 
 Circuit Monostable Multivibrator H9 
 
1 . INTRODUCTION 
 
 The storage of analog variables has always presented a 
 problem. A novel method for solving this problem was first suggested 
 by W. J. Poppelbaum, D. Aspinall, and M. Faiman . This method for 
 storing analog voltages has been developed under the guidance of 
 W. J. Poppelbaum. 
 
 The method suggested and developed is essentially that 
 shown in Figure 1. The WRITE signal is a single pulse which occurs 
 at a time corresponding to a voltage level on the periodic CLOCK 
 RAMP as shown in Figure 1. The WRITE signal can be generated by 
 using a voltage comparator which gives an output pulse when the 
 CLOCK RAMP is equal to a D.C. voltage level. The HARMONIC clock' 
 signal of Figure 1 is a harmonic of the CLOCK RAMP, that is, the 
 same number of clock pulses always occur during each ramp. The 
 HARMONIC clock gates WRITE to the delay line, thus quantizing the 
 levels on the CLOCK RAMP. This pulse circulates in the delay line 
 loop with the same frequency as the CLOCK RAMP. The feedback in the 
 delay line is gated by HARMONIC clock and thus eliminates any drift 
 in the delay time. Thus, the circulating pulse always represents 
 the same quantized voltage on the CLOCK RAMP. The D.C. voltage can 
 be recovered by using the ramp to charge a capacitor and stopping 
 this charging at the time coincident with the stored pulse. 
 
WRITE 
 
 HARMONIC 
 OF CLOCK 
 
 
 
 -c>(a\> 
 
 CLOCK 
 RAMP 
 
 HARMONIC 
 OF RAMP 
 
 WRITE ■ 
 
 STORED 
 PULSE ■ 
 
 Figure 1. Storage by Reciprocating Delay Line 
 
The accuracy of such a system can be determined by noting 
 the number of clock pulses which occur during the ramp cycle. If 
 there are p clock pulses during the ramp cycle then the maximum time 
 which can elapse before the delay line is re-triggered is equal to 
 one clock pulse; furthermore if there are n clock pulses in the useful 
 portion of the ramp (i.e. excluding any fly back and hold off time) 
 the maximum error in volts which can occur will be + l/n x 100% of 
 the total ramp voltage swing. Therefore the storage system will be 
 accurate to + l/n x 100%. 
 
 The circuits for a single storage unit system were 
 originally designed by D. Aspinall. This system was capable of 
 only a +5 volt' to -5 volt range of storage and was not sufficiently 
 stable. By unstable it is meant that the delay of the delay line 
 was not constant enough with time to keep the phase relation with 
 the clock ramp. That is, when the period of the clock ramp is 
 different from the delay of the delay line by more than one clock 
 pulse time the system loses synchronization and all stored information 
 is lost. 
 
 The initial system which was in the form of a feasibility 
 proof, has been expanded to four storage cells and has been made 
 stable enough to retain stored information for at least eight hours 
 and probably much longer. Thermal influences proved to be of greatest 
 importance in achieving stability. . 
 
The purpose of this thesis is to explain how this system 
 ■works. The system is called "PHASTOR" because the stored infor- 
 mation is actually a phase and not the actual input voltage. The 
 aim also was to investigate several delay lines which could be 
 used as the storage circuits and determine which of these were 
 best suited to this purpose. 
 
2. OPERATION OF PHASTOR SYSTEM 
 
 The block diagram of Phastor is shown in Figure 2. The 
 main sections of the diagram are (l) the ramp generator, (2) the 
 control circuit, (3) the sample and hold, and (k) the analog 
 (phase) memory units. 
 
 The ramp generator generates the ramp clock shown in 
 Figure 2 and Figure 3. This generator is driven hy a mod 125 
 counter which in turn is driven by the harmonic of the ramp clock 
 frequency generator. The harmonic of the ramp clock generator 
 is a crystal-controlled oscillator. The ramp clock rises from 
 -lOv to +I0v for one hundred of the ramp clock harmonic pulses and 
 returns and stays at -10 volts for twenty-five more pulses. Since 
 there are 100 pulses per ramp the accuracy of this system is +Vfo. 
 
 The control circuit gates one pulse from the comparator 
 (amplitude-to-phase converter) into one of the analog memory 
 units. This gating is effected in the following manner. With the 
 flip-flops in the control circuit set to the beginning state 
 (i.e. C2 = C3 = 1) and the first flip-flop reset, the "INITIATE 
 STORE" button can be pressed. This causes flip-flop Number .1 to 
 flip which in turn causes flip-flop Number 2 to change state. Flip- 
 flop Number 2 changes state only on a zero to one transition at the 
 input. At this point no more outputs from flip-flop Number 1 can 
 

 BEGINNING STATE 
 AFTER INITIATE STORE 
 
 C2 C3 
 
 1 1 
 
 Figure 2, Block Diagram 
 
INPUT 
 
 RAMP 
 
 CLOCK 
 
 MOD 125 
 COUNTER 
 
 COMPARATOR 
 OUTPUT 
 
 REGEN (C3) 
 -5 
 
 WRITE 
 
 OUTPUT +3 
 PHASE 
 
 
 
 PREVIOUSLY STORED 
 INFORMATION 
 
 K 
 
 ONLY ONE WRITE PULSE 
 I TO TRIGGER DELAY UNIT. 
 
 C3 (REGEN) HAS BLOCKED OUT FEEDBACK 
 AND MONOSTABLE DELAY UNIT IS READY 
 TO RECEIVE NEW TRIGGER. 
 
 Figure 3. Phastor Waveforms 
 
8 
 
 trigger flip-flop Number 2 since the AND gate will not let them 
 through. However, the output of the mod 125 counter is now gated 
 to the input of flip-flop Number 2 and since the ramp starts on the 
 zero to one transition of the counter flip-flop Number 2 changes 
 state at the start of each ramp. So, flip-flop Number 2 changes 
 state when the "INITIATE STORE" button is pushed and at the start 
 of each ramp after that. Flip-flop Number 3 changes state also only 
 on zero to one transitions, and it is driven directly by the one 
 side of flip-flop Number 2. Therefore flip-flop Number 3 changes 
 state only at the start of the first ramp after the INITIATE STORE 
 button is pressed and after the third ramp and so on. 
 This sequence can be summarized as follows: 
 
 System State 
 
 Beginning state 
 
 State after initiate store is 
 pressed and before start of 
 subsequent ramp 
 
 State during first ramp 
 State during second ramp 
 State during third ramp 
 
 Gating Sequence 
 
 C2 
 
 1 
 
 
 
 1 
 
 
 1 
 
 C3 
 l 
 
9 
 
 After the start of the third ramp, the output of the 
 counter is no longer gated to the input of flip-flop Number 2. 
 Flip-flop Number 2 can receive a trigger only from flip-flop 
 Number 1 and therefore the sequence stops. In other words, flip- 
 flop Number 2 and Number 3 act as a MOD k counter, which counts the 
 INITIATE STORE button signal and the beginnings of the next three 
 ramps, and then stops* The single pulse from the comparator is 
 gated to the delay line during the second ramp after the pressing 
 of INITIATE STORE, since during this time C2 = C3 = 1 and therefore 
 the gate on the comparator output is open. At the start of the 
 first ramp after the beginning of the sequence, C3 = which prevents 
 the feedback pulse in the analog (phase) memory from re-triggering 
 the delay line. This condition persists until after the line is 
 triggered by the new compare pulse. After the ramp time during 
 which the compare pulse occurs, C3 = 1 and allows feedback. 
 
 In order to select the particular storage cell in which 
 the analog voltage is to be stored sel # i must be a logical one and 
 sel # i must be a logical zero. The other cells must have sel # j = 
 
 and sel # j = 1 in order to preserve the feedback path and prevent 
 erroneous triggers. In this case, i, j = 1, 2, 3> ^ and i / j. 
 
 The SAMPLE and HOLD circuit simply lets the ramp charge 
 the capacitor until the stored pulse occurs. At this instant the 
 voltage on the capacitor represents the voltage which was originally 
 stored. The gating of the output of the storage cells is done by 
 
10 
 means of an AND on the output of each cell. The second input to these 
 AMD's is READOUT # i. READOUT # i must be a logical one in order to 
 read the information out and READOUT # J must be a logical zero. 
 
 2.1 Oscillator 
 
 The crystal-controlled oscillator is shown in Figure h. This 
 oscillator and pulse shaper generates the harmonic of the ramp frequency. 
 The circuit is a Colpitts-type oscillator and uses clipping and level 
 shifting to form the output pulses. The output pulses are Clock 1, 
 to +10v and Clock 2, -5 to Ov. The frequency of these pulses is 
 330 KHz with a duration of O.h jusec. The two different levels of 
 clock are needed because the circuit used for the storage cell requires 
 a positive signal, while the mod 125 counter requires a -5v to Ov 
 signal to operate. 
 
 2.2 Mod 125 Counter 
 
 The mod 125 counter is made frem three mod 5 counters j 
 connected in series. The circuits used are TI SN7^70 integrated 
 circuit J-K flip-flops. 
 
 The truth table for the J-K flip-flop is shown below. 
 
 t 
 
 r 
 
 L 
 
 Vi 
 
 J 
 
 K 
 
 Q 
 
 
 
 
 
 Q 
 n 
 
 
 
 1 
 
 
 
 1 
 
 
 
 1 
 
 1 
 
 1 
 
 n 
 
11 
 
 +1D +10 
 
 200 KZ 50 mh- 
 
 91 pf 
 
 /2N2219A 
 >620 ii 'll- 
 
 :O02uf 
 
 :O05uf 
 
 330 KHg 
 
 +10 
 
 +10 
 
 CLOCK 1 
 O 
 
 +10 
 
 >5.1 K 
 
 1 K 
 
 J2N1308 
 
 33 pf 
 
 2N706A L. ^-^I^NTOeA , 
 
 10 K £2 K 
 
 -25 
 
 330 ah a PARALLEL "£ TRIMMER 
 
 • RESONANT 
 CRYSTAL 
 
 15-130 pf 
 
 CAPACITOR 
 
 +10 
 
 2N1308 
 
 * 
 
 -51N751A 
 
 O CLOCK 2 
 
 J 10 K 
 
 -25 
 
 Figure k. Oscillator 
 
12 
 There are eight possible states for this counter but only- 
 five of them are used for the modulo five counter shown in Figure 5« 
 The possible states for the counter are listed below. 
 
 Possible States 
 
 Qn 
 
 Q, 
 
 Q, 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 
 
 1 
 
 
 
 
 
 1 
 
 1 
 
 r 
 
 
 
 
 
 i 
 
 
 
 1 
 
 i 
 
 1 
 
 
 
 i 
 
 1 
 
 1 
 
 The sequence of these states used and the corresponding 
 inputs are shown below. 
 
 On 
 
 State at t 
 i 
 
 Q 2 
 
 
 
 
 1 
 1 
 
 
 
 
 Input at t 
 
 n+1 
 
 Q, 
 
 J 1 K 1 
 
 ►11 
 
 J 2 K 2 
 
 00 
 11 
 00 
 01 
 00 
 00 
 
 J 3 K 3 
 
 00 
 
 00 
 00 
 10 
 01 
 00 
 
13 
 
 
 MOD 5 COUNTER 
 
 
 
 
 CLEAR 
 
 
 
 
 
 
 
 
 y 
 
 
 
 
 
 ~>^ 
 
 I c 
 
 »J, 
 
 > C 
 K| 
 
 1 
 
 
 
 
 
 
 fc 
 
 
 INPU 
 
 7 
 
 
 
 
 
 
 
 
 1 B 
 
 
 
 
 
 ~^ 
 
 
 
 
 
 
 
 fc> 
 
 
 
 
 
 s — 
 
 
 
 PRESET 
 
 
 
 
 Of 
 Q2 
 
 
 
 i 
 ■ 
 
 
 
 
 CLEAR 
 
 
 
 
 
 \ 
 
 ' 
 
 
 
 
 
 ^?i 
 
 
 
 J 2 
 C 
 K 2 
 
 1 
 
 
 
 
 i 
 
 °^ 
 
 HARMONIC OF 
 
 
 3* 
 
 
 -^1 
 
 
 _Q^ 
 
 
 
 MOD 5 
 
 MOD 5 
 
 MOD 5 
 
 
 RAMP CLOCK 
 
 
 
 
 
 
 MOD 1 
 
 ?*s r 
 
 Dl IWTFR 
 
 
 
 
 
 
 Z^7\ 
 
 
 
 
 
 
 i 
 
 
 £y 
 
 
 
 
 A 
 
 
 
 
 PRESET 
 
 
 
 02 
 Q3 
 
 
 
 
 CLEAR 
 
 i 
 
 
 
 
 
 Z^TY 
 
 J 3 
 c 
 
 K 3 
 
 1 
 
 
 
 
 
 [ 
 
 
 
 yj 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 -5V 
 
 
 
 
 
 
 
 w 
 
 
 
 
 
 A 
 
 
 
 
 
 PRESET 
 
 
 
 03 
 
 Figure 5. Modulo 5 Counte] 
 
1U 
 The three states not used must lead to the sequence shown 
 
 above or the counter will have to be preset when it is turned on. 
 
 The three states not used are Oil, 101, 111. 
 
 The table shown below shows that each of these three states 
 
 leads to one of the states in the sequence used. 
 
 State at t Input at t 
 
 n * n+1 
 
 \ % % J A J 2 K 2 J 3 K 3 
 
 Oil- — fe.01 01 
 
 1 
 
 1 
 
 
 1 1 
 
 
 
 Therefore no presetting of this counter is necessary since 
 no matter what state it starts in it always goes to the correct 
 sequence. 
 
 The signal Q,^ of the last stage is used to drive the ramp 
 generator and the signal Q,„ is used to drive the control circuit. 
 
 2.3 Ramp Generator and Analog-to-Phase Converter 
 
 The ramp generator circuit is shown in Figure 6. The 
 circuit is of the bootstrap sweep circuit type. Transistor Q, is used 
 
15 
 
 RAMP GENERATOR 
 
 PULSE 
 OUT AT 
 COINCIDENCE 
 1N914B 
 
 UNLESS OTHERWISE NOTED ALL DIODES ARE 1N995 
 
 Figure 6. Ramp Generator and Amplitude-to-Phase Converter 
 
16 
 
 as an emitter follower which turns Q on when Q,.. is at -5 volts and 
 turns Q off when Q, is at ground potential. When Q is turned off 
 Capacitor CI charges and since Q,, is an emitter follower the output 
 ramp follows the charging of capacitor CI. The bootstrap capacitor 
 C2 aids in giving a constant charging current to CI and therefore 
 the output ramp is linear. When Q_ is turned on the charging 
 current is diverted through Q, and capacitor CI discharges through 
 
 The comparator or amplitude-to-phase converter, as it is 
 
 used in Phastor, is shown in Figure 6. The operation of this 
 
 circuit is as follows: the transistor Q, draws a constant current 
 
 from the differential amplifier consisting of Q„_ and Q^ . The base of 
 
 5 o 
 
 Q, has the ramp signal applied to it and repeatedly rises from -10 
 volts to +10 volts. The base of CL- has the analog voltage which we 
 wish to store connected to it. This voltage is in the range -10 volts 
 to +10 volts. As the ramp begins to rise CL- is turned on and Q, is 
 turned off. 
 
 All of the current in Q Q comes from Q/- and consequently 
 Q is turned on. As the ramp rises it eventually reaches a point 
 where it is nearly equal to the analog input voltage on the base of 
 Q/-. Now, the current in Q is split between Q, and Q,^ and their 
 collectors rise and turn Qi off. As the ramp voltage rises still 
 further Q,^ turns off and Q conducts all of the current required by 
 Q, and again Q, is turned off. Therefore, there is a time during 
 the ramp when Q^ is turned off. 
 
17 
 
 When GL turns off Qn is turned on and an output pulse from 
 -5 volts to ground is obtained. This pulse called WRITE in Section 
 1.0, is the pulse which is gated to the delay line analog (phase) 
 storage cell. The width of this pulse is controlled by the one 
 kilohm potentiometer which controls the sensitivity of the differ- 
 ential amplifier. 
 
 2.k Control Circuit 
 
 Since the control circuit in Figure 7 consists mainly of 
 flip-flops it can most easily be explained by first explaining how 
 the flip-flop works. The circuit for this flip-flop is shown in 
 Figure 8. When SET is held at ground potential and RESET is floating, 
 transistor Q is turned off and with Q, off, Q, is turned on. The 
 transistor is driven to saturation so that the output swing will be 
 -5 volts to volts. Similarly if RESET is held at ground and SET 
 is allowed to float, Q -, will turn on and Q will turn off. 
 
 Now, returning to the control circuit in Figure 7 all three 
 flip-flops are reset by pressing the RESET button. The signal Q, is 
 the output of the mod 125 counter and the zero to one transition, 
 corresponding to the start of each ramp is not allowed to pass the 
 AND gate since the other input to the AND is the OR of C?2~ and C3 
 which are both -5 volts i.e. a logical zero. When INITIATE STORE is 
 pressed flip-flop Number 1 changes state and the zero to one 
 
18 
 
 CONTROL CIRCUIT 1834-15-30 
 
 all oiooes urns 
 
 ALL RESISTORS 1/4*, 3% EXCEPT WHERE NOTEO 
 
 •l| O O H 
 
 Q>° )\ 
 
 :?*.ec : OK 
 
 Figure 7- Control Circuit 
 
SET O 
 
 19 
 
 RESET O- 
 
 +10V 
 
 +10V 
 
 SETO 
 
 o RESET 
 
 t t 
 
 -25V -25V -5V -5V -25V 
 
 •25V 
 
 TRANSISTORS ARE 2N1309 
 DIODES ARE 1N995 
 
 Figure 8. Flip-Flop 
 
20 
 
 transition is allowed through the AND gate since C2 and C3 are 
 "both logical ones. This triggers flip-flop Number 2 which then 
 starts the series of events discussed in the third paragraph of 
 Section 2. 
 
 The level shifting circuit on the WRITE output is 
 necessary since the delay line used needs a positive pulse for 
 a trigger. The inverter on the REGEN output is used also as a 
 level shifter and for current gain. 
 
 2.5 Storage Cell Delay Line 
 
 The circuit selected for use as the delay line is an 
 emitter coupled monostable multivibrator with appropriately gated 
 feedback which allows the delay line to regenerate the original 
 input trigger and thereby to run continuously. This circuit is 
 shown in Figure 10. The circuit shown in Figure 9 is the same 
 monostable multivibrator without the feedback gating. This circuit 
 operates in the following manner. The transistor Q, is normally 
 off and Q, is normally on, When a positive trigger of sufficient 
 amplitude and duration is applied to the base of £L , Q, is 
 turned on. Now, the collector of Q drops down to approximately 
 zero volts, a jump of V volts. This jump is transmitted 
 una'tbenuated by capacitor C to the base of Q, , and thus turns Q 
 off. Now, there are approximately +V_ volts across capacitor C. 
 With t^ on and Q off capacitor C will eventually be charged to 
 
21 
 
 +V 3 = 10v+V 1 = 25v +V x =25v 
 
 ♦ ♦ 
 
 soi |R] 
 
 ;R 2 
 
 io 3 
 
 TRIGGER o- 
 
 ■ " 
 
 C 
 +V 1= 25v 
 
 ©V: 
 
 <i OA 
 
 VD 2 
 
 ff — 
 
 -V 2 =-25v -V 2 =-25v 
 
 Va 
 0- 
 
 -v. 
 
 KTH 
 
 v E 4 
 v 3 
 
 v B * 
 
 + 2V 
 -2V D ' 
 
 ^t 
 
 -|T 2 h- t 
 
 V = FORWARD BIASED 
 
 DIODE VOLTAGE DROP 
 
 Figure 9« Emitter Coupled Monostable Multivibrator 
 
+ 25 
 <3K 
 
 <!| — w- 
 
 Z?*5\ 
 
 +25 
 £l2K 
 
 -W- 
 
 |3.3K 
 
 -25 
 
 HARMONIC o W- 
 
 OF CLOCK 
 
 SEL »<0 W — f W * W 
 
 REGEN 
 (FROM Cj) 
 
 +10 
 [2N946 
 
 ;30K 
 
 ♦ HARMONIC < 
 ~ 25 OF CLOCK 
 
 +25 
 *12K 
 
 (IN) WRITE o — W— I — W— 
 SEL #iO — «} 
 
 
 +25 
 
 sk: 
 
 + 25 
 
 1K | 05 /if 
 
 H>h+2T 
 
 20 k: 
 20 k: 
 
 C 
 
 2N2219A L 2N2219A 
 <2.5K 
 
 -25 
 
 -O OUTPUT 
 PHASE 
 
 _MONOSTABLEJ 
 
 20 K 
 
 ALL DIODES ARE 1N995 
 
 -25 
 
 J I I I 
 
 Figure 10. Storage Cell 
 
23 
 
 -V volts. So C starts to discharge through R and the "base of Q 
 
 rises. Q is on so that the emitter of Q, is at approximately 
 
 ground potential. When the base of Q, rises above ground, Q, is 
 
 turned on and the emitter rises high enough to turn Q, off. The 
 
 emitter waveform V is shown in Figure 9- The collector of Q. is 
 Hi 1 
 
 now free to rise, this is waveform V in Figure 9j as now C has 
 
 l_j 
 
 approximately zero volts across it and with Q, off and Q^ on 
 
 apacitor C will eventually be charged to +V volts. The 
 collector of Q rises toward +V but it is caught at +V . The 
 circuit is now in its stable state and may be retriggered. 
 
 The feedback necessary to make this circuit run as an 
 astable multivibrator is obtained by replacing the diode D by 
 the base-emitter diode of a pnp transistor as shown in Figure 10. 
 Now, when the collector of Q, rises near the end of the cycle, it 
 eventually turns this added transistor on. The collector of this 
 added transistor rises abruptly and thereby generates the positive 
 trigger necessary to re-trigger the monostable and keep it running 
 as an astable multivibrator. In Figure 10 the positive trigger 
 occurs at the base of Q, when the harmonic of the clock pulse is 
 present and gates the pulse to the base of transistor Q . In this 
 way the period of the monostable multivibrator is quantized to an 
 integral number of harmonic clock times. Therefore, the period of 
 the monostable does not have to be adjusted exactly, but only 
 within one harmonic clock period of the exact ramp clock period. 
 
2k 
 
 2.6 Calculation of the Period of the Emitter Coupled Monos table 
 Multivibrator 
 
 The equations for the period of the emitter coupled 
 monostable multivibrator can be calculated by referring to Figure 9< 
 
 When transistor Q, is on and Q, is off the current 
 equation for point A is 
 
 3 V A (t) \ ~ V A (t) 
 
 C at " r 2 
 
 Rewriting (l) 
 
 dt R 2 C R 2 C 
 
 (1) 
 
 To solve this equation the initial and final condition on 
 
 V are needed. From previous discussion of the operation of this 
 
 circuit it appears that V. (0) = -V_ volts and V.(«° ) = +V n volts, 
 ff A v ; 3 A v 1 
 
 Therefore solving equation (l) one has 
 
 V A (t) = V 1 - (V 1 + V 3 ) e '1 , ( 2 ) 
 
 where T = R C 
 
25 
 
 Referring to Figure 9 it is seen that T is the time required 
 for the base of Q to rise to zero volts, (i.e. V (T ) = 0). 
 
 Now this equation can be solved for the time T . 
 From (2) : 
 
 V A (T 1 ) = V 1 - (V 1 + V 3 ) e x = 
 
 Therefore 
 
 V +V 
 
 T i =T i in( ~V 1) (3) 
 
 When 
 
 transistor Q,_ is off and Q^ is on the current equation 
 
 at the collector of Q. , call this point E, is as follows 
 
 d V (t) V - V (t) 
 
 C = — (k) 
 
 ° dt R { * } 
 
 Rewriting (k) 
 
 d V (t) V (t) V 
 
 + A- - A (5) 
 
 dt R C R C 
 
26 
 
 To solve this equation there is needed the initial and final 
 
 conditions on V . From the previous discussion of the operation of 
 Ji. 
 
 this circuit it follows that V„(0) = and V v ( m ) - +V_ . Hence the 
 
 ill cj L 
 
 solution of equation (5) is 
 
 V E (t) = V 1 (l - e 2 ) (6) 
 
 where T^ = R_ C 
 
 R i ( 
 
 Referring to Figure 9 T_ can be found as shown below. 
 
 W = V 3 = V 1 " e > 
 
 Therefore , 
 
 T 2 = \ ^r^r ] (7) 
 
 13 
 
 2^7 Calculation of the Circuit Parameters of the Emitter Coupled 
 Monostable Multivibrator 
 
 Referring to the circuit shown in Figure 9 % must be such 
 that the current through it is not so large as to cause excessive 
 power dissipation in the transistors. The voltage across Ri is 
 fairly constant as the emitter voltages of Q_ and Q~ do not vary- 
 very much. That is, they only vary one or two diode drops from 
 
27 
 ground. If an emitter current I = lOma is chosen, then 
 
 \ = M = 2 - 5K 
 
 Transistors Q, and Q^ are 2TT2219A's which have a minimum P of 
 
 100. Therefore, in order to determine R^.» the "base current required 
 
 "by 0^, when it is one must be determined. 
 
 ]_ = 2 = 0.1 ma 
 B 2 ~ 
 
 The required I_ is 0.1 ma. It is also known that 
 ^2 
 
 Therefore 
 
 So 
 
 T*2 R 2 
 
 0.1 ma = 2|i 
 R 2 
 
 R 2 = 250K 
 
28 
 
 Since Q will not saturate, since the emitter current is 
 fixed and the collector resistor can be chosen so that saturation 
 does not occur, the resistor R p can he chosen smaller than 250K, since 
 transistor Q, can he overdriven to be certain it gives a sharp signal 
 at its collector. For an overdrive factor of about 7.5» R p can be 
 chosen as R p = 33K. 
 
 To determine TL , the transistor Q_ must saturate so that 
 the jump transmitted to Q^ does not vary with the 3 of the 
 particular transistor used. With CL on and Q^ off, I = 10 ma. 
 There applies 
 
 I = §22: = io ma 
 
 E i h 
 
 Therefore 
 
 Rj_ - 2.5K 
 
 Choose R. = 3K since additional current must come from 
 base of 0_ if R cannot supply enough and therefore R. must nearly 
 equal R p since a large base current in il is not desirable. 
 
 R is chosen so that Q,^ does not saturate. A 10 volt drop 
 in R when Q is on would be desirable as this will give a strong 
 signal with which to operate the SAMPLE AND HOLD circuit. ThiS 
 collector (Qp's) is used as the output point since it has almost no 
 effect on the timing of the circuit and any loading at this point 
 will therefore not effect the timing cycle of the monostable. 
 
29 
 
 So 
 
 10, . I E 3 
 
 When Q is on I = 10 ma. Since I ra I 
 
 2 E 2 E 2 C 2 
 
 lOv = R I_, = R_(10 ma) 
 
 R 3 = 1K 
 
 Now, to determine the value for capacitor C, the period 
 of the RAMP CLOCK must he known since the monostahle multivibrator 
 must have the same period as the RAMP CLOCK. The frequency of the 
 harmonic of the clock is 330 KHz and therefore the period of the RAMP 
 CLOCK is 
 
 T rc ■ 12 -5 • 335155 " °- 38 msec ' 
 
 T_ 380 //.sec 
 
 re 
 
 In Figure 9, the period of the monostahle multivibrator is 
 
 equal to T plus T where 
 
and 
 
 30 
 
 - - 
 
 'l 
 
 V +v 
 = R C In (-ir-2-) 
 1 
 
 T 1 - C(33K) In (l.k) 
 
 V, 
 
 T 2 = T 2 In (^—^ ) 
 13 
 
 x v x v 3 
 
 T 2 = C(3K) In (1.67) 
 
 then 
 
 T RC = T i + T 2 = C ^33K) ln(l.U) + C(3K) ln(l.67) = 380 ^sec 
 
 C = 0.03 £*£& 
 
 The waveforms obtained experimental ly using the para- 
 meters determined in this section are shown in the oscillograms 
 Figure 11. 
 
31 
 
 Ground 
 
 (a) 
 
 Trigger Waveform 
 Time base = 100/4 sec/cm 
 Voltage Scale = 5 volts/cm 
 
 Ground 
 
 (b) 
 
 Waveform V^ 
 
 Time base = 100/t sec/cm 
 Voltage Scale = 5 volts/cm 
 
 Figure 11. Experimental Waveforms of the Emitter Coupled 
 Mono stable Multivibrator 
 
32 
 
 Ground 
 
 (c) 
 
 . , „•. Waveform V 
 
 Time base = 10©^ sec/cm 
 Voltage Scale = 5 volts /cm 
 
 Ground 
 
 (d) 
 
 Emitter Waveform 
 Time base = 100/* sec/cm 
 Voltage Scale = 5 volts /cm 
 
 Figure 11. Experimental Waveforms of the Emitter Coupled 
 Monostable Multivibrator 
 
33 
 
 2.8 Theoretical Calculation of Change of Period of Bnitter- 
 Coupled Monostable Corresponding to Small Variations of 
 Supply Voltages 
 
 The supply voltages in the circuit of Figure 9 determine 
 
 the total period of the monostable as can be seen by examining the 
 
 equations for the periods. 
 
 V +V 
 
 T i = T i ln (J T 1) 
 l 
 
 T = T 
 
 2 2 X V -V 
 
 1 3 
 
 Obviously, the period only depends to the first order on 
 the supply voltages, V and V . V does not appear in these 
 equations and therefore does not effect the period. 
 
 It is known that V = 25v and V = lOv. Knowing the 
 change in V or V the corresponding change in T and T can be 
 calculated. 
 
 Thus, if V is changed by +% 
 
 V +%Y +V 
 
 T i + *l* t i = T i ln( v 1+ ^ Vl > 
 
 and 
 
 V +5$V 
 T 2 + X 2^2 = T 2 3J1( V 1+ 9<V 1+ V 3 ) 
 
Therefore, for V +5</ V 
 
 T + x %T = 0.322 t sec 
 
 and 
 
 T 2 + X 2^ oT 2 = ' kQ2 T l SeC 
 
 for nominal values of V and V.. (i.e. V = 25v, V = 
 
 lOv) 
 
 T x = 0.336 T 1 
 
 and 
 
 T 2 = 0.506 T 2 
 
 Then 
 
 T ± + x^T = 0.322 T 1 
 
 T ] _ 0.336 T x 
 
 x^ = -hi (V 1 + 5^) 
 
 3U 
 
35 
 
 and 
 
 x 
 
 T 2 + X 2^ T 2 = °' J+82 T 2 
 
 T 2 0.506 t 2 
 
 2 * = -5$ (v x + 5^) 
 
 Therefore, a 5^> increase in V , results in h^> decrease in 
 T and a 5$ decrease in T . 
 Also, for V - %V 
 
 V -5^V +V 
 
 and 
 
 T l "^l^ = °- 35 ° T l 
 
 v,-5^v 
 
 T 2 " y 2^ T 2 = T 2 ln ( V^VV 3 ^ 
 
 T 2 - y 2 ^T 2 = 0.55^ Tj 
 
Now 
 
 and 
 
 T l " Y ^l = °- 350T i 
 T x 0.336 % 1 
 
 y ± i = -H (v 1 - 5^) 
 
 T 2 - y 2 </ 8 T 2 = 0.55*+ T 2 
 T^ 0.506 t 2 
 
 y 2 # = -10$ (V 1 - 9f>\) 
 
 X 
 
 Therefore, a reduction of V.. by 5$ should result in a 
 e in T and a 10$ increase in TU. 
 Similarly, +5$ changes in V- give: 
 
 V +V +5#V 
 T 1 + x 1 ^T 1 = i l In (-±— J i) 
 
 T x + x 1 ^T 1 = .350 T x 
 
37 
 
 and 
 
 Then 
 
 and 
 
 T 2 + x 2 f T 2= T 2 m ( Vi . (v3 ^ v ) 
 
 T 2 + x 2 iT 2 = 0.5^2 T 2 
 
 T x + x^T^ = .350 t x 
 5J .336 ^ 
 
 Cj< = ^ (v 3 + 5f v 3 ) 
 
 T 2 + V° T 2 = ' 5U2T 2 
 
 T 2 .506 t 2 
 
 x 2 </ = 7i (V 3 + 5^) 
 
 Therefore, an increase of 5% in V , results in an increase of k% in 
 T 1 and % in T . 
 
and 
 
 Then 
 
 and 
 
 Also 
 
 V +V -5*V 
 
 T i * y A = T i ln ( ~v — } 
 
 T l " y l^ T l = « 322t i 
 
 T 2 -y^^ln (__^ ) 
 
 T 2 - y^T 2 = .U76t 2 
 
 T l " y l^ T l * 322 T l 
 
 T^ = .336 T x 
 
 y^ = ki (V 3 - 5foV 3 ) 
 
 T 2 - y^T 2 m OA76 t 2 
 
 T 2 0.506 t 2 
 
 y 2 ^ = 6£ (V 3 - 5^V 3 ) 
 
 38 
 
39 
 
 Therefore, a decrease of % in V3, results in a decrease 
 of hfjo in T and a decrease of 6$ in T . 
 
 2.9 Calculation From Experimental Results of the Change of Period 
 of the Emitter-Coupled Monostable Multivibrator Corresponding 
 to Small Variations of Supply Voltages 
 
 Experiments were carried out "wherein the supply voltages 
 
 V, , V , and V» were changed by + 5$> and the resulting change in 
 
 period recorded. The results are given below. 
 
 v ] 
 
 
 T l 
 
 T 2 
 
 +25. 
 
 00 
 
 310// s 
 
 26// s 
 
 +26. 
 
 25 
 
 295// s 
 
 25//S 
 
 23. 
 
 75 
 
 329// s 
 
 29^ s 
 
 From this 
 
 T 1 + x 1 ( /oT 1 = 29 5/^ s 
 
 Jt,< - - 1 *.! 
 
 This value for x..$> compares favorably with the calculated 
 value of x <f which was -k°lo. 
 
4o 
 
 Also 
 
 T l " y l^ oT l = 320 /^ s 
 
 Y{h = -3% 
 
 This compares favorably with the theoretical calculated 
 value of -kio. 
 
 For T , 
 
 T 2 = 26^: 
 
 T 2 + V° T 2 = 25 / ZS 
 
 x 2 # = -4$ 
 
 The theoretical value from Section 2.8 was -' 
 
 T 2 - y 2 P 2 = 29 A'S 
 
 Y 2 $ = -11$ 
 
 The theoretical value from Section 2.8 was -10$. 
 
1+1 
 
 The results for variation in V are shown "below. 
 
 V, 
 
 -25.00 
 
 310 /ZS 
 
 26 ^s 
 
 -26.25 
 
 310 /*s 
 
 26 /*B 
 
 -23.75 
 
 310 /*s 
 
 26 /us 
 
 As seen from the results, the period of the monostable 
 does not depend upon V for small changes in V . 
 
 For small changes in V , the results are shown "below. 
 
 V, 
 
 From this 
 
 10.0 
 
 310 /-s 
 
 26 fu.S 
 
 +10.5 
 
 310 /us 
 
 28 JUS 
 
 + 9.5 
 
 310 /US 
 
 25/vS 
 
 T x + X-$T - 310 /^s 
 
 Therefore 
 
 ^ = 0$ 
 
k2 
 
 T 2 + X 2^ oT 2 = 28 /^ S 
 
 x 2 i = +7.7% 
 
 The calculated theoretical value of x % was k%, and for 
 x % the theoretical value was +7$>. T did not change because 
 transistor Q breaks down and the total jump is not used to 
 determine T and therefore a change in the jump does not change 
 T.. as long as the jump is greater than the voltage at which the 
 transistor breaks down. 
 
 Also for decrease in V„ 
 
 T l " y l^ oT l = 31 ° S 
 
 Y-Jo = 
 
 and 
 
 T 2 - y 2 %T 2 =25 s 
 
 y 2 i = hi 
 
 The theoretical values from Section 2.8 were h% for y .% 
 
 and 6% for y %. 
 
^3 
 2.10 Write Select Gate 
 
 The circuit shown in Figure 12 generates the signals which 
 select the storage cell in which the analog voltage is to be stored. 
 The circuit consists of a flip-flop which is similar to the flip-flop 
 shown in Figure 8. The level shifters give the required positive 
 gate to the analog storage cell. There is a double throw single 
 pole switch connected to the flip-flop as shown in Figure 13. The 
 pole of this switch is connected to ground and the normally closed 
 contact is connected to the HOLD trigger diode on the flip-flop. The 
 normally open contact is connected to READY on the flip-flop. In the 
 model of Phastor which has been built there are four such switches 
 with corresponding gating circuits, one for each of the storage cells, 
 When the switch is in the normal position SEL is a logical zero and 
 SEL is a logical one. This prevents any triggers from triggering the 
 monostable storage cell and also prevents the information which may 
 be stored in a cell from being erased when something is stored in 
 another cell. These switches and their connections are shown in 
 Figure 13 along with the readout switches. The switches used are 
 Microswitch type push button double pole double throw. When one of 
 WRITE (SELECT) switches is activated the analog input voltage is 
 connected to the METER, so that the input can be monitored. 
 
kh 
 
 + 10V 
 
 +10V 
 
 READY #1 >- 
 
 12K: 
 
 -25V 
 
 >10K 
 
 2N1309 
 
 3Z 
 
 i 
 
 '"I 
 
 -5V -25V 
 
 + 25V 
 
 :iok 
 
 2N1309 
 
 -W O HOLD #1 
 
 ■6.2K 6.2K: 
 
 -25V -5V 
 
 ;12K 
 
 •25V 
 +25V 
 
 •12K 
 
 +10V 
 
 + 25V 
 
 -W-i ^Pj)2N1308 
 
 •2.7K 
 
 -OSEL#l 
 
 +10v 
 
 + 25V 
 
 U2K 
 
 -w- 
 
 I2N1308 
 
 :2.7K 
 
 -OSEL#l 
 
 1N751 
 •1.5K 
 
 1N751 
 •1.5K 
 
 -25V 
 
 -25V 
 
 ALL DIODES ARE 1N995 EXCEPT AS NOTED. 
 1N751 IS SAME SIZE AS 1N995. 
 RESISTORS ARE 1/4WATT, C.C., 5%. 
 
 Figure 12. Select Circuit 
 
h$ 
 
 cp 
 
 STORAGE CELL SELECT SWITCHES 
 
 cp 
 
 £p 
 
 £+) 
 
 4 
 
 READY#1 
 
 HOLD#l 
 
 READY #2 
 
 HOLD #2 
 
 READY#3 ^ 
 
 HOLD'S 
 
 f 
 
 <=,=> 
 
 ran 
 
 IP 
 
 READY #4 ^ 
 
 HOLD #4 
 
 Cp 
 
 READ OUT SELECT SWITCHES 
 
 cp 
 
 L^ 
 
 LT3 
 
 I I 
 
 id M 
 
 READ#1 
 
 NORMAL#l 
 
 I 
 
 READ#2 
 
 NORMAL #2 
 
 READ* 3 
 
 NORMAL #3 
 
 H 
 
 REA0#4 
 
 NORMAL #4 
 
 Figure 13. Push Button Connection Diagram 
 
46 
 
 2.11 Readout Select Gate 
 
 The circuit used to generate the gate for the readout of 
 the information stored in a cell is shown in Figure lU. The flip- 
 flop is set and reset by one of the four READ switches in Figure 
 13. When the flip-flop is activated by setting the switch of the 
 cell selected, the SAMP signal is allowed to trigger the SAMPLE 
 and HOLD. The SAMP signal is the OUTPUT PHASE signal which comes 
 from the collector of Q^ in Figure 10 and is a 10 volt jump which 
 occurs at the time at which the ramp is to be sampled. This jump 
 is differentiated and the differentiated pulse is gated to an OR 
 circuit whose output is connected to the SAMPLE and HOLD. The 
 other inputs to this OR come from the three other cell readout 
 select circuits. Therefore, when one of the READOUT switches is 
 pushed a signal occurs at the output of the OR at the time corres- 
 ponding to a voltage on the ramp. This voltage is the voltage which 
 was originally stored in the cell. 
 
 2.12 Sample and Hold 
 
 The sample and hold circuit used in the system is shown in 
 Figure 15. The circuit is essentially a flip-flop consisting of Q_ 
 and £L and a switch Q,_ which allows a capacitor to be charged by the 
 ramp clock until the stored pulse occurs. The counter output (start 
 of ramp signal) sets the flip-flop, Q_ and Q_. Since a negative 
 going pulse is needed to set the flip-flop the complement side of the 
 
READ OUT GATE 1834-15-35 
 
 h 7 
 
 + 10v 
 
 + 10v 
 
 10K 
 
 10K 
 
 I— 2N1309 — 
 
 -5v* — N ' 
 
 NORM #10 — M — " 
 
 6.2 K 
 
 12K 
 
 •25v 
 
 -25v 
 
 -W— -5v 
 
 11 — M — O READOUT #1 
 
 2 6.2K £12K 
 
 -25v -25v +25v 
 +25v 
 
 +25v +10v 
 
 2N1308 
 
 + 10v 
 
 2.7 K 
 
 12K 
 
 12 K 
 
 2N1308 N 
 
 -M '— M 
 
 # 4.7 V 
 
 - ZENER 
 1N750 
 
 1.5 K 
 
 -25v 
 
 180 pf 
 1( — OSAMP 
 
 #1 
 
 10K 
 
 -M — H' 
 
 1.6 K 
 
 ALL DIODES 1N995 , RESISTORS 
 
 1/4 WATT C.C. 5% EXCEPT AS NOTED 
 
 Figure Ik. Readout Circuit 
 
SAMPLE AND HOLD 
 
 UQ 
 
 +10v 
 
 RAMP o- 
 
 -lOv 
 
 +10v 
 
 7 
 2 N 1308 
 
 1.5 K 
 
 -25v 
 
 10 K 
 
 2N1309 
 
 « H 1 H t W * 
 
 + 10v 
 
 ♦ 25v 
 
 1.1K 
 
 500 n 
 
 POT 
 
 06 
 
 2N1309 
 
 + 10v 
 
 +25v 
 
 33 K 
 
 Q 5 
 
 /2N1308 
 
 .47uf 
 
 , ANALOG 
 READOUT 
 
 Ol 
 2N1309, 
 
 12K >12K 
 
 -25v -25v 
 
 -lOv 
 
 -W M M " 
 
 rT)2N1308 - 2N2219(14— '"10 
 
 lOv 
 
 + 10v 
 
 + 10v 
 
 °2 , 
 2N1309 
 
 10 K 
 
 10 K 
 
 *}/ MOD 125 
 
 M — M 'i ( O COUNTER 
 
 1 \ ru itdi rr 
 
 -w— 
 
 OUTPUT 
 (START OF RAMP 
 9 - 1K SIGNAL) 
 
 3.3 K 
 
 12K ei2K <12K 
 
 -25v 
 
 -25v 
 
 -25w -25v -25v 
 
 Figure 15. Sample -and -Ho Id Circuit 
 
k 9 
 
 I 
 
 A 
 
 Figure l6. Panel Photographs 
 
50 
 
 counter output is used. When the start of ramp signal occurs, Q- is 
 turned off and allows the ramp to charge capacitor C, through 
 transistor Q . Q. is turned on at the same time and provides a 
 discharge path for C. When the PHASE INPUT signal from the 
 READOUT GATE in Figure Ik resets the flip-flop the capacitor has 
 been charged to the voltage which equals the voltage originally 
 stored. Q_ is turned on and Qi is turned off when the flip-flop 
 is reset. 
 
 Q, is turned off by Q~ turning on and therefore the 
 capacitor can no longer be charged. The purpose of the current 
 sources, Q/- and Q , is to provide a constant current through the 
 diode D.. and provide a high impedance input point for the ramp 
 signal. The potentiometer in the Qu emitter lead is used to balance 
 the currents in Q^ and Q , This balancing is accomplished by holding 
 Q off and Q. on and grounding the ramp input, Then the potentio- 
 meter is varied until the capacitor voltage is also at ground. Now 
 the drop in the diode D. is equal to the base-emitter drop of Q c , 
 
 2ol3 Phastor Model and Description 
 
 The front panel of Phastor is shown in Figure l6. The 
 system was built inside a carrying case and the only external 
 connections are to the power supplies. The meter used is a Weston, 
 10-0-10, 20,000 ohm per volt taut band meter. The meter monitors 
 both the analog input and the analog output depending upon which 
 
51 
 
 button is pushed. If any one of the four SELECT buttons is pressed, 
 the meter is connected to the input potentiometer and if any of the 
 READ buttons is pressed the output of the SAMPLE and HOLD is connected 
 to the meter. If none of the buttons is pressed, the meter connections 
 float . 
 
 The back view of the panel shows the specially designed 
 card rack which was necessary due to the limited depth of the 
 carrying case. 
 
52 
 
 3. OPERATION OF COLLECTOR - BASE COUPLED MONOSTABLE MULTIVIBRATOR 
 
 In sections 3 through 6, four circuits which could be used 
 for the storage are discussed, analized and evaluated. 
 
 The collector-base coupled monostable multivibrator shown 
 in Figure 17 is a second possibility for use as the storage element 
 in the analog storage scheme. The operation of this multivibrator 
 is as follows: the transistor Q, is normally off and Q_ is normally 
 on and saturated. Q p must be saturated in order to hold Q.^ off. A 
 positive trigger will cause Q,. to turn on and its collector will 
 jump down to approximately ground potential. This jump is of 
 magnitude V since the collector of Q, was at V before the trigger. 
 The capacitor C transmits the jump of V volts to the base of 0_ and 
 consequently Q^ turns off. Now the collector of Q^ is allowed to 
 jump up and thus 0- is held on. Initially capacitor C had +V volts 
 across it. But now with Q, on, and Q off, capacitor C will eventually 
 charge to -V volts, so the base of Q, starts to rise exponentially 
 towards +V . 
 
 However, when the base of Q rises above ground potential, 
 Q must turn on and as a result Q.. "burns off because the collector 
 of Q_ has now returned to ground. At this point capacitor C has zero 
 volts across it but with 0_ off and Q on, capacitor C will eventually 
 be charged to +V volts so point C starts charging exponentially 
 
53 
 
 +v* +v. 
 
 +v. 
 
 +v, 
 
 SDi |Ri c |R 2 
 
 I J ±Jl= 1 
 
 °0 
 
 R 4 
 
 -AAA, *A 
 
 -o TRIGGER 
 
 «© 
 
 £R 5 
 -v 3 
 
 -v 2 
 
 Vc 
 
 +v 2 
 
 h-V-l 
 
 Tl 
 
 -H"r 2 h- 
 
 V,- 
 
 V A 
 
 V1R3 t 
 
 1 R3+R4 
 
 Figure 17. Collector-Base Coupled Monostable Malt i vibrator 
 
towards +V . But when it rises above +V_, D turns on and the cycle 
 is completed. 
 
 This monos table multivibrator may be converted to an as table 
 with gated feedback by replacing D by the base-emitter diode of a 
 pnp transistor and gating the collector signal of this transistor 
 back to the base of Q_ . 
 
 3.1 Calculation of the Period of the Collector-Base Coupled Monostable 
 Multivibrator 
 
 Referring to Figure 17 with QL on and Q off, the current 
 
 equation at point D is as follows: 
 
 dV^ V n -V_ 
 r — 2. _ 1 D 
 
 at " r„ 
 
 Rewriting 
 
 dV V 
 
 -^ + ~£ = V l/R C (1) 
 
 dt R 2 C 1 / R 2 C {1) 
 
 In order to effect a solution to equation (l) the initial 
 and final values of V are needed. It is known from the discussion 
 in Section 3.0 that V (0) = -V and V (») = +V . Therefore, 
 
V D (t) = V 1 - (V ] _ + V 2 ) e 
 
 55 
 
 where t = R p C. 
 
 Now referring to Figure 17, the solution for T , the time 
 required for Q, to turn on is wanted. At this time V (T ) = 0. 
 Then 
 
 V D 
 
 -T 
 (Tj) = = V ] _ - (V 1 + V g ) e 1 / T 1 
 
 From this, 
 
 
 Again referring to Figure 17 with CL off and Q~ on, the 
 current equation at point C is as follows: 
 
 dV V -V 
 c C 1 C 
 
 dt 
 
 h 
 
 To effect a solution to this equation the initial and the 
 final values of V are needed. From the discussion in Section 3.0 
 it is known that V (0) = and V ( «) = +V 
 
56 
 
 Then 
 
 V (t) - V x - V e 
 
 -Vt 2 
 
 where t ^ = R C 
 
 V 
 
 Now the time period T as indicated in Figure 17 can "be 
 solved for as follows: It is known that V (T ) = V , so 
 
 V (T 2 ) = V 2 = Vj^d-e £ ) 
 
 T 2- 2^^' 
 
 3.2 Calculation of the Circuit Parameters of the Collector-Base 
 Coupled Monostable Multivibrator 
 
 In Figure 17, when Q_ is on <^. must be off, to guarantee 
 this Q~ should saturate. 
 
 To determine the collector and base resistors, R_ and R , 
 respectively, let 
 
 I = 5 ma 
 R 3 
 
 Then 
 
 «- = 5 ma 
 R 3 
 
57 
 R 3 = 5K 
 
 Set R„ = 5« IK. To saturate Q , sufficient base current is needed, 
 therefore, since 
 
 1=2 
 B 2 P 
 
 and since I z I p and p = 100 (minimum value for 2N2219A's) 
 
 K 3 2 
 then 
 
 I_ = 2 = 0.05 ma 
 ^2 T 
 
 Also T 2 ^ 
 
 T3 2 R 2 
 
 So 
 
 25v n nt . toq 
 — — = 0.0? ma 
 
 R 2 
 
 R 2 = 500K 
 
 This is a maximum value for R and a smaller value will do. 
 Set R = 100K. Q, must also saturate, since the drop of collector Q 
 should be made independent of variations in f3. 
 
58 
 
 Let 
 
 From this 
 
 Put 
 
 I = 5 ma = /- 
 C R 1 
 
 R 1 = 5K 
 
 ^ = 5. IK 
 
 T = 1 = 0.05 ma 
 
 A T" 
 
 R^ is the leakage current sink. Say, I _ . =10 ua. 
 5 Leakage / 
 
 then 
 
 10»a = fSS 
 
 25v 
 
 R = * — =- =2.5 megohm 
 
 5 10 x 10~ 6 ma 
 
59 
 
 Put 
 
 R_ = 1 me£ 
 
 5 
 
 Now when Q is on 
 
 : B. = R7^I 10 A a = 0.05 
 
 mm 3 4 max 
 
 Vax " 500K 
 
 This is a maximum value of R. , so choose 
 
 R^ = 20K 
 
 To calculate C, the total period required of the monostable 
 multivibrator must be known. Assume it to be the same as in the 
 Phastor system, then 
 
 T TOTAL = 38 °/^ 
 
 From previous calculations it is known that 
 
 v,+v 
 
 T l ■ R 2 ° ta ^V^> 
 
T 2 = R 1 C ln( v"^ } 
 12 
 
 T + T = T 
 1 2 TOTAL 
 
 60 
 
 V +v V 
 
 T TOTAL = C [R 2 ln(-^-^) + R 1 ln( y _^ )] = 380^s 
 
 From this, 
 
 C = 0.015/»fd 
 
 The waveforms obtained experimentally using the parameters 
 determined in this section are shown in the oscillograms of Figure 18, 
 
 3-3 Theoretical Calculation of the Change of Period of the Collector - 
 Base Coupled Monostable Corresponding to Small Variations of 
 Supply Voltage 
 
 The equations from which the period of the collector-base 
 
 V V 2 
 coupled monostable of Figure 17 are determined are T = x , ln( — — — ) 
 
 1 
 
 and T = x p ln(r= — rr- ). The supply voltages used are +25 volts for 
 2 d v !- v 2 
 
 V and +10 volts for V . Now, knowing the corresponding change in 
 the supply voltage the period can be calculated. 
 Thus, if V is changed by +% 
 
 V +5f V +V 
 T l + X A ' T l ln( V,+^ V ) 
 
 ■ r Wov ] _ 
 
61 
 
 Ground 
 
 (a) 
 
 Trigger 
 Time Base = 100 zx sec/cm 
 Voltage Scale = 5 volts /cm 
 
 Ground 
 
 ftO 
 
 Waveform V 
 
 Time Base = 100/* sec/cm 
 Voltage Scale = 5 volts /cm 
 
 Figure 18. Experimental Waveforms of Collector-Base 
 Coupled Monostable Multivibrator 
 
Ground 
 
 62 
 
 (c) 
 
 Waveform V 
 
 Time Base = 100/* sec/cm 
 Voltage Scale = 5 volts/cm 
 
 Ground 
 
 (d) 
 
 Waveform V^ 
 
 Time Base = 100/c sec/cm 
 Voltage Scale = 5 volts/cm 
 
 Figure 18. Experimental Waveforms of Collector-Base 
 Coupled Monostable Multivibrator 
 
63 
 
 T ± + x ± %T = 0.322 t 
 
 Also for T„ 
 
 
 T 2 + x 2 f T 2 = 0.1+82 T 2 
 
 Similarly, for V, decreased by 5$ 
 
 V,5#V+V 
 
 T l -^i = -l ^ \-^P 
 
 T l " y l^ oT l = 0,35 ° T l 
 
 V -5$V 
 T 2 - y/ T 2 = T 2 311 ^ ) 
 
 T 2 - y 2 %T 2 = 0.550 t 2 
 
 For nominal values of V and V (i.e. V =25 volts and 
 
 V 2 = 10 volts) 
 
 T i - T l ^Hr^ 
 
 v l 
 
6k 
 
 \ = 0.336 T x 
 
 T 2 - T 2 ta <^ 
 
 T 2 = 0.512 T 2 
 
 The percentage changes in T and T can now be solved for 
 
 as follows : 
 
 T 
 
 1 + y^o\ = 0.322 t 1 
 
 \ 0.336 T 1 
 
 x^o = -% (V ] _ + 5fo V 1 ) 
 
 Therefore, a +5$ change in V corresponds to a -5$> change 
 
 in T . 
 
 T 2 + x 2 f T 2 = 0.1+82 t 2 
 T^ 0.512 T 2 
 
 x 2 </ = -6$ (v 1 + % v 1 ) 
 
in T 2 . 
 
 65 
 Therefore, a +5</ change in V corresponds to a -6$, change 
 
 Similarly, when V is decreased by 5% 
 
 T l " y l^ T l = ° ,35 ° T l 
 T^ 0.336 t x 
 
 y-flo = -2$ (V x - 5$ V ] _) 
 
 Thus, a 5$ decrease in V corresponds to a 2$ increase in T 
 
 T 2 - y 2 </oT 2 = 0.550 t 2 
 T 2 0.512 t 2 
 
 y 2 fo = -3.6$ (V 1 - 5$ v 1 ) 
 
 Thus, a 5$ decrease in V corresponds to a 3-6$ increase in T . 
 
 Similar calculations can he done for variation in supply 
 
 voltage V . 
 
 So, for a 5> increase in V 
 
 V +V +5%V 
 "I + *i* T i = \ ln < v^ ) 
 
<x 
 
 T x + x.^ = 0.350 T 1 
 
 V^V^ ^vj 1 
 
 T 2 + X 2^° T 2 = °- 5i+2T 2 
 
 Also, for a 5> decrease in V 
 
 V +V -5</oV 
 
 T i ■ y i^ oT i =T i ^-Mj — * 
 
 = 0.322 T 
 
 V, 
 
 T 2 "^ T 2 =T 2^ ( VTV5^) ) 
 
 T 2 - y 2 ^T 2 = 0.U76 t 2 
 
 Now the percentage change in T and T for a +5% change 
 
 in V p can be calculated. 
 
 T + *-Jo\ = 0.350 T 
 T^ 0.336 t x 
 
 x^ = 2% (V 2 + 5^V g ) 
 
67 
 So a 5$ increase in V corresponds to a 2°] increase in T , and 
 
 T 2 + X 2^ oT 2 = °'^ k2 T 2 
 T^ 0.512 T 2 
 
 x 2 $ = 3fo (V 2 + 5$V 2 ) 
 
 Therefore, a 5% increase in V corresponds to a 3% increase in T . 
 
 For a 5$ decrease in V the corresponding change in T and 
 T can also be calculated 
 
 \ - y x fc = 0.322 t x 
 
 T 1 0.336 t 1 
 
 y ± i = k.% (V 2 - 9^V 2 ) 
 
 Therefore, a 5$ decrease in V corresponds to ^.5$> decrease in T . 
 
 T 2 ' y 2^ oT 2 = °' k76 T 2 
 T^ 0.512 T 2 
 
 y 2 = 7* (v 2 - 5f v 2 ) 
 
 So, a 5$ decrease in V corresponds to a 7$ decrease in T-. 
 
68 
 
 3.*+ Calculation from Experimental Results of the Change of Period 
 
 of the Collector-Base Coupled Monostable Corresponding to Small 
 Variations of Supply Voltages 
 
 The collector base coupled monostable circuit shown in 
 
 Figure 17 "was tested by varying the three supply voltages and measuring 
 
 the changes in the period of the monostable. The results of changing 
 
 V, are shown below. 
 
 v l 
 
 T l 
 
 T 2 
 
 25.00 
 
 iHO/^-s 
 
 1+7 f*s 
 
 26.25 
 
 380 /u S 
 
 U2 /us 
 
 23.75 
 
 1+30/^s 
 
 50 AS 
 
 The percentage change in T and T can be calculated, 
 
 T. + xAT- = 380^ 
 
 tyi = -7.5$ (v 1 +5foV 1 ) 
 
 The calculated theoretical Value of xA> is -x.A> = -5$ from Section 3.3. 
 Also, 
 
 T 2 + x^T 2 = 1+2 /us 
 
 x 2 i = 10. 6# (V 1 + 5^) 
 
69 
 
 The calculated theoretical value of x $> is x A> = -6ff from Section 3.3, 
 For the -5$> change in V. the experimentally obtained value of y and 
 y are found as follows: 
 
 T 1 - y 1 ( / T 1 = U30^s 
 
 y-L^ = -% (v 1 - 5^v 1 ) 
 
 T 2 " y J° T 2 = 5 °/" S 
 
 y 2 «/ = -6.5$ (v 1 -5^) 
 
 The calculated theoretical value of y is -2% and of y is -3.6% 
 for a -5$> change in V.. from Section 3.3- 
 
 Similarly, for a +5$> change in V 
 
 T + x AT = VlO z*s 
 
 x^ = (V 2 +5$V 2 ) 
 
 and 
 
Jlo. 
 
 70 
 T 2 + X 2^° T 2 = 51 /^ S 
 
 x 2 i = s.2i (v 2 +5iv 2 ) 
 
 The theoretical calculated value of x </o is 2</ and x Jf is 
 
 For a -5^ change in V , y $> and y Jfo can also be calculated 
 
 T x - y 1 f T 1 = J+10^s 
 
 y-^ = o (v 2 -5#v 2 ) 
 
 T 2 ' y 2^° T 2 = ^V^ 
 
 y 2 # = 6.1$ (v 2 -5f v 2 ) 
 
 The theoretical calculated values are y-$ = U.5^ and y A, = 
 
71 
 k. OPERATION OF COMPLEMENTARY TRANSISTOR MONOSTABLE MULTIVIBRATOR 
 
 A third possibility for the multivibrator to be used in the 
 analog storage scheme is the complementary transistor mono stable 
 multivibrator shown in Figure 19. The operation of this circuit is 
 as follows: The Transistors GL and Q> are normally biased on. The 
 collector of Q is the collector of Q . A negative trigger applied 
 to the base of 0_ turns it off. When Q, is turned off its collector 
 is allowed to jump up to the voltage determined by the voltage 
 divider R^ and R on V and V . This jump is transmitted through 
 capacitor C to the base of Q, , turning Q off. With Q, off its 
 collector falls and keeps Q, off. Before the trigger, capacitor C 
 had zero volts across it, but now with Q, and Q off point A will 
 eventually charge to -V volts and point B will eventually charge to 
 -V volts, i.e.C will have V + V volts across it. As point A drops 
 exponentially, point B rises exponentially. When point A falls below 
 ground Q_ turns on and its collector rises and Q, turns on. Now 
 both Q, and Q, are on and capacitor C has nearly +V volts on it. 
 Hence, capacitor C discharges very rapidly through Q, and Q back 
 to zero volts, thus completing the cycle. 
 
 The diode D could be replaced by the base emitter diode 
 of an n-p-n transistor and then the collector signal of this 
 transistor could be used to retrigger Q, . In this way monostable 
 would be modified to an astable multivibrator. 
 
72 
 
 +Vl 
 
 •Rl 
 
 ■■■ Hf 
 
 i 
 
 -v 2 
 
 TRIGGER O- 
 
 -W T— K 01 
 
 -v 3 
 
 R5 
 
 )Q2 < R4 
 
 1 R x +R 2 
 
 :R2 
 
 U-»-J\ 
 
 -v, 
 
 1 
 
 'b 
 
 yT| 
 
 
 v (Vi+V 2 )R! 
 
 
 
 
 1 R x +R 2 
 
 
 
 
 
 L-ii-J 
 
 
 Figure 19. Complementary Transistor Monostable Multivibrator 
 
73 
 
 k.l Calculation of the Period of the Complementary Transistor 
 Monostable Multivibrator 
 
 In the circuit of Figure 19 with Q, and Q off the current 
 equations at points A and B are as follows: At point A 
 
 dt R, 
 
 c^r^ = -M a) 
 
 2 
 
 and at point B 
 
 d( V V A ) V -V 
 
 C ° * - x D (?) 
 
 L dt IL Uj 
 
 From equations (l) and (2) 
 
 V V B - V!2 
 R l ' R 2 
 
 Now solve equation (3) for V in terms of V , thus 
 
 R R 
 
 V = V (V -V ) = V, + =— (v -vj 
 
 B 1 R 2 V A 2 ; 1 R 2 v 2 A 
 
 Substituting this into equation (l) 
 
 c ft (\ + r 2 < W - v ■ ^r 
 
 (3) 
 
lh 
 
 dV A 
 
 (R 1 +R 2 ) 
 
 dt 2 A 
 
 ^A + V A = V 2 
 
 dt cTr^Tr 2 ) Tr~TrP 
 
 In order to solve this equation the initial and final 
 conditions on V. are needed. From Figure 19 and the discussion in 
 Section k.O it is known that 
 
 (V +V )IL 
 
 +R 2 
 
 and 
 
 T(-) =-V 2 
 
 Hence 
 
 ( V V 2 )R 1 " t/T l 
 
 V (t) = (V +V — - — -) e - V 
 
 V ' K \ V 2 \ + R 2 2 
 
 where T = C(lL+R ) 
 
75 
 
 Similarly 
 
 (V +V )R 
 V (o) = X 2 I 
 
 V u; R +R 
 
 and 
 
 V B (oo) = +V 1 
 
 Therefore 
 
 V*) = \ - t^ e Tl 
 
 Referring again to Figure 19 it is seen that T is the time 
 necessary for Q, to be turned on again after the trigger. At this time 
 
 v A (i 1 ) - 0. 
 
 (V +V )R " 1/T 
 VV " ° = (V V £ - R 1+ R g > e " V 2 
 
 R„(V +V ) 
 
76 
 
 k.2 Calculation of the Circuit Parameters of the Complementary 
 Transistor Monostable Multivibrator 
 
 Referring to Figure 19, with <^ and Q^ on, there is wanted 
 V. = and V_ = 0. Therefore one must find R, . Assume supply voltages 
 
 Set I p = 5 ma 
 °1 
 
 Then 
 
 Choose 
 
 V 1 = +25v 
 
 V 2 = 25v 
 
 V 3 =10v 
 
 25v 
 
 I c 1 " 5 ma ■ 5TT 
 
 1 1 mm 
 
 R n . = 5k 
 1 rain 
 
 *1 
 
 = 6.8k 
 
 Transistors are Q^: 2N2219A and Q_: 2N1309. 
 
77 
 For this collector current, the base current required is 
 
 __ C 5 ma _ c 
 I B "_J: =100" = ' 05ma 
 1 P 
 
 5v 
 
 Since V. = R._ = -rr= ■ = 100K. This is a maximum value for R , 
 
 A 5 «05 ma 5 
 
 Select R c = 27k 
 
 To determine R,,, select !„ = 5 ma 
 
 then 
 
 T c 2 
 
 R=-^ =5 k 
 3 5 ma 
 
 Select R^ = 5.1k 
 
 "3 
 
 To determine R , the base current for Q^ is determined as 
 
 I = _2 = 5 ma = 1 ma 
 2 (3 30 6 
 
 25v 
 R 2 = ^ . 150k 
 
 Set R2 = 100 k 
 
78 
 
 To determine R. , the voltage V must be negative enough to 
 turn Q off when Q, is off. V must be less than -lOv. 
 
 Set V. = -lOv, then R, is determined from 
 
 A ' 4 
 
 -25v 
 
 -lOv = R + R, R U 
 
 R^ = 3.3K 
 
 Since the total period of this monostable is essentially T, 
 
 Set T ± = 380 ^s. 
 
 From previous calculations in Section k.l 
 
 (V 1+ V 2 )R 2 
 
 C l " V ln «TVR^ ' 
 
 From this 
 
 C = 0. 
 
 00575 A-fd 
 
 Set C = 0.005/^fd 
 
 005/^ 
 
 The waveforms obtained experimentally using the parameters 
 determined in this section are shown in the oscillograms of Figure 20. 
 
79 
 
 Ground 
 
 (a) 
 
 Ground 
 
 Trigger Waveform 
 Time Base = 100/*. sec/cm 
 Voltage Scale = 5 volts/cm 
 
 
 
 ^■H 
 
 
 Waveform V. 
 
 Time Base = 100/t sec/cm 
 Voltage Scale = 5 volts/cm 
 
 (b) 
 
 Figure 20. Experimental Waveforms of Complementary Transistor 
 Monostable Multivibrator 
 
80 
 
 Ground 
 
 (c) 
 
 Waveform V 
 B 
 
 Time Base = 100// sec/cm 
 
 Voltage Scale = 5 volts/cm 
 
 Ground 
 
 (d) 
 
 Waveform at Collector of Q^ 
 
 Time Base = 100/^.sec/cm 
 Voltage Scale = 5 volts/cm 
 
 Figure 20. Experimental Waveforms of Complementary Transistor 
 Monostable Multivibrator 
 
81 
 
 k.3 Theoretical Calculation of the Change of Period of the Complementary 
 Transistor Monos table Corresponding to Small Variations of Supply- 
 Voltage 
 
 The equation from which the period of the complementary 
 
 transistor monostable of Figure 19 is 
 
 T l ■ T l r ^V 2 (R 1+ R 2 )) 
 
 where T, = C(E^+R ), R^^ = 6.8K, R g = 100K 
 
 The supply voltages used are V = +25v, +V = +25v, and 
 V„ = +10v. The changes in the period T, , corresponding to smal 1 
 changes in the supply voltage can be calculated. 
 
 Thus, if V, is increased "by 5% the equation for T becomes 
 
 R p (V +5#V +V ) 
 
 T 1 +X A =T 1^^ V 2 (R 1+ R 2 ) ) 
 
 H + x #T = .651 ^ 
 
 Now also for no change in V, or V 
 
 R 2 ( V V 2 ) 
 
 T = .627 T 
 
82 
 
 Therefore solving for x % 
 
 T ± + x 1 il 1 m .651 T- 
 T ± .627 T, 
 
 x"o = 4% 
 
 Similarly for V, decreased "by 5% 
 
 (V 1 +5foV 1 ) 
 
 R 2 (V 1 -5foV 1 +V 2 ) 
 
 T l V° T 1 = T l * ( v g (R 1+ R 2 ) > 
 
 T-l - y^T, = 0.600 t x 
 
 Therefore solving for y,^i 
 
 T x - y^T _ 0.600 t 
 T7 0.627 t7 
 
 y^o = H (V 1 -5^V 1 ) 
 
 Similar calculations can be done for variations in supply 
 
 voltage V . 
 
For an increase of 5> in V 
 
 R (V +V +5/oV ) 
 T l + X A =T l^ ( TV^yiR7R 2 )) 
 
 T + x At = ,6oh t 
 
 Now, solving for x % 
 
 T l + x i^ oT i 0.60U t 
 
 T 0.627 ' 
 
 1 
 
 x^ = -3.5^ (V 2 +5^oV 2 ) 
 
 For a decrease of 5% in V 
 
 VW^V 
 
 C l " y A = T l ^ ( (V 2 -5%V 2 )(R 1+ R 2 ) ) 
 
 ^ - y-^ =0.651 t 1 
 
 T x - y 1 ^D 1 = 0.651 t 2 
 
 T~ 0.620 T, 
 
 yjt = -% (v 2 -5foV 2 ) 
 
 83 
 
r 6k 
 
 According to these calculations a 5% increase or decrease 
 in V should result in a h% increase or a h% decrease respectively 
 in T, . Similarly a 5% increase or decrease in V should result in a 
 3.5 decrease or a 5% increase respectively in T . 
 
 The supply voltage V does not enter into the equation for 
 T and therefore for small changes in V should not affect T . 
 
 k.k Calculation from Experimental Results of the Change of Period 
 of the Complementary^ Transistor Monos table Corresponding to 
 Small Variations of Supply Voltages 
 
 In this section the results of experiments on the depend- 
 ence of the period of the monostable on the supply voltage are 
 summarized and compared with the theoretical results obtained in 
 Section h.3- 
 
 The experimental results obtained for variation in V and 
 V„ are as follows : 
 
 V 
 
 1 
 
 25 
 26.25 
 23-75 
 
 350 A s 
 365 /^s 
 335 /-s 
 
 V 2 
 
 T l 
 
 25 
 
 350 yUS 
 
 26.25 
 
 3^0 jus 
 
 23.75 
 
 295/.S 
 
 T ± = 350 A s 
 
85 
 T ± + x ± %T 1 = 365/^s 
 
 x x i = k% (V 1 +5^V 1 ) 
 
 This compares well with the k-% value calculated, in 
 Section k.3. 
 
 T l " y A = 335 / ts 
 Y^o = ^.2f (V 1 -5/oV 1 ) 
 
 This also compares well with the k% value calculated in 
 the previous section. Similarly, for a 5% increase in V the 
 equation is 
 
 T 1 + x.^^ = 3^0 
 
 yl$ = -2.6* (V 2 +5$V 2 ) 
 
 The value of -3-5$ calculated in the previous section compares well 
 with this value. 
 
 For a 5$> decrease in V the value of y % is calculated as 
 follows : 
 

 T - y^T = 295 ^s 
 
 y-L = 15.: 
 
 (v 2 -5foV 2 ) 
 
8 7 
 5. OPERATION OF EMITTER COUPLED ASTABLE MULTIVIBRATOR 
 
 Another possibility for the storage element in the analog 
 storage scheme is the astable multivibrator shown in Figure 21. This 
 is an astable and could possibly be used without any modification as 
 was necessary in the previous three circuits. The operation of this 
 circuit is as follows. Assume Q,, on and Q off. Q is not saturated. 
 In this state point A will eventually charge to +V volts, so the 
 voltage increases at this point. When point A rises sufficiently 
 high to turn Q, on, the charging current into capacitor C is diverted 
 from C to Q, . Consequently, the current in Q, decreases by this 
 amount and allows the collector of Q to fall lower since the collector 
 current through resistor R has been decreased. This action turns Q, 
 on harder and the current in resistor R increases and point A drops 
 to approximately +V volts » Point B follows this jump, as it takes 
 place quite rapidly, and consequently, Q,-, is turned off. Now with Q 
 off and Q, on point B will eventually charge to +V, volts. Hence, it 
 rises exponentially until it rises above +V volts and turns Q, on. 
 When CL turns on its collector jumps up and turns Q off. Now point 
 A is at +V p volts and again rises towards +V, until it turns Q, on 
 again, thus completing the cycle. 
 

 +V 3 » 
 
 +Vx--- 
 
 +V, 
 
 ^n 
 
 h-Ti-^ 
 
 v B < 
 Vi- 
 
 i 
 
 
 
 ^3 1 
 
 Vi-Vz + Rg/R^-Vj) 
 
 X^2 
 
 
 k 
 
 1+Rz/Ri 
 
 ^ 
 
 t 
 
 Figure 21. Emitter Coupled Astable Multivibrator 
 
89 
 
 jp.l Calculation of the Period of the Emitter Coupled Astable 
 Multivibrator 
 
 Assume Q, is on and Q, is off in the circuit of Figure 21, 
 
 Then the current equation at point A is 
 
 dV V -V 
 p _A 1 A 
 
 at = R 2 
 
 Re"writing 
 
 dV V V 
 A = _A_ = \_ 
 
 dt CR 2 CR 2 
 
 To solve this equation the initial and final voltages at 
 point A are needed. With Q-. off and Q on, V.(0) » +V . Also it is 
 known from the previous discussion that V.(») = +V . Therefore the 
 
 solution for V.(t) is 
 
 -t/ T 
 V A (t) p V 1+ (V 2 - Vl ) e 
 
 ■where 
 
 t = R 2 c 
 
90 
 
 In order to determine when Q switches back on, the voltage 
 at the collector of Q must be known. 
 
 V _V V -V 
 I IB. 1 A 
 
 Then 
 
 From this 
 
 Now since 
 
 E 1 R 1 R 2 
 
 -*/ 
 
 V S V and V = V - (V -V ) e 
 
 -t/ 
 V -V (V -V ) e 
 
 h (t > ■ iH + 
 
 R 2 
 
 
 V Cl " V 2 + \h ~ V 2 + \S 
 
 EL Ro 't 
 
 »3 
 
 -V, 
 
 v ft) = V + — (V -V ) + — ( V -V ) 
 V C V ; 2 R, ^ 1 3 R 2 1 V 
 
 Now Q, p turns on when 
 
91 
 
 W - v 0l <V 
 
 and therefore have 
 
 T 1At Ro Bq " T 1/t-, 
 
 V l - < W e " V 2 + R^ <W + R^ < W e 
 
 From -which 
 
 i. + V £ 
 
 ^VV 
 
 T « T In 1 - _2 . 1 3 
 
 *1 ws 
 
 Then solving for V_ (T ) 
 
 °1 - 1 
 
 R. 
 
 2 
 
 V -V + ^ ( V i" V q) 
 V p (T n ) = V + 1 2 R l - 1 3 
 
 i 4 V, 
 
 C l X " 2 R 
 
 This voltage, V n (T ), is the voltage at which Q^ turns on. 
 
 When CL turns on, the charging current to capacitor C is diverted, to 
 Q and therefore the current in Q drops and consequently the voltage 
 across R_ drops and turns Q, on harder. The drop at C also occurs at 
 point A and is transmitted by capcitor C to point B and causes Q, to 
 
92 
 
 turn off which causes V to drop further and turn Q on more. 
 
 C l 2 
 
 Finally Q, will he off and Q, will he on and V will equal nearly 
 ± d L ± 
 
 +V volts. The amount by which V drops is given by the second term 
 
 d c 1 
 
 of the last equation. 
 
 While Q, p is on, the current equation at point B is 
 
 C 
 
 dt ' R 
 
 Rewriting 
 
 dV V V 
 B + _[B_ = J[l_ 
 
 dt 
 
 R^C R^ 
 
 To solve this equation the initial and final conditiQaas on 
 V are needed. To find the initial voltage at V , go back to the state 
 
 B B 
 
 with Q^ on and Q off. V = V before Q turned off and the turn off 
 jump is given by 
 
 R 2 
 
 V V 2 + 
 
 V = 
 
 l*x (v r v ) 
 
 1 + V3 
 
 Hence 
 
93 
 
 R 2 
 
 V -V + rf (V -V ) 
 
 v (o) = v - 1 2 \ - 1 3 
 
 b o : 5 
 
 i + ^ 
 
 The final voltage, V (oo), is easily seen to be +V, . 
 
 B 1 
 
 Then the solution is 
 
 R 2 
 
 or 
 
 where 
 
 v B (t) . Vl + ( v - 2 h±2 - v . -^ 
 
 1 + 2 / R l 
 
 -(t-T,) 
 
 V B (t) = V x ♦ (V 3 -V - Vl ) e 
 
 T 2 
 
 R 2 
 
 V 
 
 v n -v„ + == (v -v„) 
 
 12 R, v 1 3 
 
 If 2 / R l 
 
 When t = T, + T V^ ~ V 
 
 -TL 
 
 Y B (T 1+ T 2 ) - V 3 = Vl + (V 3 -V -V 1 ) e ^ = 1 
 
9^ 
 
 Which gives 
 
 V 
 T = t in (1 - tj-%-) 
 3 1 
 
 5.2 Calculation of the Circuit Parameters of the Emitter Coupled 
 Astable Multivibrator 
 
 Referring to Figure 21, when transistor Q.. is on, it should 
 not be saturated. Therefore, 
 
 V - 5 volt < lOv 
 C l 
 
 V- < 15 volt 
 °1 
 
 Let 
 
 Ig -« 5 ma 
 
 Also 
 
 lOv 
 
 1^ = R ± = 5 ma 
 
 Set 
 
 =1 
 
 = 2K 
 
Then 
 
 Set 
 
 Then 
 
 Since I k I- = 5 ma 
 E l C l 
 
 V n = 5 + (5 ma)(R_) < 15v 
 
 R 3 <2K 
 
 R 3 =1K 
 
 Now when Q is on and Q is off set I = 5 ma 
 d L h> 
 
 ^2 E 2 
 
 From this 
 
 R 2 = ^ 
 
 Set 
 
 R 2 - ^-3K 
 
 95 
 
96 
 
 V r must be less than +5 volts and assume I_ ~ I„ 
 C 2 C 2 E 2 
 
 Therefore, 
 
 V c = (5 ma)R u < 5v 
 
 R, < -^- = IK 
 4 5 ma 
 
 Set 
 
 R. = 910 n 
 
 To determine C, set T n = T + T = 380//S. From previous 
 calculations 
 
 R 3/R 2 
 T l ' V ta < ' R 3 (Vl -V 3 ) > 
 
 1 " h < w 
 
 From this 
 
 T x = C(4.3K) (0.496) 
 
And 
 
 T 2 = R i c ln (1 - T^- ) 
 
 3 1 
 
 Where 
 
 Vq . v i- v a + | ( VV 
 
 1 + Vi 
 
 From this 
 
 T 2 = C(2K)(0.97) 
 
 380 /*s = T-^T = C(U.3K (.496) + (2K) In (0.97)) 
 
 C = .0903/tfd 
 
 Set 
 
 C = 0.1 a£& 
 
 aft 
 
 97 
 
 The waveforms obtained experimentally using the parameters 
 determined in this section are shown in the oscillograms of Figure 22. 
 

 Ground 
 
 (a) 
 
 Waveform V 
 A 
 
 Time Base = 50/*-sec/cm 
 
 Voltage Scale = 5 volts/cm 
 
 (D) 
 
 Ground 
 
 Waveform V. 
 
 B 
 
 Time Base *= 50/* sec/cm 
 Voltage Scale ■ 5 volts/cm 
 
 Figure 22. Experimental Waveforms of the Emitter Coupled 
 Astable Multivibrator 
 
99 
 
 (c) 
 
 Ground 
 
 Waveform at Collector of Q 
 
 1 
 
 Time Base = 50*ft#e»/cra 
 
 Voltage Scale - 5 volts/cm 
 
 Figure 22. Experimental Waveforms of the Emitter Coupled 
 Astable Multivibrator 
 
LOO 
 
 5.3 Theoretical Calculation of the Change of Period of the Emitter 
 Coupled As table Multivibrator Corresponding to Small Variations 
 of Supply Voltages 
 
 The two equations for T, and T , the periods of the astable 
 
 multivibrator (obtained in Section 5.1) are 
 
 R 3/R 2 
 1 + 
 
 ? 1 = T l ln ( R- (V-Vj ) 
 
 1 £ _-i 2- 
 
 R (V -V ) 
 
 1 V 1 2' 
 
 and 
 
 V 
 
 T ' «= T In (1 %-\ 
 
 A 2 p ■" v v -V ' 
 
 v 3 1 
 
 where 
 
 VVV 2 ) + « g (V 1 -V 3 ) 
 " R l + R 2 
 
 The values of the parameters in these two equations are 
 the values calculated in Section 5.2. 
 
101 
 
 They are 
 
 R 1 = 2K V 1 = 25v 
 
 R 2 = ^.3K V 2 = 5v 
 
 R = IK V = 15v 
 
 R. = 910 ft 
 
 C = 0.1 
 
 p£& 
 
 The nominal values of T and T are calculated using the 
 
 above values. 
 
 1 + R 3/ R 2 
 
 T i = T i ^ ( — r — v~^r ) 
 
 1 _3 . 1 3 
 
 R V -V 
 
 1 1 2 
 
 T, = O.U96 T 
 1 1 
 
 \ "^ * (1 - V^> 
 
102 
 
 "where 
 
 v VW + R g (v rV 
 
 R l +R 2 
 
 Then 
 
 T 2 = 0.8^2 t 2 
 
 The calculation of the values of T, and T for variation 
 in the power supplies V, , V , and V is carried out as shown below. 
 For V-, increased by 5% the equation is 
 
 1 + V 2 
 
 T l + X A = T l to ( R^ ( V^V^ ) } 
 
 1 " R^ ' (V 1 +5%V 1 -V 2 ) 
 
 T l + X A " * 512 T l (V 1 +5%V 1 ) 
 
 And for a 5% decrease in V 
 
 1 + R 3/K 2 
 
 : i - y i* T i - T i ln ( — r — (v,-?^ -vj > 
 
 1 ^ » ■ ■,„. ,,,„.4 — Jl_ 
 
 r x (v 1 -5%v 1 -v 2 ) 
 
Thus 
 
 and 
 
 103 
 
 T i " y A = °' kl6 T i (v^V 
 
 The theoretical values of x,$ and y % can now be determined. 
 
 T, + x #E- 0.512 t 
 
 T^ 0.496 t7 
 
 X "A = j% 
 
 (V 1+ 5f V 1 ) 
 
 T l " y j/ oT l = °' klG T l 
 T^ 0.1+96 T 1 
 
 y^o = l# (V 1 -5^V 1 ) 
 
 The changes in T and T for variations in V are calculated 
 as follows? 
 
 For a 5$ increase in V^ 
 
 1 + R 3/ R 2 
 
 T i + X A * T i *» ( — r — vi — > 
 
 - 1 " R ± W r (V 2 +5%V 2 ) ; 
 
10U 
 
 T 
 
 1 + x^ = 0.500 t 1 (V 2 +5%V 2 ) 
 
 And also for a 5% decrease in V 
 
 1 + R 3/« 2 
 
 T i - ^A ■ T i ^ ( — r vt-) 
 
 X " 2 V V r (V 2 -^%V 2 ) ; 
 
 T i " y A = °- h9 ° T l (V 5 ^ oV 2 ) 
 
 The x,$> and y.$ for variation in V can now be determined. 
 
 T + x %T ^ 0.500 t 
 T^ O.i+96 T 2 
 
 x^o = 1$ (V 2 +5f V 2 ) 
 
 T l ~ y l^ oT l = °*^ 9 ° T l 
 T^ 0.1+96 t x 
 
 y^ = 1$ (V 2 -5$V 2 ) 
 
105 
 
 The values of x,% and y % for variation in V are calculated 
 
 as follows: 
 
 1 ♦ R 3/ R 2 
 
 1 2 , — u i- 
 
 R l V 1" V 2 
 
 T ± + x.^ = 0.^70 T 1 (V +5#V ) 
 
 1 + R 3/« 2 
 T l ' y A = T i ^ ( r^ V 1 -(V 3 -5%V 3 ) 
 
 1- \ V^T" 
 
 T l ' y A = °* 525 T l ( V 3 -5$V 3 ) 
 
 Now x, $> and y, $ can be determined. 
 
 T + x AT 1 _. 0.1+70 T, 
 
 t7 0.1+90 t7 
 
 x^ = -5$ (V +5#V ) 
 
106 
 
 and 
 
 T l " y r oT l = °* 525 T l 
 T^ 0.496 t 
 
 y^ = -6f (V 3 -5foV 3 ) 
 
 Similar calculations for T may be carried out. For variation in V 
 
 V 
 I 2 + x 2 *T 2 = T £ in (1 - v (v^) ) 
 
 where 
 
 R 1 (V 1 +5f V 1 -V 2 ) + R 2 (V X +5^V 1 -V 3 ) 
 
 V ° = R l +R 2 
 
 T 2 + X 2^ oT 2 = °* 8lT T 2 (V^°V 
 
 And for a 5% decrease in V, 
 
 v o 
 
 T 2 - y 2 i? 2 = T 2 in (1 - T (t ^ )) 
 
107 
 
 Then 
 
 W^yvg) + R 2 (v 1 -5f v 1 -v 3 ) 
 
 " R 1+ R 2 
 
 T 2 " y 2^° T 2 = °* 8U5 T 2 ( V 1 -^° V 1 ) 
 
 T 2 + x 2 f T 2 ^ 0.817 T 2 
 T^ 0.842 T 2 
 
 xJfo = ~>£h 
 
 (v 1 +5foV 1 ) 
 
 T 2 ' y 2^ oT 2 = °* 8i+5 T 2 
 T^ 0.842 T 2 
 
 y 2 fo = -0.5$ (V 1 -5^V 1 ) 
 
 For a 5% increase in V 
 
 V 
 T 2 ♦ x 2 «T 2 . t 2 to (1 . __ ) 
 
 ^(Vj^-fVg+atVg)) + R 2 (v 1 -v 3 ) 
 
io8 
 
 T 2 + X 2^ oT 2 = °- 8U2 ,: 2 (V 2 +5%V 2 ) 
 
 For a 5% decrease in V 
 
 T 2 -y 2 f T 2 =T 2 ln (1 - ^§-) 
 
 R 1 (v l -(v 2 -^v 2 )) + WV 
 
 V ° = R l + R 2 
 
 T 2 - y 2 foT 2 = 0.84l t 2 (V 2 -5*V 2 ) 
 
 The values of x $, and y f for variation in V can be 
 
 calculated. 
 
 T 2 + X 2^ oT 2 = °' 8U2T 2 
 T^ 0.842 T 2 
 
 x^o = (V 2 +5foV 2 ) 
 
 T 2 - y 2 f T 2 = 0.841 t 2 
 T^ 0.842 T 2 
 
 y 2 # = o (v 2 -5</oV 2 ) 
 
109 
 
 Thus, for small changes in V the period T does not change. Likewise 
 similar calculations for the variation in T corresponding to a 
 variation in V may be carried out. 
 For a 5$ increase in V 
 
 V^ 2 =T 2 lD(l+ ^ 
 
 VvV + VyCy^)) 
 
 V = 
 R l + R 2 
 
 T 2 + X 2^ oT 2 = -9 1 5' : 2 (V 3 +5foV 3 ) 
 
 And for a 57o decrease in V 
 
 V 
 
 t 2 - y 2 $T 2 = t 2 in (i + v rrv ?«*„ \ ) 
 
 v 1 -(v 3 -5%v 3 ) 
 
 VVV + r 2 (v 1 -(v 3 -5^v 3 )) 
 
 T 2 - y 2 foT 2 = 0.821 t 2 (v 3 -5foV 3 ) 
 
110 
 
 Now x € and y A, can "be determined 
 
 T 2 + X 2^ oT 2 = °'915 T 2 
 
 T 2 0.81+2 T 2 
 
 x 2 </ = 8.7% (V 3 +5^V 3 ) 
 
 T 2 " y 2^ oT 2 = °- 82lT 2 
 T^ 0.8U2 T 2 
 
 y 2 f = 2.1$ ^V^V 
 
 5.^+ Calculation from Experimental Results of the Change of Period 
 of the Collector-Base Coupled Monostable Corresponding to 
 Small Variations of Supply Voltages 
 
 In this section, the results of experiments on the 
 
 dependence of the period of the astable on the supply voltage are 
 
 summarized and compared with the theoretical results obtained in 
 
 Section 5«3. 
 
 The experimental results obtained for variation in V are 
 
 as follows : 
 
Ill 
 
 v l 
 
 T l 
 
 T 2 
 
 25.0 
 
 10 5^ s 
 
 l65/^s 
 
 26.25 
 
 ilOAs 
 
 165 us 
 
 23.75 
 
 100 As 
 
 166 jUS 
 
 T = 165^ s 
 
 T + x 1 f T 1 = 110 y^s 
 
 x A = h.2io (v +5$v ) 
 
 The theoretical value obtained in Section 5-3 "was jfo. 
 Also, for a 5$ decrease in V 
 
 T l " y r oT l = 100 /^ s 
 
 y # = 5% (v i -5 ( / v i ) 
 
 The theoretical value obtained in Section 5-3 was k%» 
 
 Similarly for T , it can be seen that xA a and y </ a 
 
 (V 1 +5 ( /oV 1 ) . 
 
112 
 
 The theoretical values for x % and y jf were -2$, and -5$, 
 respectively. 
 
 The experimental results obtained for variation in V are 
 
 as follows : 
 
 v g 
 
 > 
 
 T l 
 
 T 2 
 
 15. 
 
 00 
 
 105 
 
 165 
 
 15. 
 
 U5 
 
 105 
 
 165 
 
 11+ . 
 
 55 
 
 105 
 
 172 
 
 For T , it is seen that x % and y % are equal to zero. The 
 theoretical values for x.% and y % are 1%. For T , xJfo - 0, but 
 Y 2 i will be 
 
 T 2 - y 2 </oT 2 = 172 ^s 
 
 y 2 </ = -hi (V 2 -5foV 2 ) 
 
 The theoretical value of y % from Section 5.3 was zero. 
 The experimental results obtained for small changes in V, 
 
 are as follows : 
 
113 
 
 V 3 
 
 T l 
 
 T 2 
 
 5.00 
 
 105 
 
 165 
 
 5.25 
 
 105 
 
 165 
 
 U.75 
 
 105 
 
 I65 
 
 For T and T , x A, yA, a A and y $ are zero 
 
114 
 6. OPERATION OF INTEGRATED CIRCUIT MONOSTABLE MULTIVIBRATOR 
 
 A fifth possibility for the storage element is the integrated 
 
 circuit monostable shown in Figure 23. The operation of this circuit 
 is shown below. 
 
 With no trigger applied the logic relations are: 
 
 X 2 " S - V Z 2 * V X 3 = X 3' X 3' X 3 = X 
 
 X l " X 2 " Z 3 = Y 3 = Z l = X 
 
 X 3 " Y l " Y 2 ' Z 2 ■ ° 
 
 When X receives a negative pulse, X_ and Z switch to the 
 1 state. As a result, Z and X switch to the state. After the 
 X negative pulse is removed, X remains at 1, since X is at 0. 
 With Y„ switched to 0, capacitor C discharges toward 0. When the 
 voltage at Z reaches 0, Z switches back to 1. Thus X returns to 
 and applies feedback to Z , causing it to switch states. Capacitor 
 C recharges through R to the 1 state and the cycle is completed. 
 
115 
 
 TRIGGER 
 
 Figure 23. Integrated Circuit Monostable Multivibrator 
 
116 
 
 6.1 Calculation of the Period of the Integrated Circuit Monos table 
 Multivibrator 
 
 Only a rough calculation can be done for the period of the 
 I.C. monostable, since the exact switching voltages of the NAND's used 
 are not known. If a logical 1 level of -0.5 volts and a logical 
 level of -l+.O volts (these are levels which will assure a definite 
 1 and at the output) are used, the equation for the 1 to 
 transition at Zl is given below. 
 
 V Z1 = -5 (1 - e X ) 
 
 At time T- , (i„e, T. is time for to 1 transition) 
 
 -T, 
 
 ^ 
 
 V Z1 = " U ' 5 = " 5(1 " e ' 
 
 T n = 2 . 3 T where t = RC 
 .Li. x 
 
 This calculation only gives an order-of -magnitude value 
 for the period. 
 
 Another restriction on the parameters is the size of the 
 resistor R, since it must be small enough so that the voltage drop 
 across it caused by the input fiurrent to Zl does not cause a false 
 input. The integrated circuits used are Tl 7^00 quadruple 2-input 
 
117 
 
 positive NAND gates. The maximum input current at the "l" level is 
 
 1 ma, therefore if a one volt drop in R can be tolerated, the resistor, 
 
 R, cannot be greater than 100 ft . 
 
 Now a rough value for C can be calculated. Assume T = 380 u.s 
 as before, then 
 
 T = 380^5 = 2.3 
 
 RC 
 
 C = 1.21 at 
 
 ^ 
 
 This is only an order-of -magnitude value for C. 
 
 6.2 Calculation from Experimental Results of the Change of Period 
 of the Integrated-Circuit Monostable Corresponding to Small 
 Variations of Supply Voltages 
 
 The actual values of R and C used for the I.C. monostable 
 
 are given below. 
 
 R = 100 ft 
 C = 2.2jUt 
 
 Using these values, the experimental waveforms shown in Figure 2k 
 were obtained. The power supply was -5 volts. As seen from the 
 
118 
 
 oscillogram of Zl, T - 260 usee with the parameter values shown above, 
 
 JL / 
 
 Hence, the value calculated in the previous section was not very 
 accurate, but was an order-of -magnitude figure. 
 
 The variation in the period T corresponding to variation 
 in the power supply was also determined experimentally. The results 
 are shown below. 
 
 v l 
 
 T l 
 
 5.00 
 
 260 us 
 
 5.25 
 
 275/Us 
 
 ^.75 
 
 235/"s 
 
 T_ + x ^T 1 = 275 /^s 
 
 x x $ = 6io (v 1 +5^v 1 ) 
 
 T l " y i^ oT i = 235 
 
 y^o = lk.% (\-JlVj) 
 
 This period varies greatly with change in supply voltage. 
 The time it takes for Zl to return to a logical also varies greatly 
 with the supply voltage. 
 
 The waveforms obtained experimentally are shown in the 
 oscillograms of Figure 2k. 
 
119 
 
 Ground 
 
 (a) 
 
 Time Base = 100/u sec/cm 
 
 Voltage Scale: upper trace 
 
 lower trace 
 
 0.2 volts/cm 
 0.1 volts /cm 
 
 (b) 
 
 Time Base = 2 msec/cm 
 Voltage Scale =0.2 volts/cm 
 
 Figure 2k, Experimental Waveforms of the Integrated Circuit 
 Monostable Multivibrator 
 
120 
 
 Ground 
 
 (c) 
 
 Waveform X_ 
 
 Time Base = 2 msec/cm 
 Voltage Scale = 0.2 volts/cm 
 
 Figure 2h. Experimental Waveforms of the Integrated Circuit 
 Monostable Multivibrator 
 
121 
 
 7 . CONCLUSION 
 
 The purpose of this thesis -was to give the reader an idea 
 of the Phastor analog storage system as it was conceived and 
 implemented. Phastor is capable of storing four voltages which lie 
 in the range, +10v to -lOv. These voltages can be retained as long 
 as the periods of the monostables remain constant. Storage times 
 of eight hours have been observed in the model. 
 
 It is the author's suggestion that when this system is 
 extended, all of the digital circuits be implemented with integrated 
 circuits as this would cut down considerably on the power 
 consumption of the system. 
 
122 
 
 "REFERENCES 
 
 1. Babb, Daniel S., Contr. Author Schwarzlose, Paul F., 
 
 Pulse Circuits: Switching and Shaping , Prentice-Hall, 
 196 k. 
 
 2. Blitzer, Richard, Basic Pulse Circuits , McGraw-Hill, 196U. 
 
 3. Carroll, John M, Modern Transistor Circuits , McGraw-Hill, 
 
 1959. 
 
 k. Doyle, John M., Under the editorship of Irving L. Kosow, 
 Pulse Fundamentals , Prentice-Hall, 19&3 • 
 
 5. Farley, Francis James MacDonald, Elements of Pulse Circuits , 
 
 J. Wiley, 1955. 
 
 6. Littauer, Raphael, Pulse Electronics , McGraw-Hill, 1965. 
 
 7. Millman, J,, and Taut, H„, Pulse, Digital, and Switching 
 
 Waveforms , McGraw-Hill, 19&3* 
 
 8. Sandland, Paul, "Integrated Gates Form Fast Monostable 
 
 Multivibrator" Electronics 9 June 26, 1967. 
 
 9. Stanton, William A,, Pulse Technology , Wiley, I96U, 
 
 10 „ Strauss, Leonard, Wave Generation and Shaping , McGraw-Hill, 
 I960, 
 
Unclassified 
 
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 (Security claeeitication ol title, body of abstract and indexing annotation muet be entered when the overall report ie classified) 
 
 1 ORIGINATIN G ACTIVITY (Corporate author) 
 
 Department of Computer Science 
 University of Illinois 
 Urbana. Illinois 6l801 
 
 2a. REPORT SECURITY C L ASSI FIC A TION 
 
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 26 GROUP 
 
 3 REPORT TITLE 
 
 STORAGE OF ANALOG VARIABLES IN DELAY LINES 
 
 4 DESCRIPTIVE NOTES (Type ol report and inclusive dates) 
 
 Technical Report 
 
 5. AUTHORS (Last name, tint name. Initial) 
 
 Wallman, Lawrence H. 
 
 6 REPORT DATE 
 
 June, I968 
 
 7a. TOTAL NO. OF PASES 
 
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 12- SPONSORING MILITARY ACTIVITY 
 
 Office of Naval Research 
 219 South Dearborn Street 
 Chicago, Illino is 6060U 
 
 13 ABSTRACT 
 
 An analog storage system has been designed using delay line techniques, 
 The analog storage is accomplished by comparing the analog voltage to be 
 stored with a voltage ramp in a comparison circuit; when equality between 
 voltages is found an output signal from the comparison circuit triggers a 
 monostable multivibrator which has the same period as the voltage ramp. 
 The monostable multivibrator is made to retrigger by using feedback to 
 control the gating of a trigger pulse. The system is capable of storing 
 any voltage between approximately +10 volts and -10 volts to an accuracy of 
 Vfo of the full range. 
 
 Several possibilities for the storage circuit are investigated. 
 
 DD ,^,1473 
 
 0101-807-6800 
 
 Unclassified 
 
 Security Classification 
 
Unclassified 
 
 Security Classification 
 
 M 
 
 KEY WORDS 
 
 LINK A 
 
 ftOLC 
 
 LINK B 
 
 JhK C 
 
 ROL[ XT 
 
 analog storage 
 Phastor 
 multivibrator 
 delay line 
 
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