OPERATING INSTRUCTIONS Type139B•A PULSE GENERATOR -i ..,-< m __. (,..
OPERATING INSTRUCTIONS Type139B•A PULSE GENERATOR Form 1398-0 lOOA ID- 1032 March, 1966 Copyright 1966 by General Radio Company West Concord, Massachusetts, USA GENERAL WEST R A D I 0 CONCORD, COMPANY MASSACHUSETTS, USA
TABLE OF CONTENTS Section 1 INTRODUCTION . ..... .. .. .... .... . .... . ... . ...... .. . . . . .. . . . . 1.1 1.2 1.3 1.4 1.5 Section 2 INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 2.2 2 .3 Section 3 Purpose ... . .. . .. . ....................... ... ...... . . . ... . General Descr iption . .. .. . . . .. .. .. . ... . . . ... . ... . . . . .... . . . Controls and Connectors . .... . ... .. . . ... ... ...... . ........ .
SPECIFICATIONS PULSE REPETITION FREQUENCY 2.5 c/s to 1.2 Mc/s, with calibrated points in a 1-3 sequence from 10 c/s to 300 kc/s, and 1.2 Mc/s, all ± 5%. Continuous coverage with an uncalibrated control. Internally Generated: Aperiodic, de to 2.4 Mc/s with 1-V, rms, input (0.5 V at 1 Mc/s and lower); input impedance at 0.5 V, rms, approximately 100 kfl shunted by 50 pF. Output pulse is started by negative-going input transition. Externally Controlled: ~ 0 UTP UT .
INTRODUCTION SECTION 1 INTRODUCTION 1.1 PURPOSE. The Type 1398-A Pulse Generator is a general-purpose pulse source intended primarily for laboratory use. The repetition rates of the pulses may be either internally controlled, at frequencies from 2.5 c/s to 1.2 Mc / s, or externally controlled at frequencies up to 2.4 Mc / s . In addition to the main positive and negative output pulses, the instrument also supplies synchronizing pulses that correspond to the beginning and end of the main pulse.
~TYPEl398-A PULSE GENERATOR ~--------------------------TABLE 1-l CONTROLS AND CONNECTORS Reference (Figure 1-1) Name Function 1 PRF 12-position rotary switch Sets PRF range. In EXT DRIVE, it changes prf oscillator to an aperiodic 1nput circuit. 2 i',F Continuous rotary control Adjusts prf continuously between calibrated switch positions. When set fully clockwise, PRF switch is calibrated. When PRF switch is set to EXT DRIVE, i',F control sets triggering leve 1 of pulse generating c1rcuits.
INTRODUCTION 4 5 14 Figure 1-1. Type 1398-A Pulse Generator. Figure 1-2. Type 12177 P2 Single·Pulse Trigger.
. . TYPE 1398-A PULSE GENERATOR FRONT PANEL SCREW --.......~ r/ ) FOOT SCREW @..------A Figure 2-1. Rock Mounting : Preparation of instrument for attachment· of wings. RUBBER FOOT WING SCREW ~. LOCKWASHER f~-~f2k CL/ p /... ·~ NUT Figure 2-2. Rock Mounting : Wing assembly. WING Figure 2- 3. Rock Mounting : Attachment of wings to instrument .
INSTALLATION SECTION 2 INSTALLATION 2.1 COOLING. It is important that the interior of the instrument be adequately ventilated; therefore make sure the air holes in the cover, especially those on the right side, are not blocked. 2.2 POWER SUPPLY. Connect the pulse generator to a source of power as indicated by the legend at the input socket at the rear of the instrument, using the power cord provided.
~TYPE 1398-A PULSE GENERATOR SECTION 3 OPERATING 3.1 DEFINITION OF TERMS. main pulse .... .. .... .. . .... ..... The principal output of the instrument; available at the OUTPUT PULSE binding posts. prepulse ........................ The positive or negative sync pulse supplied just before the start of the main pulse; available at the SYNC +and SYNC binding posts . delayed pulse . . .... ... ....... .. . The pulse coincident with the end of the main pulse; available at the DELAYED SYNC binding posts.
OPERATING PROCEDURE 3.2 NORMAL INTERNAL OPERATION . 3.2.1 PRF ADJUSTMENT. Pulse repetition frequency is adjusted by the PRF controls (1 and 2, figure 1-1), over a range of 2.5 c/s to 1.2 Mc/s . The PRF switch is calibrated to indicate prf correctly only when the 6 F control is fully clockwise. When the 6F control is fully counterclockwise, the prf is lowered well below the next lower PRF switch setting.
~TYPE 1398-A PULSE GENERATOR 0,6 Iv 0.5 )0 0.4 1 / "' 0.1 ~ 0 I kc/s 2 5 10 20 50 v 100 / 7 v 200 500 DRIVING SIGNAL FREQUENCY I Mc/s 2 l tJ98·tl Figure 3-1. Typical sens itiv ity-vs-frequency characteristics. 3.3.2 EXTERNAL DRIVE PROCEDURE. For external operation, set the PRF switch to EXT DRIVE and apply the external driving signal to the EXT DRIVE binding posts.
OPERATING ~-----------TABLE 3.4 PRF VS PULSE DURATION. P R F Control Setting (6F control fully clockwise) 10 30 100 300 1 3 10 30 100 300 3.4.2 DURATION LESS THAN 50% OF PERIOD. The accuracy of the DURATION control settings rs preserved if the duty ratio is 50% or less (pulse duration is 50% or le ss of total time of period). Table 3-2 lists the 50%-of-period figures for each PRF control setting. 3.4.3 DURATION GREATER THAN 50% OF PERIOD.
~TYPE 1398-A PULSE GENERATOR be given to the equipment setup and interconnections. Bandwidth consideration s are fundamental and oscilloscopes with the desired frequency response must be chosen as indicators. 3.5.2 LONG PULSES- LOW-FREQUENCY RESPONSE. An oscilloscope with a frequency response to de is necessary to observe very long pulses.
OPERATING PROCEDURE 0 .6 volt, pe-ck-to-peak, into 10 ohms ; 0. 1 ,us/ em. 6 volts, peok-to-peak, into 100 ohms; 0 .1 ,us/ em. Figure 3-4. Pulses from circuit of Figure 3-3. Two important features should be noted from the above: (1) the rise rime can be controlled with no termination and maximum output, by the addition of fixed external capacitance according to the. equation T, (ns) = + Cexr) 2.
. . TYPE 1398-A PULSE GENERATOR 3.9 LOCKING ON HIGH FREQUENCY SIGNALS. 3.9.1 FREQUENCY DIVIDER ACTION. If an external signal is applied to the EXT DRNE binding posts and the PRF switch is set to one of the numbered positions, the internal oscillator of the Type 1398-A will lock on the external signal. For instance, if a 50-kc signal is applied at the EXT DRNE terminals and the PRF is set to nearly 10 kc/s the main pulse of the Type 1398-A can be locked at 'Is the external frequency of 50 kc / s.
OPERATING PROCEDURE pulse cons 1s ts of a negative-going trans1t1on of about 5 vo lt s and 100-n s duration, followed immediately by a pos itive transition of about 5 volt s and 150-ns duration. The initial negative-going tra n s ition will trigger the input circuits and start the main pulse of a following T y pe 1398-A. The positive-going transition will then re set the in put circuits of the second T ype 1398-A to prepare it for the ne xt de layed pulse.
~TYPE 1398-A PULSE GENERATOR SECTION 4 PRINCIPLES OF OPERATION analysis of each circuit 1s contained m the following paragraphs . 4.1 GENERAL. (See Figure 4-1.) The T ype 1398-A is composed of three basic sections: (1) the input and prf oscillator circuit, (2) the output pulse circuit, and (3) the power supply. The first two sections are shown in block diagram form in Figure 4-1. 4.2 INPUT AND PRF OSCILLATOR CIRCUITEXTERNAL OPERATION. 4.2.1 GENERAL.
PRINCIPLES OF OPERATION -VOLTAGE AMPLIFIER [iR Fl SIOI Rl02 ~r--- +150V II SCHMITT CIRCUIT-- +150V T~MS:Nc +150V EXT INT .,__..__ __.. l~F I TRIGGER TO OUTPUT PULSE CIRCUIT VIOlA Rll4 RI08 Figure 4-2. Simplified schematic diagram of the input and prf oscillator circuit. -150V 4.2.2 SCHMITT CIRCUIT . Vl02A and B form a Schmitt trigger circuit. Whether or not Vl02B is on (conducting) depends on the voltage at the grid of Vl02A.
. . TYPE 1398-A PULSE GENERATOR PRF: 0.01% 1:=: -· 100 kc/s 1--~- -- Figure 4-4a. Typical drift characteristics of prf oscillator. 5MIN I~ = 11- Figure 4-4b. Typical warmup characteristics of prf oscillator. 4.3.2 OSCILLATOR ACTION . 10.01 1 '"'"1 ""'"""'"'·""'""' 1 11 "'·"'"· 1• The PRF switch , SlOl, converts the input amplifier to a current source that translates the plate swing of Vl02A so that it is symmetrical around its own grid voltage .
PRINCIPLES OF OPERATION tor circuit is applied) VlOS is on (conducting) and about 60 rnA flows through the output resistors. 4.4.7 TRIGGER AMPLIFIERS. Start-Signal Action 4.4.5 -OUTPUT AMPLIFIER. Quiescent: Vl06 OFF Q103 and Q104 are the trigger amplifiers. Both are biased off. Since both are npn transistors, a positive pulse applied to their bases will turn them on for the duration of the pulse.
~TYPE 1398-A PULSE GENERATOR 4.4.9 OUTPUT AMPLIFIERS. Start-Signal Action As long as V103A is on, C will not charge, and Vl03B will be on, holding C 's voltage to V. Since the multivibrator driver has reversed its state, the output amplifiers have also reversed their states. VlOS is now off and the +OUTPUT PULSE voltage is 0 volts, and VI06 is now on and the -OUTPUT PULSE voltage is -60 volts instead of 0 volts.
PRINCIPLES OF OPERATION 4 .4 . 13 STOP-TRIGGER AMPLIFIER. Stop-Signal Action The stop-trigger amplifier behaves in the same fashion as the start trigger amplifier when it receives a positive pulse, i.e., it reverses the state of the multivibrator, which , in turn , reverses the state of the output amplifiers. Thus V105 is turned back on, Vl06 is turned off, all circuits have returned to their quiescent levels, and the output pulse is terminated.
. . TYPE 1398-A PULSE GENERATOR SECTION 5 SERVICE AND MAINTENANCE 5.1 WARRANTY. We warrant that each new instrument sold by us is free from defects in material and workmanship and that, properly used, it will perform in full accordance with applicable specifications for a period of two years after original shipment.
SERVICE AND MAINTENANCE each of the bras s brackets on either side of the motor laminations. 5.4.2 CLEANING THE AIR FILTER. To maintain proper cooling efficiency, the air filter should be cleaned periodically. Local air conditions determine how often this is necessary . To clean, release the air filter from its holder, rap gently to remove excess dirt, flush from the dirty side with hot soapy water, rinse, and let dry.
~ TYPE 1398-A PULSE GENERATOR 5.7 VOLTAGES AND RESISTANCES. TABLE 5-1 VOLTAGES AND RESISTANCES ** De Volts Tube Pin !:2. Ground VIOl ( 6DJ8) 1 2 3 6 7 8 1 Vl02 ( 6DJ8) 2 3 6 7 8 34 - 0.1 0.8 145 0 4.5 *** Ohms to Ground 125 34 40 150 33 40 3.2k lOOk 3.3k 2.5k 70k 3.3k 46 1 Vl03 ( 6DJ8) 2 - 125 3 - 120 6 47 7 47 8 46 60k 4.6k 4.8k 5.5k 5.5k 60k Transistor (Type) QlOl ( 2N2369) Lead E B c Ql02 ( 2N2369) E B c * *** Ohms to Ground 1 2 3 6 7 8 150 46 54 150 52 54 1.6k 63k 5k 1.
SERVICE AND MAINTENANCE A uniform error on all range s is an indication that the amp litude compari s on circuit (Vl04 and as s ociat e d components) is defective. For in s tance, a decrea s e in re s istance of Rl27 would make all pulses too long a t all s ettings of the PULSE DURATION controls , while an increase in this re s i s tance would reverse the effe c t.
. . TYPE 1398-A PULSE GENERATOR TABLE S-2------------~ P R F ACCURACY (1) Sine-wave generator. Capable of 10kc/ s, 0.1 V into 1M D and 2.2Mc /s , 0.5V into IM D. Accuracy ±10% or better. The Type 1330 Bridge Oscillator or the Type 1001 Standard-Signal Generator may be used. (2) Time-mark generator. Capable of 100-ms to 0.1-f.Ls marks in 5 decade ranges. Accuracy ±0.1% or better. The use of a time-mark generator is optional.
SERVICE AND MAINTENANCE highest dial reading was 6.6 and occurred on the ltolOms RANGE, theerrorspanis 6.6-5.8 =0.8. Set the RANGE switch to 10 to lOOms (the range where the lowest dial reading was noted) and set the PULSE DURATION dial for a measured duration of 50 ms. Loosen the hub set-screw (behind the PULSE DURATION potentiometer) and position the dial for a reading of S- 0.4 =4.6. Be careful not to disturb the setting of the potentiometer itself; the measured duration must remain 50 ms.
. . TYPE 1398-A PULSE GENERATOR Overshoot and ringing. Not greater than 10% of amplitude . input of the oscillo scope via a 10-meg ohm , 12-pF probe. Set the Type 1398-A controls as follows: L\F. Jitter-oscilloscope limitation. The amount of jitter present in the oscilloscope must be taken into account when duration and period jitter are measured. T ypical jitter for most delay ing sweep oscilloscopes is 0.02% of the amount of delay.
SERVICE AND MAINTENANCE C501 Rl28 Rl30 Cl25 Cll5 Cll6 Rl25 Figure S-3. Cl23 Cl20 Top interior view. 512 SUPPLY BOARD ASSEMBLY * • VI07 Figure S-4 . ETCHED Cl RCU IT ASSEMBLY ** Bottom interior v i ew.
, PARTS LIST REF NO DESCRIP T ION PART NO REF NO DESCRIPTION CAP ACITORS C100 C101 C102 C103 C104 C105 C106 C107 C108 C109 C110 C111 C112 C113 C114 C115 C116 C117 C118 C119 C120 C121 C122 C123 C124 C125 C126 C127 C128 C129 Cl30 C132 C133 Cl34 C135 C136 C137 C138 C139 Cl40 Cl41 C501A CS01B C501C CS01A C502B C502C C503 C504 csos CS06 Trimmer, 8 - 50 pF Ceramic, 51 pF ±5% 500 V Ceramic, 68 pF :!:10% 500 V Ceramic, 0.01 f.lF +80-20% 500 V Ceramic, 0.01 f.lF +80 - 20% 500 V Ceramic, 0.01 f.
PARTS LIST (cont) REF NO DESCRIPTION PART NO REF NO R513 R514 R515 R516 R517 R518 R519 Composition , 51 Q ±5% 1/4 W Composition, 51 n ±5% 1/4 W Composition, 1 MQ ±5% 1/2 W Composition, 51 krl ±5% 1/2 W Composition , 13 krl ±5% 1/2 W Film, 150 krl ±1 % 1/2 W Potentiometer, wire -wound 20 kn ±1o% Film, 150 krl ±1% 1/2 W Composition, 1 MQ ±5% 1/2 W Composition, 62 krl ±5% 1/2 W Composition, 10 krl ±5% 1/2 W Composition, 27 krl ±5% 1/2 W Film, 13.
Figure 5-5. Main etched - board layout (P/N 1389-2710). Figure 5.6. Power Supply etched-boord layout (P/N 1389-2750.). NOTE: The number on the foil side is not the part number for the complete assembly.
Rotary switch sections are shown as viewed from the panel end of the shaft. The first digit of the contact number refers to the section. The section nearest the panel is 1, the next section back is 2, etc. The next two digits refer to the contact. Contact 01 is the first position clockwise from a strut screw (usually the screw above the I ocat i ng key), and the other contacts are numbered sequentially (02, 03, 04, etc.), proceeding clockwise around the section.
l C/04 R/09 r--------------------------------------~A:·~T~I0~8------------·~~~--------------~_LA~.T~!1~0-------------0/~Kr------------A~.T~/1~8--~~-C-~-B---+ ~~gv 6 I'\"/&!;~ - A.T./21 1 .022 A,T./2? -;..::.::v-7 SYNC + -~ -8 0~-----------------------------------------~\lll~-----+------~ 0 Jt05 J/03 J/06 J/04 ~ ~ c~Js A.r.to9 212R R//0 ,0/ 0 0 0 ~101 0 0 0 0 206R 209R 1;!% BR --- .2/o!i,'i!iR !09F A.T./13 R/52 IOK fif ·.---.---,J!::,. F 1@ ---IE---- A.T.
NOTE UNLESS SPECIFIED I. POSIT ION OF ROTARY SWITCHES SHOWN COUN TEIKLOCKWISE. 2. CONTACT NUMBERING OF SW ITCHE S EXPLAINED ON SEPARATE SHEET SUPPLIED IN IN STRUCT ION BOOK. 3. REF ER TO SERVICE NOTES IN INSTRUC 5. RESISTANCE IN OHMS K ~ 1000 OHMS M I MEGOHM 7. 0 KNOB CONTRO L <§) TION BOOK FOR VOLTAGES 8. APPEARING ON DIAGRAM . 9 AT 4. RESISTORS .·1/ 2 WATT. WH-VT WH-RO 6. CAPACITAN.CE VALUES ONE AND OVER IN PICOFARADS. LESS THAN ONE IN MICROFARADS.
TYPE 87 4 COAXIAL COMPONENTS TYPE 874 CABLE CONNECTORS CONNECTOR TYPE ~ :J: 0 0 .... V) w ll. >- 1-- w _j Ill ~ :J: 0 ~ i 0 z <( u w _j Ill <( u - _j ll. ll. <( ~ :J: 0 0 .... ~ :J: 0 ~ i 0 z ~ :J: ....~ ~ Z:J: 0 0 Z6 ....
GENERAL WEST RADIO COMPANY CONCORD, MASSACHUSETTS 617 369-4400 5 ALE 5 NEW 01781 617 ENGINEERING ENGLAND* 22 Baker Avenue West Concord, Massachusetts 01781 Telephone 617 646-0550 METROPOLITAN NEW YORK* Broad Avenue at Linden Ridgefield, New Jersey 07657 · Telephone N.Y. 212 964-2722 N.J.
