HP-212A-Manual 电路图.pdf

《HP-212A-Manual 电路图.pdf》由会员分享，可在线阅读，更多相关《HP-212A-Manual 电路图.pdf（61页珍藏版）》请在收音机爱好者资料库上搜索。

1、RadioFans.CN 收音机爱 好者资料库 PULSE GENERATOR SERIALS PREFIXED : 419 OPERATING AND SERVICING MANUAL PRINTED 10 - 59 RadioFans.CN 收音机爱 好者资料库 O P E R A T I N G AND S E R V I C I N G MANUAL F O R MODEL 212A PULSE GENERATOR Serials Prefixed: 419- Copyright HEWLETT -PACKARD COMPANY 1954 275 PAGE MILL ROAD, PAL

2、0 ALTO, CALIFORNIA, U. S. A. RadioFans.CN 收音机爱 好者资料库 SPECIFICATIONS PULSE LENGTH: At least 0.07 to 10 microaeconda, continuously variable. PULSE AMPLITUDE: At least 50 volts peak into 50 ohm load (50 watts peak J. PULSE POLARITY: Positive or Negative. AMPWTUDE CONTROL: (a) 50 db attenuator, variable

3、 in 10 db steps. (b) Cantinuoualy variable control with range of at least 10 db. PULSE SHAPE: (a) Rise and decay time approximately 0.02 microseconds (10% to 90yoo), (b) Crest variation less than f 5% of average peak amplitude. JITTER: Less than 0.01 microseconds. INTERNAL IMPEDANCE: 50 ohms or less

4、 on either pulse polarity. REPETITION RATE: (a) Internal ynchronization, 50 to 5, 000 pps. (b) External 8 ynchronization,%Z to 5, 000 pps. SYNC IN: Positive or negative, 5 volts peak minimum. SYNC OUT: (a) 25 volt5 poaitive or 15 voIte negative into 2, 000 o h m load. (b) Duration, approximately 1 m

5、icrosecond at half voltage points. (c) Rise time, approximately 0.25 microseconds. PULSE POSITION: (a) Delay, 0 to 100 microseconds after Bync out pulse with repetition rate up to 2500 pps. (b) Delay. 0 to 50 micraseconds after sync out pulse with repetition rate up to 5000 pps. (c) Advance, 0 to 10

6、 microseconds after sync out pulse with repetition rate up to 5000 pps. CONNECTORS: (a) Main pulse, Type N. (b) Sync in, sync out, Type BNC. POWER SUPPLY: 1151230 volts flO70, 50fb0 cps, 380 watts maximum. DIMENSIONS: Cabinet Mount: 20-314 wide, 12-314 high, 14-31 16 deep. Rack Mount: 19 wide, 10-11

7、2 high, 14-314 deep. WEIGHT: Cabinet Mount: 58 lbs. , shipping weight approximately 76 lbs. Rack Mount; 50 lbs, , shipping weight approximately 73 lba. ACCESSORIES AVAILABLE: I AC-16F Cable Assembly, qype N Male to Type N Male Fittings. AC-E6K Cable xsaembly, BNC to BNC. #17 End Frames, with handles

8、 for bench use, (for 21ZAR Rack Mount). I I TABLE OF CONTENTS Page No. Section I GENERAL DESCRIPTION . 1-1 General 1-1 1-2 Accessory Cablem . 1-1 Section LI OPERATING INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . Inspection 2-1 Controls and Terminals . . . . . . . . . . . . . .

9、. . . . . . 2-1 Automatic Overload Relay Protection . 2-2 Operation . 2-2 Waveahape of Output Pulse . 2-3 Poitive and Negative Pulsa Output Levels . . . . . . . . . . . . 2-4 Operation of Pulse Length and Pulse Rate Controla . . . . . . . . 2-4 Operation of Pulae Position Control . 2-5 Section 1l1 C

10、IRCUIT DESCRIPTION General . . Rep.RateMV Delay MV and Blocking Oscillator . . . . Purse Poeitlon M V and Blocking Oacillatos . . . . . . Pulae Forming Thyratron V b Pulse Length MV and Blocking Ocillator . Pulse Terminating Thyrntron Vl6 . . . . Clipper Circuits . . . . . . . . . . . . Output Ampli

11、fier . . . . a . r n . . . . . . . . . . . . . . . . . . Powersupply Section IV MAINTENANCE 4-1 OutputPulseAnalyels . . . . . . . . . . . . . . . . . . . . . . 4-1 . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 Adjuetmenta 4-3 4-3 Servicing Negative High Voltage Supply (V4. V1Z. V14. etc .

12、) . . . . 2-5 . . . . . . . . . . . . . . . . . . . . . 4-4 Thyratron Replacement 4-5 4-5 Replacement of Load Remistor R7.1 and R22 . . . 4 4-6 4-6 TroubleShaotingChart . 4-7 SectionV TABLEOFREPLACEABLEPARTS . 5-1 SECTION I G E N E M L DESCRIPTION 1-1 GENERAL The Model 2 12A Pulse Generator is a fun

13、damental measuring instru- ment for determining the action of circuits under conditions of rapid change. The pulse produced by this instrument has a short time of rise -and decay with a flat top and minimum of overshoot. Either positive or negative pulses are available and the pulse shape is indepen

14、dent of the repetition rate, connected load, sync condition, supply voltages, and output attenuator setting. The pulse length is continuously vari - able from . 07 to 10 microseconds. This instrument is applicable to the testing of radar systems, nuclear counting circuits, television systems, respon

15、se of video amplifiers, filters and band pass circuits and pulse modulation of UHF signal generators, ACCESSORY CABLES AC-16K: RG-58 /U 50 ohm coaxial cable terminated each end with UG - 88/U Type BNC male connector. Overall length 4Bt1. AC-16B: RG-58 /U 50 ohm coaxial cable terminated on one end wi

16、th UG-88/U Type BNC male connector and dual banana plug ( 3 /4 center) on the other end. Overall length 45. AC- 16D: RG-58/U coaxial cable terminated one end only with WG-881 U Type BNG male connector. Overall length 4411. AC-16C: RG-9A/U 50 ohm coaxial cable terminated one end with UG- 2 1B /U Type

17、 N male connector and UG -23B /U Type N female connec - tor at other end. Overall length 72. AC- E6F: RG-9A/U 50 ohm coaxial cable terminated on each end with UG-21B/U Type N male connectors. Overall length 72. S EC TION 11 OPERATING INSTRUCTIONS Refer to the Warranty sheet in this manual, 2-2 CONTR

18、OLS AND TERMINALS PULSE OUT This terminal is a Type N jack located at the lower right corner of the front panel. It is the output connection for the main pulse. SYNC OUT This terminal is a BNG terminal on the lower right side of the panel. This terminal provides a voltage to synchronize an osciLlosc

19、ope or ather device for use with the Pulse Generator. +r - This toggle switch, on the panel above the SYNC OUT terminal, con- trols the polarity of the synchronizing voltage fed to the SYNC OUT terminal. SYNC IN The SYNC IN terminal is4a BNC connector on the lower left side of the panel. A voltage c

20、an be fed into this terminal to trigger the pulse generating circuit. SYNC SELECTOR The SYNC SELECTOR knob selects two ranges of internally generated pulse rates, and also selects necessary circuitry for external syn- chronization from either positive or negative externally generated sync pulses. PU

21、LSE POSITION The PULSE POSITION control adjusts the timing between the MAIN P U l S E OUTPUT and the SYNC OUTPUT pulse. Its main use is to poaition the main pulse on an oscilloscope screen when the oscil- loscope has been synchronized with the SYNC OUT pulse. PULSE RATE The PULSE RATE control, locat

22、ed on the upper left hand side of the panel, adjusts the repetition rates of the pulse from 50 to 5000 cycles per second in conjunction with the X1 and X10 position of the SYNC SELECTOR switch. PULSE WIDTH The PULSE WIDTH control is the large dial at the center of the panel and controls the width of

23、 the MAIN OUTPUT pulse. AMPLITUDE The AMPLITUDE control gives a continuous variation af the MAIN OUT- PUT pulse. ATTENUATION The ATTENUATION control, located an the right hand side of the panel, provides attenuation of the Main pulse in 10 db steps so that low levels of pulse output can be obtained.

24、 POLARITY The POLARITYcontrol at the lower right hand side of the panel switches the polarity of the MAIN OUTPUT pulse from positive to negative. FUSE The fuseholder, on the panel next to the POWER ON switch, contains a 4 ampere cartridge fuse. A 2 ampere fuse should be used when the power transform

25、er is connected for 230V operation. The fuse may be replaced by unscrewing the fuseholder cap and inserting a new fuse. 2-3 AUTOMATIC OVERLOAD RELAY PROTECTION An overload relay is incorporated in the instrument to protect the 45 thyratron if, for any reason, continuous plate current conduction occu

26、rs. Operation of the relay is indicated by a buzzing sound, If this occurs when the instrument is first turned on, it may indicate that there is in- sufficient warm-up and turning the SYNC SELECTOR to the + or - po- sition without any external triggering for two or three minutes should then place th

27、e instrument in normal operating condition. The Model 21ZA Pulse Generator is operated as follows: 1. Plug the power cable into a nominal 115V, 50 to 60 cycles power line and turn on the toggle switch. (The pilot lamp should light when the swftch is on. ) 2. Allow several minutes for the instrument

28、to warm up with the SYNC SELECTOR in the t or - position and with no sync in, Although the unit can be used after 2 or 3 minutes of warm up, it is desirable to allow about ten minutes warm up time if possible. 3. Connect the equipment to be driven to the PULSE OUT terminal. This connection should be

29、 made, if possible, through a nominal 50 ohm cable. The output circuit of the Model 212A is terminated with ap- proximately 50 ohms se termination of the output cable with 50 ohms is not absolutely necessary fox many measurements. If the overall system is sensitive to frequencies on the order of 20

30、to 30 megacycles, the output cable should be termin- ated in a non-inductive 50 ohm load to prevent reflections from the load which may cause ringing. This is especially true when the ATTENUATION and OUTPUT controls are set for full output. Under these conditions the Model Z12A OUTPUT source impeden

31、ce is less than 50 ohms thus result- ing in an imperfect output cable termination at the source end, The SYNC OUT terminal may be connected to the synchronizing ter - minals on an oscilloscope and the polarity of the S Y NC OUT signal may be switched to select the best performance. The SYNC SELECTOR

32、 should be set to either the XI or the X10 position, and the PULSE RATE dial set to the desired repetition rate, The PULSE WIDTH dial may then be set to select the pulse width desired and the P U L S E POSITION control is then adjusted until the pulse appears at the desired position on the oscillosc

33、ope screen. The amplitude of the pulse can be adjusted by means of the AMPLITUDE CONTROL arrd the OUTPUT ATTENUATOR to give the desired output level. CAUTION I Do not set the PULSE POSITION delay to greater than 50 micreseconds when a repetition rate of 5000 cps is used. Maximum delay of 1015 micro-

34、 seconds may be used for repetition rates up to 2500 cps, Above 2500 cps the maximum delay must be decreased as the repetition rate is in- creased so as not to overload the tubes in the pulse position circuit. 2-5 WAVESHAPE OF OUTPUT PULSE The output pulse from the Model 2 1 ZA has extremely good wa

35、ve shape and, in general, the waveshape is quite independent of the load and the operating conditions of the Pulse Generator. However, when the gen- erator is operated a t zero attenuation, with a length of cable between the generator and an unterminated load, reflections may occur due to the intern

36、al impedance of the generator being less than 50 ohms. This condition may be corrected by properly terminating the cable, As the attenuation is increased, the internal impedance approaches 50 ohms, The waveshape is best with the AMPLITUDE control set to provide a- bout 50 volts of output. As the amp

37、litude is reduced with the AMPLITUDE control, the waveshape deteriorates slightly and, if the best waveshape is desired, it is preferable to reduce the output level with the attenuator and operate the AMPLITUDE control as close to the 50 volts position as possible. The AMPLITUDE control is not calib

38、rated, but, with no attenuation in the circuit, there will be at least 50 volts peak available from the out- put terminals into a 50 ohm load. On most units, the maximum position of the AMPLITUDE control will give appreciably more than SO volts out- put. Unless this additional output is absolutely n

39、ecessary, it is desirable to operate the unit with the AMPLITUDE control slightly below the max- imum position. In some cases the pulse output waveshape will show a little deterioration with the AMPLITUDE control at full maximum. 2-6 POSITIVE AND NEGATIVE P U U E OUTPUT LEVELS The positive and negat

40、ive pulse outputs are adjusted to be approximately equal and either can be selected by means of the switch on the front panel. These outputs, however, cannot be expected to have exactly the same value and it is normal that there will be a little difference in am- plitude between the positive and neg

41、ative output position. 2-7 OPERATION OF PULSE LENGTH AND PULSE RATE CONTROLS The pulse length is adjustable from less than . 07 of a microsecond to 10 microseconds. This continuously adjustable feature in the Model 2 1 ZA is convenient for a great many applications and is one of the useful fea- ture

42、s of this instrument. The generation of these very short, continuously adjustable pulses involves a differential operation whereby the diff esence between two larger time periods is used to control the actual time of the output pulse duration, With this excellent flexibility in the control of the pu

43、lse output, there is a little sacrifice in absolute accuracy. In general the pulse length control can be expected to be correct within f 10 percent except for very short pulse lengths where considerably more variation in the length may be ob- tained from time to time. Where accurate pulse lengths ar

44、e necessary, it is desirable to use some sort of an auxiliary calibrating means to set the pulse length to the correct value. One of the main causes of varia- tion i n the pulse length is the variation in the characteristics of the hy; drogen thyratron tubes used in the equipment, As tubes are chang

45、ed i n the equipment, some change in pulse length will be obtained, and also there m a y be some change in the pulse length calibration as the tubes age over a period of time. Controls are provided on the chassis just behind the main pulse dial so that the pulse length calibration can be reset from

46、time to time if necessary. See Section IV, Maintenance, regarding the adjustment of these controls. The length of the main pulse is essentially independent of the other controls except that the pulse length will tend to change slightly as the repetition sate i s changed especially above repetition r

47、ates o f 1 kc. The internal repetition rate generator is a rnultivibrator adjustable over the range from 50 to 5000 cycles /set. Calibration of this cohtrol should, in general, hold within f 2 570, but when accurate repetition rates are desired, it is preferable to use an external oscillator to driv

48、e the pulse generator. The Model 2L2A can be synchronized from external pulses having a t least a 5 volt amplitude and a rise time in the order of a microsecond or two. If it is desired to synchronize from a sine wave source, it is necessary to u s e a wave shaper of some sort to increase the rise time of the synchroniz- ing voltage. The unit synchronizes very well from an Model 21 1A Square Wave Generator. Another typical waveshaper which may be used for a sine wave input is s h o w in Figure 2-1. It is important that the Model 212A not be driven at a pulse rate in excess of 5000