HP-1750A-Manual-Dual-Trace-Vert-Amp 电路图.pdf

HEWLETT-PACKARD COPANY 1750A DUAL TRACE VERTICAL AMPLIFIER (;1 0 ) RadioFans.CN 收音机爱 好者资料库 CERTIFICATION THE HEWLETT-PACKARD COMPANY CERTIFIES THAT THIS INSTRUMENT WAS THOROUGHLY TESTED AND INSPECTED AND FOUND TO MEET ITS PUBLISHED SPECIFICATIONS WHEN . IT WAS SHIPPED FROM THE FACTORY. FURTHER CERTIFIES THAT ITS CALIBRATION MEASUREMENTS. ARE TRACEABLE TO THE NATIONAL BUREAU OF STANDARDS TO THE EXTENT ALLOWED BY THE BUREAUS CALI- BRATION FACILITY. RadioFans.CN 收音机爱 好者资料库 01539-2 OPERATING AND SERVICE MANUAL MODEL1750A SERIALS PREFIXED: 321- DUAL TRACE VERTICAL AMPLIFIER H EWLETT-PACKAao COMPANY Printed: APR 1963 RadioFans.CN 收音机爱 好者资料库 Model 1750A Table of Contents List of Illustrations and Tables TABLE OF CONTENTS Section Page I GENERAL INFORMATION . 1-1 1-1. Description and Purpose . . . . . . 1-1 1-3. Instrument Identification . 1-1 II INSTALLATION . 2-1 2-1. Incoming Quality Control Inspection . 2-1 2-4. Storage and Reshipment . 2-1 2-6. Installation . 2-1 ID OPERATING INSTRUCTIONS . 3-1 3-1. Introduction . 3-1 3-3. Controls . 3-1 3-12. Single Trace Operation . . 3-3 3-14. Dual Trace Operation . 3-3 3-18. Differential Operation . 3-3 3-20. Input Considerations . . 3-3 IV PRINCIPLES OF OPERATION . . . 4-1 4-1. Introduction . . . . . . . . . . . . . . . 4-1 4-3. Circuit Details . . . . . . . . . . 4-1 4-13. Electronic Switch . 4-2 Section Page V MAINTENANCE 5-1 5-1. Introduction 5-1 5-3. Performance Check 5-1 5-6. Preliminary Procedure 5-1 5-7. Single Channel Operation 5-2 5-8. Alternate Operation 5-2 5-9. Chopped Operation 5-2 5-10. Sensitivity Calibration 5-2 5-11. Vertical Position Range 5-2 5-12. Dynamic Range 5-2 5-13. Common Mode Rejection 5-2 5-14. Rise Time 5-3 5-15. Bandwidth 5-3 5-16. Troubleshooting 5-3 5-22. Repair 5-4 5-26. Adjustments 5-4 5-30. Preliminary Settings 5-6 5-32. Vertical Position 5-6 5-33. Channel Balance 5-6 5-34. Gain 5-7 5-35. Amplifier Input Capacitance 5-7 5-36. Attenuator Compensation 5-8 5-37. Attenuator Input Capacitance 5-8 5-38. Pulse Response 5-9 VI REPLACEABLE PARTS 6-1 6-1. Introduction 6-1 6-4. Ordering Information 6-1 LIST OF ILLUSTRATIONS Number Title Page 1-1. Model 1750A Dual Trace Vertical 3-1. 3-2. 3-3. 3-4. 3-5. 4-1. 4-2. 4-3. 4-4. 4-5. Amplifier . Control Location . BAL. and SENS. CAL Adjustment . Single Trace Operation . . . . . . . Dual Trace Operation . . . . . . . . . . . A-B Operation . Dual Trace Amplifier Block Diagram . Attenuator Simplified Schematic . Amplifier Simplified Schematic . Constant Current Generator . . . . . . . Electronic Switch . 1-1 3-2 3-4 3-5 3-6 3-7 4-0 4-0 4-1 4-2 4-3 Number Title Page 5-1. Parts Location, Channel A Attenuator . 5-4 5-2. Parts Location, Channel B Attenuator 5-5 5-3. Parts Location, Top 5-6 5-4. Parts Location, Right Side . 5-7 5-5. Amplifier Input Capacitance Adjustment Location . 5-8 5-6. Attenuator Compensation Adjustment Location 5-8 5-7. Attenuator Input Capacitance Adjustment Location 5-9 5-8. Pulse Response Adjustment Location 5-9 5-9. Attenuator Schematic. . . 5-11 5-10. Amplifier Schematic 5-12 LIST OF TABLES Number Title Page 1-1. Specifications . . . . . . . . . 1-0 3-1. Pulse Width vs Sag . 3-1 5-1. Recommended Test Equipment . 5-1 5-2. Sensitivity Calibration . 5-2 5-3. Trouble Localization . 5-3 5-4. Unbalance . 5-3 01539-1 Number Title Page 5-5. Recommended Adjustments Following Tube or Diode Replacement . . 5-5 5-6. Attenuator Compensation . . 5-8 5-7. Attenuator Input Capacitance . . 5-9 6-1. Reference Designation Index . 6-2 6-2. Replaceable Parts . . . 6-9 iii Section I Table 1-1 MODE OF OPERATION EACH CHANNEL Sensitivity Range: Attenuator Accuracy: Pass Band; Rise Time: Dynamic Range: Vertical Position Control Range: Input Impedance: Input capacitor rating: Polarity of presentation: DIFFERENTIAL INPUT Amplifier: Common Mode Rejection: GENERAL Weight: Power: Accessories Available; Model l 750A Table 1-1. Specifications 1. Channel A alone 2. Channel B alone 3. Channels A and B displayed on alternate sweeps 4. Channels A and B displayed by switching at 200 kc rate, with blanking during switching 5. Channel A minus Channel B (differential input) 0.05 v/cm to 20 v/cm. Nine calibrated ranges in l, 2, 5, 10 sequence. Vernier extends minimum sensitivity to at least 50 v I cm, and provides continuous control between ranges. A sensitivity calibration adjustment for each channel is provided on the instrument front panel. 3% DC-coupled, de to 40 me; AC-coupled 2 cps to 40 me Less than 9 ns Input amplifiers can be overloaded by 18 cm signal without causing noticeable signal distortion. 9 cm 1 megohm shunted by approximately 28 pf 600 vdc (ac-coupled input) +up or -up, selectable for each channel Both inputs, with their associated attenuators, may be switched to one channel to give differential input. The input attenuators may be set separately to allow mixing signals of different levels. Channel A; amplifier input: A minus B At least 40 db at maximum sensitivity or 30 db when using attenuators at frequencies to 1 me Net 5 lb Supplied by Model l 75A Oscilloscope 10002A (AC-21C) Probe, 50:1 Divider, 30 me frequency response 10003A (AC-21M) Probe (two supplied with Model l 75A Oscilloscope) 10110A (AC-76A) Adapter, terminal post to male BNC 1-0 01539-1 HP Archive This vintage Hewlett Packard document was preserved and distributed by Please visit us on the web ! Prepared by on-line curator: Tony Gerbic For FREE Distribution Only * Model l 750A Section I Paragraphs 1-1to1-4 SECTION I GENERAL INFORMATION 1-1. DESCRIPTION AND PURPOSE. 1-2. The Hewlett-Packard Model 1750A Dual Trace Vertical Amplifier is a wide-band vertical amplifier designed to be used with the l$jJ Model 175A Oscil- loscope. It provides calibrated sensitivity with 40 megacycle bandwidth and provides the capability of viewing two traces simultaneously. The two channels may also be combined in differential operation, with the difference signal displayed. 1-3. INSTRUMENT IDENTIFICATION. 1-4. Hewlett-Packard instruments use an eight- digit, two-section serial number. The first three digits form the serial prefix, which remains the same until a change is made in the instrument. If the serial prefix on your instrument does not agree with that shown on the title page of this manual, change sheets will describe differences between your instrument and this manual. Figure 1-1. Model 1750A Dual Trace Vertical Amplifier 01539-1 1-1/1-2 Model 1750A Section II and III Paragraphs 2-1 to 3-6 SECTION II INSTALLATION 2-1. INCOMING QUALITY CONTROL INSPECTION. 2-2. MECHANICAL INSPECTION. Upon receipt of your rFf; Model 1750A, unpack it, check the contents against the packing slip and inspect the instrument for mechanical damage. If the instrument is damaged in any way, notify the carrier immediately (refer to the warranty on the inside back cover ofthis manual). Your local Hewlett-Packard Engineering represent- ative is prepared to give you assistance with any problem involving this instrument and its application. 2-3. PERFORMANCE CHECK. Make the perform- ance check as outlined in paragraph 5-3 of this manual. 2-4. STORAGE AND RESHIPMENT. 2-5. Following is a general guide for repackaging an instrument for storage or reshipment. If there are any questions involving the. packaging materials to be used, contact an authorized Hewlett-Packard Engi- neering representative. a. Wrap the instrument in heavy paper or plastic before placing it in the shipping container. b. Use plenty of packing material around all sides of the instrument and protect panel faces with card- board strips. c. Use a heavy cardboard carton or wooden box to house the instrument and use heavy tape or metal straps to seal the container. d. Mark the packing box, FRAGILE-DELICATE INSTRUMENT. 2-6. INSTALLATION. 2-7. The Model 1750A is designed to be plugged into the vertical amplifier compartment of the Model 175A Oscilloscope. To install the Model 1750A, slide it into the vertical amplifier compartment and lock it into place with the LOCK knob on the front panel. All necessary connections between the Model 1750A and the Model 175A are automatically completed. SECTION Ill OPERATING INSTRUCTIONS 3-1. INTRODUCTION. 3-2. The Model 1750A may be used in five modes, selectable by a front panel control. The five modes, are: Channel A only, Channel B only, Channels A and B on alternate sweeps, Channels A and B chopped on the same sweep, and Channel A minus Channel B (differential mode). Each channel has a polarity switch, position control, and attenuator with continu- ous vernier. 3-3. CONTROLS. 3-4. The froO. ! . rtNOER 1. Connect one signal to channel A INPUT, and set channel A controls as desired (procedure shown in figure 3-4). 2. Connect the second signal to channel B INPUT, and set channel B controls as desired. 3. Select CHOPPED for display of both signals during the same sweep, or ALTERNATE for -: tlL TR: CE 0 ,.kv :T f8t HOfUZOtHAL. DISPLAY ,-C oc LD-S-679 Model 1750A display of signals on alternate sweeps. (CHOP- PED is suitable for slower sweep rates, ALTERNATE for fast sweep rates.) Note For accurate time or phase difference measurements use external triggering. Figure 3-4. Dual Trace Operation 3-6 01539-1 Model 1750A 1. Select A-B. AUl:Jl. . ltth.IJt-lf .,ttl-# 2. Set channel A POLARITY to +UP for A-B or -UP for B-A presentation. 3. Connect one signal to channel A INPUT. 4. Connect second signal to channel B INPUT. tolf .t.ONf,T HOfUO.TAL POSITION SWE(P MOOE Tlt1GGEJt SOOAC / TRIG. lfr(PUT - . ,_ l T .IK ilAHft (ll(lllf.W,yJtlj!fl H()RtlOHTAL OISPL.AY LO-S-680 Section ill Figure 3-5 5. Set SENSITIVITY as desired. For greatest rejection of common mode signals set both channels to the same sensitivity. 6. Adjust VERTICAL POSITION as desired. Note Channel B VERTICAL POSITION, PO- LARITY, and VERNIER are inoperative in A-B mode. Figure 3-5. A-B Operation 01539-1 3-7 Section IV Figures 4-1 and 4-2 ,DI AC-DC / / JQ I SENSITIVITY / / / / / _(Q I POLARITY! _(gj / / I SENS CAL I / / / / t61 I VERNIER I / / / . ., . / / /!VERTICAL POSITION I / / / / / / /,. / / / / / / / CHANNEL A t-DIFFERENTIALt-.-i !INPUT! -1ATTENUATOR ._ _ _.r-91.AMPLlFlER_J VERTICAL Q-_ PRESENTATION - ELECTRONIC SWITCH CONSTANT- CURRENT GENERATOR CHANNELS -ATTENUATOR l1NPUTI t- AMPLIFIER -.- . -.,. . , , , YoIPOLARITY , ,!VERTICAL POSITION! , :=:.:_-_-_-_ _, . I SENSITIVITY I Q I VERNIER I o 1 AC-DC , , 1 SENS CAL 1 IBALl Figure 4-1. Dual Trace Amplifier Block Diagram 0 SENSITIVITY 0 SIOI r-r- :6: POLARITY I , ( I I / / 5102 : 5103 l+uPl I CHANNEL A l1NPUTI I I CHANNEL A 2 1-uPI 100 4 Q CHOPPED ALTERNATE CHANNEL 8 Rl61 I ; S301A,8: IA-Bl Q I lg) I SENSITIVITY I l S201 : 0 r-,- : 6: POLARITY CJ / I . I . I / / S202: : 5203 l+uPl J201 I I CHANNEL B l l j 1NPUTI C208 10 2 1 -uPI 100 4 R261 ; Figure 4-2. Attenuator Simplified Schematic 4-0 Model 1750A VERTICAL OUTPUT TO CHANNEL A AMPLIFIER TO CHANNEL B AMPLIFIER 01539-1 Model 1750A Section IV Paragraphs 4-1 to 4-6 SECTION IV PRINCIPLES OF OPERATION 4-1. INTRODUCTION. 4-2. The Model 1750A is a wide-band, calibrated vertical amplifier consisting of two independent channels which may be selected for separate or com- bined viewing. As shown in figure 4-1 the Model l 750A basically consists of a frequency-compensated attenuator and a differential amplifier in each channel. The output of each channel is combined in the output to the main oscilloscope vertical amplifier. The channels are turned on or off by a switching multi- vibrator whose function is controlled by the Vertical Presentation switch. 4-3. CIR CUil DETAILS. 4-4. The two channels in the Model l 750A are identical in function, so only channel A will be dis- cussed in detail. 4-5. INPUT ATTENUATOR. The input attenuator consists of two cascaded voltage dividers which are compensated by shunt capacitors so that their division ratio is constant over the entire frequency range of the instrument. A simplified schematic of the atten- uator is shown in figure 4-2. The first section has +v + +v VIOIA -+ VERTICAL Rll3 INPUT Rll4 V102B RllO VIOIB t +v t +v division ratios of 1, 1/ 10, and 1/ 100, while the following section has division ratios of 1, 1/2, and 1/ 4. This combination of ratios divides the input signal to the most sensitive range ( 0. 0 5 v I cm). The output of the channel A attenuator is fed through channel A POLARITY switch Sl03 to input cathode follower VlOl. The output of the channel B attenuator is fed through Vertical Presentation switch S301 ahead of channel B POLARITY switch S203 to allow A-B presentation. 4-6. INPUT CATHODE FOLLOWER. As shown in figure 4-3, the output of the attenuator is fed to the cathode follower VlOl which serves as an impedance transformer and isolates the attenuator and input from the rest of the amplifier. In all modes of oper- ation except A-B, VlOlA carries the signal from the attenuator to the grid of differential amplifier Vl02A, while VlOlB sets the de bias for the grid of Vl02B. In A-B both VlOlA and VlOlB carry the signal to V102A/B. The BAL. control R104 adjusts the plate current distribution of VlOlA and VlOlB and also the de level of the grids of V102. Further discussion of the use of this control is found in paragraph 4-8. +V + Vl03A +v + Rl27 t I I -v I I VERTICAL VERTICAL -v POSITION OUTPUT I -v I + I I Rl28 t. +v t +V S O lllIOll Figure 4-3. Amplifier Simplified Schematic 01539-1 4-1 Section IV Paragraphs 4-7 to 4-14 4-7. DIFFERENTIAL AMPLIFIER. Differential amplifier Vl02A/ B amplifies the signal from cathode follower V 101A/ B and converts it from a single-ended signal to the balanced signal necessary for the main vertical amplifier. In any operating mode other than A-B, the grid of V102B is fixed at a de level set by cathode follower VlOlB. When a signal appears at the grid of Vl02A it is amplified and appears as a signal at the plate. At the same time a signal appears at th