HP-1728A-Manual-Display-Scanner 电路图.pdf

1-F.WLE:T -PACKARD COMPANf 1782A DISPLAY SCANNER RadioFans.CN 收音机爱 好者资料库 01550 1 OPERATING AND SERVICE MANUAL MODEL1782A SERIALS PREFIXED: 305- DISPLAY SCANNER Copyright HlWllTT-PACKAIO COMPANY 1963 1$01 PAOl Mill IOAO, PALO ALTO, CAllfOINIA, U.S.A. Printed: FEB 1963 RadioFans.CN 收音机爱 好者资料库 it Some Model 175A Oscilloscopes with serial prefixes below 305-require modification in order to operate the Model 1782A Display Scanner. Please contact your nearest Hewlett-Packard representative for information regarding the changes. Model 1782A 01550-1 ; ; RadioFans.CN 收音机爱 好者资料库 . Model 1782A Table of Contents List of Illustrations and Tables TABLE OF CONTENTS Section Title Page I GENERAL INFORMATION . 1-1 1-1. Description . . . . . 1-1 1-3. Pen Stabilizer . 1-1 1-5. Marker . 1-1 1-7. Digital Recording . . . . . . . . . 1-1 1-9. Serial-Number System . . 1-1 Il PREPARATION FOR USE . 2-1 2-1. Incoming Inspection . 2-1 2-2. Mechanical Inspection . 2-1 2-4. Performance Check 2-1 2-6. Power Requirement . 2-1 2-8. Repackaging for Shipment 2-1 Ill OPERATION . 3-1 3-1. Controls and Terminals . 3-1 3-3. Function SWitch . 3-1 3-8. Scanning SWitch . 3-1 3-10. Recorder Characteristics . 3-2 3-11. X-Y Recorders . 3-2 3-13. Strip-Chart Recorders . 3-2 3-15. Operating Instructions . 3-2 3-19. Preliminary Adjustments 3-2 3-21. Step-By-Step Procedures 3-2 IV PRINCIPLES OF OPERATION . 4-1 4-1. Over-All Functional Description . 4-1 4-6. Circuit Description . . . . . . . 4-1 4-7. Integrator . . . . . . . . . . . . . 4-1 4-12. Comparator . 4-2 4-14. Marker Output Circuit . . . . . . 4-2 Section Title Page IV PRINCIPLES OF OPERATION (Contd) 4-16. Sampler Circuit 4-2 4-18. Stretcher Circuit 4-3 4-21. Stabilizer Circuit 4-3 V MAINTENANCE 5-1 5-1. Performance Check 5-1 5-3. Test Equipment . 5-1 5-5. Preliminary Settings 5-2 5-7. Horizontal Output 5 -2 5-11. Vertical Output . . . . . . 5-2 5-14. Adjustments 5-3 5-16. Test Equipment 5-3 5-18. Preliminary Settings . . 5-3 5-19. Stretcher Gate Width 5-3 5-20. Comparator Compensation 5-3 5-21. Scan Start and Termination 5-4 5-22. Horizontal DC Level . . . . . 5-4 5-23. Input Attenuator Compensation . 5-4 5-24. Sampling Efficiency and Vertical Feedback . . . . 5-4 5-25. Sampling Gate Neutralization 5-5 5-26. Stabilizer DC Balance 5-5 5-27. Repairs . 5-5 5-29. Equipment Required 5-5 5-32. Procedure . . 5-5 5-34. Troubleshooting . . . . . . 5-6 5-35. Isolating Troubles to a Major Section 5-6 5-3 7. Circuit Troubleshooting 5-6 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 1782A Display Scanner . 1-0 3-1. Model 1782A Controls and Terminals . 3-3 3-2. Recorder Calibration . . . . . . . 3-4 3-3. Automatic Scanning . . . . . . . . . . 3-5 3-4. Manual Scanning . 3-6 3-5. External Scanning . 3-7 4-1. Model 1782A Overall Block Diagram . 4-0 4-2. Model 1782A Simplified Block Diagram 4-1 4-3. Miller Integrator Simplified Circuit 4-2 5-1. Special Attenuator . 5-1 5-2. Al Sampler Assembly, Location of Adjustments and Test Points . 5-3 Number Title 5-3. A2 Scan Generator Assembly, Location 5-4. 5-5. 5-6. 5-7. 5-8. 5-9. of Adjustments and Test Points . Vertical Feedback Adjustment . Sampler Storage Capacitor Adjustment Component Locations, Al Sampler Assembly . Sampler Waveforms . Sampler Schematic . Component Locations, A2 Scan Generator Assembly . 5-10. Component Locations, Bottom View 5-11. Scan Generator Waveforms . 5-12: Scan Generator . . LI ST OF TA B L E S Number Title Page 1-1. Specifications . 1-1 5-1. Test Equipment for Check and Adjustment . . . . . . . 5-0 5-2. Circuit Troubleshooting 5-6 6-1. Reference Designation Index 6-2 6-2. Replaceable Parts 6-7 Page 5-4 5-4 5-5 5-8 5-8 5-9 5-10 5-10 5-10 5-11 01550-1 iii Section I Figure 1-1 1-0 UNCT ON ARM RECORDE!lRECORD OFF SCAN START LOCK .a ,_ . MANUAL SCAN :-i . - DISPLAY liai SCANNER MODEL </!f) 178ZA VERT tiORIZ. AMPLITUDE l I .; . I OUTPUT l 0 SCANNING STAB LIZED LINEAR MANUAL. EXTERNAL : Figure 1-1. Model 1782A Display Scanner Model 1782A 01550-1 Model 1782A Section I Paragraphs 1-1to1-10 SECTION I GENERAL INFORMATION 1-1. DESCRIPTION. 1-2. The Model 1782A Display Scanner provides outputs necessary to drive X-Y recorders so that the waveform displayed on the screen of Model 175A Oscil- loscope may be reproduced. Automatic scan and pen control are provided, with manual reset. Horizontal and vertical amplitude may be adjusted independently of zero. The effective bandwidth of the scanner is 30 me. Through the use of sampling techniques, the Model 1782A transforms high-speed phenomena to the bandwidth of conventional X-Y recorders such as the F. L. Moseley 3S or 2D. Sampling density is high enough to give a continuous presentation on the X-Y recorder. 1-3. PEN STABILIZER. 1-4. An electronic pen stabilizer circuit provides a nearly constant writing rate to the recorder so that fast pulses may be recorded faithfully in a minimum of time. The pen stabilizer slows the horizontal pen speed during vertical deflection so that fast rise and fall time may be recorded in detail. When there is no vertical deflection, the stabilizer increases horizontal pen speed to reduce scanning time. 1- 5 . MARKER. 1-6. With each sweep of the trace on the screen of the oscilloscope, the Model 1782A samples the am- plitude of the waveform at a single point and intensifies the trace beyond that point. Therefore the start of the intensified trace forms a marker which indicates the point being sampled at any particular instant. 1-7. DIGITAL RECORDING. 1-8. The Model 1782A may be used with auxiliary equipment to digitize the CRT display. By applying the appropriate external scanning signal, the desired portion of the trace can be scanned either once or repeatedly, and the output reduced to digital form for recording or analysis. For example, an entire pulse train or a single pulse can be continuously monitored and the results permanently recorded in digital form. 1-9 . SERIAL-NUMBER SYSTEM. 1-10. Hewlett-Packard instruments carry a two- section eight-digit serial number (000-00000). The first three digits are the serial prefix. If the serial prefix on your instrument does not agree with that shown on the title page of this manual, change sheets included with this manual will describe the difference between the manual and your instrument. If the serial prefix on your instrument is not mentioned in the change sheets, obtain correct information through your Hewlett-Packard representative. Table 1-1. Specifications VERTICAL OUTPUT: HORIZONTAL OUTPUT: 01550-1 BANDWIDTH: SCANNING: SCANNING TIME: OSCILLOSCOPE SWEEP SPEED: REMOTE PEN LIFT: POWER: WEIGHT: 200 mv/ cm. Amplitude and de level are independently adjustable. Level: Adjustable to 0 v Amplitude: Adjustable from 0 to +15 v Greater than 30 me when installed in the Model 175A Oscilloscope with a 40-mc vertical plug-in. Manual, internal (with pen speed either stabilized or linear), or external (scan voltage approximately 0 to +15 volts). Internal, linear: approximately 1-1/2 minutes. Internal, with pen speed stabilized: approximately 20 seconds when displaying time base only. Maximum external scan rate, 1 kc. From fastest sweep time down to 5 msec/ cm at signal repetition rates of 20 cps or greater. Contact opening provided to lift X- Y recorder pen from paper when switching from RECORD to ARM RECORDER. SUpplied by the Model 175A Oscilloscope. Net 5 lb 1-1/1- 2 Model 1782A Sections II and ill Paragraphs 2-1 to 2-9 and 3-1 to 3-9 SECTION II PREPARATION FOR USE 2-1. INCOMING INSPECTION. 2-2. MECHANICAL INSPECTION. 2-3. Upon receipt of your Model 1782A, inspect the instrument for any obvious damage received in transit. If damage is evident, file claim with the carrier (see the Warranty Sheet at the rear of this manual). 2-4. PERFORMANCE CHECK. 2-5. Refer to section V of this manual for a series of checks which may be made to assure that the instru- ment is operating within specifications. 2-6. POW ER REQUIREMENT. 2-7. All power for the Model 1782A is supplied auto- matically when the instrument is plugged into its com- partment in the Model 175A Oscilloscope. Tighten the lock screw to assure firm electrical contact. 2-8. REPACKAGING FOR SHIPMENT. 2-9. To repack the Model 1782A for shipment, always use the best packing methods available. If the original container with its packing pads and fillers is not on hand, these materials may be obtained from the factory through your nearest Hewlett-Packard representative. The following steps are a general guide for proper packing: a. Wrap the instrument in heavy paper or plastic. b. Protect the panel with cardboard strips. c. Use a strong cardboard or wooden box. d. Use ample packing material around all sides, top and bottom of the instrument. e. Seal with heavy tape or metal bands. f. Mark packing box with FRAGILE - DELICATE INSTRUMENT. SECTION Ill OPERATION 3-1. CONTROLS AND TERMINALS. 3-2. The Model l 782A Display Scanner fits into the horizontal plug-in compartment of the Model l 75A Oscilloscope. The Display Scanner uses sampling techniques to scan the display on the CRT of the oscil- loscope, and produce a low-frequency replica of the waveform suitable for driving a recorder. The hor- izontal output of the Scanner is proportional to the position of the sampled point on the waveform, and the vertical output is proportional to the amplitude at the sampled point. A marker (start of intensified trace) indicates the point being sampled at any instant. Figure 3-1 shows the controls of the Model l 782A. Operation of the Model l 75A Oscilloscope and its ver- tical plug-in units is described in the manuals for those instruments. 3-3. FUNCTION SWITCH. 3-4. FUNCTION controls the output of the Model 1782A. It may be set to OFF, ARM RECORDER, or RECORD. 3-5. In the OFF position, internal circuits are dis- abled and no output is delivered to the VERT and HORIZ OUTPUT terminals. 01550-1 3-6. The ARM RECORDER position returns the marker to the start of the trace (when scanning is in LINEAR or STABILIZED) and arms the internal ramp generator, preparing it to scan the CRT display. 3-7. The RECORD position lowers the pen on the X-Y chart and starts the linear or stabilized scan. 3-8. SCANNING SWITCH. 3-9. SCANNING selects the mode of operation of the Display Scanner. There are four positions: MANUAL, LINEAR, STABILIZED, and EXTERNAL. SCANNING and MANUAL SCAN are concentric controls, the inner knob being MANUAL SCAN. a. In MANUAL the scan generator of the Model l 782A is disconnected and the sampling point may be selected by means of the MANUAL SCAN control. b. In LINEAR the sampled point moves across the CRT at a constant horizontal rate, and horizontal output varies from 0 to approximately +15 volts at a constant rate. Although about 90 seconds is allowed for full scan in LINEAR the speed may be too fast to allow a recorder to follow sharp vertical deflections in the trace. 2-1 3-1 Section III Paragraphs 3-10 to 3-22 c. In STABILIZED, horizontal movement of the sampled point is decreased in proportion to the slope of the trace. Scan time for a straight-line trace is about 20 seconds. STABILIZED improves the fidelity of reproduction on an X-Y recorder by holding the pen speed almost constant. d. EXTERNAL allows the use of an external scan voltage, connected to the EXTERNAL INPUT terminal. 3-10. RECORDER CHARACTERISTICS. 3- 11. X-Y RECORDERS. 3-12. Almost any X-Y recorder will function with the Model 1782A Display Scanner. Maximum vertical output is at least 200 mv per centimeter of deflec- tion on the CRT. Maximum horizontal output is from 0 to approximately + 15 volts at full horizontal deflec- tion on the CRT. Both are adjustable. 3-13. STRIP-CHART RECORDERS. 3- 14. The Model 1782A may be used with strip-chart recorders. However, there are some limitations. a. Only LINEAR, MANUAL, or EXTERNAL scan can be used. The recorder is motor-driven, therefore a linear scan is required. b. Unless the recorder has a speed which will spread the display over a satisfactory length in 90 seconds, external scan should be used, obtaining the scan voltage from a sawtooth generator or from the recorder. c. Horizontal calibration is not as convenient with the strip-chart recorder as with the X-Y recorder. Either the motor speed must be variable, or a variable external scan voltage must be used. 3-2 Model 1782A 3-15. OPERATING INSTRUCTIONS. 3-16. As explained in paragraph 1-5, the Model 1782A Display Scanner samples the waveform on the screen of the CRT at one point on each sweep, then intensifies the remainder of that sweep. The start of the inten- sified portion is the marker that indicates the sam- pled point at any moment. Set oscilloscope INTENSITY for best contrast between the blanked part and the intensified part of the sweep. 3-17. With FUNCTION in LINEAR or STABILIZED, the sampled point advances along the display automat- ically, and the sampled voltage is retained by the Display Scanner until the next sample is taken. How- ever, there is a practical limit to the length of time the sampled voltage can be retained. As the oscillo- scope is switched to slower sweep speeds the time between samples increases. The slowest speed at which a smooth recording can be made is 5 msec/ cm. The signal repetition rate (synchronizing the oscillo- scope) must be at least 20 cps. 3-18. EXTERNAL SCAN. Scan times much faster than 90 seconds may be used, so long as the recording device is capable of following the vertical output volt- age. The maximum external scan rate is 1 kc. The ratio of scan time to oscilloscope sweep time must be kept high enough to produce a smooth output. 3-19. PRELIMINARY ADJUSTMENTS. 3-20. There are five screwdriver adjustments on the front panel of the Model 1782A. These are VERT DC LEVEL, HORIZ DC LEVEL, VERT AMPLITUDE, HORIZ AMPLITUDE, and SCAN START. The pro- cedure for setting these controls is given in figure 3-2. 3-21. STEP-BY-STEP PROCEDURES. 3-22. Figures 3-2 through 3-5 give step-by-step instructions for operating the Model 1782A Display Scanner. The circled numbers refer to the text below each diagram. 01550-1 Model 1782A PEN LIFT DISPLAY fb. SCANNER MODEL q!/ 782A SCAN 2 r-r-LQi:i(-ST.:ART LOCK - INPUT 13 MANUAL SCAN =l SCANNING STABILIZED LINEA