HP-3048A_cal_03048_90015 电路图.pdf

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1、Errata Title been impaired, the instrument must be made. inoperative and be secured against any uhin-; tended operation. If this instrument is to be energized via an autotransformer (for voltage reduction) make sure the common terminal is connected to the earth terminal of the power source. Servicin

2、g instructions are for use by service trained personnel only. To avoid dangerous elec tric shock, do not perform any servicing unless qualified to do so. Adjustments described in the manual are per formed with power supplied to the instrument while protective covers are removed. Energy available at

3、may points may, if contacted, result in personal injury. Capacitors inside the instrument may still be charged even if the instrument has been discon nected from its source os supply. For continued protection against fire hazard, re place the line fuse(s) only with 250V fuse(s) of the same current r

4、ating and type (for exam ple, normal blow, time delay, etc.) Do not use repaired fuses or short circuited fuseholders. ATTENTION Static Sensitive Devices This instrument was constructed in an ESD (electro-static discharge) protected environment. This is because most of the semi-conductor devices use

5、d in this instrument are susceptible to damage by static discharge. Depending on the magnitude of the charge, device substrates can be punctured or destroyed by contact or mere proximity of a static charge. The results can cause degradation of device performance, early failure, or immediate destruct

6、ion. These charges are generated in numerous ways such as simple contact, separation of materials, and normal motions of persons working with static sensitive devices. When handling or servicing equipment containing static sensitive devices, adequate precautions must be taken to prevent device damag

7、e or destruction. Only those who are thoroughly familiar with industry accepted techniques for handling static sensitive devices should attempt to service circuitry with these devices. In all instances, measures must be taken to prevent static charge build-up on work surfaces and persons handling th

8、e devices. Model 3048A Table of Contents TABLE OF CONTENTS General Information 1 Quick Check 5 Spur Accuracy Test 7 Noise Flatness Test 11 Noise Floor Test 14 Microwave Phase Detector Conversion Loss (Option 201) Test 16 Functional Tests 19 DAC Tests 21 A3 Adjustments 23 A4 Adjustments 29 Option 1 C

9、alibration 37 Option 2 Calibration 40 Internal Sources Calibration 46 Spectral Purity Tests for Options 001 and 002 49 Spectral Purity Tests for Options 003 and 004 51 Spectral Purity Tests for Options 005 and 006 55 Appendix A: Block Diagram and System Troubleshooting : A-l Appendix B: HP 8662A or

10、HP 8663A 640 MHz Spectral Purity Test B-l Model 3048A Calibration General Information INTRODUCTION This manual documents the procedures which calibrate the HP 3048A Phase Noise Measurement System. System calibration assures that the System meets its published specifications. The proce dures consist

11、of system checks, adjustments, performance tests, and signal path characterization. Calibration of the HP 11848A Phase Noise Measurement Interface results from calibration of the System. NOTE Calibration as referred to in this manual should not be confused with the measurement calibration referred t

12、o in the normal course of making a phase noise measurement. Measurement calibration (especially, a mea surement with phase lock) refers to the characterization of such parameters as the detector constant, tuning sensitivity of the signal sources FM input, and determination of the phase lock loop ban

13、dwidth. iter The need for calibration is governed by the situation. It is usually not necessary nor even desirable to recalibrate the System frequently. Testing guidelines are summarized below. Most tests are automatic. Operator intervention is documented in the Systems test software. It is recommen

14、ded, however, that the user follow along in this manual as the tests are running. EQUIPMENT REQUIRED Equipment required, but not part of the System, is minimal. A feature of the System is the four sources built into the Interface which substitute for external sources in many cases. Extensive use is

15、made of the HP 3561A Dynamic Signal Analyzer both as a signal source (using its built-in noise source) and as a signal analyzer. Any calibrated HP 3561A can be used in calibrating the System; it does not need to be the specific HP 3561A in the System. The external test equipment requirements are giv

16、en in Table 1. PERFORMANCE TEST RECORD Most test results can be hardcopied on the Systems printer. This practice is recommended. It is also recommended that the serial number of the Interface under test be recorded in the System Configuration Table so that it will appear on the printouts. rev. 29MA

17、Y90 General Information Calibration Model 3048A Table 1. Recommended Test Equipment Instrument Type Frequency Counter Microwave Sources Noise Floor Test Fixture Power Meter and Sensor Printer Critical Specifications Frequency Range: 10 to 550 MHz For systems with Option 201 only(1); 2 required Frequ

18、ency Range: 1.2 to 18 GHz Maximum Level: +7 dBm (source 1), 0 dBm (source 2) Stability: drift small compared to 100 kHz Supplied with system. No substitute recommended. For systems with Option 201 only(2) Frequency Range: 1.2 to 18 GHz Level Range: +7 dBm HP-IB; graphics; usually part of the System

19、Suggested Model HP5315A See note (2). HP 11848-61032 HP 435B HP 8481A HP ThinkJet (1) Option 201 adds the 1.2 to 18 GHz input. 2 A variety of combinations of sources with adequate output and frequency range can be used for this test. Table 2. Performance Verification Guideline Situation1) New Instal

20、lation Annual Calibration Ambient Change Confidence Check HP 11848A Repair HP 3561A Repair Check or Test to Run Quick Check X X X Performance Tests xro X3) x X(3) Functional tests X(3) X(3) DAC Tests X(3) X(3) Calibration Option 1 X Option 2 (3) (3) Sources X(3) X(3) W Perform the Adjustments when r

21、ecommended by the other tests. (2) Run the Performance Tests when it is desired to ensure that the System meets its published specifications. (3) Perform these in the following order: Functional Tests, DAC Tests, Option 2 Calibration, Internal Sources Calibration, then Performance Tests. 2 General I

22、nformation Model 3048A Calibration WHEN AND WHAT TO TEST Use Table 2 as a guideline for verifying the performance of the System. The checks and tests are summarized below. The procedures are listed in the order in which they are described except for the Source Options Spectral Purity Tests which fol

23、low the Adjustments. Quick Check is a confidence check which performs a complete phase-locked measurement of the phase noise of the 10 MHz A vs. B internal sources. Performance Tests verify that the System meets its published specifications. The tests are as follows: Spur Accuracy Test verifies the

24、accuracy of noise measurements by measuring the level of phase modulation on a carrier with a known discrete sideband level. (In the context of phase noise measurements, discrete sidebands are often referred to as spurious signals or spurs.) Noise Flatness Test measures the unflatness of noise signa

25、ls at offsets greater than 500 kHz. This test needs to be performed only when an RF spectrum analyzer is in the Systems Configuration Table. Noise Floor Test verifies the measurement sensitivity. Microwave Phase Detector Conversion Loss (Option 201) Test measures the conversion loss of the 1.2 to 18

26、 GHz phase detector. If the detector is not within specification, the noise floor will be degraded when the detector is used. (Option 201 adds the 1.2 to 18 GHz input to the Interface.) Source Options Spectral Purity Tests verify the contribution of optional sources to the noise floor. (The procedur

27、es for these tests follow the Adjustments.) Functional Tests verify the functionality of the HP 11848A Phase Noise Interface. The tests measure the paths for proper switching, DC offsets, amplifier gains, filter responses, etc. (Adjustments to the HP 11848A can be made when Functional Tests show a p

28、roblem.) DAC Tests verify the accuracy of the three DACs in the HP 11848A Phase Noise Interface. (Adjustments to the DACs should be made if a DAC is out of limits.) The DAC Tests require accessing the interior of the Interface. Option 1 Calibration totally characterizes the HP 11848A measurement pat

29、hs and generates new calibration data. The data collected replaces the data generated during the previous calibration. The new data may be stored in mass storage. (However, it does not replace the extra data obtained from the Option 2 Calibration.) Option 2 Calibration is the same as Option 1 Calibr

30、ation but includes the characterization of two additional reference paths. Internal Sources Calibration determines and records as data the nominal DAC 2 and DAC 3 voltages (VNOMs) required to set the three tuneable, internal sources (VCOs) to their center frequencies. Adjustments are made when other

31、 tests or checks indicate the need. Adjustments require accessing the interior of the Interface. A3 Adjustments are made to the A3 Analyzer Interface Assembly. A4 Adjustments are made to the A4 Phase Detector Assembly. General Information 3 Calibration Model 3048A THE IMPORTANCE OF SYSTEM CALIBRATIO

32、N DATA Phase noise measurements are ultimately made by the HP 3561A Dynamic Signal Analyzer after the ( demodulated noise signal has passed through the HP 11848A Phase Noise Interface. Phase lock loop control signals also pass through the Interface. The Interface conditions the signals for best meas

33、urement sensitivity and accuracy. It is therefore important to know the characteristics of the circuits in the Interface. The Interfaces characteristics are acquired during the Option 1, Option 2, and Internal Sources Calibrations that are described above. The acquired data is stored on the mass-sto

34、rage media (hard or floppy disc). During the normal course of operation, the System loads the data into the computers memory (RAM) where it is accessed by the program as needed to correct the raw measurement data. Therefore, the stored data must match the specific Interface being used. It is a good

35、practice to keep the Interfaces serial number in the Systems Configuration Table which will then appear on data printouts. The calibration data is stored in two data files: CALDATALO and CALDATAHI. CALDATALO is used for signal-path circuits through 100 kHz. CALDATAHI is used for signal paths above 1

36、00 kHz plus the VNOMs (the nominal tuning voltage of the tuneable, internal sources) and noise-flatness data for flatness variations greater than 2 dB. General Information Model 3048A Calibration Quick Check DESCRIPTION The Quick Check is a straight-forward, phase-lock-loop measurement of the phase

37、noise of the two internal 10 MHz sources (A vs. B). Though the check is easy to run, a large portion of the circuitry in the HP 11848A Phase Noise Interface is exercised. A completed measurement with good results verifies that the System is operating correctly but does not verify its accuracy. The c

38、heck uses only equipment that is part of the System. Measurement definition parameters for this test are retrieved from a Test File named DEFAULT. NOTE This check duplicates some of the guided tour in the Getting Started section of the Operating Manual. PROCEDURE 1. Press the System Preset softkey.

39、This softkey appears at the Main Software Level menu. 2. Press the New Msrmnt softkey to initiate the measurement. 3. Press the |Yes, Proceedj softkey to indicate that new measurement data is desired. The System now addresses each instrument listed in the Systems Configuration Table. If an instrumen

40、t does not respond to the HP-IB address listed for it, the System will inform you with a display message. (For details on adding an instrument to the Systems Configuration Table or verifying an HP-IB address, refer to Setting Up the HP-IB Addresses in the installation section of the HP 3048A Operati

41、ng Manual.) 4. Connect the HP 3561A input and the two 10 MHz source outputs to the HP 11848A as shown in the connect diagram on the computer display and in Figure 1. Note especially the rear-panel connections. NOTE The Interfaces SPECTRUM ANALYZER output should either be termi nated in 50Q or an RF

42、spectrum analyzer should be connected to it. 5. Press the Proceed softkey to run the test. The measurement should proceed without error messages, and the measured noise results should be within 10 dB of that in Figure 2. (The plot in Figure 2 is typical for a System without an RF spectrum analyzer.

43、The measurement takes about 10 minutes depending on the controller and the presence of the RF spectrum analyzer.) Quick Check 5 Calibration Model 3048A HP 3561A DYNAMIC SIGNAL ANALYZER NOISE INPUT FROM HP 3561A SOURCE OUTPUT (REAR PANEL) HP 11848A PHASE NOISE INTERFACE TO HP 3561A INPUT (CONNECT RF

44、SPECTRUM ANALYZER OR 5 0 - O H M LOAD HEREO SPECTRUM ANALYZER Figure 1. Quick Check Setup m 0 -10 -20 -30 -40 -50 -G0 -70 -80 -90 -100 -1 10 -120 -130 -140 -150 -160 -170 H P 3 0 4 8 H Qhp: 3048H Carrier i iii - - - - - - - - - Y/u Hu fc ji ml i - i III DEMO: 10 MHz : 10.E+6 Hz i III 1 1 il . JU. if

45、l Jtdi vvlilL 1 111 R v s . 10 Mr 28 Dec 1987 16; i III - _ i III Hz B 37:27 - 16:40:33 i III - - - - - - - - - - - - - - - i III s 10 100 IK 10K I t f ) C d B c / H z : v s f C H z : 100K Figure 2. Typical Noise Plot for the System Quick Check 6 Quick Check Model 3048A Calibration Spur Accuracy Tes

46、t DESCRIPTION In this test an external audio tone is input to the phase modulator of the internal 10 MHz B Oscillator to generate a 10 MHz carrier with discrete, phase-modulation sidebands. The sideband level (relative to the carrier) is calibrated with the HP 3561A Dynamic Signal Analyzer then meas

47、ured as a normal phase noise measurement (with the 10 MHz A Oscillator phase locked to 10 MHz B Oscillator). The measurements are made with audio tones of 5.5, 55, 550, 5500, 55 000, and (if an RF spectrum analyzer is present) 550 000 Hz. To calibrate the sideband level (relative to the carrier), th

48、e two 10 MHz Oscillators (A and B) are set 785 Hz apart and fed into the RF Phase Detector. The amplitude of the 785 Hz beatnote is measured by the HP 3561A. This level is the carrier reference level. Then the phase modulation sidebands for each modulation rate are measured with the HP 3561A and the

49、 relative sideband level is computed as the ratio of the two measurements. The RF signal simulates the spurious discrete phase modulation (often called spurs) frequently appearing in phase noise measurements. Although testing is done on discrete tone sidebands, the general accuracy of the noise sideband measurement is verified. If an RF spectrum analyzer is not present, the test covers offsets of 1 Hz