HP 8568B 252

22. Comb Generator Adjustments

a typical comb tooth display. See Figure 3-83 for location of adjustments.

14.The majority of the comb teeth should be above the -30 dBm Display Line. No comb teeth should exceed -22 dBm, and no comb teeth should be less than -36 dBm.

15.If unable to adjust comb teeth as described in previous steps, proceed with the next step. If comb teeth are adjusted properly, do not perform the adjustments in the following steps. Skip to step 21.

16.Adjust A23A6 COMB PEAK A23A6L2 for maximum amplitude of comb teeth. See Figure 3-83 for location of adjustment.

17.If the highest-frequency comb tooth is too low (c-36 dBm), remove screws from cover of A23A6 Comb Generator and lift cover from housing, being careful not to break wire connections to internal circuit. It will be necessary to hold cover away from housing while performing the following adjustment.

18.Adjust A23A6 HF PEAK A23A6C7 for maximum amplitude of the highest-frequency comb tooth displayed ( comb tooth to far right of CRT). See Figure 3-84 for location of adjustment.

19.Replace cover on A23A6 and install screws.

20.Go back to step 12 and proceed with adjustments.

21.Remove cable from between A23A65J2 and A23A3J 1 and reconnect instrument cables to connectors from which they were removed.

3-138 Adjustments

Contents

HP 8568B Spectrum Analyzer HP 8568B HEWLETT PACKARD HP Part No Page Certification Warranty Assistance Safety Symbols Caution Warning General Safety Considerations HP 8568B Spectrum Analyzer Documentation Outline HP 8568B Installation Contents Page Page Figures Page Page Page lhbles General Information Operation Verification Option 462 Instruments Option 857 Instruments Page Page Page 20 dB Page Page Performance Tksts Equipment Required Test Record Note 1.Center Frequency Readout Accuracy ‘I&t Page Page 2.Frequency Span Accuracy lkst 2. Frequency Span Accuracy Test 83640A HP10503A Procedure 1. Connect equipment as shown in Figure 2.Press QNsTR PRESET]on analyzer Page 3.Sweep Time Accuracy Test (220 ms) Related Adjustment Equipment Sweep Times 220 ms 1. Connect equipment as shown in Figure 2.Press [INSTR PRESET)on the spectrum analyzer 3.Key in the following settings: 0 kHz Page Sweep Times 220 ms (Alternate Procedure) Start-UpTime Measurement Sweep Time 4.Resolution Bandwidth Accuracy Test 300 kHz 330.0 kHz 200 kHz 33.00 kHz 20 kHz Page Page Page 6.Resolution Bandwidth Switching Uncertainty Test Page Page Page 8.Frequency Response Test 8. Frequency Response Test Additional Equipment for Option 001: 20 MHz to 1.5 GHz 2.Set controls as follows: Power Meter MODE 9 . Key in the following spectrum analyzer settings: km) 1.5GHz 10.Press TRACE A [MAX) on the analyzer 11.Press SWEEP SINGLE on the synthesized sweeper Option 001: Set [REFERENCE LEVEL] TO -6.0dBm Repeat steps 6 through 11. Press DISPLAY LINE ENTER) (-1 (ENTE Page k=) 100Hzto 100 kHz (1 kHz to 100 kHz) 43.Set Display Line to peak of trace at 1 kHz 44.Key in the following spectrum analyzer settings: TRACE A .l kHz 1 kHz iO0 Hz Page Page 9. RF Gain Uncertainty Test Figure 2-16.RF Gain Uncertainty Measurement 10.IF Gain Uncertainty Test Procedure 1. Press ( INSTR pfwm-) Press 2.Connect CAL OUTPUT to SIGNAL INPUT 3.Press Cm]8. Adjust AMPTD CAL for a MARKER amplitude of -10.00dBm 50.02 dB 10 dB Gain Steps Page 2 dB Gain Steps dB Gain Steps Page Page Page 12. Amplitude Fidelity Test 12. Amplitude Fidelity Test Procedure Log Fidelity 2.Connect equipment as shown in Figure 3.Press ~NSTR PRESET) on the analyzer. Key in analyzer settings as follows: MHZ The fidelity error for amplitude steps from 9.The fidelity error at the -90dB setting should be s&l.5 dB Figure 2-22.Amplitude Fidelity Measurement Linear Fidelity 10. Key in analyzer settings as follows: (jEGi Page 13.Average Noise Level Tkst Page 14.Residual Responses Test Option 400: Page 15.Spurious Responses Test 10 DB Page Intermodulation Distortion Figure 2-26.Intermodulation Distortion Test Setup 11.Connect equipment as shown in Figure 12.Set the controls of the spectrum analyzer as follows: 211 2f2 Page Page 16.Residual FM Test Page Page Page 17.Line-RelatedSidebands Tests 17. Line-RelatedSidebands Tests Figure 2-31.Line Related Sidebands Measurement O p t i o n 4 0 0 1. Press ~NSTR PRESET].Connect CAL OUTPUT to SIGNAL INPUT (ml - 1 0 dBm 18.Calibrator Amplitude Accuracy Test 19.Fast Sweep Time Accuracy Test (430 ms) Page Page 20.1st LO Output Amplitude Test 21.Frequency Reference Error Test Specification Aging Rate Page ‘lhble 2-19.Performance Tkst Record Tkst 1. Center Frequency Readout Accuracy Test W-W -5000 Hz 5000 Hz -5,005 Hz 20 MHz Test 3. Sweep Time Accuracy Step 6. Sweep Time Accuracy, Sweep Times 220 ms Marker A Time Step 12. Sweep Time Accuracy, Sweep Times 220 s ‘I&t 4. Resolution Accuracy Test 4. Resolution Bandwidth Accuracy Step Accuracy Test 5. Resolution Selectivity Steps 7, 8 and 9. Resolution Bandwidth Selectivity Spectrum Analyl er Maximum lkst 6. Resolution Bandwidth Switching Uncertainty Test Ito kO.50 Test 7. Input Attenuator Switching Uncertainty Test Test 8. Frequency Response Test Test 8. Frequency Respons g& kep Signal Input Test 9. RF Gain Test 10. IF Gain Page Page YLkst 11. Log Scale Uncertainty Tkst Test 12. Amplitude Fidelity ‘I&t Test 13. Average Noise Level Test Test 14. Residual Responses Test Tkst 15. Spurious Responses Tkst Description Test 16. Residual FM Test Tkst Sidebands Test Min 1 M e a s u r e d M a 7. Option Test 18. Calibrator Amplitude Accuracy ‘I&t Sweep Time Accuracy Test (~20 Test 20. 1st LO Output Amplitude Test Test 21. Frequency Reference Error Test DescriDtion 1 Min 1 Measured Adjustments Safety Considerations Factory-SelectedComponents Related Adjustments Location of lkst Points and Adjustments ‘Ihble 3-2.Adjustable Components Adjustment Function Designator Name Number ‘Ihble 3-2.Adjustable Components (continued) ‘able 3-2.Adjustable Components (continued) Table 3-2.Adjustable Components (continued) ‘Ih.ble 3-2.Adjustable Components (continued) Page ‘lhble 3-2.Adjustable Components (continued) For Serial Prefix 2737A and below, see back of table for A22 IF Serial Prefix 3001A and Below IF Serial Prefix 2637A and Below ‘Ihble 3-3. Factory-SelectedComponents Range of Values Procedure (0 or PF) Function of Component l’hble 3-3. Factory-SelectedComponents (continued) Adjustmenl ‘Ihble 3-3. Factory-SelectedComponents (continued) of Component Option Ifable 3-3. Fhctory-SelectedComponents (continued) ?or Serial Prefix 2813A to 2816A, and Serial Prefix 2810A and below Page ‘able 3-3. Factory-SelectedComponents (continued) Function of Component Serial Prefix 2813A to 2816A Serial Prefix 2810A and Below Range of Values rapaors Standard Value Replacement 0.125 Resistors Resistors Value (n) EP Fart Number Value (fl) ‘Ihble (continued) Resistors1 Value (0) BP Part Number co Value (!I) ElP Fart Number Table 3-6.Standard Value Replacement 0.5 Resistors BP Part Number Value (0) EIP Fart Number Ihble Standard Value Replacement 0.5 Resistors Value (0) EIP Fart Number CD Value (a) EIP Fart Number 1.Low-VoltagePower Supply Adjustments 1.Low-VoltagePower Supply Adjustments Figure IF-DisplaySection Low-VoltageAdjustments (SN 3001A and Below) IF-DisplaySection Low-VoltageAdjustments (SN 3004A and RF Section Figure 3-4.Location of RF Section Low-VoltageAdjustments Page 2.High-VoltageAdjustment (SN 3001A and Below) Figure 3-5.High Voltage Adjustment Setup (2 required) High-VoltageAdjustment Procedure 1.Set the spectrum analyzer’s LINE switch to STANDBY Remove the top cover from the Figure 3-6.Location of High Voltage Adjustments With the protective cover removed in the following step, do not place hands near the AlA High-Voltageassembly. High voltage (approximately -4000V dc) can be present even when the ac line cord is disconnected With power supplied to the instrument, AlA3TP3 is at a voltage Focus and Intensity Adjustments 0.00099 x (-3875V) = -3.836V dc With the 18.If a new CRT has just been installed do the following: a.Set the front-panelINTENSITY control so the CRT trace is barely visible 2.High-VoltageAdjustment (SN 3001A and Below) Figure 3-8.Location of AlA Components Figure 3-9.CRT Cut-OffVoltage Figure 3-10.Waveform at AlA3TP5 Discharge Procedure for High Voltage and CRT Page 2.High-VoltageAdjustment (SN 3004A and Above) Figure 3-12.High Voltage Adjustment Setup Figure 3-13.Location of High Voltage Adjustments (approximately -2400V dc) can present even when the ac line 2.High-VoltageAdjustment (SN 3004A and Above) Figure 3-14.Location of AlA Label and Test Point for several days if the post-acceleratorcable is improperly disconnected Figure 3-15.Discharging the CRT Post-AcceleratorCable 3.Preliminary Display Adjustments (SN 3001A and Below) X and Y Deflection Amplifier Pulse Response Adjustments ~000uu000000u00ur Figure 3-18.AlA2, AlA4, and AlA Adjustment Locations 10. Set the Pulse/Function Generator controls as follows: Page Page TiTiiQ CHANNEL Page 3.Preliminary Display Adjustments (SN 3004A and Above) 3.Preliminary Display Adjustments (SN 3004A and Above) Figure 3-23.Preliminary Display Adjustments Setup 3. Preliminary Display Adjustments (SN 3004A and Above) Figure 3-24.Location of AlA and A3A2 Figure 3-25.AlA Adjustment Locations 12.Set the oscilloscope controls as follows: Press [CHAN]: V/div offset Press (TRIG): Figure 3-27.Composite X Deflection Waveform m, CHANNEL Page 4.Final Display Adjustments (SN 3001A and Below) 4.Final Display Adjustments (SN 3001A and Below) Location of Final Display Adjustments on AlA2, AlA4, and AlA 4.Final Display Adjustments (SN 3004A and Above) Figure 3-32.Location of Final Display Adjustments on AlA ‘Ihble 3-6.Initial Adjustment Positions AdjustmentPosition 4.Final Display Adjustments (SN 3004A and Above) Page 5.Log Amplifier Adjustments Offset Adjustment Check Figure 3-34.Location of Log Amplifier Adjustments Bandpass Filter Center Adjustment Bandpass Filter Amplitude Adjustment -12VTV and ATTEN Adjustments Linear Gain Adjustments Page 6.Video Processor Adjustments 6.Video Processor Adjustments Figure 3-36.Location of Video Processor Adjustments LOG Offset Adjust Page 7.3 MHz Bandwidth Filter Adjustments 7. 3 MHz Bandwidth Filter Adjustments Frequency Zero Check Filter Center and Symmetry Adjustments Location of Center, Symmetry, and 10 Hz Amplitude 7.3 MHz Bandwidth Filter Adjustments 11.Remove crystal filter bypass network near C23 SYM 13.Remove crystal filter bypass network near C32 SYM 15.Remove crystal filter bypass network near C41 SYM Filter Peak Adjust Figure 3-39.Location of 3 MHz Peak Adjustments 10 Hz Amplitude Adjustments 8.21.4 MHz Bandwidth Filter Adjustments +10 V Temperature Compensation Supply Check A4A4 LC Adjustments Location of A4A4 21.4 MHz LC Filter Adjustments 8.21.4 MHz Bandwidth Filter Adjustments A4A4 XTAL Adjustments Location of A4A4 21.4 MHz Crystal Filter Adjustments A4A8 LC Adjustments Location of A4A8 21.4 MHz LC Filter and Attenuation A4A8 XTAL Adjustments Location of A4A8 21.4 MHz Crystal Filter Adjustments LC Dip Adjustments AlOdB and A20dB Adjustments 9.3 dB Bandwidth Adjustments 9. 3 dB Bandwidth Adjustments Figure 3-45.Location of 3 dB Bandwidth Adjustments 9.3 dB Bandwidth Adjustments 10.Step Gain and 18.4 MHz Local Oscillator Adjustments 10. Step Gain and 18.4 MHz Local Oscillator Adjustments Step Gain and 18.4 MHz Local Oscillator Adjustments Setup Set instrument LINE switch to ON and press MHz - 1 0 dBm 0 dB 0 Hz 10.Step Gain and 18.4 MHz Local Oscillator Adjustments 10 dB Gain Step Adjustment Figure 3-48.Location of 10 dB Gain Step Adjustments 1 dB Gain Step Checks .l dB Gain Step Adjustment 18.4MHz Local Oscillator Adjustment Location of .l dB Gain Step, 18.4 MHz LO, and + 1OV + 1OV Temperature Compensation Supply Adjustment Converter Adjustments 11. Down/Up Converter Adjustments Optional Page 12.Time Base Adjustment (SN 2840A and Below, also 3217AO5568 and Above) Page 6. Set the Frequency Counter controls as follows: On the Frequency Counter, select a 10 second gate time by pressing GATE] 8.Offset the displayed frequency by -10.0MHz by pressing MATH Figure 3-53.Location of A27Al Adjustment 12. Time Base Adjustment (SN 2848A to 3217A05567) 12.Time Base Adjustment (SN 2848A to 3217A05567) Figure 3-54.Time Base Adjustment Setup Page Page 12.Time Base Adjustment (SN 2848A to 3217A05567) Figure 3-55.Location of A27A2 Adjustment Reference Adjustments 4.Reconnect A27 Time Base output to A16Jl JumDer A16TP4 to Ground. Set the HP 8566A/B Spectrum Analyzer to 1 MHz +20 dBm, and 100 kHz. Connect A16J3 to RF INPUT of HP 8566A/B Soectrum Analyzer and set Page Figure 3-58.Typical Signal at A16TP3 14.249 MHz Phase Lock Oscillator Adjustments Location of 249 MHz Phase Lock Oscillator Adjustments 14.249 MHz Phase Lock Oscillator Adjustments Set LINE switch to STANDBY. Adjust A7L2 Set LINE switch to ON and key in @KKK 18.Set LINE switch to STANDBY and place A7 249 MHz PLO on extender Page Page 16.Second IF Amplifier and Third Converter Adjustment Second IF Amplifier Adjustments 16. Second IF Amplifier and Third Converter Adjustment BNC to SMB Snap-On(Service Accessory) (2 required) Position instrument on right side as shown in Figure 5.Press [cwl301.4 MHz on synthesized sweeper Location of 301.4 MHz BPF and 280 MHz AMPTD Adjustments 301.4MHz Bandpass Filter Adjustment Waveform Figure 3-66.Minimum Image Response at 258.4 MHz Third Converter Adjustment 17.Pilot Second IF Amplif’ier Adjustments A9 Pilot Second IF Amplifier A10 Pilot Third Converter Figure 3-67.Pilot Second IF Amplifier Adjustments Setup Power Splitter . . . . . . . . . . . . . . . . . . . . . . HP 11667A Opt 17. Pilot Second IF Amplifier Adjustments Location of 269 MHz Bandpass Filter Adjustments 269 MHz Bandpass Filter Adjustments Waveforms 18.Frequency Control Adjustments Start-UpTime Full Sweep FM SPAN Adjustment 19.Second Converter Adjustments Page Page Second Converter Bandpass Filter Adjustments Page Page Page Voltage-TunedOscillator Adjustments DACS Accuracy Check Positive Supply VT0 Center-Frequency Checks 21.Slope Compensation Adjustments Page 21. Slope Compensation Adjustments Figure 3-81.Location of A22R66 TIIIT Adjustment Figure 3-82.Slope Compensation Adjustment Waveforms 22.Comb Generator Adjustments 22. Comb Generator Adjustments Figure 3-84.Comb Teeth Display Page 23. Analog-To-DigitalConverter Adjustments A3A8 Analog-to-DigitalConverter Figure 3-85. Analog-To-DigitalConverter Adjustments Setup Standard Procedure a. Key in [BLANK)TRACE A and SWEEP [S’NGLE] b. Disconnect cable 0 (black) from sweep ramp input A3A8Jl c. Short A3A8TP4 to A3A8TP5 or connect SMB snap-onshort to A3A8J e. Set the oscilloscope settings as follows: Alternate Procedure 24.Track and Hold Adjustments 24. Track and Hold Adjustments Figure 3-88.Location of Track and Hold Adjustments 24.Track and Hold Adjustments 25.Digital Storage Display Adjustments 25. Digital Storage Display Adjustments A3A 1 Trigger A3A2 Intensity Control A3A3 Line Generator 2 5 . Digital Storage Display Adjustments Figure 3-90.Location of Digital Storage Display Adjustments Sample and Hold Balance Adjustments 25.Digital Storage Display Adjustments Figure 3-91.Sample and Hold Balance Adjustment Waveforms Figure 3-92.Waveform Before Adjustment Page Final Graticule Adjustments X and Y Expand Adjustments Low-NoiseDC SUPPlY Figure 3-93. Low-NoiseDC Supply ‘Ihble 3-7.Parts for Low-NoiseDC Supply Reference/Designation HP Fart Number Crystal Filter Bypass Network Configuration Crystal Filter Bypass Network Configuration Figure 3-94.Crystal Filter Bypass Network Configurations 6 dB Bandwidths: Impulse Bandwidths: 4.6 dB Resolution Bandwidth Accuracy Test Page Related Adjustment Impulse Bandwidth Adjustments Specification *20%, 3 MHz bandwidth flO%, 1 MHz to 1 kHz bandwidths -0,+50%, 300 Hz to 10 Hz (6 dB bandwidths) iZZiZK Page INGLEI @Z’ l,S’NGL Es) 30 kHz (i) @GiF Page Page Page Specification 60 dB/6 dB bandwidth ratio: ~11: 1, 3 MHz to 100 kHz bandwidths ~8: 1, 30 kHz to 30 Hz bandwidths 60 dB points on 10 Hz bandwidth are separated by ~100 Hz Equipment None required Page VlDEoj Page Page Page Procedure 1. Press ~NSTR PRESET) Page ‘RES) Page Page Page Page Page Related Performance Page Page Page Page Page Page Specification Log: 2.Press (JNSTR PRESET]on the analyzer. Key in analyzer settings as follows: + 10 dBm 4.Connect equipment as shown in Figure 5-l 7.Press MARKER [PEAK SEARCH), MARKER In] 8.Step the frequency synthesizer output amplitude down 10 dB + 10 (ref) sf1.5 dB 14.Set the frequency synthesizer for output amplitude to + 10 dBm 15.Key in the following analyzer settings: sk1.0 dB <%1.5 dB 22. Key in analyzer settings as follows: 23.Set the frequency synthesizer for an output power level of + 10 dBm 24.Press SCALE LIN pushbutton. Press MARKER Page Page Page Page . . . . . . 6-4 . . 6-4, 6-5 6-4, 6-5 6-6 . . . . . . 6-6