Second Converter Final Adjustments

19.Second Converter Adjustments

53.Repeat steps 14 through 19 to ensure that Second LO frequency and shift are still properly adjusted.

54.Check the bandpass at the 3 dB points for both the 2ND LO T

and 1. On the scalar network analyzer, press [%i?%@ Max. Press cursor A a and set the cursor at the -3 dB point 50.1 dB. Press cursor A, cursor A, and set the cursor to the corresponding -3 dB point on the opposite side of the signal. The cursor should now read 0 kO.1 dB.

55.On the synthesized sweeper, press Ihns) and place the marker on either cursor A. Press (M4), and place the marker on the cursor A on the opposite side of the trace.

56.On the synthesized sweeper, press [MKRn), and read the bandpass (M3 - M4) shown on the ENTRY DISPLAY. Press C-1 OFF. See Figure 3-74 and Figure 3-75.

57.Disconnect all test equipment from HP 8568B Spectrum Analyzer and reconnect all cables within the instrument: cable 80 (gray/black) between A23A3J6 and A9J1, and cable 92 (white/red) between A23A3J5 and A19Jl.

58.Connect HP 8568B Spectrum Analyzer CAL OUTPUT to SIGNAL INPUT 2. Key in (CENTER FREQUENCY) 20 MHz, (FREQUENCY SPAN) 1 MHz, (REFERENCE LEVEL] -7 dBm, SCALE LOG [ENTER dB/DIv) 1 dB, (REs) 300 kHz.

59.Key in @iFi] @j u , (PEAK SEARCH] Key in m @ T and note signal amplitude as indicated by marker level CRT annotation.

60.Continue to key in ISHIFT) @) u then (SHIFT) (IJ T while adjusting A23A3Z4 for maximum amplitude and the same amplitude in both states of the Second LO 3x0.1 dB.

61.Reinstall RF Converter in instrument. See installation procedure in RF Section of Troubleshooting and Repair Manual, Volume 1.

Adjustments 3-129