HP 8568B manual AlOdB and A20dB Adjustments

8. 21.4 MHz Bandwidth Filter Adjustments

approximately -17 kHz (to the left). If unable to achieve a “dip” in signal amplitude, increase or decrease value of A4ABR30. Refer to ‘&ble 3-3 for range of values.

62.Remove short from A4ABTP6 and short A4ABTP3 to ground.

63.Adjust A4ABC67 LC DIP for minimum amplitude of signal peak. See Figure 3-43 for location of adjustment. Key in [PEAK SEARCH) MARKER [nl, and adjust LC DIP again to offset the signal peak approximately -17 kHz (to the left). If unable to achieve a “dip” in signal amplitude, increase or decrease value of A4ABR55. Refer to ‘Pdble 3-3 for range of values.

64.Set LINE switch to STANDBY.

65.Reinstall A4A8 Attenuator-Bandwidth Filter without extenders. Remove short. from A4ABTP3.

66.Set LINE switch to ON. Press ~NSTR PRESET].

67.Go back and repeat LC adjustments for both the A4A4 Bandwidth filter and the A4A8 Attenuator-Bandwidth Filter.

AlOdB and A20dB Adjustments

68.Set, step attenuators to 25 dB.

69.Key in ~CENTER FREQUENCY] 20 MHz, ~FREQUENCY SPAN_) 3 kHz, CATTEN] 0 dB, [REsBWI) 1 kHz, and [REFERENCE LEVEL) -30 dBm.

70.Key in LOG [ENTER dB/DIv] 1 dB then press MARKER (PEAK SEARCH) MARKER [nl

71.Key in [REFERENCE LEVEL) -20 dBm. Set step attenuators to 15 dB.

72.Adjust A4ABR7 AlOdB to align markers on display. MARKER A level should indicate 0.00 dB. See Figure 3-43 for location of adjustment.

73.Key in (REFERENCE LEVEL) -10 dBm. Set step attenuators to 5 dB.

74.Adjust A4ABR6 A2Od.B to align markers on display. MARKER A level should indicate 0.00 dB. See Figure 3-43 for location of adjustment.

Adjustments 3-83