HP 8568B manual DB Resolution Bandwidth Adjustments, Test

9.6 dB Resolution Bandwidth Adjustments

Reference IF-Display Section

A4A9 IF Control

Related Performance 6 dB Resolution Bandwidth Accuracy Test

Test

Description The CAL OUTPUT signal is connected to the RF INPUT. Each of the adjustable resolution bandwidths is selected and adjusted for the proper bandwidth.

Equipment No test equipment is required for this adjustment.

Procedure 1. Position the instrument upright and remove the top cover.

2.Set the LINE switch to On, press (INSTR PRESET) and select

SIGNAL INPUT 1.

3.Connect CAL OUTPUT to SIGNAL INPUT 1.

4.Key in (CENTER FREQUENCY) 100 MHz, [FREQUENCY SPAN) 5 MHz

(-13 MHz, and ILIN_).

5.Press [REFERENCE LEVEL) and adjust the DATA knob to place the signal peak near the top CRT graticule. The signal should be centered about the center line on the graticule.

6.Press PEAK SEARCH , MKR + a, and MARKER (al.

7.Using the DATA knob, adjust the marker down one side of the display signal to the 6 dB point; CRT MKR A annotation indicates

.500 x

8.Adjust A4A9R60 3 MHz for MKR In] indication of 1.5 MHz while maintaining the marker at .500 X using the DATA knob. Refer to Figure 4-7 for the adjustment location.

9.Press MARKER [nl. Adjust the marker to the 6 dB point on the opposite side of the signal (CRT MKR A annotation indicates 1.00 X. There are now two markers; one on each side of the signal at the 6 dB point.

10.CRT MKR A annotation now indicates the 6 dB bandwidth of the 3 MHz bandwidth filter. The bandwidth should be 3.00 MHz *0.60 MHz

11.Key in (REsBW) 1 MHz, CFREQUENCY SPAN) 2 MHz, (PEAK SEARCH),

and [MKR). If necessary, readjust by pressing

PREFERENCE LEVEL) and using the DATA knob to place the signal peak near the top of the graticule.

12.Press MARKER IOFF) then MARKER a.

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