9. 3 dB Bandwidth Adjustments

A4A9

IF CONTROL

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A4A3

Figure 3-45. Location of 3 dB Bandwidth Adjustments

9.Press MARKER a. Adjust marker to 3 dB point on opposite side of signal (CRT MKR A annotation indicates 1.00 X). There are now two markers; one on each side of the signal at the 3 dB points.

10.CRT MKR A annotation now indicates the 3 dB bandwidth of the 3 MHz bandwidth. 3 dB bandwidth should be 3.00 &to.60 MHz.

11.Key in @YWBW) 1 MHz and [FREQUENCY SPAN] 2 MHz. If necessary, readjust [REFERENCELEVEL)~CENTERand FREQUENCY), using DATA knob to place signal peak near top of graticule and centered on center graticule line.

12.Press MARKER [OFF), then MARKER @].

13.Using DATA knob, adjust marker down one side of displayed signal to the 3 dB point; CRT MKR A annotation indicates .707 X.

14.Adjust A4A9R61 1 MHz for MKR A indication of 500 kHz while maintaining marker at 3 dB point (.707 X) using DATA knob. See Figure 3-45 for location of adjustment.

15.Press MARKER a. Adjust marker to 3 dB point on opposite side of signal (CRT MKR A annotation indicates 1.00 X). There are now two markers; one on each side of the signal at the 3 dB point.

16.CRT MKR A annotation now indicates the 3 dB bandwidth of the 1 MHz bandwidth. 3 dB bandwidth should be 1.00 fO.10 MHz.

17.Key in @G?G-BW) 300 kHz and CFREQUENCY SPAN) 500 kHz. If necessary, readjust CREFERENCE LEVEL) and [CENTER FREQUENCY], using DATA knob to place signal peak near top of graticule and centered on center graticule line.

18.Press MARKER (OFF), then MARKER @J.

19.Using DATA knob, adjust marker down one side of the displayed signal to the 3 dB point; CRT MKR A annotation indicates .707 X.

20.Adjust A4A9R62 300 kHz for MKR A indication of 150 kHz while maintaining marker at 3 dB point (.707 X) using DATA knob. See Figure 3-45 for location of adjustment.

2 1. Press MARKER [nl. Adjust marker to 3 dB point on opposite side of signal (CRT MKR A annotation indicates 1.00 X).

Adjustments 3-85