Agilent Technologies 856290216 service manual Common if Signature Problems

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SETTINGS PAST HERE ARE FOR AUTOMATIC ADJUSTMENT OF THE 30kHz RESOLUTION BANDWIDTH

CENTER 1 0 . 7 0 0 0 0 0 M H z		SPAN	0 Hz
R E S B W 3 0 0 kHz	VBW 1 kHz	SWP 2 . 0 0	set

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Figure 9-8. Detailed IF Adjust Signature (5)

Common IF Signature Problems

Region A of Figure 9-4 is noisy:

Suspect the first LC pole.

Region B of Figure 9-4 is flat:

Suspect the third step-gain stage, the fine attenuator, or the fourth LC-pole output amplifier.

Region C of Figure 9-4 has no 15 dB step:

Suspect the reference 15 dB attenuator.

Region D of Figure 9-4 is flat:

Suspect the second step-gain stage.

Entire signature noisy:

If the signature resembles Figure 9-9, suspect a broken first step-gain stage or a break in the signal path in the input switch, first crystal pole, or second crystal pole.

Correct shape but noisy:

If the signature resembles Figure 9-10, suspect the second crystal-pole output amplifier.

Amplitude of Region B of Figure 9-11 varies more than 12 dB:

Suspect the third step-gain stage output amplifier.

Region B of Figure 9-12 is kinked:

Suspect the fourth LC-pole output amplifier.

9-26 IF Section