HP 8562E - Page 341

Detailed If Adiust Sinnnture (Sl
MKR 1 854 <cc
10 dB/
SAMPLE 1
IIilI I
--- - \-,
-510 cjBm,-‘-ifTiN= dB
..-_. ___
hP
REF
-84.40 dBm
I I II ill I
LC POLE LC POLE LC POLE
-
SETTINGS PAST HERE ARE FOR
AUTOMATIC ADJUSTMENT OF THE
30kHz RESOLUTION BANDWIDTH
CENTER
10.700 000 MHz
SPAN 0 Hz
RES BW 300 kHz VBW 1 kHz
SWP 2.00 set
sp148e
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