Common IF Signature Problems
nRegion A of Figure 8-4is noisy: Suspect the first LC pole.
nRegion B of Figure 8-4is flat: Suspect the third step-gain stage, the fine attenuator, or the fourth LC-pole output amplifier.
H Region C of Figure 8-4 has no 15 dB step: Suspect the reference 15 dB attenuator.
nRegion D of Figure 8-4 is flat: Suspect the second step-gain stage.
nEntire signature noisy: If the signature resembles Figure 8-9, 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.
nCorrect shape but noisy: If the signature resembles Figure 8-10, suspect the second crystal-pole output amplifier.
nAmplitude of Region B of Figure 8-11varies more than 12 dB: Suspect the third step-gain stage output amplifier.
nRegion B of Figure 8-12is kinked: Suspect the fourth LC-pole output amplifier.
R E F 1 0 . 0 dBm ATTEN 2 0 dB
5dB,’
S A M P L E
C E N T E R 1 0 7 0 0 | | S P A N 0 H z |
R E S B W 3 0 0 kHz | V B W 3 0 0 kHz | S W P 5 0 0 set |
S K 1 7 8
Figure 8-9. Noisy Signature