Agilent Technologies 8564EC, Service Manual

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Chapter 9 445
IF Section
Log Amplifier (P/O A4 Assembly)
The linear amplifiers consist of two variable gain stages, U201C and
U201E as well as the buffer amplifier A4U201B, A4U201D, and
A4Q201. The linear amplifiers provide 0 to 40 dB of IF gain in 10 dB
steps. The gain of A4U201C can be increased by 20 dB by turning on
A4CR201 and A4CR210 with the control line LIN_20B. The gain of
A4U201E can be increased by either 10 dB or 20 dB with the control
lines LIN_10 or LIN_20A respectively. The gain can be selected by
setting the reference level of the 8564EC or 8565EC spectrum
analyzer.
Table 9-2 IF Gain Application Guidelines (ATTEN=10 dB)
Power into
A4J3 Reference
Level Gain of
A4U201C
(Pin 8 in;
Pin 3 out) Gain of
A4U201E
(Pin 3 in;
Pin 10 out) Total Gain
+6 dBm
−
50 dBm 0 dB 0 dB 0 dB
−
4 dBm
−
60 dBm 0 dB 10 dB 10 dB
−
14dBm
−
70 dBm 0 dB 20 dB 20 dB
−
24 dBm
−
80 dBm 20 dB 10 dB 30 dB
−
34 dBm
−
90 dBm 20 dB 20 dB 40 dB