Agilent Technologies 8510C, Operating And Programming Manual

Page: 173 / 391

Service Functions
Figure 5-13. Gain Stages in the IF section
Notice that, in Figure 5-12 , the 100 kHz mixers are sho wn as ha ving only a single output
eac h. This is not really true. Figure 5-13 sho ws a closer represen tation of the actual circuitry .
The dieren t signals (a1, a2, b1, and b2) are split o and routed to input sele ctors . When
y ou select a sp ecic parameter, a ratio suc h a b1/a1 is selected. The net w ork analyzer
automatically selects the correct p ositions on the input selector to send the b1 signal to the
test c hannel, and a1 to the reference c hannel.
The signals then go to a series of 12 dB ampliers. In automatic IF gain mo de, the net w ork
analyzer con trols these ampliers. These ampliers can also b e con trolled man ually with the
softkeys in the IF Gain Select Men u.
Ho w to Use Manual IF Gain Controls Properly
Y ou can solve the IF O VERLO AD problem b y using xed IF gain, and setting it as necessary
for the higher p ower level .
Press 4 SYSTEM 5
NNNNNNNNNNNNNN
MORE
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
SERVICE FUNCTIONS
NNNNNNNNNNNNNNNNNNNNNNN
IF GAIN . Then select gain con trol for either the
test or reference path with
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
TEST AMP. GAIN or
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
REFERENCE AMP. GAIN .
5-22 Using System Functions