BNC 130 User Manual
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THEORY OF OPERATION
The path of the CW OR BASELINE LEVEL signal may be followed on schematic sheet 1. First, we note
that the PEAK LEVEL control voltage is inverted by Z13-1 and delivered to Z16-3 via R20. Second, we
determine the status of the switches that affect the CW OR BASELINE LEVEL signal. Z11-3, for
example, is connected to three such switches. From Table 3-1 it is seen that its control signal is
IMPULSE from Z9-2, and that it is high in the CW Mode. Thus, Z9-3 is not conducting. Z14-16 is similarly
found to be low so this switch is conducting. Also, Z14-1 is high which renders this switch open. Since
Z14-9 is low, the EXT MOD OR CW FEEDBACK signal from Z16-7 is applied to Z16-2. The output from
Z13-1 is also applied to Z16-3. The output from Z13-1 is not influenced by R22 because Z14-6 is open
and no voltage is applied to R22.
Table 3-2. Control Signals
IC
Mode
Destination Signal Label
Pulse
CW
EXT MOD
Impulse
Zero Bsln Nonzero BSln
Z9-1 L
L
L
L
H
IMPULSE
Z9-2 H
H
H
H
L
Z3 (Sheet 2) IMPULSE
Z9-11 L
L
H
L
H
Z4 (Sheet 2) EXT MOD
Z9-10 H
H
H
L
H
Z10-5
EM
Z9-13 L
L
H
L
L
Z4 (Sheet 2) CW
Z9-12 H
H
L
H
H
Z10-4
CW
Z9-5 L
H
L
L
L
BIAS
Z9-6 H
L
H
H
H
Z14-1
BIAS
Z10-6 L
L
H
H
L
Z14-8
CW + EM
Z10-3 H
H
L
L
H
Z14-9
CW + EM