11.5-mc, or the 47.0-mc amplifier, de-
voltage divider which provides the
pending on the selector switch position.
fixed-hissing portion of emitter-
b a s e bias for Q7703. Resistor
R7714 develops the self-biasing
transistor Q7301 in an emitter-follower
portion of the emitter-base bias
stage.
and stabilizes the emitter. Capac-
(1) The input signal from the test probe
itor C7711 places the base of Q7703
tip is coupled through capacitor
at rf ground potential. Capacitor
C7301 to the base of Q7301. The
C7716 and inductor L7703 form a
output of Q7301 is coupled through
decoupling network in the +16-volt
C7303 and C7901 to the input of the
dc supply line.
selected rf amplifier.
c. The output from the second 47.0-mc
(2) Resistors R7301 and R7302 form a
amplifier is rectified by diode CR7702.
voltage divider that provides the
The rectified signal is filtered by capac-
fixed-biasing portion of the
itor C7714. Part of the dc voltage, as de-
emitter-base bias for Q7301. Re-
termined by the setting of R7718, is fed to
sistor R7303 establishes the self-
the Schmitt trigger circuit.
biasing portion of the collector-
base bias and stabilizes the emitter
8. Test Probe Rf Preamplifier
current. Positive voltage is applied
to the collector through rf choke
L7302. Capacitor C7302 is an rf
T h e test probe rf preamplifier is a
bypass capacitor for the collector
single-stage wide-band rf amplifier which
of Q7301.
develops a gain of about 1. Power and out-
put connections are made to the test probe
b. Power to the test probe rf preampli-
fier Is supplied from the +16-volt dc supply
rf preamplifier when switch S7902 is in
position 7, 9, 12, 13, 14, 15, 16,17, or 18.
line as selected by switch S7902. Inductor
The output from the test probe rf pre-
L7501 keeps rf voltages out of the supply
line. Diode CR7401 is associated with the
amplifier is fed to either the 5.65-mc,
Figure 4. Amplifier, 47.0-mc, s c h e m a t i c diagram.
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