Specifications

voltage divider which provides the
fixed-hissing portion of emitter-
base bias for Q7703. Resistor
R7714 develops the self-biasing
portion of the emitter-base bias
and stabilizes the emitter. Capac-
itor C7711 places the base of Q7703
at rf ground potential. Capacitor
C7716 and inductor L7703 form a
decoupling network in the +16-volt
dc supply line.
c. The output from the second 47.0-mc
amplifier is rectified by diode CR7702.
The rectified signal is filtered by capac-
itor C7714. Part of the dc voltage, as de-
termined by the setting of R7718, is fed to
the Schmitt trigger circuit.
8. Test Probe Rf Preamplifier
(fig. 5)
The test probe rf preamplifier is a
single-stage wide-band rf amplifier which
develops a gain of about 1. Power and out-
put connections are made to the test probe
rf preamplifier when switch S7902 is in
position 7, 9, 12, 13, 14, 15, 16,17, or 18.
The output from the test probe rf pre-
amplifier is fed to either the 5.65-mc,
11.5-mc, or the 47.0-mc amplifier, de-
pending on the selector switch position.
a. The test probe rf preamplifier uses
transistor Q7301 in an emitter-follower
stage.
(1)
(2)
The input signal from the test probe
tip is coupled through capacitor
C7301 to the base of Q7301. The
output of Q7301 is coupled through
C7303 and C7901 to the input of the
selected rf amplifier.
Resistors R7301 and R7302 form a
voltage divider that provides the
fixed-biasing portion of the
emitter-base bias for Q7301. Re-
sistor R7303 establishes the self-
biasing portion of the collector-
base bias and stabilizes the emitter
current. Positive voltage is applied
to the collector through rf choke
L7302. Capacitor C7302 is an rf
bypass capacitor for the collector
of Q7301.
b. Power to the test probe rf preampli-
fier Is supplied from the +16-volt dc supply
line as selected by switch S7902. Inductor
L7501 keeps rf voltages out of the supply
line. Diode CR7401 is associated with the
Figure 4. Amplifier, 47.0-mc,
schematic diagram.
7