its base to emitter Q420. A feedback winding on T424, to
is tuned to 5 MHz and couples the signal to the 5 MHz IF
the hose of Q420, provides the neutralization far the col-
lector-to-base capacitance.
amplifier Q460. Diode D454 in the collector load of Q450
improves the overload characteristics of the amplifier. Out-
The 75 MHz IF and the output from o crystal controlled
put of the 5 MHz IF signal is applied through an insulated
70 MHz oscillator Q440, are applied to the mixer amplifier
connector J470 to the input of the variable resolution am-
Q450. The collector output circuit of Q450 is T454, which
plifier.
Fig. 3-8. Crystal variable resolution filter.
Fig. 3-9. Crystal filter, equivalent circuit and impedance response
curves.
3-9
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