produce the desired listening level upon receipt of a
the squelch circuit is contained in the detector integrated
circuit Z5. The squelch circuit responds to the 150 Hz
input signal and activates (within Z5) the audio amplifier.
1-15. Power Source
b. Electronic component assembly Z4 and
capacitor C34 comprise the 150 Hz notch filter and
The receiver is designed to operate from a battery (BA1)
enable the squelch circuit to respond to the 150 Hz tone
The receiver is capable of full
signal and reject other signals.
performance over the voltage range of 3.6V to 2.6V.
determines the squelch circuit open and close
Power is applied to the receiver when the control is
characteristic. Capacitor C38 is the signal bypass for
moved from the fully counterclockwise position which
the squelch circuit.
closes switch S2.
c. The squelch circuit is disabled when the
1-16. Summary of Integrated Circuit and Electronic
receiver control is manually rotated fully clockwise b})
Component Connection Points
the closure of switch S1. In this condition, the audio
amplifier is energized regardless of the receiver input
The following table summarizes the signals or functions
signal conditions. To reactivate the squelch circuit, the
of connection points of the integrated circuits and
control must be rotated fully counterclockwise (opening
electronic component assemblies.
S2) and then rotated clockwise to a setting which will
Figure 1-1. AN/PRR-9(XE-9) block diagram.