TM 11-5805-424-15/NAVELEX 0967-220-9013/TO 31W2-2G-41
amplifier NSA-1 is applied to 6-volt clamp Q19 that
signal in the high 1,800cycle-per-second (cps) channel;
produces a 0-volt to a -6 volt DC NEUTRAL signal to
for all other channels, this delay equalization is
AND gate GAI-3 in the receiver data output module.
unnecessary.
(1) With delay equalizer assembly A25A3 in
e. The output of AND gate GAI-3 is fed to AND
use, pin 26 of the MX-73(*)/G module is open and the
gate GAS-3, amplifier IN-12, and bistable FFA-1.
input signal is passed through the delay equalizer
(1) AND gate GAI-3 inverts the input data
module to second input amplifier Q2, Q16.
signal when a talk-request signal (para 5-23) is not
(2) If the delay equalizer assembly is not
applied to its second input. If a talk-request signal is
used, the input signal from resistor A9R3 is routed direct
applied to its second input, the output remains at a
to second input amplifier Q2, Q16.
constant negative level for the duration of the talk-
request signal, thus inhibiting all subsequent circuits. In
b. Second input amplifier Q2, Q16, a constant-
normal operation, a positive output from AND gate GAI-
current generator, matches the input characteristics of
3 triggers timing bistable FFA-1. When the bit-timing
receive filter FL1, which filters out all undesired
signal is applied in coincidence, negative output from
frequencies and provides only the correct channel
AND gate GAI-3, inverted by amplifier IN-12, is applied
frequencies (including the mark and space frequencies)
as a positive pulse to the S (set) input of bistable FFA-1.
to amplifier AM-5 in the demodulator module (c below).
Thus, bistable FFA-1 output is generated in accordance
The input signal is also applied through resistor A8R2 to
with the corrected bit-timing signal from the 128 divider-
third input amplifier Q15 in the receive input and carrier
B module (para 5-21) and provides a retimed output
alarm module for operation of the receive carrier alarm
data signal that is in synchronism with the master clock
signals (para 5-24).
timing.
c. The output of amplifier AM-5 is applied through
(2) The output of bistable FFA-1 is applied to
amplifier AM-6 to receive discriminator FL3 and to
AND gate GAD-2 and to strap terminal 3 at the input of
demodulator Q2-Q8, Q12-Q16.
the risetime and falltime shaper.
(1) Receive discriminator FL3 demodulates
(a) If straps 3 and 4 are connected, a
the fsk input signals, producing a dc output signal that
retimed (regenerated data signal is applied to the
contains the original transmitted data information. At
risetime and falltime shaper, which provides a sharply
the mark frequency, the phase shift from the
defined square-wave input for polar output data
discriminator is more than 900; a 90shift is produced at
amplifier POD-1. Amplifier POD-1 supplies a polar
the center frequency. At the space frequency, the
output data signal with a +6volt mark bit, and a -6-volt
phase shift is less than 90 The shifted output signal
.
space bit.
from the discriminator is applied through isolation
amplifiers AM-7 and AM-8 to demodulator Q2-Q8, Q12-
(b) If an unregenerated receive data
Q16.
output signal is desired, terminal straps 2 and 4 are
connected so that recovered data is applied directly
(2) Demodulator Q2-Q8, Q12-Q16 compares
from amplifier IN-12 to the risetime and falltime shaper.
the fsk signals from amplifiers AM-5 and AM-8. Phase
relationships of the two signals applied to the
(c) Received
data
may
be
demodulator vary (on either side of 90, causing the
)
automatically
switched
from
regenerated
to
demodulator output pulse to vary in duty cycle. The
nonregenerated through the talk-request facility as
average dc level at the output of the demodulator
described in paragraph 5-23. If the data output signal is
represents the recovered data signal.
to be regenerated terminal straps 1 and 4 are connected
together. In this case, AND gate GAD-2 is enabled and
d. The demodulator output is applied to post
applies the regenerated signal from bistable FFA-1
detection filter FL3, which blocks the carrier center
through the hidden OR gate to the risetime and falltime
frequency and applies the resultant dc signal (containing
shaper. If the data output signal is unregenerated, AND
the mark and space information) to nonsaturating
gate GAD-4 is enable and applies the recovered data
amplifier NSA-1 which acts as a slicer, to limit output
signal
signal levels. Polar output signal from nonsaturating
Change 5
5-24
