Attenuator assembly 1A3

TM 11-5820-695-35

The 150 MHz frequency modulated output of 1A8 is

alarm condition (data aim, transmitter alm, receiver alm,

applied to transmitter frequency mixer stage 1A9 where

or remote traffic in alm) is detected, the CNTRL ALARM

it is mixed with a 4.55 to 4.85 GHz local oscillator signal,

indicator lights red and an audible alarm is heard over

which is produced by electrical frequency synthesizer

the loudspeaker. The RESET pushbutton on 1A15A8 or

1A14 and a times 16 multiplier chain. The electrical

the external alarm disable switch is used to silence the

frequency synthesizer generates a highly stable

audible alarm; however, the red CNTRL ALARM

frequency in the range of 284.375 to 303.125 MHz. The

indication will remain until the alarm condition is

detected output level (synth level) is applied to metering

removed. The WAVEGUIDE SW indicator on 1A15A8

circuits on 1A15A8. The SYNTH OVEN lamp (press-to-

is lighted green when Switch, Waveguide SA-1679/GRC

test) on meter panel assembly 1A15A8 lights white when

is set to the ANTENNA (NORMAL) position and lights

the standard radio frequency oscillator oven in 1A14 is

red when the SA-1679/GRC is set to the TO LOAD

at the correct temperature. In addition, a synthesizer

(TEST) position.

monitor signal is applied from 1A14 alarm monitor 1A5.

This signal indicates if the radio frequency oscillator and

(3) Attenuator assembly 1A3 provides

the standard radio frequency oscillator contained in

attenuation and phase shift circuits for the to radio data

1A14 are phase locked. If an in-phase lock condition

and digital ow signal and attenuation to analog ow

exists, the SYNTH LOCK indicator on 1A15A8 lights

signals. A detected analog ow test signal from 1A3 is

green. An out-of-phase lock condition causes the

applied to the metering circuits on 1A15A8. The data

SYNTH LOCK and CNTRL ALARM indicators to light

and analog ow output signals from 1A3 are combined at

red. The 284.375 to 303.125 MHz output from 1A14 is

the output of af-rf amplifier 1A4. The data signal is

applied to the times 16 multiplier chain which is

amplified in 1A4 and the combined data and ow output

comprised of transmitter amplifier frequency multiplier

is applied to 4.5 MHz low pass filter 1A6. The 4.5 MHz

1A11, coaxial circulator 1HY1, and transmitter

low pass filter shapes the data signal before it is applied

frequency multiplier group A10. The signal is amplified

to radio transmitter modulator 1A8. A detected traffic

and multiplied to 1137-1213 MHz in 1A11. The signal is

level, (representative of the input to 1A8) is fed back to

then coupled through 1HY1 to 1A10. Coaxial circulator

the alarm monitor 1A8 through attenuator assembly

1HY1 provides isolation between the frequency

1A3. If the traffic level signal is present (normal

multiplier circuits.

Transmitter frequency multiplier

condition), alarm monitor 1A5 causes the TRAF

group 1A10 multiplies the 1137 to 1213 MHz signal up

indicator on 1A15A8 to light green. If the traffic level

to the 4.55 to 4.85 GHz local oscillator frequency for

signal is absent (alarm condition), 1A5 causes the TRAF

application to transmitter frequency mixer stage 1A9.

and CNTRL ALARM INDICATORS TO LIGHT WRD.

Detected signal levels in the times 16 multiplier chain

The traffic level signal is also routed to the metering

are applied to the metering circuits in 1A15A8. The

circuits in 1A15A8 through alarm monitor 1A5.

1137 to 1213 MHz output of 1A11 is detected (ampl-

mult) within 1HY1 and applied to the metering circuits.

(4) The combined data and ow signal

The 2275 to 2425 MHz signal generated by the 2nd

frequency modulates a 150 MHz carrier in 1A8.

frequency multiplier circuits in 1A10 is detected (2nd

Electronic frequency control 1A7 provides automatic

mult) and applied to the metering circuits. The 4.55 to

frequency control (afc) of the 150 MHz carrier.

4.85 GHz output generated by the 3rd frequency

Frequency control and modulator signal levels from 1A7

multiplier circuits in 1A10 is detected

and 1A8 are applied to the metering circuits in 1A15A8.

Change 6 2-6.2