Power Supply 1A6 Functional Operation

TM 11-5820-873-34

and the reference frequencies needed in the

2-7.

Power Supply 1A6 Functional Operation

synthesizer. All of the frequencies generated by the

(Fig. 2-2 and Fig. FO-31)

spectrum generator are derived by a combination of

a. The power supply provides regulated DC

multiplying, dividing and/or mixing the 5 MHz reference

voltages to operate the circuits in the RT-1277/URC-92.

signal from TCXO 1A8U1. The outputs from the

The input to the power supply can be from 115 or 230

spectrum generator are the 10.5 MHz, 3rd local

volt, 50 to 60 Hz AC power sources or from 13 or 26 volt

oscillator signal, 17 MHz and 1 kHz signals that are

DC power sources.

coupled to low digit generator 1A4A2, 20 and 21 MHz

b. When operated from a DC power source, the

signals that are coupled to translator 1A4A3 and a 100

input DC is applied to DC inverter 1A6A2. The DC

kHz signal that is coupled to VHF divider 1A4A4.

inverter converts the DC input to a 120 to 200 Hz square

b. Low Digit Generator 1A4A2.

The low digit

wave which is applied to primary 2 of transformer

generator controls the 10 kHz, 1 kHz and 100 Hz

1A6T1. When operated from an AC power source, the

components of the radios operating frequency. The

input AC is applied directly to primary 1 of transformer

inputs to the low digit generator are 17 MHz and 1 kHz

1A6T1.

signals from the spectrum generator, binary coded

c. Transformer 1A6T1 has three secondary outputs

decimal from the selected to 10 kHz, 1 kHz and 100 Hz

of 40 VAC, 20 VAC and 12 VAC. The secondary

FREQUENCY switches and a coarse steering voltage

outputs are applied through bridge rectifiers to the

from the 10 kHz FREQUENCY switch. The output is a

regulator circuits. The 28, 12 and 5 volt outputs from

1.5 to 1.5999 MHz signal with the frequency of the

the regulator circuits are used to operate the circuits In

signal being equal to 1.5 MHz plus the frequency set by

the radio.

the selected 10 kHz, 1 kHz and 100 Hz FREQUENCY

switches.

2-8.

Synthesizer

1A4

Simplified

Functional

c. Translator 1A4A3. The translator generates the

Operation (Fig. 2-3).

80.75 MHz, 2nd local oscillator frequency.

The

translator also combines the 80.75 MHz signal with the

20 MHz signal from spectrum generator 1A4A1, the 21

a. Spectrum Generator 1A4A1.

The spectrum

MHz signal from spectrum generator 1A4A1 (or from

generator generates the 3rd local oscillator frequency

2-8