ISOLATION AMPLIFIER MODULE A6600.

TM 11-5820-670-30

1-41. BUFFER AMPLIFIER MODULE A6400 AND REGULATOR ASSEMBLY. (CONT)

BUFFER AMPLIFIER

The output of master oscillator A6300 is applied to isolation amplifier Q6401 which isolates the master

oscillator to maintain frequency stability. Amplified signals from Q6401 are developed in the two

secondary windings of transformer T6401.

One secondary winding couples the signal to isolation amplifier module A6600 and the other winding

applies the same signal to buffer amplifier Q6402 in module A6400.

Buffer amp Q6402 amplifies the signal and applies it through the tuning circuits to the rf drivers in

module A6500.

The mechanically tuned circuits function identical to those contained in the master oscillator module.

BUFFER VOLTAGE REGULATOR ASSEMBLY

The buffer voltage regulator assembly provides 10.3 and 6.3 vdc to the master oscillator and isolation

amplifier stages. An input voltage of + 16 vdc is supplied to the regulator through relay K9603 when the

radio set transmission section is activated.

Zener diodes contained in the regulator assembly provide regulated 10.3 and 6.3 voltages to the

master oscillator and isolation amplifier when + 16 vdc is supplied.

The 10.3 and 6.3 vdc are used for the purpose of biasing the stages.

1-42. ISOLATION AMPLIFIER MODULE A6600.

EL1AT115

Frequency modulated signals from buffer amp A6400 are applied to isolation amplifier Q6601 for

amplification and applied to mixer module A1400. Q6601 also prevents undesired signals from local

oscillator A1500 mixed in A1400 from feeding back into buffer amp A6400, causing spurious outputs.

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