Figure 2-7. 3.975-MHz osillator circuit, functional diagram.

11-6625-467-34

Figure 2-7. 3.975-MHz osillator circuit, functional diagram.

lator circuit).

nects +27.5 volts dc to the HIGH FREQ AMPL con-

trol which adjusts the oscillator output level. In

2-14. 30 MHz Switch Signal Paths.

position 6, CIRCUIT SELECTOR C completes the

path from the HIGH FREQ AMPL control to the 68

The 30 megahertz switch circuit applies a 30 mega-

megahertz oscillator circuit.

hertz signal modulated by a 100 hertz squarewave to

2-13. 500 kHz Switch Signal Paths

the homer module. The signal simulates homer left

and right signals. The 100 hertz oscillator in the

homer module applies the 100 hertz square wave

The 500 kilohertz switch circuit applies a 500 kilo-

modulating signal direct to the switch circuit.

hertz signal modulated by a 100 hertz square wave

Ground applied to either gate input causes a 180

to the homer module. The signal simulates homer

phase reversal of the modulating voltage. In posi-

left and right signals. The 100 hertz oscillator in the

tion 0, CIRCUIT SELECTOR C applies ground to

homer module applies the 100 hertz square wave

m o d u l a t i n g signal direct to the switch circuit.

both the minus and plus gate switch circuit inputs;

in position 1, it grounds the plus gate input, and in

Applying ground to either gate input causes a 180

phase reversal of the modulated output signal. In

position 2, the minus gate input is grounded. The 30

position 3, CIRCUIT SELECTOR C applies ground

megahertz oscillator connects to the switch circuit

to the minus gate input and in position 9, CIRCUIT

through an RF jumper cable connected between the

SELECTOR C grounds the plus gate input. In posi-

30 MC and RF SW IN jacks on the test front panel.

tion 6 or 7, CIRCUIT SELECTOR A connects the

The circuit output appears at the RF SW OUT jack

500 kHz fm oscillator to the gate circuit. (Refer to

on the front panel and connects to the homer module

paragraph 2-8 for details of the 500 kHz fm oscil-

through an RF jumper cable.

2-8