Figure 5-6(1). Pin connections of integrated circuits (part 1 of 2).

TM 11-6625-922-15

produced at the sweep sync output at the start of each

Resistors R25 and R27 shift the dc level of the output

sweep.

signal so that the baseline at pin E is about -3 volts,

instead of 0 volt at pin C. Resistors R32, R33, and R52

d. 2-MHz Modulator Mixer A14 (fig. 9-9). This

are used in a network to generate test voltages to the

circuit has three inputs: 2 MHz square wave, sine-wave

input of the operational amplifier for statically

modulating signal (25, 83-1/3, or 250 Hz), and a vfo 2-

determining the end frequencies when ii the sweep

to 2.6--MHz square wave. The output is a modulated

mode. The resistors are switched in and out by the

sine wave, between 0 and 600 kHz. Transistors Q1 and

SWEEP CALIBRATE switch. Transistor Q14 is a

Q5 are emitter-follower buffers for the 2-MHz and

switching circuit the input at pin R of which is the output

modulating signals, respectively. The two frequencies

of the variable frequency oscillator, 8 to 10.4 MHz.

are mixed ill Q3, then fed to two 2-MHlz tuned amplifier

Integrated circuit M2 operates as a divide-by-4 and M1

stages, Q7, Q8 and Q9, Q10. Transistors Q11 and Q12

is a divide-by-10, giving square-wave outputs between

comprise a compound emitter follower. The vfo input is

ground and approximately +5 volts. A positive pulse is

sent to amplifier Q18 and emitter

Figure 5-6(1). Pin connections of integrated circuits (part 1 of 2).

5-10