Section IV
Paragraphs 4-33 to 4-39
plifier with the input signal fed to its cathode. The
2 0 0 - m c oscillations appearing across L1523 a r e
transformer coupled to L1524 in the cathode of uni-
verter mixer V1511.
4-35. Plate voltage is applied to V1510A and B when
the NAV-GS switch is set to GS. R-f filters in the
plate circuits prevent rf from entering the B+ supply.
Avc voltage from univerter amplifiers V1512 and
V1513 is applied to the grid of V1512B, controlling
the amplitude of oscillations for different settings of
the MICROVOLTS control in order to keep the overall
gain of the univerter chassis constant.
4-36. UNIVERTER MIXER V1511.
(See figure 4-13.)
4-37. Univerter mixer V1511 receives the r-f outputs
of the r-f chassis and 200-mc oscillator V1510 during
GS operation. The output of the r-f chassis, 129.3 to
135.0 mc, is fed to the tuned grid circuit of V1511 and
coupled through C1575 to the grid of V1511. The in-
put is connected to a tap on L1524 to match the low
output impedance of the r-f chassis. The output of
200-mc oscillator V1510 is transformer coupled to
the cathode of V1511 by L1524. The sum frequency,
329.3 to 335.0 mc, is developed across L1526 and
coupled to L1527 in the univerter amplifier V1512 grid
circuit. The coupling circuit is overcoupled to have
a broad response and pass all signals in the range
329.3 to 335.0 mc equally well.
4-38. UNIVERTER AMPLIFIERS V1512 AND V1513.
(See figure 4-14.)
4-39. The 329.3 to 335. O-me signal from V1511 is
coupled through L1526 and L1527 to the grid of uni-
verter amplifier V1512. The signal is amplified by
V1512 and coupled through L1529 and L1530 to the
grid of univerter amplifier V1513. The amplified sig-
(See figure 4-12.)
nal appearing in the plate circuit of V1513 is coupled
through L1531 and L1532 to GS OUTPUT jack J1501.
4-34. The 200-mc oscillator V1510 is a crystal-con-
The output is taken from a tap on L1532 in order to
trolled, two-stage oscillator using both sections of a
reduce the output impedance at the GS OUTPUT jack
twin triode. The oscillator uses the fourth harmonic
to approximately 53 ohms. (See paragraph 4-24. )
of crystal Y1539. Feedback to sustain oscillations is
The coupling circuits are overcoupled to have a broad
accomplished by connecting the plate V1510A to the
response and pass all the required frequencies equally
grid of V1510B. V1510A acts as a grounded grid am-
well.
