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constant output voltage in order that the final recording will be a direct
indication of relative response.
In the block diagram of Figure 3, a
Type 908-R96 Dial Drive is shown driving a Type 1215-B Unit Oscillator,
with the detected output of a low-pass filter plotted by an x-y plotter.
1.3.7 SENSITIVE DETECTOR. A Type 874-VQ Voltmeter Detector fol·
lowed by a Type 1232-A Tuned Amplifier and Null Detector tuned to 1 kc
be used for increased detector sensitivity when 1-kc modulation from the
Type 1263-B is applied to the oscillator.
Section
2
THEORY
OF
OPERATION
2.1 GENERAL.
In the cw mode of operation, the Type 1263-B Amplitude-Regu-
lating Power Supply compares the de potential developed by the oscil-
lator output rectifier with a de reference potential, and applies a correction
to
the oscillator plate supply to minimize the difference.
The load re-
sistance presented to the output rectifier is 100,000 ohms. A maximum
of 300 volts at 30 milliamperes is available for the oscillator plate. The
de reference potential is adjustable from 0 to 2.5 volts, which corre-
sponds to an rf output of 0 to 2 volts with the normal output rectifier.
This power supply will maintain any preset level within 2 percent over
the frequency range (subject to additional variations due to harmonics
and possible errors of the output rectifier), provided that the oscillator
produces at least 2 volts with a 300-volt, 30-milliampere plate supply
at all frequencies within its range.
-In the 1-kc modulated mode of operation, the regulating action is
maintained and the carrier, or average
rf,
level is controlled. This level
is one-half the "on" level of the rf-modulated output. Carrier output is
limited to 1 volt with the recommended oscillators.
6
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