TM 11-6625-444-14-1
provides a variable sample rate for control of the
instrument are produced in the power supply
measurement cycle. The circuitry consists of a
(A1). The voltages produced are +200V, 18V
sample rate oscillator, range counter, decoder,
and +5V. Each voltage is derived from the ac
and display indicators. The sample rate oscillator
input using a series regulator.
frequency is controlled by a SAMPLE RATE
5-3. Ratio Mode
control on the front panel and determines the rate
a. The ratio mode of operation is essentially
at which the input is sampled. The range counter
the same as the dc measurement mode, with the
receives autorange commands from the range
exception of the V REF supply. In this mode of
delay and manual range commands from the front
operation, an external reference voltage of 1.0
panel switches. The range counter applies range
to +100V DC is processed by the ratio input (A3)
information to the decoder and all input signal
and substituted in place of V REF. The resulting
conditioning circuity. Range, polarity and digit
digital readout is then expressed as a ratio ( %) in
information is processed in the decoder, which
relation to the external reference.
then produces the correct display condition in the
b. The ration assembly (A3) receives the
indicators.
external reference voltage (1.0 to 100V DC),
g . Range Delay. The range delay (A2)
determines its polarity and magnitude, and
processes switching inputs from the front panel
applies the voltage to a difference amplifier. The
and produces control commands for the decoder in
output of the difference amplifier is buffered and
the display. It also produces up/down autorange
used in place of the internal v REF. Circuitry
commands for the range counter. The circuit
consists of a polarity detector, range detector,
consists of logic, range delay one-shot, and a
difference amplifier, and buffer. The polarity
detector senses the polarity of the applied ex-
control signals for the pulse generator and the
ternal reference by the use of a relay and always
decoder in the display. A clock signal for the
applies a fixed polarity voltage to the difference
range counter in the display is produced by the
amplifier. The range detector senses the voltage
pulse generator. This clock signal is required for
level and conditions the difference amplifier
the autorange feature. The range delay one-shot
accordingly. The difference amplifier processes
produces a programed time delay after any range
t h e external reference a n d p r o d u c e s a
change to allow for settling time of analog signal
corresponding voltage ( +0.7 to +7.0V DC). This
conditioners which process the input.
voltage is then buffered and applied in place of the
h. Power Supply. Operating voltages for the
internal V REF.
5-2
