Table of Contents
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1.
GENERAL
1.1
Outline
The Model VP-7721A Audio Analyzer
is a versatile audio measurement
system that combines a low-dis¬
tortion signal
source with three
functions in one unit as illustrat¬
ed in Fig.
1-1.
Since the distortion measurement
frequency is tuned to the oscil¬
lator frequency,
the
instrument
is most effectively used as an
automatic tuning distortion
Fig.
1-1
Functional
construction o
the VP-7721a
measurement set.
Besides the normal mode of operation using digital displays and auto
ranging meters,
the VP-7721A can perform preset operations.
The
VP-7721A stores sixteen front panel
setups and recalls them at a time
whenever needed.
The operational ease has been largely improved by microprocessor
control,
however,
the analyzer is compact in size measuring only 10 cm
high and 35 cm deep.
It is convenient for use in the production or
inspection line and on
service benches as well as research and develop¬
ment of audio equipment.
1.2
Oscillator
Signal
source used in the VP-7721A is a "bridged-T" oscillator which
provides a sine—wave
signal from 5 Hz to 159.9 kHz.
It attains a dis¬
tortion factor of 0.002% or less
in the range of 50 Hz to 20 kHz.
The
maximum output voltage
is 1.58 V rms into a 600-ohm load
(3.16 V rms
open-circuited)
and can be attenuated in 0.1-dB
steps by an attenuator
with a total attenuation of
79.9
dB.
Either display
in dBm
(0 dBm =
1 mW into 600—ohm)
or dB
(0 dB = 1 V rms,
into 600—ohm)
is selectable.
The direct reading range covers -73.7 dBm to 6.2 dBm or -75.9 dB to 4.0
dB
(0.16 mV to 1.58 V rms) .
The four
7-segment LED's
indicate frequencies up to four digits and
output amplitudes up to three drgits
(with a minus
sign) -
The lower
Output
Input
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