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HP 450A Operating And Servicing Manual page 12

Hp 450a amplifier serials prefixed: 010
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Model 450A
Section IV
b. Set the front-panel controls on the amplifier as
follows:
d. Set the front-panel controls on the distortion ana-
lyzer as follows:
e. After a lO-minute warmup connect the amplifier
INPUT terminals to the METER INPUT terminals on
the analyzer, and adjust the AMPLITUDE CONTROL
on the oscillator to obtain exactly 0.1 volt on the
analyzer.
c. Set the front-panel controls on the oscillator as
follows:
FREQUENCY dial - - - - - - - - - - - -
20
FREQUENCY range - - - - - - - -
Xl
OUTPUT ATTENUATOR (upper) - -
30
OUTPUT ATTENUATOR (lower)
5
AMPLITUDE
- - - -
0
IMPEDANCE
~O
POWER
ON
LOAD - - - -
OFF
f. Set the analyzer function switch to SET LEVEL;
meter range switch to 100% (10 VOLT) and connect
the analyzer AF INPUT terminals to the amplifier
OUTPUT terminals. Adjust the analyzer INPUT sen-
sitivity control to obtain a full scale reading on the
0-1 scale on the analyzer meter.
g. Set the analyzer function selector to DISTORTION
and tune FREQUENCY dial for a dip. Reduce setting
of the meter range switch as necessary and tune
analyzer FREQUENCY and BALANCE controls for a
minimum reading.
The final reading in distortion
must be less than 1%.
If
it is higher than this, mea-
sure the distortion in the oscillator output alone which
should be less than 0.5%.
i. Disconnect oscillator from amplifier INPUT termi-
nals, and short the input terminals together with
a wire jumper.
h. Repeat above procedure using an oscillator fre-
quency of 20,000 cps.
Again, distortion must be
below 1%.
j. Set the analyzer function switch to SET LEVEL
and set the INPUT sensitivity control to MAX; set
the meter range switch to the 0.03 range. The actual
voltage input is now only 0.1 that indicated on the
meter scale.
The input voltage must not exceed
4 millivolts.
k.
Set the amplifier GAIN switch to 20 DB. The
analyzer voltmeter should indicate less than 2.5 milli-
volts using the same XlO factor used in step j.
ON
- - 40 DB
MIN
- - Xl
20
- METER
.10 VOLT
AF
- - - - - ON
POWER switch
GAIN switch - -
INPUT SENSITIVITY- -
- - - -
FREQUENCY range - - - - -
FREQUENCY dial- -
Function switch - - - -
Meter Range switch - -
AF-RF selector
Power switch - - - -
)
)
)
4-5

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