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Input Impedance Check; Output Impedance Check; Distortion Check - HP 465A Operating And Service Manual

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Section V
Paragraphs 5-9 to 5-11
Table 5-2
-hp- Model 465A
GAIN
(db)
20
20
20
20
20
40
40
40
40
40
d. Set frequency response test set to
EXTERNAL; OUTPUT ATTENUATOR to 1. 0 .
e. Set oscillator frequency to 1 kc; adjust output
amplitude to provide ac voltmeter reading of
9.0 v.
f. Adjust frequency response test set METER
SET to convenient SET LEVEL.
g. Reset oscillator frequency to 10 cps. Adjust
oscillator amplitude to re-establish SET LEVEL,
if required.
AC voltmeter should read between
B. I and 9. 9 v.
h.
Repeat step g above for oscillator frequencies
listed in Table 5-2.
within limits specified.
When going from 20 db to 40 db, re-adjust
j.
oscillator output for ac voltmeter reading of
9. 0 v at 1 kc.
Reset frequency response test
set METER SET for SET LEVEL. Repeat above
test using frequency settlings provided in Table
5-2.
5-9.

INPUT IMPEDANCE CHECK.

a. A Test Oscillator (-hp- Model 651A), an
AC Voltmeter (-hp- Model 3440A/3445A) and a
1 M ohm ±I%, 1/2 watt resistor (-hp- Part No.
0757-0059) will be required.
b. Set Model 465A GAIN to 20 db.
c. Connect ac voltmeter to Model 465A OUT­
PUT.
Set
RANGE to 10 V.
d. Connect oscillator OUTPUT to Model 465A
INPUT. Set oscillator frequency to l O O cps;
adjust output amplitude for ac voltmeter reading
of 10 v.
e. Insert 1 M ohm resistor in series with osci-
5-2
Frequency Response Test
Table 5-2
Oscillator
-hp- Model 651A
Range
Frequency
(cps)
I K
I
10
1
100
1
10 K
. 5
I M
l K
1
1
10
100
1
10 K
5
I M
1
AC voltmeter should read
F. R. T. S.
-hp- Model 739AR
-hp- Model 3440A/3445A or 331A
Output
Attenuator
1. 0
1.0
1.0
1.0
1.0
.1
.1
. 1
.1
. 1
llator and Model 465A INPUT (resistor must be
connected directly to Model 465A INPUT with
nothing else across input terminals),
voltmeter should read approximately 9.1 v
(±0.4v).
This verifies a Model 465A input
resistance of 10 M ohms.
f.
Reset oscillator frequency to 10 kc. Insure
that oscillator output is still 1. 0 v. AC volt­
meter should read more than 6. 0 v. This verifies
a Model 465A input impedance of 10 M ohms,
shunted by 20 pf.

5-10. OUTPUT IMPEDANCE CHECK.

a.
A Test Oscillator (-hp- Model 651A), an
AC Voltmeter (-hp- Model 331A) and a 50 ohm
±I%, I watt resistor (-hp- Part No. 0727-0024)
will be required for this test.
b.
Set Model 465A GAIN to 20 db.
c.
Connect ac voltmeter to Model 465A OUT­
PUT; set RANGE to 10 V.
d.
Connect oscillator OUTPUT to Model 465A
INPUT.
Set frequency to I kc; adjust output
for ac voltmeter reading of 10 v.
e.
Place 50 ohm resistor acrOss Model 465A
OUTPUT.
AC voltmeter reading should drop
to 5. 0 v.
This verifies Model 465A output
impedance of 50 ohms.

5-11. DISTORTION CHECK.

a. Figure 5-2 describes the test arrangement
recommended. A Test Oscillator (-hp- Model
65IA), a Distortion Analyzer (-hp- Model 331A)
and a Frequency Response Test Set (-hp- Model
739AR) will be required.
b. Connect Model 465A as shown in Figure 5-2.
Model 465A
AC Voltmeter
Range
Readings
10
9.0 v
10
OB. 1 to 09.9 v
10
OB. 9 to 09.1 v
10
OB. 9 to 09.1 v
10
7.2 to 10.B v
10
9.0 v
10
OB. 1 to 09.9 v
OB.9 to 09.1 v
10
10
OB.9 to 09. 1 v
10
7.2 to I0.B v
AC
01775-1

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