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Section V
Paragraphs 5-8 t o 5-9
f . Set FREQ. dial t o 50, counter should read 20.0
*O.
6 milliseconds.
g. Set RANGE t o XlOand FREQ. dial t o 5, counter
should read the same
as
step f .
h. Repeat steps
e
and f withRANGE atX10. Coun-
ter
should read 5.00
*O.
15 milliseconds and
2.00
f0.06 milliseconds respectively.
i.
Set frequency counter function switch t o FRE-
QUENCY
(.
1).
j .
Complete check by setting RANGE switch and
FREQ. dial
as
shown in table 5-2, columns one and
two.
The counter reading should be
as
shown in
column three
.
Table 5-2. Dial Accuracy
Range
Switch
XlOO
XlOO
XlOO
X1 K
X1K
X1K
X1 O K
X1 O K
X1 O K
Freq.
Dial
5
20
50
5
20
50
5
20
50
500 cps
k
15 cps
2000 cps
i
60 cps
5000 cps
f
150 cps
5 kc
i
150 cps
20 kc
i
600 cps
50 kc
f
1 . 5 kc
50 kc
f
1 . 5 kc
200 kc
i
6 kc
500 kc
f
15 kc
5-8. FREQUENCY RESPONSE AND OUTPUT
VOLTAGE CHECK.
a.
Connect
ac
voltmeter and 600-ohm load t o oscil-
lator output
as
shown in figure 5-2.
t o 25.
b. Set Model 204B RANGE t o X1 and FREQ. dial
c.
Adjust AMPLITUDE for 2.5 volt reading on
voltmeter.
d. Sweep FREQ. dial by hand t o read 50. As dial
is swept, voltmeter reading should not vary more
than &O.
075 volts.
e. Set Model 204B RANGE t o X10.
f . Set FREQ. dial t o 5 and repeat step d.
g . Complete check with RANGE switch
set
t o each
untested position while repeating step d.
Model 204B
0
2040
@ 4 0 0 H
2 0 4 0 - S - S A
Figure 5-2. Test Setup for Frequency Response
and Output Voltage Check
5-9. DISTORTION CHECK.
a.
Connect distortion analyzer and 600-ohm load
t o oscillator output
as
shown in figure 5-1.
b. Set Model 204B controls
as
follows:
RANGE.
. . . . . . . . . . . . .
XI00
FREQ..
. . . . . . . . . . .
10 (1 kc)
AMPLITUDE.
MAX.
. . . . . . . . .
c. Set distortion analyzer controls as follows:
FREQUENCY RANGE.
. . . . .
XlOO
I N P U T . .
. . . . . . . . . . . . .
A F
FUNCTION.
. . . . . . .
SET LEVEL
METER RANGE
. . . . . . . . .
100%
d. On distortion analyzer:
(1) Adjust
INPUT
SENSITIVITY for full scale
(2) Set FUNCTION t o DISTORTION.
(3) Adjust FINE and COARSE frequency controls
and BALANCE control for dip
at
fundamental
frequency (1 kc); switch METER RANGE
as
necessary t o monitor dip.
(4) Readjust controls untilabsolute dip is located
e.
Meter reading should be
less than 1 . 0 on the 1%
reading (1.0).
range.
5-2
01369-3
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