TB 9-6625-1356-35
(3)
Position controls as listed in (a) through (c) below:
(a) FREQUENCY RANGE switch to X1M.
(b) FREQUENCY dial to 10.
(c) OUTPUT ATTENUATOR switch to +20 DBM.
(4) Adjust attenuator to 60 dB.
(5) Adjust AMPLITUDE controls for a 1 mV reference indication on true rms
voltmeter. Record exact indication.
(6) Set OUTPUT ATTENUATOR switch to +10 DBM.
(7) Adjust attenuator to 50 dB. Record true rms voltmeter indication.
(8) Set OUTPUT ATTENUATOR switch to 0 DBM.
(9) Adjust attenuator to 40 dB. Record true rms voltmeter indication.
(10) Repeat technique of (6) through (9) above for each OUTPUT ATTENUATOR
switch setting from -10 through -40 DBM.
(11) Compute voltage difference between reference value recorded in (5) above and
voltage value recorded for each OUTPUT ATTENUATOR switch setting checked.
Example:
Voltage obtained in (5) above = 1.0050 mV
Voltage obtained at OUTPUT ATTENUATOR -30 DBM switch setting = 1.0095 mV
Voltage difference = 1.0050 - 1.0095 = -4.5 V
Voltage difference of -4.5 V yields 0.04 dB change as obtained from table 8
(12) Refer to table 8 and record attenuation change. Designate attenuation change
as +c if true rms voltmeter indicates a decrease from reference, and as -c if true rms
voltmeter indicates an increase from reference.
Voltage difference (V)
Equivalent attenuation change in dB(c)
0
to 1.7
0.01
1.7
to 2.8
0.02
2.8
to 4.0
0.03
4.0
to 5.1
0.04
5.1
to 6.4
0.05
6.4
to 7.5
0.06
7.5
to 8.7
0.07
8.7
to 9.8
0.08
9.8
to 11.0
0.09
11.0
to 12.2
0.10
12.2
to 13.3
0.11
13.3
to 14.5
0.12
14.5
to 15.7
0.13
15.7
to 16.8
14
