Electro-Metrics EM-2115, Instruction Manual

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EM-2115 4.0 SERVICE, MAINTENANCE, CALIBRATION
(EM2115S4-17)
level, if required (usually ±1.0 dB), to obtain a suitable reference on the RMS
Voltmeter.
d. Check the IF bandwidth using the procedure given below.
1) Increase the frequency of the Signal Generator until the RMS Voltmeter reads -
6 dB down from the reference point. Note the frequency at this point.
2) Decrease the frequency of the Signal Generator until the RMS Voltmeter reads
-6 dB down from the reference point. Note the frequency at this point.
3) Subtract the frequency reading in Step 2 from the reading in Step 1 to obtain
the IF bandwidth.
e. Set the Bandwidth for 9/10 kHz (Wideband IF Bandwidth for the 175 kHz IF
channel).
f. Using the procedure in Step d, check the 9/10 kHz IF Bandwidth for the 175 kHz
IF channel, specification limit: 11.5 kHz1 ±10%.
g. Set the Bandwidth for 1 kHz (Middle IF Bandwidth of the 175 kHz IF channel).
Verify that IF center frequency is at 175.00 kHz. If not, adjust A3A1-L2004.
h. Using the procedure in Step d, check the 1 kHz IF Bandwidth for the 175 kHz IF
channel, specification limit: 1 kHz ±10%.
i. Set the Bandwidth for 200 Hz (Narrow IF Bandwidth for the 175 kHz IF channel).
j. Using the procedure in Step d, check the 200 Hz IF Bandwidth for the 175 kHz IF
channel, specification limit: 100 Hz ±10%.
NOTE: This bandwidth parameter is established by the Narrow-
band Filter Module A6.
k. Set the Frequency Range to 2.4-5.5 MHz (8) and repeat Steps e thru j for the 1.6
MHz IF channel, except for the following:
1) Apply a 1.600 MHz signal at an input level of 71.5 dB(µV) to A3J1.
2) Widest IF Bandwidth: 100/120 kHz, specification limit: 130 kHz ±10%.
1
The receiver specifications for the widest bandwidths of the 175 kHz and 1.6 MHz IF channels are 9.5 kHz and
105 kHz respectively. The bandwidths through the IF Amplifier Module are set wider than this in order to obtain
these specifications.