GE LOGIQ E9 Service Manual page 308

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5535208-100, R

Analog CW (cont'd)

Name: Service Diagnostics / Analog CW / GRX aCW Post Mixer Gain

For each subtest, a signal is set up with f0=2.521 MHz, the BP filter at 3.1 MHz and a mixer frequency

of 2.5 MHz. The dither and Pedof inputs are disabled. The TSIG_GAIN parameter is set to give -26.1

dB gain. The test is run by setting up the four different IQ_GAIN parameter settings that corresponds to

the 4 post mixer gain setting of 0 dB, -4 dB, -8 dB and -12 dB. The RMS and RMS attenuation between

the four mixers gain settings on both I- and Q-data are tested.

Are the probes connected? The test will run with probes connected to the scanner, but it is

recommended to disconnect all probes before running diagnostics.

Run Time: 00:05

1.) Verify the following tests pass:

If these tests pass, and the GRX aCW Post Mixer Gain test fails:

2.) Replace the CW GRX board.

Name: Service Diagnostics / Analog CW / GRX aCW Doppler LPF

For the Low Pass Filter test, Doppler test frequencies, both in the filter pass band and the stop band are

set up. The mixer clock frequency is set to 2.5 MHz and the band pass filter to 3.1 MHz. The dither and

Pedof inputs are disabled. The LP-filter 3 dB frequency will typically be at about 40 kHz. The following

parameters are tested: fdop, spectrum peak and RMS both in the I- and Q-data.

Are the probes connected? The test will run with probes connected to the scanner, but it is

recommended to disconnect all probes before running diagnostics.

Run Time: 00:05

1.) Verify the following tests pass:

If these tests pass, and the GRX aCW Doppler LPF test fails:

2.) Replace the CW GRX board.

Analog Receive Tests

Analog Receive Tests

Section 7-5 - Common Service Desktop