DTX to RRX DP
1 Diagnostic Link:
Diagnostics >> System Function >> RF >> Transmitter Diagnostics
Diagnostics >> Hardware Location >> System Cabinet >> Transmitter Diagnostics
Figure 1. DTX to RRX DP
2 Purpose
The DTX to RRX Datapath diagnostic tests the analog signal quality and filter response of the DTX, Mega SW, and RRX modules. This is the only diagnostic that tests the signal quality of the Exciter output and the Mega SW analog signal paths. This loops the DTX signal through the Mega SW Receiver Chain.
3 Components Tested
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Narrowband Exciter output; DTX1, (Signal quality)
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Mega SW (Signal quality)
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Recever Modules (Signal quality)
4 Requirements
This diagnostic should not be run until after the IRF3 BLD, DTX BLD, RRX BLD, Mega SW, and RF Calib diagnostics have run and passed. If the RRX BLD passes and the DTX to RRX DP fails, the fault should be in either the DTX or the Mega SW. Since the same DTX signal is sent to all RRX input channels, if the DTX to RRX DP fails for only some channels, the fault is likely to be in the Mega SW.
5 Block Diagrams
Figure 2. Block Diagram
6 Test Sequence
The narrowband and broadband (if installed) data paths are tested separately. The narrowband path is tested over the normal range of proton frequencies. The broadband path is tested at proton frequencies and over several MNS frequencies.
For the narrowband tests, the DTX-1 is programmed to send a signal through a cable connected to the control board of the Mega SW. The control board routes this signal to each switch board in the Mega SW. The switch boards send the DTX-1’s signal to each input channel of each RRX module. The RRX are commanded to digitize the DTX-1’s signals and send the data directly to the IRF3. The ICNs are not used in this diagnostic. The AGP analyzes the signals captured by the RRX modules and creates a log file with the results. The log file is /usr/g/service/log/dtxRrx_loopback_<date>.log
7 Expected Results
The diagnostic passes.
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The log file:/usr/g/service/log/dtxRrx_loopback_<date>.log