Troubleshooting (cdma2000/1xEV-DV)
This topic contains information to help you troubleshoot measurements when using cdma2000 Demodulation. Also review Setting up a cdma2000 Measurement for additional measurement information.
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PROBLEM |
POSSIBLE CAUSE |
SOLUTION |
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Demodulation fails to lock-on to signal |
Signal not present |
Check test setup connections |
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Carrier too far from center frequency |
Adjust center frequency to ± 500 Hz of the carrier frequency |
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Input signal is over-loaded or under ranged |
Adjust input range |
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Frequency span is too narrow |
Increase frequency span |
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Incorrect chip rate |
Enter correct chip rate (not symbol rate or bit rate) |
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No Pilot Channel missing or level to low |
Set pilot channel at Walsh Code Number Zero. Try adjusting pilot channel power level. |
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Incorrect Long Code Mask |
Generally only cdma2000 reverse link signals with Long Code Mask equal to zero can be demodulated. |
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cdma2000 signal spectrum is inverted |
Check the Mirror Frequency Spectrum setting (MeasSetup > Demodulator > Format tab). |
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I/Q Offset too large |
Reduce the LO feedthrough (or DC Offset for I+jQ receiver) |
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If using an Keysight ESG to generate the input signal you need to check the firmware revision level. |
Use firmware revision B.03.60 or newer.
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Wrong channel marked as active |
Poor SNR Signal-to-Noise Ratio (signal to noise ratio). |
Increase signal power or remove cause of noise/distortion. |
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All bits not transmitted within a physical channel. |
Transmit all bits within a physical channel, or select code-domain power for the layer associated with the physical channel of interest (single-layer code-domain power displays are accurate even if the VSA is unable to identify active channels in the composite code-domain power display). |
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Data pattern induces large disparity in power between slower channels overlaid by the channel of interest. |
Verify that your transmitter is transmitting properly. |
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ADS application has failed to work with cdma2000 demodulation |
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The trace data constellation symbol location shape, such as dots, is not properly displayed. |
The display driver is not functioning correctly. |
Contact your PC manufacturer to see if a newer version of the display driver is available. If not, try decreasing the hardware acceleration. See the Windows documentation for instructions. |
See Also
Setting up a cdma2000 measurement
Measurement Speed Considerations
About Opt B7T: cdma2000/1xEV-DV Demodulation
