I'm trying to run the initialization script for the KAT 16K
spectrometer. I get FFT overflow even though all the shift bits are
set. How is this possible? Here's the transcript:
$ ./rfi_init.py
Connecting to ROACH... done.
------------------------
Programming FPGA... done
Checking clocks... ok, 200 MHz.
Auto-calibrating ADC... done
Attempting automatic RF gain adjustment...
Gain was -11.5dB, resulting in an ADC input level of -29.30dB.
Trying gain of -7.20dB...
Gain was -7.0dB, resulting in an ADC input level of -28.54dB.
Trying gain of -3.46dB...
Gain was -3.0dB, resulting in an ADC input level of -26.66dB.
Trying gain of -1.34dB...
Gain was -1.0dB, resulting in an ADC input level of -25.45dB.
Trying gain of -0.55dB...
done!
Setting FFT shift... set to 0xffff.
Configuring accumulation period to 1.00 seconds... done
Resetting counters... done
Current status: FFT is overflowing!
Thanks for your help.
Tom
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