FFT overflow is a latching flag. It probably overflowed before you set the shift schedule? Try clearing the error and then reading it again. Or just run rfi_spectrum.py which does a clear after every read (ie it will print FFT overflows on the screen; if you don't see errors, all is well).
Jason On 18 Jun 2012, at 20:10, Tom Kuiper wrote: > 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 > > -- > I or me? http://www.oxforddictionaries.com/page/145 > > >
