GALFA System Code Revisions

• Wideband transform is now 512-points. Both 8k- and 512-point PFBs are still 4x overlap.
• Narrowband now reports 7679 points instead of previous 7935 points. Bin width is still 871.9Hz, bandwidth is now 6.696MHz reduced from 6.919MHz.
• Shape of the low-pass filter slightly changed. The window function was offset by half a sample.
• Math in the LPF changed to round coefficient multiplies correctly. Incorrect rounding was creating a small DC component in the middle of the narrowband transform. The spur is now gone.
• Added a PFB bypass to both transforms. If the host sets a bit, the hardware will bypass the frontend filter on the PFB and the transform becomes an FFT. This is in the gdiag user interface with the "(" and " )" keys for PFB and FFT, respectively.
• GALFA now records ADC overflows as an error condition. This is stored in 2-bits of the G_ERR column of the FITS file like the other error conditions
• GALFA-generated FITS files (GXFITS) now have 512 points for wideband, 7679 points for narrowband.
• GXFITS now reports only one DAC value for each beam/polarity instead of all 14 values every time.
• New optimization for setting DAC levels, 5x faster than previous method
• Time-domain diagnostics can now trigger on ADC overlap to better capture RFI-related overflows (-ovftrig option to gdiag).
• Tweaky new features and bug fixes in graphical diagnostic user interface. See gdiag --help.
• Socket interface for controlling and getting data from GALFA through a TCP socket connection.