|
From: | mleech |
Subject: | [Discuss-gnuradio] Bandpass spectral correction |
Date: | Mon, 08 Apr 2013 14:11:41 -0400 |
User-agent: | Roundcube Webmail/0.7.2 |
I have a need to have a *very flat* passband for some of the analysis I'm doing of neutral hydrogen. Real hardware, of course, produces passbands that aren't quite flat--some worse than others.
So, I've tried an experiment in one of my flow-graphs where I take the (aggressively-averaged) FFT magnitudes by taking each bin magnitude and dividing by the maximum, and then using the inverse of that to produce a correction curve, as normalized magnitudes.
I then use those normalized magnitudes in an FFT filter (after converting into time-domain), and the result works less-well than I would expect. The result is a *much-flatter* spectrum, but at the fine-scales I'm doing analysis at (0.5dB), it's not nearly as flat -- the outer edges are under-corrected, and the inner bits are over-corrected.
Anybody have any pointers to good papers on passband flattening techniques?
[Prev in Thread] | Current Thread | [Next in Thread] |