Wouldn't it be easier to add some front-end filtering? On Fri, Jul 18, 2014 at 1:32 AM, <[email protected]> wrote: > Thanks Tom ... you are right it is not surprising -- but what I am surprised > at is how good a job the builtin AGC does for most cases and maximizes the > value of the limited dynamic range. Also, your explanation of the AGC > matches my observations so its out. > > This is what I'm thinking (out-loud so don't laugh) ... I have a channel > that should be free of most signals (through FCC allocation and observation > ... lets call it dark_channel). I can put that through an xlat_fir and get > the resulting power of the noise floor in that channel ( should be relative > noise floor of the sampled spectrum, call it dark_channel_power). I assume I > can also measure the peak coming out of the source (call this > peak_source_power). I'm envisioning a block that would set a gain based on > the limiting peak_source_power to less than say 80% of signal peak and > limiting dark_channel_power to some acceptable upper limit (probably derived > from experimentation). The gain value would have to be filtered obvious to > some reasonable time-constant. > > Questions: > -- Does this sound reasonable? Can anyone poke a hole in it? Is there a more > conventional approach? > -- What would be a good block would measure the power of the dark_channel > and source signals? > -- For the near-far paradox ... dark_channel_power sets my max gain for far > signals and source_power sets my min_gain for near signals -- is this a > reasonable approach > -- Is there a good starting point for the block to convolve these two power > measurements into a hardware gain setting? (remote, but had to ask) > > Jim > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
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