On Mon, 2009-11-30 at 23:41 -0800, Jeff Campbell wrote: > Hello All, > > I was using the ATSC tuner side of the HVR-1600 over the weekend and I > had a hard time determining my signal strength or finding a place > where I can get a consistent SNR reading that can be used to compare > the relative strength of the various channels I am able to tune. What > is the recommended way to determine signal strength and SNR?
I'm sure Devin has a lot more details than I, but you can look at the output of femon. Keep the following in mind: 1. The status is coming from the s5h1409 module, the driver module for the ATSC/QAM demodulator 2. The signal strength is bogus. From the code it looks like a copy of the SNR. 3. The SNR value will only be valid when there is a lock. Don't count on it otherwise. 4. Since Steve Toth wrote the driver, I'm assuming the SNR value is in 0.1 dB, but I'm not sure. That of coure still doesn't give you what your margins are for good, bad, and marginal for 8-VSB, QAM-64 and QAM-256. I suppose one can look up the theoretical BER vs SNR curves to find out. That's actually one status output I would like: SNR margin. The absolute values don't mean much to people. Regards, Andy > -Jeff _______________________________________________ ivtv-devel mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-devel
