On Friday 08 July 2005 11:03 pm, stonewall@xxxxxxxxxxxxx wrote: > Working with szap on a satellite multicast application, > does anyone have documentation to the meaning or value of > the bits set on the frontend read for the SNR (or also > known as EbN0) and BER? > > The values from szap only are relational, but the tuner > on these PCI cards are calculating absolutes. For > instance, a nominal SNR for the work I'm doing is around > 15dB . . . but the report from szap, even if you convert > to decimal, is 58,000 . . . I think szap just returns whatever value the driver supplies. The raw data for the lgdt3302 chip is noise. There is a formula to convert it to SNR in dB in the specifications. I coded that up but it produces a negative number when the noise is greater than the signal and a small value around 15 dB for good signal. The DVB interface is an unsigned integer so a weak signal results is a large positive value and a good signal is a small positive value. Mythtv seems to expect the opposite so I changed the driver to return the raw data from the chip. > And with BER, this is normally a double precision number > . . . with a good status of around 10e-6 or so. > > Thanks in advance for any assistance > > Stonewall > > _______________________________________________ > > linux-dvb@xxxxxxxxxxx > http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
