On Thursday 13 April 2006 22:02, Klaus Schmidinger wrote: > Hartmut Hackmann wrote: > > A comment / question: > > > > Does it make sense to spend significant effort on computing an accurate > > SNR value? > > It might make sense for VSB and DVB-C / S, i cant tell. > > But i am sure that for DVB-T, it doesn't. > > A signal to noise ratio might be excellent but reception very poor due > > to several (short) echoes. > > For antenna optimization and comparison there (to my experience) are 2 > > useful values: signal strength (minor) and the raw bit error rate > > (major). The raw ber can be normalized to the maximum correctable ber and > > this would be a useful measure since this number tells about the real > > safety margin. > > > > Just my opinion > > Hartmut > > An actual application (like VDR, for instance) isn't interested in all > the various signal parameters and their scaling and units etc, etc. All > it needs is an idea about signal *strength* and *quality*. So I agree with > Hartmut. I'd like to have a way of asking the driver for exactly these > two values, both on a fixed scale from 0 to some maximum (which should > be the same for all devices, since it's an abstract value). I guess only > the particular device's driver can take all the various parameters to > form a useful "strength" and "quality" value. That's what the application > would finally present to the user in, say, the form of a bar graph. > > The average user doesn't care about "dB" or "BER" or whatever. He wants > to know whether the signal is "strong" and "good". At least that's what > the STBs I've seen show. Its a pity we can't just add these to the dvb_frontend_info structure :( Or at least I assume we can't since we cannot change the binary API. _______________________________________________ linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
