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. Just my 2ct. Klaus _______________________________________________ linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
