My understanding is that the Eb/No is more of what you would find at the antenna terminals, without the bandwidth of the receiver?
Using your data on your web site, how does this relate to say, PSK31 modulation? Would the SNR also be at zero with the 31 bps baud rate with the B/C (Bandwidth in Hz divided by the Channel capacity in bps) at ~ 1.0000? Then how do you get the much lower SNR ascribed to a mode such as PSK31? ( ~ 10dB or so?) According to your chart it would need about 7 times the B/C ratio? I had thought the ratio would be somewhat fixed at about 63 Hz BW to 31 bps or around ~ 2.0000. What am I missing? The BW is actually much wider than the number we usually use for PSK31 to get the much lower SNR? How do you make a wider bandwidth for a given mode? Isn't the bandwidth based on the baud rate to begin with? 73, Rick, KV9U Rud Merriam wrote: > Rick, > > The measurement of SNR and Eb/No are two different measurements. The > confusion comes because they are both cited in dB. It took me quite a lot of > rereading material to clearly understand them. I dumped my understanding of > it onto my web site at > http://thehamnetwork.net/wiki/#Shannon-Hartley%20%5B%5BShannon%20Limit%5D%5D > . To see the math and graphs clearly you need to have some support software > installed. See > http://thehamnetwork.net/wiki/#Graphics%20%5B%5BMath%20Expressions%5D%5D for > details. > > The actual Shannon Limit is -1.6 dB for Eb/No. The limit for SNR is not > expressible, that I have seen, as a single number. Instead it is determined > by the power, noise, and bandwidth. More simply, by the SNR and bandwidth. > One of the datum I found interesting is that below 0 dB SNR the channel > capacity drops precipitously. > > Rud Merriam K5RUD > ARES AEC Montgomery County, TX > http://TheHamNetwork.net > >
