On Mon, 2011-04-25 at 21:08 -0400, [email protected] wrote: > Try to make me understand why you would use ESSB > > Bob K3DJC>
I use it with the bandwidth set to minimum (3 kHz) and the TX equalizer set to limit the transmitted bandwidth to about what it would be using regular SSB. I do that to get better, more natural-sounding transmitted audio. Audio quality is not only, or even mainly, determined by the bandwidth and amplitude flatness. The phase response is critical. If you look at a crystal filter on a vector network analyzer you can easily see that the phase response is very non-linear. A "good" crystal filter with a small shape factor (large number of poles) is worse in this respect than a cheaper filter with a poorer shape factor. I believe the un-natural sound of most SSB signals is primarily due to the non-linear phase of the crystal filters. ESSB uses the 6 kHz crystal filter, which has a smoother phase response. The transmitted bandwidth is limited by the digital filter, which is inherently linear-phase and contributes no additional phase distortion. Alan N1AL ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
