[Elecraft] (no subject)

[Gary D Krause]

Thanks for the explanation, Alan. So, my next question is, how does it compare 
with a crystal filter? It is better? Does it give you more flexibility with 
filtering?

Thanks,
Gary, N7HTS


On Tue, 26 Jul 2011 08:08:38 -0700
  Alan Bloom <n1al at sonic.net> wrote:

     On Tue, 2011-07-26 at 08:44 -0600, Gary D Krause wrote:

         I've been wondering what Quadarature down-sampling is? This is the 
first that I have heard of it.


     It's like a two-channel direct-conversion receiver. The two channels
     are on the same frequency but use local oscillators that are 90 degrees
     out of phase. With suitable processing, the in-phase (I) and quadrature
     (Q) mixer outputs give both the amplitude and phase of the signal.
     Among other things, that makes it possible to suppress the unwanted
     sideband of an SSB signal without a crystal filter.

     Alan N1AL