View Single Post
  #53   Report Post  
Old August 25th 13, 07:00 PM posted to uk.radio.amateur,rec.radio.amateur.boatanchors,rec.radio.amateur.homebrew
Ian Jackson[_2_] Ian Jackson[_2_] is offline
external usenet poster
 
First recorded activity by RadioBanter: Nov 2007
Posts: 568
Default Crystal phasing & single signal reception

In message , gareth
writes
"Ian Jackson" wrote in message
...

You're not confusing SSB generation (and reception) by the 'phasing
method', are you?


Neither that nor Weaver's Third Method.


While a single crystal filter can provide a fair amount of selectivity
(combined, if you choose to use it, useful suck-blow or blow-suck
frequency response), it is not really suitable for 'serious' SSB
filtering. Its frequency selectivity characteristics don't really use
clever phasing out of the audio image. The passband peak is really too
sharp for either the generation or reception of good quality SSB, and you
usually need a 'proper' flat-topped filter, a 'proper' SSB phasing TX or
RX (which also does exist in a direct-conversion form) - or if you're
really clever, a 'third method' phasing TX (or, I suppose, RX).


Actually easier to set up for the Third Method, because all the phasing is
done
at a single audio frequency. But that's not what this thread is about.


That said, I'm sure that 'KISS' transmitters and receivers have been made
using a single-crystal filter - albeit having a somewhat limited
performance.


It's not for SSB. CW forever!

However, ISTR G3VA (RIP) in his TT column discussing Stenode
correction when trying to resolve voice through a single-Xtal filter.

That is indeed true, where 'Stenode' is a fancy name for lots of HF
boost to compensate for what otherwise would be very bassy audio.
--
Ian