[Lowfer] Homebrewed SSB Filter question - Clarification

[Johan H. Bodin]

Andy,

a phasing TX is the way to go. You don't even need an audio phase shifter with
Jason, v0.99 has an I/Q quadrature output already! The left and right soundcard
outputs are 90 degrees apart, ready to inject into the mixer(s).

See "Options/Tx Port/Ampl. and phase compensation" in the Jason Program.

All you need is a pair of mixers fed with quadrature LO, an I/Q summing point
and a simple band pass filter at the output. You could also use a "commutating
mixer" built with a 74HC4052 or similar analog multiplexer.

Some ideas:
  http://yu1lm.qrpradio.com/homebrew.htm
  http://www.qsl.net/dl4yhf/phasing_lf_exciter/index.html
  http://www.w1tag.com/Phasing.htm

73
Johan SM6LKM


Steve Dove wrote:
> Simple, because the has-to-be-accurate quadrature phase shift of the 
> audio source (which is ordinarly in analogue a pain to get right over 
> the full audio band) only has to be right at effectively a single 
> frequency;  it could be achieved with just an equal RC / CR pair to make 
> the +/-45 degrees for the quadrature pair, centred at whatever frequency 
> Jason pops out of the soundcard.