On Fri, 08 Sep 2006 19:05:49 +0200, "i3hev, mario held"
wrote:

Dave Platt wrote:

As I understand it, in order to do SSB via direct conversion, you must
use a modern version of the old IQ phasing technique. ...

that's correct
the problem here is that you need a phasing filter offering a constant
(and precise) 90 degrees phase shift all over the receiver band, and
that can be tricky to do...

This is not that hard and there are tricks to do this over very wide
ranges. The easiest is create a fixed 90 degree reference and down
convert it.

Another is use one of the I&Q output DDS chips.

These days, of course, you can apply the phase shift by
converting the two baseband signals to digital format...

well, you're opening doors to digital radio
But, AFAIK, the actually attainable dynamics does
not seem to incite enthusiastic greetings...

The problem is finding fast A/D with enough bits (more than 16)
and using 32bit processors to grind the data. Those two things
are not easy or cheap.. yet. But we are getting there.

Allison