Jerry,
The problem is the source is square and the DBM is being used for a switch.
That means the output is square.? AS to CW it works better than the old pump
in a tone and can be clean with the exception of managing harmonics.
In the old days and even now the tube rigs with SI5351 as a synthetic crystal
is clean, why?? Tubes are not fast they make lousy square waves even when
fed them.? that and many of the radios have tuned circuits before the final and
the output is tuned.? OFten if you qsy across them band touching up the tuning
is required.? ?That is what selectivity and tuning does for us and too us.
Modern radios are wide band amps that will make efforts to reproduce what
they were fed.? So the basic solution is still, filters, lacking that, a very clean
source.? Alas the uBitx has a square wave source and no way to clean up
before the amp, a hole is there to fill.
Allison
