[Elecraft] AM with FM filter (was: Re: [Elecraft_K3] Re: Close to Ordering)

[Guy Olinger K2AV]

On Mon, Nov 7, 2011 at 8:23 PM, Joe Subich, W4TV <lists at subich.com> wrote:

> Since modulation is performed in DSP, there is no change in the TX
> width.

DSP modulation is an oxymoron of sorts.

Since modulation involves imposing one signal on a second signal to
obtain the wanted third signal, technically there is no modulation in
a K3.  The desired signal is directly formed digitally via algorithm
and placed without further processing into the linear TX string at the
15 kHz IF via a DAC.  And we don't normally refer to up-conversion to
the TX frequency as "modulation."  So there is no modulation.  The K3
uses firmware directed direct signal generation.

We have SUCH a hard time walking away from our analog roots.  It's
comforting to call that voltage scalar pot plus an ADC the "RF" gain.
But it's real hard to find the RF gain lead going to the CPU, cause
the digital variable gain advice is time division multiplexed with a
bunch of other stuff sent on a single lead to the CPU.  It's "advice"
because it has no direct affect on anything unless the firmware and
CPU want it to, in very severe contrast to our daddies' analog radios.

73, Guy.