Yes I do remember the NBVM (ACSSB) units being
advertised back in the late 70's early 80's. Sure
didn't catch on then I suspect because it was
relatively complicated and expensive.
But you now have to wonder if that particular
modulation scheme can be implemented in the new DSP-IF
radio with just a firmware upgrade?? Wouldn't that be
a neat gimmick feature of the Orion? It could be a
bunch of fun right along with an "inside the radio"
implementation of the Thales digital voice system.
Its a shame to see all this DSP IF technology in
radios like the Orion to be only used for the same old
SSB/CW/AM/FM modes that the less sophisticated
competitive radios already do quite well.
--- email@example.com wrote:
> At 11:38 AM 04/22/2003 -0500, Jerry wrote:
> >The voice spectrum has two major groups, one at a
> few hundred Hz and
> >another out maybe three times that frequency with a
> gap in between.
> >There was a proposed scheme in the ARRL handbook a
> few years back to
> >separate those with separate bandpass filters, then
> heterodyne the upper
> >one into the gap at the transmitter, then shift it
> back to its normal
> >range in the receiver. Saved at least a third of
> the spectrum, maybe
> >more, but it went over like a lead balloon.
> There was a commercial unit made, think it was
> NBVM (narrow band voice modulation) or something
> It comes to me that Henry radio produced it, or sold
> it..... (?)
> ......and Jerry was right. It was a bust! Probably
> because it
> sounded bad when listening on standard receivers....
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