Carl Moreschi N4PY
919-494-2363
Franklinton, North Carolina
n4py@earthlink.net
----- Original Message -----
From: "Carl Moreschi" <n4py@earthlink.net>
To: "Barry N1EU" <n1eu@hotmail.com>
Sent: Thursday, February 01, 2001 3:34 AM
Subject: Re: [TenTec] Updated "Lineage" Release to Public (long)
> The PBT in the Corsairs, Paragon's, OMNI V, OMNI VI all use a 9 mhz to 6.3
> mhz
> and back to 9 mhz to accomplish PBT.
>
> The scheme works like this. The signal is first filtered at 9 mhz. A
> variable oscillator
> then converts this signal to 6.3 mhz. The exact value of the oscillator
> determines what
> part of the converted signal goes through the 6.3 mhz filter. This very
> same oscillator
> then converts filtered 6.3 mhz signal back to 9 mhz. What you end up with
> is the 6.3 mhz filter
> becomes essentially tunable to allow you to vary what part of the passband
> passes
> through it. This tunability is accomplished by the variablity of the
> oscillator doing
> the back and forth conversion from 9 to 6.3 and back to 9.
>
> So when you speak of passband tuning with a scheme like this, you really
> need to talk about 2 IF freq's. For DSP radios, this all gets done in
> software because you really can
> move the filters since they are just software anyway.
>
> Carl Moreschi N4PY
> Franklinton, North Carolina
> n4py@earthlink.net
> ----- Original Message -----
> From: "Barry N1EU" <n1eu@hotmail.com>
> To: <tentec@contesting.com>
> Sent: Wednesday, January 31, 2001 11:16 AM
> Subject: Re: [TenTec] Updated "Lineage" Release to Public (long)
>
>
> >
> > Dumb question - is the PBT in late rigs really at 9Mhz? It's not at
> 6.3Mhz?
> >
> > 73,
> > Barry N1EU
> >
> >
> > >From: Kevin L Anderson <k9iua@juno.com>
> > >Corsair I: 3 IF filters, same AGC system as Omni-C, dual conversion
> > > (IFs at 9 and 6.3 MHz and then back to 9 MHz for PBT), Corsair II
> > >(8/87): same basic receiver, 3 IF filters, dual conversion,
> > > stock 9 MHz IF filter upgraded to 8 poles, PBT,
> > > audio filter, NB?, transformer feedback amplifier stages before and
> > > after first mixer (diode ring), adds 3 selectable audio filters and
> > > a notch filter within the AGC loop to Corsair I
> > >
> > >Omni V (11/90): uses synthesizer rather than PTO; IFs at 9 and 6.3 MHz
> > > (and then back to 9 MHz for PBT, like Corsairs)
> > >Omni VI (1/93): added RIT, sidetone that follows CW offset, internal
> > > keyer, low pass DSP filter to reduce IF hiss instead of "tone
> control",
> > > increased microprocessor clock speed, crystal oven for xtal osc,
> > > minor changes in firmware controlled items
> > _________________________________________________________________
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> >
> >
> > --
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> > Administrative requests: tentec-REQUEST@contesting.com
> > Problems: owner-tentec@contesting.com
> >
> >
>
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