Plz read the access rules careful
http://www.rdfwt.com/forumdisplay.php?f=74
-------Original Message-------
From: Wolfgang Hartmann
Date: 04/10/06 06:23:18
To: [email protected]
Subject: [soft_radio] Re: phase noise and spectrum
analyzers, plls (3)
Hallo Cecil,
I wrote originally some notes about pll's because I
was asked to do
So. It is a very simple and maybe basic type of
information, I gave.
Now, I would like to hear from You the "other side of
the world",
Which advantages are to await from a digitial system?
Would You like to send some lines about the essential
parts and give
An explanation about the main topics?
Wolfgang
--- In [email protected], KD5NWA <[EMAIL PROTECTED]>
wrote:
>
> You are thinking in terms of analog mixers, Digital
QSD mixers are a
> whole other world. QSD mixers have to have a square
wave clock, and
> function way better than a analog mixer if given a
low phase noise
> "digital" clock. If they are given an analog sine
wave for a clock,
> you would have to turn that back into a digital
signal which can
> introduce jitter, so when possible it's best to keep
the clock
> digital as much as possible. In a well designed QSD
system a clock
> divider will improve the phase noise figures not
make it worse.
>
>
> Food for thought.
>
>
> At 04:03 PM 4/8/2006, you wrote:
> >An addendum to my info:
> >
> > From this paper, I gave You the Internet-address,
You can clearly see
> >and take some consequences for receiver
constructing.
> >
> >1.1. If one has an oscillator with phase-noise, You
not only mix the
> >oscillator not only with the incoming frequency,
but also with the
> >phase-noise of the oscilltor. It is something like
a synchronous
> >mixing with a lot of frequencies and a lot of
mixing products. The
> >less the bandwidth of the phase-noise the better
for quality of mixing
> >result.
> >
> >1.2. At mixing You mix a strong signal (the
oscillator-signal) with a
> >very little one, the incoming signal. Partly You
have to filter the
> >product.
> >
> >1.3. You should avoid all solutions with phase
noise inclusive
> >solutions with IC-dividers.
> >
> >1.4. The better the signal of the mixing process,
the better the
> >result. Because of that, to gain ultimate quality,
You should forget a
> >lot of solutions and change to a DDS-circuit with a
very high
> >working-frequency. All other solutions have a lack
of quality, to
> >reach ultimate success.
> >
> >1.5. The alternative could be a quartz-osciallator,
but one is not
> >able to change the frequency in a wider range.
> >
> >1.6. My "feeling is" even concepts with
I,Q-solutions could be better,
> >if a fast DDS-circuit is used.
> >
> >1.7. Having a rectangular signal meens a lot of
filtering.... And a
> >lot of useless noise.
> >
> >One can see, that using a fast DDS-circuit is at
the moment even for
> >traditional receveiver concepts in let me say AM,
SSB and other
> >modulation-types is "state of the art" and You
miss-use time and
> >effort for other versions.
> >
> >I will look for answers coming. In the meantime, I
will work with
My DRT1.
> >
> >An incoming signal is always not a digital one
even, if its
> >constructed digital by modulation as DRM.
> >
> >Wolfgang
> >
> >--- In [email protected], "Wolfgang
Hartmann"
> ><dadalbinder@> wrote:
> > >
> > > Hallo to all, especially to Dan.
> > >
> > > Here is an email address, wher You can find some
informations in
German
> > > language.
> > >
> > > http://www.elexs.de/clock3.htm
> > >
> > > You see the phase-noise and the noise carpet of
several designs.
> > >
> > > They have a lot more on DRM, Elektor-receiver.
> > >
> > > Wolfgang
> > >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >Yahoo! Groups Links
> >
> >
> >
> >
>
>
> Cecil Bayona
> KD5NWA
> www.qrpradio.com
>
> "Windows the worlds most successful software virus"
>
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