Well you've managed to hit my kill file. Good riddance
to your anti-social pap.

Bruce Raymond



"Frank Gilliland" wrote in message
...
In , "Harry - SM0VPO"
wrote:

Frank Gilliland ) writes:

... as I write this it occured to me that it might be
easier for Harry to mix the VCO signal down to a frequency where
the average logic IC can work. You don't have to find a prescaler,
and the design's frequency steps won't be limited by the division of
that prescaler. There are various mixer schemes that will result
in the needed frequency. There may be reasons for not doing it this
way, but it may not even be explored because Harry hasn't given this
alternative any thought.

Michael VE2BVW

Hello Michael. Down-conversion has been considered, but quickly
dismissed.
The sysnthesiser I need is a tool to be used for a wide variety of
projects:
projects that include modulation.

Down conversion of frequency preserves any applied modulation. The
prescaler
and subsequent dividers filter out modulation so that a true phase lock
may
be achieved.

WHAT? Even -with- modulation all you need is a low-pass filter on the
output of
the phase detector, which is what you have to do anyway. The phase lock is
"true" whether you have modulation or not, it just takes a couple extra
milliseconds to lock. If the VCO drifts faster than that then you have
some
other problems that have a higher priority than a prescaler.

BTW, if you don't have any transistors in Sweden that will work at 100
MHz, what
are you using for your VCO?

This is especially true with WBFM where the total divide rate
must be greater than 10000 to achieve a phase lock. NBFM, with a minimum
modulating freq of, say, 250Hz, still needs a divider to divide by more
than
60.

Down conversion could make a simple synth if modulation were never to be
used.

It makes a simple synth even -with- modulation.

I intend the project area to be both TX + RX, and to become a
"building block" for a variety of circuits.

Anyway, I have received a lot of response. My original question was "is
there a good cheap source of prescalers" (but in a long-winded way) and
this
I have received. Many thanks to you and all who have given me positive
suggestions. Unfortunately I will not be melting down horses hooves to
make
the glue to bond the home-beaten copper to a board to make the PCB. The
only
thin board available would be ready-made plywood, and that would not be
"homebrew" ;-)

From what you say about the availability of materials in Sweden, do you
need any
help finding some quality plywood (not obsolete, of course), and maybe an
inexpensive source? You might try posting in alt.plywood.pirate.....





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