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Re: Re: 1.2 Gig sig. Source



I'm currently working to deliver some Qualcomm surplus parts to a couple of
individuals for distribution. Before I do it, I want top be sure we're
headed in the right direction & would like to get some input from possible
users of this type of equipment.  One project is a simple 10 MHz comb
generator using a 10 MHz TCXO reference and a 74AC00 IC which generates 10
MHz pulses maybe 1 ns wide .  This puts out usable harmonics easily into
the 4 GHz range.  The other projects are synthesizers for various
frequencies.  The PLLs nominally have a range of about 2.3-2.8 GHz and  by
adding a capacitor to the VCO will typically go down to 2.1 GHz.  My
thoughts are that these synthesizers should be useful for both a 2556 MHz
LO for a 2.4 GHz down converter as well as a direct marker for 2.4 GHz if
programmed for that frequency.

I have one question that concerns me about the usefulness of markers
directly on 2.4 GHz.  What IF tuning range do most operators have for
receiving 2.4 GHz?  That is, can most stations tune below 2.4  GHz or is
this the bottom end of the tuning range?  My concern is that if a marker is
a few KHz low at 2.4 GHz, can it be tuned in for most stations?

The same 10 MHz comb generator will  put out a good signal at 1270 MHz.
Another approach to generating a 1268 or 1270 MHz marker could be to
program one of the synthesizers to 2X 1268 or 2536 MHz. It has a divide by
two prescaler on board which will output the desired 1268 MHz signal.  I
have a schematic drawn up of the 10 MHz comb generator and will see if we
can get it posted on the web shortly along with modifying the synthesizers
for the frequencies mentioned above.  
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