[time-nuts] Generating a stable 26MHz and 19.2MHz from 10MHz

[Don Latham]

Hi Magnus: I goofed, it's actually 5.12 MHz, the driving crystal
standard for the ICOM 260A 2 meter transceiver synthesizer. I want to
use it with a transverter for moonbounce, hence would like to start out
with a solid reference frequency. Might even be overkill. See, I knew it
could be done with (almost) some 7400's :-)
Thanks for the hint! The thing to do then is to pick off some of the
existing xtal frequency, and as you say count to the common denominator.
A little varicap in the crystal circuit can then be driven by the phase
comparator...
Should not be too hard to do...
Don

Magnus Danielson
> Don,
>
> On 07/02/2011 09:48 PM, Don Latham wrote:
>> Hi Anders:
>>
>> I need something to give 2.048 MHz from a 10 MHz source, and have not
>> too aggressively tried to find a way; have followed with interest many
>> suggestions from TN's.  I found a company called Vectron that makes,
>> ostensibly, very nice frequency translators, with an fin and an fout,
>> with reasonable phase noise characteristics (?), the data sheets are
>> available and intriguing, but I spent an hour or more trying to find a
>> way to actually buy one.
>
> Getting 10 MHz to 2,048 MHz isn't all that hard. You can do it in good
> old 4000 CMOS series if you need to. What application to you need it
> for? I recognice it as a standard telecom frequency and well have in
> fact implemented 10 MHz to 2,048 MHz conversion (even if that was not
> the primary target). The wideband noise needs isn't very daunting in
> telecom applications, but long-term stability is another thing.
>
> If you really do not need to have very good wideband phase-noise, a 4046
> and a few dividers will help you.
>
> 10 MHz and 2,048 MHz has the highest common frequency in 16 kHz, so you
> need to divide by 625 on the 10 MHz and 128 on the 2,048 MHz. If you
> settle with the 4046 oscillator or chooses an off the shelf VCXO depends
> on what you need, but it is not too hard and too expensive to come by.
>
> Cheers,
> Magnus
>
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Dr. Don Latham AJ7LL
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