[time-nuts] Things to look for when buying a few FE-5680A's?
Chris Albertson
albertson.chris at gmail.com
Thu Jan 26 17:36:18 UTC 2012
On Thu, Jan 26, 2012 at 9:13 AM, Bob Camp <lists at rtty.us> wrote:
> Hi
>
> If you *need* to lock one of the new FE-5680's 10 or 20 Hz high, you
> probably can adjust the cap on the VCXO center it's range up there.
The frequency division is done by digital logic inside a CPLD and
you'd need to re-program the firmware. I think people have found that
these new FE5680s don't lock if you move far from 10MHz and you can't
get more than a few hundred Hz from 10Mhz by analog adjustment.
The "option 2" that is in the book is different from the fine scale
adjustment the current $40 can do. the true option two units can be
programmed over a range of many MHz by sending RS232 commands but the
current units can only by programmed over rs232 withina very narrow
range about like you'd find on a typical OCXO.
I think if you want a wide range oscillator you are best using a DDS
chip whos clock is locked to the FE5680 or a Thunderbolt. The
FE5680's advantage over a t-bolt is portability.
Chris Albertson
Redondo Beach, California
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