Hi Bert
I want to monitor the frequency deviation continuously (that means: i
don't want to look at a scope ;)
and log the data several times per second. The goal is not to make a
'quality test' of the oscillator,
but to look for frequency deviations which are caused by external
influences of various kind.
I have a digital 500 MS scope, so i can use this for circuit
development, but i don't want to use it
for the actual measurements. Time measurements with microsecond accuracy
can be done
with a microcontroller, that's not a problem. BTW i'm using the
Parallax 'Propeller' controller
which has 8 cores running at 80 MHz each, and can measure time intervals
with 12.5 ns resolution.
It has also some very interesting timing circuitry, and can even
generate VGA video signals with
user-defined timing without any external special components. May be of
interest for one or the other
here on the list. :)
For those who are interested:
http://www.parallax.com/Portals/0/Downloads/docs/prod/prop/Propeller-P8X32A-Datasheet-v1.4.0.pdf
I think the DDMTD could be a good solution. The question is, if 74HCxx
parts would be good enough
to get < 1 mHz resolution for a 10 MHz frequency with an update rate of
< 1 sec.
Can i use a 74HCT4046 PLL for the 'helper PLL' or is this one not good
enough ?
Maybe i will do some tests next weekend to see what i can achieve with
these 74HC parts, before
looking for better ones...
Regards,
Wolfgang
Am 19.04.2012 23:14, schrieb ewkeh...@aol.com:
Wolfgang
It would help if you would let us know what equipment other than a scope
you have. Also what resolution you would want to achieve. One time set up or
want to use repeatedly.
Bert Kehren
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