[time-nuts] Sound Cards for locking to GPSDO 10 MHz references

Stan W1LE stanw1le at verizon.net
Tue Jun 2 15:01:17 EDT 2009


Hello The Net:

For portable operations with a laptop, usually only one input channel is 
available
and it is at mike (not line) level.

The alternative to sum the analog reference and the analog signal of 
interest may be
possible if the reference noise can be kept out of the signal of 
interest bandwidth.
Maybe a external USB soundcard with at least 2 input channels is more 
appropriate.

Stan, W1LE    FN41sr     Cape Cod


Alberto di Bene wrote:
> J.D. Bakker wrote:
>> You could always transform this from a hardware problem to a software 
>> problem. Take the output of your GPSDO, divide it down to somewhere 
>> inside the audio band, feed it to a spare input on your USB sound 
>> card and have software track this reference and correct the received 
>> signal.
>>
>> JDB.
>
> I am in complete agreement with this kind of solution. Sampling on the
> second channel a reference signal of known value allows the software
> to make a simple adjustment. No need to switch on the soldering iron...
> Never do in hardware what can be done in software.... :-)
>
> 73  Alberto  I2PHD





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