[time-nuts] Using cheap sound cards for measurements

[Magnus Danielson]

Lux, Jim (337C) wrote:
> 
> 
> On 8/21/09 8:09 PM, "Tom Van Baak" <tvb at LeapSecond.com> wrote:
> 
>> Add internal or external (5/10 MHz) clock.
>>
>> /tvb
> 
> 
> None will have that...<grin>
> Maybe a multiple of 48 or 44.1 kHz

Wordclock is common. Black burst is rare. 5 or 10 MHz is yeat a level of 
conversions away. It will not be a cheap board, even if the feature 
isn't necessarilly expensive. Locking a 24,576 MHz crystal to 5 or 10 
MHz isn't particular hard since 24,576 M = 2^16 * 3 * 5^3 and 10 M = 2^7 
* 5^7 so common divisor 2^7*5^3 = 16 kHz will leave 24576/16 = 1536 and 
10000/16 = 625 so it could be done without too much effort. With smart 
buildup of the division chain can the power of 2 multiple of the sample 
rate be selected from the lockup division chain by choosing the tap, so 
a mux could select tap.

The 24,576 MHz VCXO isn't too hard to find.

Cheers,
Magnus