[time-nuts] disciplining sound card

[Azelio Boriani]

The integer greatest common divisor 10MHz/25.576MHz is 16KHz so a simple
PLL should go through that frequency.

On Fri, Jul 6, 2012 at 6:38 PM, Bill Dailey <docdailey at gmail.com> wrote:

> Tips on this process if anyone wants to do this.  From the cards I have
> there are 2 different types of oscillators/resonators... one is SMD with 4
> pads and the other was a through hole crystal.  The right sided hole when
> reading the label is the one you want..  With the SMD (most of the
> oscillators that I have looked at of this caliber).  The upper right pad is
> the RF out.  So... simply remove the oscillator, find a convenient ground
> nearby (I used a nearby pad that I verified to be ground)  pre-tinned the
> shield and center conductor and the hole/pads, applied a little liquid
> flux.. touched both with the iron and done.  A little hot glue to hold
> everything in place.. Bulkhead connector through a hole in the box (for ext
> usb) or in a pci cover (for pci cards).
>
> I searched and searched for a card that would take 10MHz and they aren't to
> be found.  I didn't want to invest in a word clock that may have oddball
> timing issues that I don't understand so I went this route.  It seems to
> work very well and is a simple modification.  The only problem is the
> 24.576 MHz.... I have tried to find a board that was plug and play but the
> frequency is not a nice one to play well with 10MHz.  There are numerous
> ways to get 24.576 disciplined but since I am not an electronics guru it
> appears the best for me is the valon synthesizer.  If someone wants to
> build a better mousetrap.. I have a nice VCXO that is begging to be put in
> a PLL and would probably give better phase noise performance.   I have
> considered injection locking it with the synthesizer but can't get my head
> around how to get that done.  To me that would provide the best of both
> worlds although it may introduce some injection-locking phase noise nearby
> the carrier (from what I have read).
>
> I am getting incredible performance and have phase stable audio in spectrum
> lab without any calibration which is what I was trying to achieve.  Also,
> it seems to make the audio better when listening to music although I can't
> verify this claim and don't want to start another audiophile thread.
>
> --
> Doc
>
> Bill Dailey
> KXØO
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>