Re: [linrad] Delta44 board

["Rein A .Smit" <rein0zn@xxxxxxxxxxxxx>]

   Hi Leif and others.

   Tnx. Yes I understand the phase aspect in music!

    73 Rein

Leif Asbrink wrote:

> Hi Rein and Kohjin,
>
> >   Thanks and OK about "word" I imagine that if the sampling is
> > not accurate this will
> >   introduce distortion in music. Whether this is really a problem
> > I do not know.
>
> For Linrad there is no reason to use synchronization
> of the sampling clock.
>
> In music it is extremely important to synchronize boards to each
> other if several boards are used for input simultaneously.
> Otherwise the phase relation between different channels will vary
> slowly with time.
>
> Linrad uses a single board for input and all channels on a Delta44
> board are already properly synchronized. There may be other boards
> which do not keep good synchronizm and such boards are useless
> for direct conversion (I/Q) mode.
>
> Synchronizing the Delta44 sampling clock at 64*96kHz = 6.144 MHz
> to an external frequency reference could be done by injecting
> a stable signal at 24.576 MHz into X1, the 24.576 MHz X-tal.
> This will be useful only if all other oscillators are GPS stabilized
> and if you want a sub Hz absolute accuracy. Already a really bad
> X-tal with 100 ppm accuracy will not cause more than 1Hz frequency
> error if the audio tone is 10kHz.
>
> 73
>
> Leif  /  SM5BSZ

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