Multi-frequency clock

[mcs]

I'm looking for a multifrequency clock for my A/D converter (described in another thread).

I currently use a standard 12.288MHz xtal oscillator, but I need something that can generate all the standard frequencies (8.192, 11.2896, 12.288, 24.576 etc.) so I can record at difference samplerates.

Has anybody here made a circuit for that purpose?

This BB chip looks interesting:
http://focus.ti.com/docs/prod/folder...t/pll1700.html

Has anybody tried it?

Best regards,

Mikkel C. Simonsen

[Elso Kwak]

Originally posted by mcs
I'm looking for a multifrequency clock for my A/D converter (described in another thread).

I currently use a standard 12.288MHz xtal oscillator, but I need something that can generate all the standard frequencies (8.192, 11.2896, 12.288, 24.576 etc.) so I can record at difference samplerates.

Has anybody here made a circuit for that purpose?

This BB chip looks interesting:
http://focus.ti.com/docs/prod/folder...t/pll1700.html

Has anybody tried it?

Best regards,

Mikkel C. Simonsen

Hi Mikkel,
You can use my clock that is the KWAK-CLOCK, connect all outputs together and enable each frequency with the Latch of the comparator. So for the four frequencies listed you will need four clocks.
The PLL1700 has too much jitter I believe.

[fmak]

[QUOTE]Originally posted by mcs
[B]I'm looking for a multifrequency clock for my A/D converter (described in another thread).

I currently use a standard 12.288MHz xtal oscillator, but I need something that can generate all the standard frequencies (8.192, 11.2896, 12.288, 24.576 etc.) so I can record at difference samplerates.

Has anybody here made a circuit for that purpose?

------------------------------------------------------
You can get a word clock generator for less. Swissonics WD8 at thomann.de is on sale for 200 euro. Generates 44.1 to 96, plus superclock.

[ukram]

I have been dreaming about 21.168 MHz crystal, is there such a thing? (441 * 480) * 100 = 21.168M.

After learning the Xilinx stuff i could easily design EPLD chip that divides the necessary frequencies, as long as the main clock is not more than about 100 MHz, depending on the chip used.

[mcs]

Originally posted by fmak
You can get a word clock generator for less. Swissonics WD8 at thomann.de is on sale for 200 euro. Generates 44.1 to 96, plus superclock.

Less than what?

The PLL1700 chip only costs $2...

Best regards,

Mikkel C. Simonsen

[mcs]

Originally posted by Elso Kwak
Hi Mikkel,
You can use my clock that is the KWAK-CLOCK, connect all outputs together and enable each frequency with the Latch of the comparator. So for the four frequencies listed you will need four clocks.
The PLL1700 has too much jitter I believe.

It looks interesting - but I think a bit too complicated for this purpose... As long as I use the A/D for recording, does the jitter matter? The data goes directly into a FIFO and on to a harddrive anyway...

But perhaps I should try one of your clocks in my CD-player

[EDIT]I just realised that the jitter probably does matter - but how much? Perhaps I should use a "good" clock for the main frequency, and a simple one for the rest...

BTW, how do you "distribute" the clock? I will need a clock for the A/D, the D/A and the playback circuit. Do you simply connect the loads in parallel, or do you need some kind of buffer?[/EDIT]

Best regards,

Mikkel C. Simonsen

[fmak]

[QUOTE]Originally posted by mcs
[B]
Less than what?

The PLL1700 chip only costs $2...

Best regards,

-----------------------------------------------------
When you add up the cost of high quality components, ancilliaries, power supply, enclosure, plus the amount of time in development and testing, it is cheaper to spend 200 euros as you can spend the time doing something alse!

[rbroer]

The PLL1700 is ok.
For better jitter numbers I suggest SM8706, SM8707 (used in better DVD players for example.

Originally posted by mcs
As long as I use the A/D for recording, does the jitter matter?
BTW, how do you "distribute" the clock?
Do you simply connect the loads in parallel, or do you need some kind of buffer?

But to be honest, reading all these questions on very basic issues, you might seriously want to consider the solution FMAK posed in stead of doing something that might be over your head

[Elso Kwak]

Originally posted by rbroer
The PLL1700 is ok.

Sandwich Ape Rudolf?
Sorry couldn't resist

[rfbrw]

Originally posted by fmak
You can get a word clock generator for less. Swissonics WD8 at thomann.de is on sale for 200 euro. Generates 44.1 to 96, plus superclock. [/B]

The problem with this solution is that the WD8 is designed to drive a complete device as opposed to individual chips. The OP's ADC still has to have an internal clock system capable of locking to an external clock. That usually means a VCXO or two and a PLL.

ray.