Relationship between master clocks, system clocks, and audio freqs

Garbz · 12th March 2006, 09:41 AM

This is something I can't quite understand. Digital sources have a master clock in them usually in the form of a crystal oscillator. In my cdplayer's case this is 27Mhz.

What is the relationship between this clock and the system clock of a DAC (i.e. the MCLK line in an I2S signal) which is not 27MHz IIRC. While on these relationships at what frequency is S/PDIF clocked?

And how does this mess relate to the frequency of the digital audio (44.1khz 48khz 96khz etc)

A 8 · 12th March 2006, 12:14 PM

Your cdp can not be 27Mhz as it has a 44.1khz base only. A dvd player has a 27Mhz clock to handle the video processing.

The pic shows typical relationship between bit, word and data.

A 8 · 12th March 2006, 12:23 PM

Clock vs sampling freq

Garbz · 13th March 2006, 02:53 AM

Ok so can you tell me how the clock is derrived from the 27Mhz crystal oscillator that I replaced with a 27mhz Tentclock? (indeed it is a dvd-audio player). But the tentclock also re-clocks the S/PDIF output through a flipflop no doubt. How would that work since the result is 27Mhz.

A 8 · 13th March 2006, 05:13 AM

Nippon

It also explains why reclocking works

Elso Kwak · 13th March 2006, 07:04 AM

Quote:

Originally posted by A 8
Nippon

It also explains why reclocking works

In my humble opinion synchronous reclocking does not bring a thing

A 8 · 13th March 2006, 08:10 AM

You must mean other then getting all samples exactly right

Elso Kwak · 13th March 2006, 08:19 AM

Quote:

Originally posted by A 8
You must mean other then getting all samples exactly right

I just tried it!

Garbz · 14th March 2006, 02:11 AM

IMHO asynchronous reclocking doesn't work.

Synchronous reclocking however I found (did this to the output of my cdplayer) yielded a slight bit of improvment. That said my standard source was a shocker to begin with

Garbz · 14th March 2006, 12:40 PM

Hey A8 thanks for that link it obviously explains that a cdplayer can derrive it's audio/video clocks from a 27Mhz crystal.

But i'm still at a loss as to how S/PDIF then propegates at 27Mhz if that is not an audio frequency. I could be way off the mark but it appears that the S/PDIF output of a Tentlabs XO-3 reclocker runs at the frequency of the crystal itself.

12th March 2006, 09:41 AM	#1
Garbz diyAudio Member Join Date: Dec 2003 Location: Brisbane	Relationship between master clocks, system clocks, and audio freqs This is something I can't quite understand. Digital sources have a master clock in them usually in the form of a crystal oscillator. In my cdplayer's case this is 27Mhz. What is the relationship between this clock and the system clock of a DAC (i.e. the MCLK line in an I2S signal) which is not 27MHz IIRC. While on these relationships at what frequency is S/PDIF clocked? And how does this mess relate to the frequency of the digital audio (44.1khz 48khz 96khz etc)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
different clocks in one DVD player	spendorspain	Digital Source	6	7th June 2008 09:55 AM
I'm confused with Clocks	jkeny	Digital Source	14	25th April 2008 01:46 PM
Audio Clocks	quiller	Digital Source	12	2nd January 2008 02:28 AM
The digital system - On clocks, x-ports, S/PDIF, DAC's, etc	PBeyer	Digital Source	32	2nd October 2005 08:41 AM
Clocks	hacknet	Digital Source	9	21st June 2004 08:52 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

13th March 2006, 02:53 AM	#4
Garbz diyAudio Member Join Date: Dec 2003 Location: Brisbane	Ok so can you tell me how the clock is derrived from the 27Mhz crystal oscillator that I replaced with a 27mhz Tentclock? (indeed it is a dvd-audio player). But the tentclock also re-clocks the S/PDIF output through a flipflop no doubt. How would that work since the result is 27Mhz.

13th March 2006, 05:13 AM	#5
A 8 diyAudio Member Join Date: Mar 2003 Location: Gothenburg	Nippon It also explains why reclocking works

13th March 2006, 08:10 AM	#7
A 8 diyAudio Member Join Date: Mar 2003 Location: Gothenburg	You must mean other then getting all samples exactly right

14th March 2006, 02:11 AM	#9
Garbz diyAudio Member Join Date: Dec 2003 Location: Brisbane	IMHO asynchronous reclocking doesn't work. Synchronous reclocking however I found (did this to the output of my cdplayer) yielded a slight bit of improvment. That said my standard source was a shocker to begin with

14th March 2006, 12:40 PM	#10
Garbz diyAudio Member Join Date: Dec 2003 Location: Brisbane	Hey A8 thanks for that link it obviously explains that a cdplayer can derrive it's audio/video clocks from a 27Mhz crystal. But i'm still at a loss as to how S/PDIF then propegates at 27Mhz if that is not an audio frequency. I could be way off the mark but it appears that the S/PDIF output of a Tentlabs XO-3 reclocker runs at the frequency of the crystal itself.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)