| Relationship between master clocks, system clocks, and audio freqs - Click HERE for Original Thread |
| Garbz |
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) |
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| A 8 |
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. |
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| A 8 |
| Clock vs sampling freq |
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| Garbz |
| 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. |
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| A 8 |
Nippon
It also explains why reclocking works |
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| Elso Kwak |
| quote: | Originally posted by A 8
Nippon
It also explains why reclocking works |
In my humble opinion synchronous reclocking does not bring a thing
:bigeyes: |
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| A 8 |
| You must mean other then getting all samples exactly right:D |
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| Elso Kwak |
| quote: | Originally posted by A 8
You must mean other then getting all samples exactly right:D |
I just tried it!
:rolleyes: |
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| Garbz |
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 :dodgy: |
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| Garbz |
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. |
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| A 8 |
The 27mhz is not free flowing or fully asynchronous to the audio stream, all the audio streams are a direct decendent of the 27mhz master clock.
There is always a fixed timing difference and its not big enough to miss samples. |
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