One sample delay between channels

percy · 1st October 2006, 10:06 PM

For stereo digital data the series of samples contain alternating channel information - i.e. L,R,L,R,...L,R.... One channel is always following the other. And thats how its fed the DAC as well. So when the DAC ouputs analog signal for both L and R channels is it simultaneous or is it still lagging in the analog domain as well ? Does the DAC compensate for that delay ?

I'd like to extend this question to Analog-to-Digital conversion also. Is there only one ADC that alternates to sample each channel ? or two ADCs (one per channel) that sample simultaneously ?

rfbrw · 1st October 2006, 10:17 PM

Sampling and conversion are simultaneous

percy · 2nd October 2006, 06:39 PM

ok that takes care of the A->D part.

but what's the deal with the channel delay in the DAC ?
For now all I want to know is if ALL well regarded dac chips out there exhibit this 'delay' and something needs to be taken care of as part of the big picture of the whole DAC design ? or is it something that the DAC chip generally takes care of already ?

(is there a definite term for this ? what's it called ? I tried searching the forum and all I could find was one really old (and hijacked) thread where the discussion trailed into this delay but didnt really help).

rfbrw · 2nd October 2006, 07:10 PM

Quote:

Originally posted by percy
ok that takes care of the A->D part.

but what's the deal with the channel delay in the DAC ?
For now all I want to know is if ALL well regarded dac chips out there exhibit this 'delay' and something needs to be taken care of as part of the big picture of the whole DAC design ? or is it something that the DAC chip generally takes care of already ?

(is there a definite term for this ? what's it called ? I tried searching the forum and all I could find was one really old (and hijacked) thread where the discussion trailed into this delay but didnt really help).

There is no delay. Sampling (A to D) and conversion (D to A) are simultaneous

percy · 2nd October 2006, 07:26 PM

so the dac holds the first channel data until the second channel data becomes available and then converts both simultaneously ?
sorry for my novice questions. When it comes to digital audio I am!

rfbrw · 2nd October 2006, 07:57 PM

Something like that.

percy · 2nd October 2006, 08:08 PM

while you were responding to my post I found this
Apparently they would need a "workaround".

Interestingly they dont have a similar errata for the new chips(CS4270/71/72).

rfbrw · 2nd October 2006, 08:20 PM

Quote:

Originally posted by percy
while you were responding to my post I found this
Apparently they would need a "workaround".

Interestingly they dont have a similar errata for the new chips(CS4270/71/72).

They aren't typical of the breed and are at least 5 years out of date. Besides from the POV of a standard serial datastream, the delay is half a sample not one.

1st October 2006, 10:06 PM	#1
percy diyAudio Member Join Date: Apr 2004 Location: MN	One sample delay between channels For stereo digital data the series of samples contain alternating channel information - i.e. L,R,L,R,...L,R.... One channel is always following the other. And thats how its fed the DAC as well. So when the DAC ouputs analog signal for both L and R channels is it simultaneous or is it still lagging in the analog domain as well ? Does the DAC compensate for that delay ? I'd like to extend this question to Analog-to-Digital conversion also. Is there only one ADC that alternates to sample each channel ? or two ADCs (one per channel) that sample simultaneously ?

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1st October 2006, 10:17 PM	#2
rfbrw diyAudio Member Join Date: Oct 2001 Location: .	Sampling and conversion are simultaneous

2nd October 2006, 06:39 PM	#3
percy diyAudio Member Join Date: Apr 2004 Location: MN	ok that takes care of the A->D part. but what's the deal with the channel delay in the DAC ? For now all I want to know is if ALL well regarded dac chips out there exhibit this 'delay' and something needs to be taken care of as part of the big picture of the whole DAC design ? or is it something that the DAC chip generally takes care of already ? (is there a definite term for this ? what's it called ? I tried searching the forum and all I could find was one really old (and hijacked) thread where the discussion trailed into this delay but didnt really help).

2nd October 2006, 07:26 PM	#5
percy diyAudio Member Join Date: Apr 2004 Location: MN	so the dac holds the first channel data until the second channel data becomes available and then converts both simultaneously ? sorry for my novice questions. When it comes to digital audio I am!

2nd October 2006, 07:57 PM	#6
rfbrw diyAudio Member Join Date: Oct 2001 Location: .	Something like that.

2nd October 2006, 08:08 PM	#7
percy diyAudio Member Join Date: Apr 2004 Location: MN	while you were responding to my post I found this Apparently they would need a "workaround". Interestingly they dont have a similar errata for the new chips(CS4270/71/72).

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