Thanks, but... - Homer - Video Asylum

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Thanks, but...

In Reply to: Re: Any 12-bit / 108MHz DVD Players ? posted by Charles Hansen on May 2, 2002 at 08:45:43:

Wow, thanks for the info - it's always good to learn something new!!
Anyhow, you've addressed the issue of DAC precision, but how about sampling frequency? Is the performance of 108 MHz DACs not generally much lower than that of 54 MHz DACs?

> However if there is any video processing going on (brightness,
> contrast, gamma, et cetera), then additional resolution is required
> in the DACs to avoid a loss of resolution in the final output
> signal. In this case, a 14-bit DAC would be required to achieve the
> resolution of a 12-bit DAC in a system without video processing.
> That is one reason why we don't offer any such adjustments in the
> Ayre D-1. Higher performance can be achieved by making these
> adjustments in the analog domain in the monitor itself.
I don't quite believe that, however. If all the processing is done after resampling (108 MHz is 4x oversampling), and carries full intermediate precision, until it's dithered down to the precision of the DAC, I think a good 12-bit 108 MHz DAC would be hard for analog processing to beat. Certainly the analog performance would be much less stable, over time, and with varying environmental conditions.

BTW, couldn't you test each unit, off the line, and program it to digitally compensate for much of its integral (and even some differential) nonlinearity?

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Follow Ups Full Thread

Topic - Any 12-bit / 108MHz DVD Players ? - vulcanman 20:19:28 04/30/02 (10)

Re: Any 12-bit / 108MHz DVD Players ? - Homer 22:02:07 04/30/02 (9)

Re: Any 12-bit / 108MHz DVD Players ? - Charles Hansen 08:45:43 05/02/02 (5)

Thanks, but... - Homer 00:33:10 05/03/02 (4)

Re: Thanks, but... - Charles Hansen 08:11:30 05/03/02 (3)

Accumulating noise - Homer 05:57:32 05/05/02 (2)

Re: Accumulating noise - Charles Hansen 12:55:19 05/05/02 (1)

Clearing up a few things... I hope - Homer 23:45:11 05/06/02 (0)

I'm no expert either, but... - Joe Murphy Jr 19:25:25 05/01/02 (0)

Thank you for an insighful analysis (I will shut up now :-)) - vulcanman 08:41:21 05/01/02 (1)

No offense, BTW - Homer 00:46:08 05/02/02 (0)

Follow Ups

Thanks, but... - Homer 00:33:10 05/03/02 (4)

Re: Thanks, but... - Charles Hansen 08:11:30 05/03/02 (3)

Accumulating noise - Homer 05:57:32 05/05/02 (2)

Re: Accumulating noise - Charles Hansen 12:55:19 05/05/02 (1)

Clearing up a few things... I hope - Homer 23:45:11 05/06/02 (0)

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