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Digital Drive: Re: Defining upsampling. by rfbrw Upsamplers, DACs, jitter, shakes and analogue withdrawals, this is it. |
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In Reply to: Re: Defining upsampling. posted by Ted Smith on August 27, 2003 at 16:07:46:
Once one is clear about why one is changing the samplerate there is no cause for confusion.
The function of the SAA7220 and its descendants is trade complexity in the analogue domain for complexity in the digital domain and in so doing easing the design of the analogue filter at the output of the D/A converter ic. It does this by increasing the sample rate thus pushing the aliased images further up the spectrum. The key point wth thse devices is that the ratio is fixed. You may have a selection of ratios i.e. 2x,4x or 8x etc but these ratios are set in stone and the coefficients for these ratios are set and stored and do not have to be calculated at any point. In effect changing the sample rate is simply the means by which it accomplishes its objective.
For the AD1890 and it descendants the changing of the sample rate is the objective. It has to support arbitrary sample rates and possibly even dynamically varying sample rates. Precalculation of the coefficients is simply not an option. Now it is possible to have a sample rate converter based on the same techniques as a digital oversampling filter but it will be very limited and it certainly won't be asychronous like the AD1890. The AD1890 and its descendants operate on a very different basis in order to support what they do and are in no way the same as oversampling digital filters.ray.
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Topic - upsampling article - solidgore 08:08:38 08/22/03 ( 47)
- Re: upsampling article - Werner 05:31:36 08/27/03 ( 0)
Erroneous Stuff... - Todd Krieger 14:23:36 08/22/03 ( 44)
- Re: Erroneous Stuff... - csown 21:44:29 08/22/03 ( 43)
- Re: Erroneous Stuff... - Todd Krieger 23:39:51 08/22/03 ( 42)
- Re: Erroneous Stuff... - csown 10:56:04 08/23/03 ( 40)
- Re: Erroneous Stuff... - Todd Krieger 21:24:51 08/23/03 ( 39)
- Re: Erroneous Stuff... - csown 23:37:53 08/23/03 ( 38)
- Re: Erroneous Stuff... - Todd Krieger 15:37:44 08/24/03 ( 34)
- Re: Erroneous Stuff... - csown 16:17:17 08/25/03 ( 33)
- This Wasn't as Bad as Expected... - Todd Krieger 21:31:58 08/25/03 ( 31)
- Re: This Wasn't as Bad as Expected... - csown 21:03:54 08/26/03 ( 26)
- A DAC's "Brickwall Filter" is *Not* the Analog Post Filter... - Todd Krieger 01:04:25 08/27/03 ( 14)
- PMD-100 was one with selectable dither - Wavy Davy 07:29:59 08/27/03 ( 8)
- Re: PMD-100 was one with selectable dither - Todd Krieger 09:18:47 08/27/03 ( 7)
- You can lead a horse to water ..... - Wavy Davy 19:54:26 08/27/03 ( 6)
- But Can't Make Him Drink.... - Todd Krieger 22:10:25 08/27/03 ( 5)
- Re: But Can't Make Him Drink.... - Werner 22:19:27 08/27/03 ( 4)
- High Resolution Signal versus Upsampled Signal - Todd Krieger 22:52:10 08/27/03 ( 3)
- Re: High Resolution Signal versus Upsampled Signal - Werner 23:02:15 08/27/03 ( 2)
- Think About It... - Todd Krieger 00:57:23 08/28/03 ( 1)
- Re: Think About It... - Werner 01:38:26 08/28/03 ( 0)
- Re: A DAC's "Brickwall Filter" is *Not* the Analog Post Filter... - Werner 03:58:47 08/27/03 ( 4)
- Domain Dementia... - Todd Krieger 09:10:29 08/27/03 ( 3)
- Re: Domain Dementia... - csown 10:36:24 08/27/03 ( 2)
- Re: Domain Dementia... - Todd Krieger 12:37:14 08/27/03 ( 1)
- sigh ... - Werner 22:43:03 08/27/03 ( 0)
- Re: This Wasn't as Bad as Expected... - Werner 22:27:06 08/26/03 ( 10)
- Defining upsampling. - csown 08:33:56 08/27/03 ( 9)
- Re: Defining upsampling. - Werner 22:52:31 08/27/03 ( 0)
- Re: Defining upsampling. - Ted Smith 16:07:46 08/27/03 ( 7)
- Re: Defining upsampling. - rfbrw 08/28/03 06:59:09 08/28/03 ( 6)
- Re: Defining upsampling. - Werner 08:20:46 08/28/03 ( 5)
- Re: Defining upsampling. - rfbrw 19:44:47 08/28/03 ( 3)
- Re: Defining upsampling. - Werner 22:36:48 08/28/03 ( 2)
- Re: Defining upsampling. - rfbrw 15:04:47 08/29/03 ( 1)
- Re: Defining upsampling. - Werner 22:34:07 09/2/03 ( 0)
- Re: Defining upsampling. - Todd Krieger 11:31:43 08/28/03 ( 0)
- Re: This Wasn't as Bad as Expected... - Werner 23:34:54 08/25/03 ( 3)
- ZOH... - csown 16:50:11 08/26/03 ( 2)
- Re: ZOH... - Werner 22:32:08 08/26/03 ( 1)
- Re: ZOH... - csown 07:43:04 08/27/03 ( 0)
- I'm Not Ignoring You... - Todd Krieger 18:33:48 08/25/03 ( 0)
Upsampling sample provided by philips 963sa - gialitt 02:25:34 08/24/03 ( 2)
- Re: Upsampling sample provided by philips 963sa - Todd Krieger 21:59:55 08/25/03 ( 1)
- Re: Upsampling Products - gialitt 08:53:05 08/26/03 ( 0)
Followed by confused stuff (nt) - rfbrw 07:22:40 08/23/03 ( 0)
Good article in general... - csown 13:23:21 08/22/03 ( 0)