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Re: lynx-dev LYNX: Missing stuff, and no hint it is gone:
From: |
Ismael Cordeiro |
Subject: |
Re: lynx-dev LYNX: Missing stuff, and no hint it is gone: |
Date: |
Mon, 28 Sep 1998 10:47:08 -0400 (EDT) |
On Mon, 28 Sep 1998, David Combs wrote:
> What is missing is the word after "with a period of". You can tell from
> the English that something is missing, but there is no hint of what it
> might be -- a picture, a graf, who knows. Maybe the writer just left it
> out, typing fast without paying close attention, the way sometimes do
> myself, when actually there IS something there, Lynx just can't show it.
>
> It was only after several of these seeming ommissions that I
> decided to look via \.
If you had enabled links for all images you would have seen what was
"missing":
| Downsampling
|
| [invis_anchor.xbm]-[invis_anchor.xbm] The dual operation of upsampling
| is downsampling. It is defined as follows:
|
| Definition: A downsampler is characterized by a resampling matrix
| [_1940_tex2html_wrap2364.xbm] called the downsampling matrix. The
| downsampling operation, with input [_1940_tex2html_wrap2342.xbm]
| and output [_1940_tex2html_wrap2344.xbm] , is defined as
|
| [invis_anchor.xbm]-[invis_anchor.xbm] [_1940_equation278.xbm]
|
| and is denoted by [_1940_tex2html_wrap2346.xbm] .
|
| A downsampler maps the input signal [_1940_tex2html_wrap2348.xbm] to
| the output signal [_1940_tex2html_wrap2350.xbm] by discarding samples
| of [_1940_tex2html_wrap2352.xbm] which do not lie on
| [_1940_tex2html_wrap2354.xbm] and then compacts
| [_1940_tex2html_wrap2356.xbm] onto [_1940_tex2html_wrap2358.xbm] .
| Downsampling introduces aliasing and increases the sampling density by
| a factor of [_1940_tex2html_wrap3136.xbm] , the downsampling factor.
|
| The equivalent input/output Fourier transform relationship is
|
| [invis_anchor.xbm]-[invis_anchor.xbm] [_1940_equation290.xbm]
|
| where [_1940_tex2html_wrap2362.xbm] is a distinct coset vector of
| [_1940_tex2html_wrap2364.xbm] so that [_1940_tex2html_wrap2366.xbm]
| is the zero vector. The term [_1940_tex2html_wrap2368.xbm]
| [_1940_tex2html_wrap2370.xbm] is called an aliasing vector. Aliasing
| vectors are periodic with a period of [_1940_tex2html_wrap2372.xbm] in
| each dimension. A normalized aliasing vector is an aliasing vector
| with the [_1940_tex2html_wrap2372.xbm] term removed so it is periodic
| with period 1 in each dimension.
Ismael
--
+--------------------------------------------------------------+
| ISMAEL CORDEIRO | mailto:address@hidden |
| Production sound mixer | http://www.cam.org/~ismael/ |
| Montréal - Québec - Canada | ftp://ftp.cam.org/users/ismael/ |
+--------------------------------------------------------------+
- lynx-dev LYNX: Missing stuff, and no hint it is gone:, David Combs, 1998/09/24
- Re: lynx-dev LYNX: Missing stuff, and no hint it is gone:, dickey, 1998/09/24
- Re: lynx-dev LYNX: Missing stuff, and no hint it is gone:, David Combs, 1998/09/28
- Re: lynx-dev LYNX: Missing stuff, and no hint it is gone:,
Ismael Cordeiro <=
- Re: lynx-dev LYNX: Missing stuff, and no hint it is gone:, David Combs, 1998/09/28
- Re: lynx-dev LYNX: Missing stuff, and no hint it is gone:, Laura Eaves, 1998/09/29