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From: robert bristow-johnson on 11 Dec 2009 02:32
On Dec 9, 1:26 pm, Jerry Avins <j...(a)ieee.org> wrote:
>
> Zero padding is always necessary with fast convolution. Without it, you
> get circular convolution.

actually that's true for one method of fast convolution (overlap-
add). the other method, called "overlap-save", does not zero pad the
data (oh, i guess both methods zero-pad the impulse response), but
they you have to recognize that L-1 samples coming out are bad. you
toss them and "save" the remaining N-(L-1) samples.

i tread lightly on commengr, given the country where he lives.

r b-j
From: robert bristow-johnson on 11 Dec 2009 02:36
On Dec 9, 11:25 am, Rune Allnor <all...(a)tele.ntnu.no> wrote:
>
> You, for listening to the delusions of almost all the
> regulars here; Almost all the regulars for messing around
> with the cyclic proerties of the DFT causing this
> kind of confusion among the incopmpetent and mentally
> challenged!

i need to know if i'm delusional, Rune. what is "messing around with
the cyclic properties of the DFT"?

r b-j
From: commengr on 11 Dec 2009 08:29
>On Dec 9, 1:26=A0pm, Jerry Avins <j...(a)ieee.org> wrote:
>>
>> Zero padding is always necessary with fast convolution. Without it,
you
>> get circular convolution.
>
>actually that's true for one method of fast convolution (overlap-
>add). the other method, called "overlap-save", does not zero pad the
>data (oh, i guess both methods zero-pad the impulse response), but
>they you have to recognize that L-1 samples coming out are bad. you
>toss them and "save" the remaining N-(L-1) samples.
>
>i tread lightly on commengr, given the country where he lives.
>
>r b-j
>

To be honest I realized 5 minutes after posting this question (when I
re-read it) that I had written some really poor and stupid statements but
there is no way to edit it.

And ... Thanks for not treading upon me Robert. I will be the first to
admit that the educational system can't be compared to a developed
country.

But politeness should be shown or perhaps we think of it too much? I don't
know.


From: Vladimir Vassilevsky on 11 Dec 2009 09:51


commengr wrote:


> To be honest I realized 5 minutes after posting this question (when I
> re-read it) that I had written some really poor and stupid statements but
> there is no way to edit it.

Excuses, excuses.

> And ... Thanks for not treading upon me Robert. I will be the first to
> admit that the educational system can't be compared to a developed
> country.

So the entire country is responsible for you being stupid? LOL.

> But politeness should be shown or perhaps we think of it too much? I don't
> know.

Sure. World is obliged to be nice to you.
:)))

VLV
From: Eric Jacobsen on 11 Dec 2009 12:47
On 12/11/2009 6:29 AM, commengr wrote:
>> On Dec 9, 1:26=A0pm, Jerry Avins<j...(a)ieee.org> wrote:
>>> Zero padding is always necessary with fast convolution. Without it,
> you
>>> get circular convolution.
>> actually that's true for one method of fast convolution (overlap-
>> add). the other method, called "overlap-save", does not zero pad the
>> data (oh, i guess both methods zero-pad the impulse response), but
>> they you have to recognize that L-1 samples coming out are bad. you
>> toss them and "save" the remaining N-(L-1) samples.
>>
>> i tread lightly on commengr, given the country where he lives.
>>
>> r b-j
>>
>
> To be honest I realized 5 minutes after posting this question (when I
> re-read it) that I had written some really poor and stupid statements but
> there is no way to edit it.

You can always make a second post clarifying or correcting a previous
one. I do this a fair amount as it seems pretty common for me to have
some sort of realization right after hitting "send". In most
newsreaders (I think) it's easy to see posts by the same author that are
adjacent in time, so it's not hard to realize that the second post was
likely an update.

Not clarifying, on the other hand, can lead to the obvious issues.

> And ... Thanks for not treading upon me Robert. I will be the first to
> admit that the educational system can't be compared to a developed
> country.

There's a balance to be had between keeping the bar high enough to
discourage people who just want their hands held through a problem (or
their homework done or something) and giving people enough slack for
language or other hurdles like yours. Clearly not everybody here draws
that line in the same place, and I guess that's to be expected.

> But politeness should be shown or perhaps we think of it too much? I don't
> know.

The internet is not always a pretty place, just because of the
differences in the people here. It seems too much to expect people to
change on either side, so we get what we get.

--
Eric Jacobsen
Minister of Algorithms
Abineau Communications
http://www.abineau.com
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