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Hi all,

 Could you please explain the relation between IMDCT and IFFT?

Thanks in Advance,
Jebaraj S.Peter.

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In fact, MDCT uses cosine transation, but FFT uses sine transation.MDCT
can=
 be implemneted by FFT.

=D4=DA2009-04-04 20:30:53=A3=AC"peter jebaraj" <j...@gmail.com>
=D0=B4=
=B5=C0=A3=BA
Hi all,

 Could you please explain the relation between IMDCT and IFFT?
=20
Thanks in Advance,
Jebaraj S.Peter.=20

_____________________________________

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Dear Jebaraj,

FFT is an efficient algorithm to compute DFT & its inverse.=A0 A DFT
decomp=
oses a sequence of values into components of different frequencies.

MDCT is based on DCT4 with property of overlapping.=A0=20

DCT expresses a sequence of finitely many data points in terms of a sum of =
cosine functions oscillating at different frequencies.=A0 For compression, =
it turns out that cosine functions are much more efficient (fewer are neede=
d to approximate a typical signal).=A0 Essentially it is similar to DFT but=
 using only real numbers.=A0 DCTs are equivalent to DFTs of roughly twice t=
he length, operating on real data with even symmetry.=A0 There are eight st=
andard DCT variants, of
which four are common.

MDCT is designed to be performed on consecutive blocks of a larger
dataset, where subsequent blocks are overlapped so that the last half
of one block coincides with the first half of the next block.

It is possible to compute MDCT recursively factorizing the computation, as =
in FFT.

Regards,
abhishek

--- On Sat, 4/4/09, peter jebaraj <j...@gmail.com> wrote:

From: peter jebaraj <j...@gmail.com>
Subject: [audiodsp] Relation between IMDCT and IFFT
To: a...@yahoogroups.com
Received: Saturday, 4 April, 2009, 6:00 PM

=20=20=20=20
            Hi all,

=A0Could you please explain the relation between IMDCT and IFFT?
=A0
Thanks in Advance,
Jebaraj S.Peter.=20

=20

_____________________________________

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