Fast Fourier Transforms on Motorola's Digital Signal Processors

F( k)
where:
N – 1
2c( k)
----------- x
N ∑
n = 0
n cos 0 1 …
2N
( 2n + 1kπ)
= ( ) ----------------------- ; k =
c( k)
=
1
------ , k =
2
0
= 1,
k = 1, 2,
…,
= 0,
elsewhere
and the inverse transform is:
x n
N– 1
N – 1
Eqn. 7-3
( 2n + 1kπ)
( ) = c( k)F(
k)
----------------------- ; n =
∑
n = 0
Eqn. 7-4
A fast discrete cosine transform (FDCT) proposed
by Chen and Smith [see reference 1] is adapted in
this application note, and it’s flow diagram is plotted
in Figure 7-1. Many optimized implementations
on the FDCT have been published. The code given
on the Motorola DSP bulletin board is not fully
optimized; it simply demonstrates the simplicity of
the DSP96002 assembly code.
, , ,
cos 0 1 …
2N
, , ,
N– 1
N– 1
MOTOROLA 7-3