Traitement du signal sur syst`eme embarqué ... - J.-M Friedt
Traitement du signal sur syst`eme embarqué ... - J.-M Friedt
Traitement du signal sur syst`eme embarqué ... - J.-M Friedt
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i n x n r e / x n im . When the FFT i s done ,<br />
the spectrum (X( n ) ) has r e p l a c e d the input<br />
s t o r e d i n x n r e / x n im . ∗/<br />
f o r ( s t a g e =0; stage >7) ;<br />
resultMulImCos=( s h o r t ) ( ( ( i n t ) cosLUT [ t f i n d e x ] ∗ ( i n t ) x n im [ b index ] ) >>7) ;<br />
resultMulImSin=( s h o r t ) ( ( ( i n t ) sinLUT [ t f i n d e x ] ∗ ( i n t ) x n im [ b index ] ) >>7) ;<br />
x n r e [ b index ] = x n r e [ a i n d e x ]− resultMulReCos+resultMulImSin ;<br />
x n im [ b index ] = x n im [ a i n d e x ]− resultMulReSin−resultMulImCos ;<br />
x n r e [ a i n d e x ] = x n r e [ a i n d e x ]+ resultMulReCos−resultMulImSin ;<br />
x n im [ a i n d e x ] = x n im [ a i n d e x ]+ resultMulReSin+resultMulImCos ;<br />
i f ( ( ( s b i n d e x +1) & ( s o f b −1) ) == 0)<br />
a i n d e x = a i n d e x r e f ;<br />
e l s e<br />
a i n d e x++;<br />
t f i n d e x += n o f b ;<br />
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a i n d e x = ( ( s o f b = 1 ;<br />
s o f b