Xilinx V2.1 Manual de usuario descargar pdf (Pagina 76)

76 Xilinx Development System

Xilinx System Generator v2.1 Reference Guide

for k=0, 1, ... , N-1, where

is a principal N-th root of unity.

The FFT block accepts as input a stream of complex data represented as a pair of

Xilinx ﬁxed point data and computes successive DFTs of nonoverlapping frames of N

data samples.

Block Interface

The block interface (inputs and outputs as seen on the FFT icon) are

as follows:

Block Parameters Dialog Box

The FFT block parameters dialog box can be invoked by double-clicking the icon in

your Simulink model.

Figure 3-50: FFT block parameters dialog box

Parameters speciﬁc to the FFT block are:

• Number of Sample Points: transform length, one of 16, 64, 256, or 1024.

Input signals:

xn_r real component of input data stream

xi_r imaginary component of input data stream

reset reset signal

inv 0 for forward transform, 1 for inverse

Output signals:

Xk_r real component of output data stream

Xk_i imaginary component of output data stream

done active high on ﬁrst output sample in a frame

rfd active high when block can accept input data

i–()

2π

------

1 2 ... 71 72 73 74 75 76 77 78 79 80 81 ... 147 148

Sin comentarios

Xilinx V2.1 Manual de usuario Pagina 76