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ADSP-BF535 Complex FFT Demo

Analog Devices, Inc.
DSP Division
Three Technology Way
P.O. Box 9106
Norwood, MA 02062

Date Created:	3/11/02	

This directory contains example ADSP-BF535 program that implements a complex FFT 
routine.

Files contained in this directory:

readme.txt			this file
cfft.dpj			VisualDSP++ 4.5 project file
test_cfft.c			C source file for the fft routine
in.dat				example input data file
out.ans				example output data file

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CONTENTS

I.   FUNCTION/ALGORITHM DESCRIPTION
II.  IMPLEMENTATION DESCRIPTION
III. OPERATION DESCRIPTION
IV.  DESCRIPTION OF INPUT DATA         

I. FUNCTION/ALGORITHM DESCRIPTION

The project cfft.dpj contains the implementation of a complex FFT algorithm.
  

II.   IMPLEMENTATION DESCRIPTION

The Blackfin DSP library routine is used to apply the FIR filter. The twiddle 
factors are generated by another DSP library routine.


III.  OPERATION DESCRIPTION

1. Open the VDSP project cfft.dpj in the IDE (Integrated Development 
	Environment).  

2. Under 'Session'->'Select Session', select the ADSP-BF535 ADSP-BLACKFIN Family 
	Platform session.

3. Under the 'Project' tab, select 'Build Project'.  This will automatically 
	load the executable.

4. Select 'Run' from the 'Debug' tab on the menu bar.

5. The demo routine performs a 64-point FFT. Please be patient, because the simulator 
	must simulate every hardware memory access. The output will be written to the 
	file "out.ans" and can be found under the Debug folder in the project directory. 
	
	The file "out.ans" is provided for comparison and is the FFT output for the 
	example input data, "in.dat".

Note that the FFT output data is scaled to be between 0 and 1. Also note that because 
of scaling and rounding, there may be slight differences between the DSP output and 
the exact output values.