Cfft

Overview

Forward and inverse FFT of complex data

Discussion

Computes the forward or inverse FFT of complex data. At instantiation time (on the module name and arguments dialog) you specify whether a forward or an inverset transform should be computed. The internal hidden variable .dir controls whether a forward (= +1) or inverse (= -1) FFT is computed. The module supports multichannel signals.

Module Pack

Advanced

ClassID

classID = 1230

Type Definition

typedef struct _ModuleCfft
{
ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
INT32 dir;                                    // Transform direction.  Forward = 1. Inverse = -1
void * hardware_specific_struct_pointer;      // This may point to a struct that varies based on the target platform
void * fft_size_aligned_io_buffer_pointer;    // This points to a buffer which is aligned by fft size on SHARC
void * fft_twiddle_buffer_pointer;            // This points to twiddle buffer on SHARC
} ModuleCfftClass;

Variables

Properties

Name	Type	Usage	isHidden	Default Value	Range
dir	int	const	0	1	-1, 1
hardware_specific_struct_pointer	void *	state	1		Unrestricted
fft_size_aligned_io_buffer_pointer	void *	state	1		Unrestricted
fft_twiddle_buffer_pointer	void *	state	1		Unrestricted

Pins

Input Pins


Name	in
Description	Complex input
Data type	float
Channel range	Unrestricted
Block size range	4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384
Sample rate range	Unrestricted
Complex support	Complex

Output Pins


Name	out
Description	Complex output
Data Type	float

Scratch Pins


Channel Count	1
Block size	5
Sample rate	48000

Matlab Usage

File Name: cfft_module.m 
 M=cfft_module(NAME, ISFFT) 
 Computes the forward or inverse FFT of complex input data.  The input 
 block size must be a power of 2.  The module supports multichannel 
 signals.  Arguments: 
    NAME - name of the module. 
    ISFFT :  1 for calculating FFT 
             -1 for calculating IFFT 

 ISFFT is an optional argument and is used to set the internal const 
 variable 'dir'.  You can change .dir in design mode but not in tuning 
 mode.