Ifft

Overview

Inverse FFT of real data

Discussion

Computes the inverse fast Fourier transform of a complex half spectrum yielding a real-valued result. The blockSize, N, of the real valued output must be a power of 2 in the range [4...16384]. The input pin is complex with a blockSize of N/2+1 complex samples. The input contains the complex transform at samples k=0, 1, ..., N/2. The DC (k=0) and Nyquist (k=N/2) samples always have an imaginary component of 0.

Type Definition

CODE

typedef struct _ModuleIfft
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    void * hardware_specific_struct_pointer;      // This may point to a struct that varies based on the target platform
} ModuleIfftClass;

Variables

Properties

Name	Type	Usage	isHidden	Default value	Range	Units
b0	float	parameter	0	1	Unrestricted
b1	float	parameter	0	0	Unrestricted
b2	float	parameter	0	0	Unrestricted
a1	float	parameter	0	0	Unrestricted
a2	float	parameter	0	0	Unrestricted
state	float*	state	1	[2 x 1]	Unrestricted

Pins

Input Pins

Name: in

Description: Complex input

Data type: fract32

Channel range: Unrestricted

Block size range: 4, 8, 16, 32, 64, 128, 256, 512, 1024

Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: Complex output

Data type: fract32

Scratch Pins

Channel count: 1

Block size: 8

Sample rate: 48000

MATLAB Usage

File Name: fft_fract32_module.m

CODE

 M=fft_fract32_module(NAME)
 Computes the forward FFT of real input data.  The input block 
 size must be a power of 2.  The module supports multichannel signals.
 Arguments:
    NAME - name of the module.