This version (18 May 2021 08:43) was approved by John Joseph.The Previously approved version (02 Jul 2020 15:41) is available.
Table of Contents
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Inverse FFT
Description
IFFT
N-point IFFT is performed on the samples, where MaxN is configurable and should be a power of greater than or equal to N mentioned in the preceding FFT. The twiddle coefficients are calculated within the code and input of IFFT are PCMx samples, the BlockSize of which 3 * Schematic BlockSize. The first Schematic Block Size number of samples in a PCMx input contains the header information carried from the previous Module (say in this case FFT). Only when the PCMx type matches, IFFT is performed and output is given as PCM samples. The header information contains fields such as PCMx type (Windowing done), N, Count (if N>Schematic BlockSize).
IFFT Windowed
In the Windowed version, windowing is done in the FFT Module for 2N samples. Overlap and add for N samples are done at the IFFT end. Hence the output is delayed by N samples. Since memory size depends on the value of MaxN, downloading the Schematic (Link-Compile-Download) is necessary when MaxN value is changed.
Real IFFT
Real IFFT is a block processing module which computes the IFFT of real signals.
Complex IFFT
Complex IFFT is a block processing module which performs N point complex IFFT of the input signal, where N stands for BlockSize.
Variants
- IFFT
- IFFT Windowed
- Real IFFT
- Complex IFFT
Targets Supported
| Name | ADSP-214xx | ADSP-215xx/SC5xx | ADAU145x/146x |
|---|---|---|---|
| ————————————-- | ——————-- | ——————————-- | —————————- |
| IFFT | NA | B | NA |
| IFFT Windowed | NA | B | NA |
| Real IFFT | NA | NA | B |
| Complex IFFT | NA | NA | B |
Pins
Input
| Name | Type | Description |
|---|---|---|
| ———————- | ————-- | ———————- |
| Input0 | PCMx | First Input channel (IFFT and IFFT Windowed) |
| Input0 | PCMx | Second Input channel (IFFT and IFFT Windowed) |
| Input | Audio | Input channel (Real IFFT) |
| Input | Complex | Input channel (Complex IFFT) |
Output
| Name | Type | Description |
|---|---|---|
| ———————- | ————-- | ———————- |
| Output0 | Audio | First Output channel (IFFT and IFFT Windowed) |
| Output0 | Audio | Second Output channel (IFFT and IFFT Windowed) |
| Output | Audio | Output channel (Real IFFT and Complex IFFT) |
Configurable Parameters
| GUI Parameter | Default | Range | Function Description |
|---|---|---|---|
| —————————————- | ———————- | —————— | —————————————- |
| Max N | 64 | 16 - 1024 | Max N-point IFFT to be performed. This should be value greater than “N” mentioned in the preceding FFT Module. This parameter is required by the Module for memory allocation. |
DSP Parameters
| Name | Description | ADSP-214xx/215xx/SC5xx | ADAU145x/146x |
|---|---|---|---|
| —————————- | ————————————————-- | —————————————- | ———————————- |
| Max N | Max N-point IFFT to be performed | Integer | NA |
resources/tools-software/sigmastudiov2/modules/advanceddsp/inversefft.txt · Last modified: 12 May 2021 13:21 by John Joseph