(8.D.2.3) FilterbankFIRV2
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Overview
Efficient filterbank based FIR filter
Discussion
DSP Concepts Proprietary IP.
This module implements a long FIR filter using filterbank processing. This yields a significant reduction in the processing load and allows much longer filters to be implemented. The filterbank reduces computation by breaking a large convolution into multiple smaller independent convolutions. The implementation supports mono audio channels and an arbitrary block size.
When you instantiate the module you specify the blockSize and the length of the filter L. The larger the blockSize the more efficient the processing. The latency through the filter is zero and is numerically equivalent to having a time domain FIR filter.
On the Inspector (or Numeric Inspector) you specify the time domain FIR filter coefficients. The module will automatically take care of converting the time domain coefficients into the appropriate frequency domain coefficients. For ease of use, it is better to use the Numeric Inspector and then load the coefficients from a text file.
Type Definition
-Not Shown-
Variables
Properties
Name | Type | Usage | isHidden | Default value | Range | Units |
L | int | const | 0 | 1024 | Unrestricted |
|
FFTSize | int | const | 0 | 256 | Unrestricted |
|
numBlocks | int | const | 0 | 4 | Unrestricted |
|
coeffs | float* | parameter | 0 | [1024 x 1] | Unrestricted |
|
Pins
Input Pins
Name: in
Description: Time domain input
Data type: float
Channel range: 1
Block size range: 256
Sample rate range: Unrestricted
Complex support: Real
Output Pins
Name: out
Description: Time domain output
Data type: float
Scratch Pins
Channel count: 1
Block size: 256
Sample rate: 48000
Channel count: 1
Block size: 256
Sample rate: 48000
Channel count: 1
Block size: 257
Sample rate: 48000
Channel count: 1
Block size: 256
Sample rate: 48000
Channel count: 1
Block size: 256
Sample rate: 48000
Channel count: 1
Block size: 256
Sample rate: 48000
Channel count: 1
Block size: 512
Sample rate: 48000
MATLAB Usage
File Name: filterbank_fir_v2_subsystem.m
SYS = filterbank_fir_v2_subsystem(NAME, L, BLOCKSIZE)
Creates a subsystem which implements a long FIR filter efficiently using
a filterbank based algorithm. Arguments:
NAME - name of the subsystem
L - length of the time domain FIR filter
BLOCKSIZE - time domain block size. This allocates sizes of internal
modules and the prebuild function checks that this matches the
actual block size.
This v2 version of the module no longer requires that the input
block size is a power of 2.
The function internally uses a combination of Audio Weaver blocks
in order to achieve the desired filtering. The input and output