Multirate and Multistage Filters

Decimation, interpolation, rate conversion

Objects

Single Stage Filters

`dsp.Channelizer`	Polyphase FFT analysis filter bank
`dsp.ChannelSynthesizer`	Polyphase FFT synthesis filter bank
`dsp.FarrowRateConverter`	Polynomial sample rate converter with arbitrary conversion factor
`dsp.FIRDecimator`	Polyphase FIR decimator
`dsp.FIRHalfbandDecimator`	Halfband decimator
`dsp.FIRHalfbandInterpolator`	Halfband interpolator
`dsp.FIRInterpolator`	Polyphase FIR interpolator
`dsp.FIRRateConverter`	Sample rate converter
`dsp.HDLChannelizer`	Polyphase filter bank and fast Fourier transform—optimized for HDL code generation
`dsp.HDLFIRRateConverter`	Upsample, filter, and downsample—optimized for HDL code generation
`dsp.IIRHalfbandDecimator`	Decimate by factor of two using polyphase IIR
`dsp.IIRHalfbandInterpolator`	Interpolate by a factor of two using polyphase IIR

Multistage Filters

`dsp.ComplexBandpassDecimator`	Extract a frequency subband using a one-sided (complex) bandpass decimator
`dsp.DigitalDownConverter`	Translate digital signal from intermediate frequency (IF) band to baseband and decimate it
`dsp.DigitalUpConverter`	Interpolate digital signal and translate it from baseband to IF band
`dsp.FilterCascade`	Create cascade of filter System objects
`dsp.SampleRateConverter`	Multistage sample rate converter

CIC Filters

`dsp.CICCompensationDecimator`	Compensate for CIC decimation filter using FIR decimator
`dsp.CICCompensationInterpolator`	Compensate for CIC interpolation filter using FIR interpolator
`dsp.CICDecimator`	Decimate signal using cascaded integrator-comb (CIC) filter
`dsp.CICInterpolator`	Interpolate signal using cascaded integrator-comb filter
`dsp.HDLCICDecimation`	Decimate signal using cascaded integrator-comb filter — optimized for HDL code generation

Filter Bank

`dsp.DyadicAnalysisFilterBank`	Dyadic analysis filter bank
`dsp.DyadicSynthesisFilterBank`	Reconstruct signals from subbands
`dsp.SubbandAnalysisFilter`	Decompose signal into high-frequency and low-frequency subbands
`dsp.SubbandSynthesisFilter`	Reconstruct signal from high-frequency and low-frequency subbands

Functions

`cascade`	Cascade of filter system objects
`convert`	Convert filter structure of discrete-time filter
`filter`	1-D digital filter
`polyphase`	Polyphase decomposition of multirate filter
`sysobj`	Create filter System object from discrete-time filter

Blocks

expand all

Single Stage Filters

Channelizer	Polyphase FFT analysis filter bank
Channelizer HDL Optimized	Polyphase filter bank and fast Fourier transform—optimized for HDL code generation
Channel Synthesizer	Polyphase FFT synthesis filter bank
Farrow Rate Converter	Polynomial sample-rate converter with arbitrary conversion factor
FIR Decimation	Filter and downsample input signals
FIR Halfband Decimator	Decimate signal using polyphase FIR halfband filter
FIR Halfband Interpolator	Interpolate signal using polyphase FIR half band filter
FIR Interpolation	Upsample and filter input signals
FIR Rate Conversion	Upsample, filter, and downsample input signals
FIR Rate Conversion HDL Optimized	Upsample, filter, and downsample input signals—optimized for HDL code generation
IIR Halfband Decimator	Decimate signal using polyphase IIR halfband filter
IIR Halfband Interpolator	Interpolate signal using polyphase IIR halfband filter

Multistage Filters

Complex Bandpass Decimator	Extract a frequency subband using a one-sided (complex) bandpass decimator
Digital Down-Converter	Translate digital signal from Intermediate Frequency (IF) band to baseband and decimate it
Digital Up-Converter	Interpolate digital signal and translate it from baseband to Intermediate Frequency (IF) band
Sample-Rate Converter	Multistage sample-rate conversion

CIC Filters

CIC Compensation Decimator	Compensate for CIC filter using FIR decimator
CIC Compensation Interpolator	Compensate for CIC filter using FIR interpolator
CIC Decimation	Decimate signal using cascaded integrator-comb filter
CIC Interpolation	Interpolate signal using cascaded integrator-comb filter
CIC Decimation HDL Optimized	Decimate signal using cascaded integrator-comb filter optimized for HDL code generation

Filter Bank

Dyadic Analysis Filter Bank	Decompose signals into subbands with smaller bandwidths and slower sample rates or compute discrete wavelet transform (DWT)
Dyadic Synthesis Filter Bank	Reconstruct signals from subbands with smaller bandwidths and slower sample rates or compute inverse discrete wavelet transform (IDWT)
Two-Channel Analysis Subband Filter	Decompose signal into high-frequency and low-frequency subbands
Two-Channel Synthesis Subband Filter	Reconstruct signal from high-frequency and low-frequency subbands

Topics

Multirate Filters

Defines a multirate filter and describes its uses.

Multistage Filters

Defines a multistage filter and describes its uses.

Filter Banks

Multirate filters alter the sample rate of the input signal during the filtering process.

FIR Nyquist (L-th band) Filter Design

This example shows how to design lowpass FIR Nyquist filters.

Design of Decimators/Interpolators

This example shows how to design filters for decimation and interpolation.

Compare Single-Rate/Single-Stage Filters with Multirate/Multistage Filters

Shows the efficiency gains that are possible when using multirate and multistage filters for certain applications.

Use Filter Designer with DSP System Toolbox Software

Presents a detailed reference covering the fixed-point, multirate, and scaling pages of the Filter Designer App.

Multirate Filtering in Simulink

DSP System Toolbox™ software provides a collection of multirate filtering examples that illustrate typical applications of the multirate filtering blocks.

Calculate Channel Latencies Required for Wavelet Reconstruction

Learn how to calculate the latencies required for perfect wavelet reconstruction.

Variable-Size Signal Support DSP System Objects

List of System objects which support variable-sized signals in DSP System Toolbox.

Model Multirate Signal Processing Systems Using Dataflow

Use a Dataflow Subsystem to automatically calculate frame sizes in multirate systems.

Featured Examples

Wavelet Denoising

Use the DyadicAnalysis and DyadicSynthesis System objects to remove noise from a signal.

Open Script

GSM Digital Down Converter in Simulink

Simulate steady-state behavior of a fixed-point digital down converter for GSM (Global System for Mobile) baseband conversions. The example model uses blocks from Simulink® and the DSP System Toolbox™ to emulate the operation of the TI GC4016 Quad Digital Down Converter (DDC).

Open Model

Wavelet Reconstruction and Noise Reduction

Uses the Dyadic Analysis Filter Bank and Dyadic Synthesis Filter Bank blocks to show both the perfect reconstruction property of wavelets and an application for noise reduction.

Open Model

Reconstruction Through Two-Channel Filter Bank

Design perfect reconstruction two-channel filter banks, also known as the Quadrature Mirror Filter (QMF) Banks since they use power complementary filters.

Open Script

Three-Channel Wavelet Transmultiplexer

Reconstruct three independent combined signals transmitted over a single communications link using a Wavelet Transmultiplexer (WTM). The example illustrates the perfect reconstruction property of the discrete wavelet transform (DWT).

Open Script