Upsample, filter, and downsample input signals
DSP System Toolbox / Filtering / Multirate Filters
The FIR Rate Conversion block resamples the discrete-time input such that its sample period is K/L times the input sample period (Tsi). K is the integer value you specify for the Decimation factor parameter, and L is the integer value you specify for the Interpolation factor parameter.
The block treats each column of the input as a separate channel and resamples the data in each channel independently over time. To do so, the block implements a polyphase filter structure and performs the following operations:
Upsamples the input to a higher rate by inserting
L−1
zeros between input
samples.
Passes the upsampled data through a direct-form II transpose FIR filter.
Downsamples the filtered data to a lower rate by discarding
K-1
consecutive samples following each
sample that the block retains.
The polyphase filter implementation is more efficient than a straightforward upsample-filter-decimate algorithm. See Orfanidis [1] for more information.
Data Types |
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Direct Feedthrough |
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Multidimensional Signals |
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Variable-Size Signals |
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Zero-Crossing Detection |
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[1] Orfanidis, Sophocles J. Introduction to Signal Processing. Upper Saddle River, NJ: Prentice-Hall, 1996.
firceqrip
| firgr
| firhalfband
| firnyquist
dsp.CICCompensationDecimator
| dsp.CICCompensationInterpolator
| dsp.FIRDecimator
| dsp.FIRHalfbandDecimator
| dsp.FIRHalfbandInterpolator
| dsp.FIRInterpolator