Frequency Transformations

Transform filters to other forms, use features in a filter to develop another filter

DSP System Toolbox™ offers several functions that transform existing FIR and IIR filters into other forms to achieve different frequency responses. The general idea of frequency transformation is to use an existing prototype filter to produce another filter that retains some characteristics of the prototype filter in the frequency domain. For more information, see Digital Frequency Transformations.

Functions

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FIR

`firlp2hp`	Transform FIR lowpass filter to Type I FIR highpass filter
`firlp2lp`	Transform FIR Type I lowpass to FIR Type 1 lowpass with inverse bandwidth

IIR

`iirbpc2bpc`	Transform IIR complex bandpass filter to IIR complex bandpass filter with different characteristics
`iirftransf`	IIR frequency transformation of digital filter
`iirlp2bp`	Transform IIR lowpass filter to IIR bandpass filter
`iirlp2bpc`	Transform IIR lowpass filter to complex bandpass filter
`iirlp2bs`	Transform IIR lowpass filter to IIR bandstop filter
`iirlp2bsc`	Transform IIR lowpass filter to complex bandstop filter
`iirlp2hp`	Transform lowpass IIR filter to highpass filter
`iirlp2lp`	Transform lowpass IIR filter to different lowpass filter
`iirlp2mb`	Transform IIR lowpass filter to IIR multiband filter
`iirlp2mbc`	Transform IIR lowpass filter to IIR complex multiband filter
`iirlp2xc`	Transform IIR lowpass filter to IIR complex N-point filter
`iirlp2xn`	Transform IIR lowpass filter to IIR real N-point filter
`iirpowcomp`	Power complementary IIR filter

Topics

Digital Frequency Transformations
Learn how to transform discrete-time filters.
References — Frequency Transformations
Suggested reading and sources for information about filter frequency transformations.