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tf

Return transfer function of overall prototype lowpass filter

Description

example

[num,den] = tf(obj) returns the vector of numerator coefficients, num, and the vector of denominator coefficients, den, for the overall prototype lowpass filter used for the filter bank in dsp.Channelizer and dsp.ChannelSynthesizer System objects.

Examples

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Determine the transfer function of the overall prototype lowpass filter used for the filter bank in the dsp.Channelizer System object.

Design a channelizer with the number of frequency bands or polyphase branches set to 8, the number of taps or coefficients per band set to 12, and stopband attenuation set to 80 dB. The function tf returns the transfer function of the prototype lowpass filter.

channelizer = dsp.Channelizer;
[num,den] = tf(channelizer);

View the magnitude response of the prototype lowpass filter using fvtool.

fvtool(num,den);

Input Arguments

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Input filter, specified as either a dsp.Channelizer or a dsp.ChannelSynthesizer System object.

Example: channelizer = dsp.Channelizer;

Example: channelizer = dsp.ChannelSynthesizer

Output Arguments

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Numerator coefficients, returned as a row vector.

Denominator coefficients, returned as a row vector. For a finite Impulse response (FIR) filter, this value is 1.

Introduced in R2016b