MATLAB: Magnitude of a filter

filters

Why does filters generally have a magnitude of 1?

Best Answer

Hi Lisa, Filtering a signal usually implies convolving the signal with the impulse response of a linear time-invariant system.

In the frequency domain this is equivalent to mulitplying the frequency response of the signal with the frequency response of the filter.

Accordingly, it is desirable to have the magnitude of the filter as close to 1 as possible in the passband, so that in the passband, the frequency content of the signal is not modified in magnitude, just in phase.

Related Solutions

MATLAB: How to design FIR lowpass filter with cutoff frequency, fc1 = 20 Hz and FIR bandpass filter with cutoff frequency fc2 = 10 Hz and fc3 = 35 Hz.

Déjà vu

how to design IIR highpass filter with cutoff frequency of 20Hz and FIR bandpass filter with cutoff frequency of 10Hz and 15Hz?

Make the appropriate changes to get the cascaded filter you want.

MATLAB: Bode() magnitude

Magnitude and phase outputs of bode are 3-D arrays, for representing multi-input multi-output systems. The first two dimensions correspond to the number of inputs and outputs, the third dimension corresponds to the number of frequency points. In your case you have a single-input single-output system, so size(mag) is 1 1 n, where n is the number of frequency points.

To get a standard bode plot you can just do

bode(sys)

If you want access to mag and phase as regular vectors, just do

mag=squeeze(mag)

All of this is covered in the doc.

Arkadiy

Best Answer

Related Solutions

MATLAB: How to design FIR lowpass filter with cutoff frequency, fc1 = 20 Hz and FIR bandpass filter with cutoff frequency fc2 = 10 Hz and fc3 = 35 Hz.

MATLAB: Bode() magnitude

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