Documentation

# Digital Filter Analysis

Magnitude, phase, impulse, and step responses, phase and group delays, pole-zero analysis

Analyze frequency- and time-domain responses of filters. Visualize filter poles and zeros in the complex plane.

## Functions

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 `abs` Absolute value and complex magnitude `angle` Phase angle `freqz` Frequency response of digital filter `grpdelay` Average filter delay (group delay) `phasedelay` Phase delay of digital filter `phasez` Phase response of digital filter `unwrap` Shift phase angles `zerophase` Zero-phase response of digital filter `zplane` Zero-pole plot for discrete-time systems
 `impz` Impulse response of digital filter `impzlength` Impulse response length `stepz` Step response of digital filter
 `filtord` Filter order `filternorm` 2-norm or infinity-norm of digital filter `firtype` Type of linear phase FIR filter `isallpass` Determine whether filter is allpass `isfir` Determine if digital filter has finite impulse response `islinphase` Determine whether filter has linear phase `ismaxphase` Determine whether filter is maximum phase `isminphase` Determine whether filter is minimum phase `isstable` Determine whether filter is stable

## Apps

 Filter Designer Design filters starting with algorithm selection

## Filter Visualization Tool

 FVTool Filter Visualization Tool

## Topics

Frequency Response

Compute and display frequency responses of IIR and FIR lowpass, highpass, and bandpass filters.

Phase Response

Extract the phase response of a filter.

Delay

Measure the average time delay of a filter as a function of frequency.

Zero-Pole Analysis

Find and visualize poles and zeros of a linear system.

Impulse Response

Generate and display the impulse response of a simple filter.

Compensate for the Delay Introduced by an FIR Filter

Use indexing to counteract the time shifts introduced by filtering.

Compensate for the Delay Introduced by an IIR Filter

Remove delays and distortion introduced by filtering, when it is critical to keep phase information intact.