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Reference guides are available for functions and commands supported by OML, Tcl, and Python.
Reference Guide for OpenMatrix Language Functions
The Reference Guide contains documentation for all functions supported in the OpenMatrix language.
Signal Processing Commands
bessel3ap
Create a normalized Bessel analog lowpass prototype filter in zero-pole-gain form.

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- Scripting Guide for OpenMatrix Language
  OpenMatrix is a mathematical scripting language.
- Reference Guide for OpenMatrix Language Functions
  The Reference Guide contains documentation for all functions supported in the OpenMatrix language.
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    - barthannwin
      Bartlett-Hann window.
    - bessel3ap
      Create a normalized Bessel analog lowpass prototype filter in zero-pole-gain form.
    - besselap
      Create a normalized Bessel analog lowpass prototype filter in zero-pole-gain form.
    - besself
      Create a Bessel filter.
    - besself3
      Create a Bessel filter.
    - blackman
      Blackman window.
    - buttap
      Create a normalized Butterworth analog lowpass prototype filter in zero-pole-gain form.
    - butter
      Create a Butterworth filter.
    - buttord
      Design a Butterworth filter.
    - cheb1ap
      Create a normalized Chebyshev I analog lowpass prototype filter in zero-pole-gain form.
    - cheb2ap
      Create a normalized Chebyshev II analog lowpass prototype filter in zero-pole-gain form.
    - cheb1ord
      Design a Chebyshev I filter.
    - cheb2ord
      Design a Chebyshev II filter.
    - chebwin
      Dolph-Chebyshev window.
    - cheby1
      Create a Chebyshev I filter.
    - cheby2
      Create a Chebyshev II filter.
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      Generate a chirp signal.
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      Generate a complex Morlet wavelet.
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      Compute cross power spectral density.
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      Downsample a signal.
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      Acoustic A-weighting function.
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      Acoustic B-weighting function.
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      Acoustic C-weighting function.
    - dbu
      Acoustic U-weighting function.
    - diric
      Generate the Dirichlet function.
    - ellip
      Create an Elliptic filter.
    - ellipap
      Create a normalized Elliptic analog lowpass prototype filter in zero-pole-gain form.
    - ellipord
      Design an Elliptic filter.
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      Fast Fourier Transform.
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      Two Dimensional Fast Fourier Transform.
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      N dimensional fast Fourier transform (FFT).
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      Shift frequency spectrum related vectors to center the dc element
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      Locate the peaks of a signal.
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      Create a digital FIR filter.
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      Create a digital FIR multi-band filter with a least squares fitting.
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      Create one-sided spectrum amplitude vectors from the two-sided equivalents.
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      Generate a vector of frequency locations.
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      Compute analog filter frequency response values.
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      Compute digital filter frequency response values.
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      Generate a sampled Gaussian modulated sinusoidal pulse centered at zero, with a specified center frequency and fractional bandwidth.
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      Generate a sampled Gaussian monopulse.
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      Compute digital filter group delay values.
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      Hamming window.
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      Hann window.
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      Hilbert transform.
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      Inverse Fast Fourier transform.
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      Two-dimensional inverse fast Fourier transform.
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      N dimensional inverse fast Fourier transform.
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      Shift frequency spectrum related vectors to uncenter the dc element to the first position.
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      Compute the impulse response of a digital filter.
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      Compute analog filter coefficients from frequency response values.
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      Compute digital filter coefficients from frequency response values.
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      Inverse Short-Time Fourier Transform.
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      Kaiser-Bessel window.
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      Applies a moving median filter in one dimension.
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      Generate a Mexican hat wavelet.
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      Generate a Meyer auxiliary wavelet.
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      Estimates the mean squared coherence of time domain signals.
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      Generate a Morlet wavelet.
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      Parzen window.
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      Compute signal maximum to minimum differences.
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      Compute signal peak to rms ratios.
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      Generate a pulse train, with the pulse defined either by a function or a sampled pulse.
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      Computes the power spectral density.
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      Generate a sampled rectangular pulse centered at zero, with a specified width.
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      Resample a real signal by a rational factor using a polyphase FIR filter.
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      Compute root sum squared values.
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      Generate a sawtooth wave with range [-1,1] and period 2*pi.
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      Generate a complex Shannon wavelet.
    - shiftdata
      Transfer a designated matrix dimension to the lead position.
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      Filter a real signal with a second order section IIR filter.
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      Generate a square wave with range [-1,1] and period 2*pi.
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      Compute the sinc function.
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      Short-Time Fourier Transform.
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      Spectrogram.
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      Generate a stair step plot.
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      Estimates the transfer function from time domain signals.
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      Generate a sampled triangular pulse centered at zero, with a specified width and skew.
    - udecode
      Convert quantized integer matrix elements to floating-point values.
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      Quantize real matrix elements to integer values.
    - unshiftdata
      Revert the order of matrix dimensions modified by shiftdata.
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      Unwrap a vector of phase angles.
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      Upsample a signal.
    - welchwin
      Welch window.
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      Cross correlation, computed over a range of lags.
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      Cross covariance, computed over a range of lags.
    - zplane
      Plot zeros and poles of a discrete transfer function.
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bessel3ap

Create a normalized Bessel analog lowpass prototype filter in zero-pole-gain form.

Syntax

[z,p,k] = bessel3ap(n)

Inputs

n: The filter order.; Type: integer; Dimension: scalar

Outputs

z: The zeros of the filter.; Type: vector
p: The poles of the filter.; Type: vector
k: The gain factor.; Type: scalar

Examples

Create a fourth order Bessel analog prototype filter.

[z,p,k] = bessel3ap(4)

z = [Matrix] 0 x 1
p = [Matrix] 4 x 1
-0.99521 + 1.25711i
-0.99521 - 1.25711i
-1.37007 + 0.41025i
-1.37007 - 0.41025i
k = 5.25819901

Comments

This function corresponds to the besself3 filter, which has an alternate specification compared with besself.

The Bessel prototype has -3dB attenuation at a 1 radian/sec cutoff frequency. Analog Bessel filters have no zeros.