filtertype : string or name, the type of filter

window : string or name, the window type

normalize : truefalse, whether to normalize

container : Array, predefined Array for holding the result

The GenerateFiniteImpulseResponseFilterTaps( n, freq ) command generates a taps array for a finite impulse response filter.  The resulting array may be used with the command FiniteImpulseResponseFilter to effect filtering operations on a sample.

For a low-pass or high-pass filter, a single frequency freq is required. It must be strictly positive and less than $\frac{1}{2}$.

For a band-pass or band-stop filter, a pair [lowfreq, highfreq] of low and high frequencies are required.  Each frequency must be positive and less than $\frac{1}{2}$; they must additionally satisfy $\mathrm{lowfreq}<\mathrm{highfreq}$.

Specify the type of filter with the filtertype option.  It can take any of the values "lowpass", "highpass", "bandpass" and "bandstop". The option values can be given as a name or as a string.

The type of window to use is indicated by the window option.  It can take any of the following values: "Bartlett", "Blackman", "Hamming" and "Hann". The option values can be given as a name or as a string.

The normalize option specifies whether to normalize the filter coefficients produced, and can be either of the values true or false.  The default is normalize = true.

If the container=C option is provided, then the results are put into C and C is returned. With this option, no additional memory is allocated to store the result. The container must be an Array of size $n$ having datatype float[8].

The GenerateFIRFilterTaps command is provided as an alias.

The SignalProcessing[GenerateFiniteImpulseResponseFilterTaps] command is thread-safe as of Maple 17.

For more information on thread safety, see index/threadsafe.

$\mathrm{with}\left(\mathrm{SignalProcessing}\right)\&colon;$

$\mathrm{GenerateFiniteImpulseResponseFilterTaps}\left(8\&comma;\frac{1}{3}\right)$

$\left[\begin{array}{cccccccc}0.0& -0.03571428572508216& 4.318575495781763{10}^{-11}& 0.5357142856818964& 0.5357142856818964& 4.318575495781763{10}^{-11}& -0.03571428572508216& 0.0\end{array}\right]$

$\mathrm{GenerateFiniteImpulseResponseFilterTaps}\left(8\&comma;\frac{1}{3}\&comma;\mathrm{normalize}\&equals;\mathrm{true}\right)$

$\left[\begin{array}{cccccccc}0.0& -0.03571428572508216& 4.318575495781763{10}^{-11}& 0.5357142856818964& 0.5357142856818964& 4.318575495781763{10}^{-11}& -0.03571428572508216& 0.0\end{array}\right]$

$C≔\mathrm{Array}\left(1..8\&comma;\&apos;\mathrm{datatype}\&apos;\&equals;{\&apos;\mathrm{float}\&apos;}_8\&comma;\mathrm{order}\&equals;\mathrm{C\_order}\right)\&colon;$

$\mathrm{GenerateFiniteImpulseResponseFilterTaps}\left(8\&comma;\frac{1}{3}\&comma;\mathrm{container}\&equals;C\right)$

$\left[\begin{array}{cccccccc}0.0& -0.03571428572508216& 4.318575495781763{10}^{-11}& 0.5357142856818964& 0.5357142856818964& 4.318575495781763{10}^{-11}& -0.03571428572508216& 0.0\end{array}\right]$

$C$

$\left[\begin{array}{cccccccc}0.0& -0.03571428572508216& 4.318575495781763{10}^{-11}& 0.5357142856818964& 0.5357142856818964& 4.318575495781763{10}^{-11}& -0.03571428572508216& 0.0\end{array}\right]$

$\mathrm{GenerateFiniteImpulseResponseFilterTaps}\left(8\&comma;\frac{1}{3}\&comma;\mathrm{filtertype}\&equals;''highpass''\right)$

$\left[\begin{array}{cccccccc}0.0& 0.022058823507641434& -0.14705882351764402& 0.3308823529747145& -0.3308823529747145& 0.14705882351764402& -0.022058823507641434& -0.0\end{array}\right]$

$\mathrm{GenerateFiniteImpulseResponseFilterTaps}\left(8\&comma;\left[0.2\&comma;0.4\right]\&comma;\mathrm{filtertype}\&equals;''bandstop''\&comma;\mathrm{window}\&equals;''Hann''\right)$

$\left[\begin{array}{cccccccc}-0.0& 0.02501254691992837& 0.07293693000045436& 0.40205052307961725& 0.40205052307961725& 0.07293693000045436& 0.02501254691992837& -0.0\end{array}\right]$

The SignalProcessing[GenerateFiniteImpulseResponseFilterTaps] command was introduced in Maple 17.

For more information on Maple 17 changes, see Updates in Maple 17.