PDL::DSP::Windows Window functions for signal processing
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Perl module perl functions window signal processing

PDL::DSP::Windows Description

PDL::DSP::Windows is a Perl module that provides symmetric and periodic (DFT-symmetric) window functions for use in filtering and spectral analysis. It provides a high-level access subroutine "window". This functional interface is sufficient for getting the window samples. For analysis and plotting, etc. an object oriented interface is provided. The functional subroutines must be either explicitly exported, or fully qualified. In this document, the word function refers only to the mathematical window functions, while the word subroutine is used to describe code.Window functions are also known as apodization functions or tapering functions. In this module, each of these functions maps a sequence of $N integers to values called a samples. (To confuse matters, the word sample also has other meanings when describing window functions.) The functions are often named for authors of journal articles. Be aware that across the literature and software, some functions referred to by several different names, and some names refer to several different functions. As a result, the choice of window names is somewhat arbitrary.The "kaiser" window function requires PDL::GSLSF::BESSEL. The "dpss" window function requires PDL::LinearAlgebra. But the remaining window functions may be used if these modules are not installed.The most common and easiest usage of this module is indirect, via some higher-level filtering interface, such as PDL::DSP::Fir::Simple. The next easiest usage is to return a pdl of real-space samples with the subroutine "window". Finally, for analyzing window functions, object methods, such as "new", "plot", "plot_freq" are provided.In the following, first the functional interface (non-object oriented) is described in "FUNCTIONAL INTERFACE". Next, the object methods are described in "METHODS". Next the low-level subroutines returning samples for each named window are described in "WINDOW FUNCTIONS". Finally, some support routines that may be of interest are described in "AUXILIARY SUBROUTINES".SYNOPSIS use PDL; use PDL::DSP::Windows('window'); my $samples = window( 10, 'tukey', { params => .5 }); use PDL; use PDL::DSP::Windows; my $win = new PDL::DSP::Windows(10, 'tukey', { params => .5 }); print $win->coherent_gain , "\n"; $win->plot;Product's homepage

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