#! /usr/bin/env perl
#
# $Id: x26.pl 11730 2011-04-29 22:16:08Z huntd $
#
# -*- coding: utf-8; -*-
#
# Demo x26 for the PLplot PDL binding
#
# Multi-lingual version of the first page of example 4.
#
# Copyright (C) 2006 Alan Irwin
# Copyright (C) 2006 Andrew Ross
#
# Thanks to the following for providing translated strings for this example:
# Valery Pipin (Russian)
#
# This file is part of PLplot.
#
# PLplot is free software; you can redistribute it and/or modify
# it under the terms of the GNU Library General Public License as published
# by the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# PLplot is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Library General Public License for more details.
#
# You should have received a copy of the GNU Library General Public License
# along with PLplot; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
# This example designed just for devices (e.g., psttfc and the
# cairo-related devices) that use the pango and fontconfig libraries. The
# best choice of glyph is selected by fontconfig and automatically rendered
# by pango in way that is sensitive to complex text layout (CTL) language
# issues for each unicode character in this example. Of course, you must
# have the appropriate TrueType fonts installed to have access to all the
# required glyphs.
# Translation instructions: The strings to be translated are given by
# x_label, y_label, alty_label, title_label, and line_label below. The
# encoding used must be UTF-8.
# The following strings to be translated involve some scientific/mathematical
# jargon which is now discussed further to help translators.
# (1) dB is a decibel unit, see http://en.wikipedia.org/wiki/Decibel .
# (2) degrees is an angular measure, see
# http://en.wikipedia.org/wiki/Degree_(angle) .
# (3) low-pass filter is one that transmits (passes) low frequencies.
# (4) pole is in the mathematical sense, see
# http://en.wikipedia.org/wiki/Pole_(complex_analysis) . "Single Pole"
# means a particular mathematical transformation of the filter function has
# a single pole, see
# http://ccrma.stanford.edu/~jos/filters/Pole_Zero_Analysis_I.html .
# Furthermore, a single-pole filter must have an inverse square decline
# (or -20 db/decade). Since the filter plotted here does have that
# characteristic, it must by definition be a single-pole filter, see also
# http://www-k.ext.ti.com/SRVS/Data/ti/KnowledgeBases/analog/document/faqs/1p.htm
# (5) decade represents a factor of 10, see
# http://en.wikipedia.org/wiki/Decade_(log_scale) .
# SYNC: x26c.c 1.1
use PDL;
use PDL::Graphics::PLplot;
use Math::Trig qw [pi];
use Getopt::Long;
@x_label = (
"Frequency",
"Частота"
);
@y_label = (
"Amplitude (dB)",
"Амплитуда (dB)"
);
@alty_label = (
"Phase shift (degrees)",
"Фазовый сдвиг (градусы)"
);
@legend_text = (
[ "Amplitude", "Phase shift" ],
[ "Амплитуда", "Фазовый сдвиг" ],
);
@title_label = (
"Single Pole Low-Pass Filter",
"Однополюсный Низко-Частотный Фильтр"
);
@line_label = (
"-20 dB/decade",
"-20 dB/десяток"
);
sub main {
# Parse and process command line arguments
plParseOpts (\@ARGV, PL_PARSE_SKIP | PL_PARSE_NOPROGRAM);
# Initialize plplot
plinit();
plfont(2);
# Make log plots using two different styles.
for (my $i=0; $i