mirror of
git://projects.qi-hardware.com/openwrt-packages.git
synced 2024-11-25 23:31:54 +02:00
107 lines
2.7 KiB
Lua
107 lines
2.7 KiB
Lua
--[[ $Id: x04.lua 9414 2009-01-29 22:48:54Z airwin $
|
|
|
|
Log plot demo.
|
|
Simple line plot and multiple windows demo.
|
|
|
|
Copyright (C) 2008 Werner Smekal
|
|
|
|
This file is part of PLplot.
|
|
|
|
PLplot is free software you can redistribute it and/or modify
|
|
it under the terms of the GNU General Library 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
|
|
--]]
|
|
|
|
-- initialise Lua bindings for PLplot examples.
|
|
dofile("plplot_examples.lua")
|
|
|
|
----------------------------------------------------------------------------
|
|
-- plot1
|
|
--
|
|
-- Log-linear plot.
|
|
----------------------------------------------------------------------------
|
|
|
|
function plot1(type)
|
|
freql = {}
|
|
ampl = {}
|
|
phase = {}
|
|
|
|
pl.adv(0)
|
|
|
|
-- Set up data for log plot
|
|
f0 = 1
|
|
for i=1, 101 do
|
|
freql[i] = -2 + (i-1) / 20
|
|
freq = 10^freql[i]
|
|
ampl[i] = 20 * math.log10(1 / math.sqrt(1 + (freq / f0)^2))
|
|
phase[i] = -(180 / math.pi) * math.atan(freq / f0)
|
|
end
|
|
|
|
pl.vpor(0.15, 0.85, 0.1, 0.9)
|
|
pl.wind(-2, 3, -80, 0)
|
|
|
|
-- Try different axis and labelling styles.
|
|
pl.col0(1)
|
|
if type == 0 then
|
|
pl.box("bclnst", 0, 0, "bnstv", 0, 0)
|
|
end
|
|
|
|
if type == 1 then
|
|
pl.box("bcfghlnst", 0, 0, "bcghnstv", 0, 0)
|
|
end
|
|
|
|
-- Plot ampl vs freq
|
|
pl.col0(2)
|
|
pl.line(freql, ampl)
|
|
pl.col0(1)
|
|
pl.ptex(1.6, -30, 1, -20, 0.5, "-20 dB/decade")
|
|
|
|
-- Put labels on
|
|
pl.col0(1)
|
|
pl.mtex("b", 3.2, 0.5, 0.5, "Frequency")
|
|
pl.mtex("t", 2, 0.5, 0.5, "Single Pole Low-Pass Filter")
|
|
pl.col0(2)
|
|
pl.mtex("l", 5, 0.5, 0.5, "Amplitude (dB)")
|
|
|
|
-- For the gridless case, put phase vs freq on same plot
|
|
if type == 0 then
|
|
pl.col0(1)
|
|
pl.wind(-2, 3, -100, 0)
|
|
pl.box("", 0, 0, "cmstv", 30, 3)
|
|
pl.col0(3)
|
|
pl.line(freql, phase)
|
|
pl.col0(3)
|
|
pl.mtex("r", 5, 0.5, 0.5, "Phase shift (degrees)")
|
|
end
|
|
end
|
|
|
|
|
|
----------------------------------------------------------------------------
|
|
-- main
|
|
--
|
|
-- Illustration of logarithmic axes, and redefinition of window.
|
|
----------------------------------------------------------------------------
|
|
|
|
-- Parse and process command line arguments
|
|
pl.parseopts(arg, pl.PL_PARSE_FULL)
|
|
|
|
-- Initialize plplot
|
|
pl.init()
|
|
pl.font(2)
|
|
|
|
-- Make log plots using two different styles.
|
|
plot1(0)
|
|
plot1(1)
|
|
|
|
pl.plend()
|