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#!/usr/bin/env python
from cvxopt import matrix, cos
from cvxopt.solvers import options
from cvxopt.modeling import op, variable, max
from math import log10, pi, floor
import gtk
import matplotlib
matplotlib.use('GTKAgg') # or 'GTK'
from matplotlib.backends.backend_gtkagg import FigureCanvasGTKAgg as FigureCanvas
import pylab
def frange(a,b,N):
return [ a+k*float((b-a))/N for k in range(N) ]
def design_lowpass(N, d1, wc, ws, solver=None, Q=50):
h = variable(N+1)
d1 = 10**(d1/20.0) # convert from dB
n = matrix(range(N+1), (1,N+1), 'd')
n1 = int(round(N*Q*wc/pi));
G1 = cos(matrix(frange(0,wc,n1))*n)
n2 = int(round(N*Q*(pi-ws)/pi));
G2 = cos(matrix(frange(ws,pi,n2))*n)
op(max(abs(G2*h)), [G1*h <= d1, G1*h >= 1.0/d1]).solve(solver=solver)
return (h.value, max(abs(G2*h.value)))
class MainGUI:
def check_values(self, param=None):
page = self.nb.get_current_page()
if page>=0:
N = self.fo_spinner.get_value_as_int()
co = self.co_spinner.get_value()
sb = self.sb_spinner.get_value()
pr = self.pr_spinner.get_value()
if (co == self.tabs[page][1] and sb == self.tabs[page][2] and
pr == self.tabs[page][3] and N == self.tabs[page][4]):
self.compute_filter.set_sensitive(False)
else:
self.compute_filter.set_sensitive(True)
def change_co(self, param1):
self.sb_spinner.set_range(param1.get_value()+0.01,
self.sb_spinner.get_range()[1]);
self.check_values()
def change_sb(self, param1):
self.co_spinner.set_range(0.1, param1.get_value()-0.01);
self.check_values()
def switch_page(self, page, page_num, page_int, notebook):
if len(self.tabs)>page_int:
self.tabs[page_int][0].draw()
self.co_spinner.set_value(self.tabs[page_int][1])
self.sb_spinner.set_value(self.tabs[page_int][2])
self.pr_spinner.set_value(self.tabs[page_int][3])
self.fo_spinner.set_value(self.tabs[page_int][4])
self.compute_filter.set_sensitive(False)
def new_tab(self, button, notebook):
N = self.fo_spinner.get_value_as_int()
co = self.co_spinner.get_value()
sb = self.sb_spinner.get_value()
pr = self.pr_spinner.get_value()
try:
h, d2 = design_lowpass(N, pr, pi*co, pi*sb)
except:
x = gtk.MessageDialog(flags=gtk.DIALOG_MODAL, \
type=gtk.MESSAGE_WARNING, message_format= \
"Please tighten the filter specifications.");
x.run()
return
w = matrix(frange(0,pi,N*50));
C = cos(w*matrix(range(N+1),(1,N+1)));
fig = pylab.figure()
canvas = FigureCanvas(fig) # a gtk.DrawingArea
ax = fig.add_subplot(111)
ylim = [floor((20*log10(d2)-30)/100)*100,10]
ax.plot(list(w/pi),[20*log10(abs(x)) for x in C*h])
ax.plot(2*[co],[-pr,ylim[0]],'g--')
ax.plot(2*[co],[10,pr],'g--')
ax.plot(2*[sb],[10,20*log10(d2)],'g--')
ax.plot([sb, 1],2*[20*log10(d2)],'g--')
ax.plot([0, co],2*[-pr],'g--')
ax.plot([0, co],2*[pr],'g--')
pylab.setp(ax,ylim=ylim)
pylab.setp(ax,xlabel="Normalized frequency")
pylab.setp(ax,ylabel="Attenuation [dB]")
ax.grid()
canvas.show()
notebook.append_page(canvas)
notebook.set_current_page(notebook.get_n_pages()-1)
self.tabs.append([canvas,co,sb,pr,N])
self.compute_filter.set_sensitive(False)
def close_tab(self, button, notebook):
page = notebook.get_current_page()
notebook.remove_page(page)
if page>=0: del(self.tabs[page])
# Need to refresh the widget --
# This forces the widget to redraw itself.
notebook.queue_draw_area(0,0,-1,-1)
if notebook.get_n_pages() == 0:
self.compute_filter.set_sensitive(True)
def delete(self, widget, event=None):
gtk.main_quit()
return gtk.FALSE
def __init__(self):
window = gtk.Window (gtk.WINDOW_TOPLEVEL)
window.connect("delete_event", self.delete)
window.set_default_size(600, 400)
window.set_border_width(10)
table = gtk.Table(4,6,False)
window.add(table)
# Create a new notebook, place the position of the tabs
notebook = gtk.Notebook()
notebook.connect("switch-page", self.switch_page, notebook)
notebook.set_tab_pos(gtk.POS_BOTTOM)
table.attach(notebook, 0,6,0,1)
notebook.show()
self.nb = notebook
self.tabs = []
# Stopband frequency
co_label = gtk.Label("Cutoff")
co_label.show()
table.attach(co_label, 0,1,1,2, gtk.SHRINK, gtk.SHRINK)
co_adj = gtk.Adjustment(0.25, 0.1, 0.34, 0.01, 0, 0)
self.co_spinner = gtk.SpinButton(co_adj, 0.0, 2)
self.co_spinner.set_numeric(True)
self.co_spinner.connect("value-changed", self.change_co);
self.co_spinner.show()
table.attach(self.co_spinner, 0,1,2,3, gtk.SHRINK, gtk.SHRINK)
# Stopband frequency
sb_label = gtk.Label("Stopband")
sb_label.show()
table.attach(sb_label, 1,2,1,2, gtk.SHRINK, gtk.SHRINK)
sb_adj = gtk.Adjustment(0.35, 0.26, 0.5, 0.01, 0, 0)
self.sb_spinner = gtk.SpinButton(sb_adj, 0.0, 2)
self.sb_spinner.set_numeric(True)
self.sb_spinner.connect("value-changed", self.change_sb);
self.sb_spinner.show()
table.attach(self.sb_spinner, 1,2,2,3, gtk.SHRINK, gtk.SHRINK)
# Passband ripple
pr_label = gtk.Label("Passband ripple")
pr_label.show()
table.attach(pr_label, 2,3,1,2, gtk.SHRINK, gtk.SHRINK)
pr_adj = gtk.Adjustment(1, 0.3, 3, 0.01, 0, 0)
self.pr_spinner = gtk.SpinButton(pr_adj, 0.0, 2)
self.pr_spinner.connect("value-changed", self.check_values);
self.pr_spinner.set_numeric(True)
self.pr_spinner.show()
table.attach(self.pr_spinner, 2,3,2,3, gtk.SHRINK, gtk.SHRINK)
# Filter order
fo_label = gtk.Label("Filter order")
fo_label.show()
table.attach(fo_label, 3,4,1,2, gtk.SHRINK, gtk.SHRINK)
fo_adj = gtk.Adjustment(10, 5, 50, 1, 0, 0)
self.fo_spinner = gtk.SpinButton(fo_adj, 0.0, 0)
self.fo_spinner.connect("value-changed", self.check_values);
self.fo_spinner.set_numeric(True)
self.fo_spinner.show()
table.attach(self.fo_spinner, 3,4,2,3, gtk.SHRINK, gtk.SHRINK)
# Buttons
button = gtk.Button("compute filter")
button.connect("clicked", self.new_tab, notebook)
table.attach(button, 4,5,2,3, gtk.FILL, gtk.SHRINK)
button.show()
self.compute_filter = button
button = gtk.Button("close tab")
button.connect("clicked", self.close_tab, notebook)
table.attach(button, 5,6,2,3, gtk.FILL, gtk.SHRINK)
button.show()
table.show()
window.show()
options['show_progress']=False
gui = MainGUI()
gtk.main()
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