From 35871625e84c5e91af1fa8b7e741629e3880d323 Mon Sep 17 00:00:00 2001
From: Tom <trondeau@vt.edu>
Date: Sun, 23 Aug 2009 22:30:35 -0400
Subject: Adding plotting of group delay.
---
gr-utils/src/python/gr_filter_design.py | 46 +++++++++++++++++++++++++++------
1 file changed, 38 insertions(+), 8 deletions(-)
(limited to 'gr-utils/src')
diff --git a/gr-utils/src/python/gr_filter_design.py b/gr-utils/src/python/gr_filter_design.py
index 352e275db2..7a15b40301 100755
--- a/gr-utils/src/python/gr_filter_design.py
+++ b/gr-utils/src/python/gr_filter_design.py
@@ -46,6 +46,9 @@ class gr_plot_filter(QtGui.QMainWindow):
self.gui.designButton.setShortcut("Return")
self.taps = []
+ self.fftdB = []
+ self.fftDeg = []
+ self.groupDelay = []
self.nfftpts = int(10000)
self.gui.nfftEdit.setText(Qt.QString("%1").arg(self.nfftpts))
@@ -184,7 +187,7 @@ class gr_plot_filter(QtGui.QMainWindow):
designer = {"Low Pass" : self.design_opt_lpf,
"Band Pass" : self.design_opt_bpf,
"High Pass" : self.design_opt_hpf}
- taps,r = designer[ftype](fs, gain)
+ self.taps,r = designer[ftype](fs, gain)
else:
designer = {"Low Pass" : self.design_win_lpf,
@@ -194,11 +197,11 @@ class gr_plot_filter(QtGui.QMainWindow):
self.taps,r = designer[ftype](fs, gain, wintype)
if(r):
- self.get_fft(self.taps, self.nfftpts)
+ self.get_fft(fs, self.taps, self.nfftpts)
self.update_time_curves()
self.update_freq_curves()
self.update_phase_curves()
-
+ self.update_group_curves()
# Filter design functions using a window
def design_win_lpf(self, fs, gain, wintype):
@@ -328,13 +331,16 @@ class gr_plot_filter(QtGui.QMainWindow):
self.update_time_curves()
if(tab == 2):
self.update_phase_curves()
+ if(tab == 3):
+ self.update_group_curves()
- def get_fft(self, taps, Npts):
+ def get_fft(self, fs, taps, Npts):
+ Ts = 1.0/fs
fftpts = fftpack.fft(taps, Npts)
- self.freq = scipy.arange(0, Npts)
-
+ self.freq = scipy.arange(0, fs, 1.0/(Npts*Ts))
self.fftdB = 20.0*scipy.log10(abs(fftpts))
self.fftDeg = scipy.unwrap(scipy.angle(fftpts))
+ self.groupDelay = -scipy.diff(self.fftDeg)
def update_time_curves(self):
ntaps = len(self.taps)
@@ -362,8 +368,10 @@ class gr_plot_filter(QtGui.QMainWindow):
# Reset the x-axis to the new time scale
ymax = 1.5 * max(self.fftdB[0:npts/2])
ymin = 1.1 * min(self.fftdB[0:npts/2])
+ xmax = self.freq[npts/2]
+ xmin = self.freq[0]
self.gui.freqPlot.setAxisScale(self.gui.freqPlot.xBottom,
- 0, npts/2)
+ xmin, xmax)
self.gui.freqPlot.setAxisScale(self.gui.freqPlot.yLeft,
ymin, ymax)
@@ -381,8 +389,10 @@ class gr_plot_filter(QtGui.QMainWindow):
# Reset the x-axis to the new time scale
ymax = 1.5 * max(self.fftDeg[0:npts/2])
ymin = 1.1 * min(self.fftDeg[0:npts/2])
+ xmax = self.freq[npts/2]
+ xmin = self.freq[0]
self.gui.phasePlot.setAxisScale(self.gui.phasePlot.xBottom,
- 0, npts/2)
+ xmin, xmax)
self.gui.phasePlot.setAxisScale(self.gui.phasePlot.yLeft,
ymin, ymax)
@@ -391,6 +401,26 @@ class gr_plot_filter(QtGui.QMainWindow):
self.gui.phasePlot.replot()
+ def update_group_curves(self):
+ npts = len(self.groupDelay)
+ if(npts > 0):
+ self.groupcurve.setData(self.freq, self.groupDelay)
+
+ # Reset the x-axis to the new time scale
+ ymax = 1.5 * max(self.groupDelay[0:npts/2])
+ ymin = 1.1 * min(self.groupDelay[0:npts/2])
+ xmax = self.freq[npts/2]
+ xmin = self.freq[0]
+ self.gui.groupPlot.setAxisScale(self.gui.groupPlot.xBottom,
+ xmin, xmax)
+ self.gui.groupPlot.setAxisScale(self.gui.groupPlot.yLeft,
+ ymin, ymax)
+
+ # Set the zoomer base to unzoom to the new axis
+ self.groupZoomer.setZoomBase()
+
+ self.gui.groupPlot.replot()
+
def setup_options():
usage="%prog: [options] (input_filename)"
--
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