1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
#!/usr/bin/env python
#
# Copyright 2009,2012,2013 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# GNU Radio is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
#
# GNU Radio 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GNU Radio; see the file COPYING. If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
#
from gnuradio import gr
from gnuradio import filter
from gnuradio import blocks
import sys
try:
from gnuradio import analog
except ImportError:
sys.stderr.write("Error: Program requires gr-analog.\n")
sys.exit(1)
try:
import scipy
except ImportError:
sys.stderr.write("Error: Program requires scipy (see: www.scipy.org).\n")
sys.exit(1)
try:
import pylab
except ImportError:
sys.stderr.write("Error: Program requires matplotlib (see: matplotlib.sourceforge.net).\n")
sys.exit(1)
class mytb(gr.top_block):
def __init__(self, fs_in, fs_out, fc, N=10000):
gr.top_block.__init__(self)
rerate = float(fs_out) / float(fs_in)
print "Resampling from %f to %f by %f " %(fs_in, fs_out, rerate)
# Creating our own taps
taps = filter.firdes.low_pass_2(32, 32, 0.25, 0.1, 80)
self.src = analog.sig_source_c(fs_in, analog.GR_SIN_WAVE, fc, 1)
#self.src = analog.noise_source_c(analog.GR_GAUSSIAN, 1)
self.head = blocks.head(gr.sizeof_gr_complex, N)
# A resampler with our taps
self.resamp_0 = filter.pfb.arb_resampler_ccf(rerate, taps,
flt_size=32)
# A resampler that just needs a resampling rate.
# Filter is created for us and designed to cover
# entire bandwidth of the input signal.
# An optional atten=XX rate can be used here to
# specify the out-of-band rejection (default=80).
self.resamp_1 = filter.pfb.arb_resampler_ccf(rerate)
self.snk_in = blocks.vector_sink_c()
self.snk_0 = blocks.vector_sink_c()
self.snk_1 = blocks.vector_sink_c()
self.connect(self.src, self.head, self.snk_in)
self.connect(self.head, self.resamp_0, self.snk_0)
self.connect(self.head, self.resamp_1, self.snk_1)
def main():
fs_in = 8000
fs_out = 20000
fc = 1000
N = 10000
tb = mytb(fs_in, fs_out, fc, N)
tb.run()
# Plot PSD of signals
nfftsize = 2048
fig1 = pylab.figure(1, figsize=(10,10), facecolor="w")
sp1 = fig1.add_subplot(2,1,1)
sp1.psd(tb.snk_in.data(), NFFT=nfftsize,
noverlap=nfftsize/4, Fs = fs_in)
sp1.set_title(("Input Signal at f_s=%.2f kHz" % (fs_in/1000.0)))
sp1.set_xlim([-fs_in/2, fs_in/2])
sp2 = fig1.add_subplot(2,1,2)
sp2.psd(tb.snk_0.data(), NFFT=nfftsize,
noverlap=nfftsize/4, Fs = fs_out,
label="With our filter")
sp2.psd(tb.snk_1.data(), NFFT=nfftsize,
noverlap=nfftsize/4, Fs = fs_out,
label="With auto-generated filter")
sp2.set_title(("Output Signals at f_s=%.2f kHz" % (fs_out/1000.0)))
sp2.set_xlim([-fs_out/2, fs_out/2])
sp2.legend()
# Plot signals in time
Ts_in = 1.0/fs_in
Ts_out = 1.0/fs_out
t_in = scipy.arange(0, len(tb.snk_in.data())*Ts_in, Ts_in)
t_out = scipy.arange(0, len(tb.snk_0.data())*Ts_out, Ts_out)
fig2 = pylab.figure(2, figsize=(10,10), facecolor="w")
sp21 = fig2.add_subplot(2,1,1)
sp21.plot(t_in, tb.snk_in.data())
sp21.set_title(("Input Signal at f_s=%.2f kHz" % (fs_in/1000.0)))
sp21.set_xlim([t_in[100], t_in[200]])
sp22 = fig2.add_subplot(2,1,2)
sp22.plot(t_out, tb.snk_0.data(),
label="With our filter")
sp22.plot(t_out, tb.snk_1.data(),
label="With auto-generated filter")
sp22.set_title(("Output Signals at f_s=%.2f kHz" % (fs_out/1000.0)))
r = float(fs_out)/float(fs_in)
sp22.set_xlim([t_out[r * 100], t_out[r * 200]])
sp22.legend()
pylab.show()
if __name__ == "__main__":
main()
|
