filtdemo

来自「speech signal process tools」· 代码 · 共 392 行 · 第 1/2 页

echo "(save the response in win.spec)"
echo " "
echo "   %filtspec -s 8000 -n513 win.filt - | tee win.spec | plotspec -"
filtspec -s 8000 -n513 win.filt - | tee win.spec | plotspec -y-60: -t "FIR multiband by Kaiser-Windowing method by win_filt(1-ESPS)" -W "=450x400+0+0" -  2> /dev/null
rm $param
echo " "
###################################BUTTERWORTH##################
cat >$param <<EOF
string filt_method = "BUTTERWORTH": "Desired filter type:":{"BUTTERWORTH", "CHEBYSHEV1", "CHEBYSHEV2", "ELLIPTICAL"};
float samp_freq = 8000: "Desired sampling frequency.";
float gain = 1: "Desired pass band gain.";
string filt_type = "LP": "Desired filter reponse":{"LP", "HP","BP","BS"};
float pass_band_loss = 1: "Desired maximum pass band loss (dB).";
float stop_band_loss = 20.: "Desired minimum stop band attenuation (dB).";
float p_freq1 = 500: "Passband frequency 1";
float s_freq1 = 1500: "Stopband frequency 1";
EOF
echo Now design a lowpass IIR filter by the Butterworth method
echo with 0 to 500 Hz as passband, 1500 to 4000 Hz 20dB down stopband.
echo " "
echo "   %iir_filt -P$param butt.filt"
iir_filt -P$param butt.filt
echo " "
echo Compute the spectral response of the lowpass filter, and plot it
echo "(save the response in butt.spec)"
echo " "
echo "   %filtspec -s 8000 -n513 butt.filt - | tee butt.spec | plotspec -"  
filtspec -s 8000 -n513 butt.filt - | tee butt.spec | plotspec -y-50: -t "IIR Butterworth Lowpass by iir_filt(1-ESPS)" -W "=450x400+0+0" -  2> /dev/null
rm $param
echo " "
####################################CHEBYSHEV1###################
cat >$param <<EOF
string filt_method = "CHEBYSHEV1": "Desired filter type:":{"BUTTERWORTH", "CHEBYSHEV1", "CHEBYSHEV2", "ELLIPTICAL"};
float samp_freq = 8000: "Desired sampling frequency.";
float gain = 1: "Desired pass band gain.";
string filt_type = "HP": "Desired filter reponse":{"LP", "HP","BP","BS"};
float pass_band_loss = 1: "Desired maximum pass band loss (dB).";
float stop_band_loss = 20.: "Desired minimum stop band attenuation (dB).";
float s_freq1 = 1500: "Stopband frequency 1";
float p_freq1 = 1800:  "Passband frequency 1";
EOF
echo Now design a highpass IIR filter by Chebyshev I method
echo with 0 to 1500 Hz as 20 dB down stopband and 1800 to 4000 Hz as passband.
echo " "
echo "   %iir_filt -P$param chev1.filt"
iir_filt -P$param chev1.filt
echo " "
echo Compute the spectral response of the highpass filter, and plot it
echo "(save the response in chev1.spec)"
echo " "
echo "   %filtspec -s 8000 -n513 chev1.filt - | tee chev1.spec | plotspec -" 
filtspec -s 8000 -n513 chev1.filt - | tee chev1.spec | plotspec -y-50: -t "IIR Chebyshev I Highpass by iir_filt(1-ESPS)" -W "=450x400+0+0" -  2> /dev/null
rm $param
echo " "
###################################CHEBYSHEV II##################
cat >$param <<EOF
string filt_method = "CHEBYSHEV2": "Desired filter type:":{"BUTTERWORTH", "CHEBYSHEV1", "CHEBYSHEV2", "ELLIPTICAL"};
float samp_freq = 8000: "Desired sampling frequency.";
float gain = 1: "Desired pass band gain.";
string filt_type = "BP": "Desired filter reponse":{"LP", "HP","BP","BS"};
float pass_band_loss = 1: "Desired maximum pass band loss (dB).";
float stop_band_loss = 20.: "Desired minimum stop band attenuation (dB).";
float p_freq1 = 1500: "Passband frequency 1";
float p_freq2 = 2200: "Passband frequency 2";
float s_freq1 = 1300: "Stopband frequency 1";
float s_freq2 = 2400: "Stopband frequency 2";
EOF
echo Now design a bandpass IIR filter by Chebyshev II method
echo with passband 1500 to 2200 Hz, and 20 dB down on stopbands of 0 to 1500 Hz
echo and 2400 to 4000 Hz.
echo " "
echo "   %iir_filt -P$param chev2.filt"
iir_filt -P$param chev2.filt
echo " "
echo Compute the spectral response of the bandpass filter, and plot it
echo "(save the response in chev2.spec)"
echo " "
echo "   %filtspec -s 8000 -n513 chev2.filt - | tee chev2.spec | plotspec -"
filtspec -s 8000 -n513 chev2.filt - | tee chev2.spec | plotspec -y-50: -t "IIR Chebyshev II Bandpass by iir_filt(1-ESPS)" -W "=450x400+0+0" -  2> /dev/null
rm $param
echo " "
###################################ELLIPTICAL##################
cat >$param <<EOF
string filt_method = "ELLIPTICAL": "Desired filter type:":{"BUTTERWORTH", "CHEBYSHEV1", "CHEBYSHEV2", "ELLIPTICAL"};
float samp_freq = 8000: "Desired sampling frequency.";
float gain = 1: "Desired pass band gain.";
string filt_type = "BS": "Desired filter reponse":{"LP", "HP","BP","BS"};
float pass_band_loss = 1: "Desired maximum pass band loss (dB).";
float stop_band_loss = 65: "Desired minimum stop band attenuation (dB).";
float p_freq1 = 1300: "Passband frequency 1";
float p_freq2 = 2400: "Passband frequency 2";
float s_freq1 = 1500: "Stopband frequency 1";
float s_freq2 = 2200: "Stopband frequency 2";
EOF
echo Now design an bandstop IIR filter by Elliptical polynomial approximation 
echo technique with 40 dB down on stopband 1500 to 2200 Hz.
echo " "
echo "   %iir_filt -P$param elli.filt"
iir_filt -P$param elli.filt
echo " "
echo Compute the spectral response of the bandstop filter, and plot it
echo "(save the response in elli.spec)"
echo " "
echo "   %filtspec -s 8000 -n513 elli.filt - | tee elli.spec | plotspec -"
filtspec -s 8000 -n513 elli.filt - | tee elli.spec | plotspec -y-60: -t "IIR Elliptical Bandstop by iir_filt(1-ESPS)" -W "=450x400+0+0" -  2> /dev/null
rm $param
echo " "
############FILTERING############FILTERING############FILTERING###########
echo Now sampled data files can be filtered using any of the above designed
echo "filters by filter(1-ESPS), spectrum for pre-filtered and post-filtered "
echo "sampled data can be computed and viewed by refcof(1-ESPS) and me_spec(1-ESPS)"
echo " "
echo Generate 2500 points of three summed sine waves \(1000Hz, 2000 Hz, and 3000 Hz.\)
echo " "
echo "   %testsd -p2600 -Tsine -f1000 sine1.sd"
testsd -p2600 -Tsine -f1000 sine1.sd
echo "   %testsd -p2600 -Tsine -f3000 - | addsd - sine1.sd sines2.sd"
testsd -p2600 -Tsine -f3000 - | addsd - sine1.sd sines2.sd
echo "   %testsd -p2600 -Tsine -f2000 - | addsd - sines2.sd  sines3.sd"
testsd -p2600 -Tsine -f2000 - | addsd - sines2.sd  sines3.sd
echo "Now filter the three sine waves with the notch filter, and then compute"
echo "the pre- and post-filter spectrum based on 25th order maximum entropy"
echo " "
echo "First filter the data."
echo "   %filter -Fnotch.filt sines3.sd nfiltered.sd"
filter -Fnotch.filt sines3.sd nfiltered.sd
echo " "
#note that the first 100 points (transient) are skipped
echo "Now compute reflection coefficients and pipe them to me_spec(1-ESPS)"
echo "to compute a maximum entropy spectrum estimate of the pre-filtered signal."
echo "   %refcof -o25 -p100:+2500 -l0 sines3.sd -\ "
echo "     | me_spec - sines3.spec"
echo " "
echo "Finally, compute the spectrum estimate for the post-filtered signal."
refcof -o25 -p100:+2500 -l0 sines3.sd - | me_spec   - sines3.spec
echo "   %refcof -o25 -p100:+2500 -l0 nfiltered.sd -\ "
echo "     | me_spec  - nfiltered.spec"
refcof -o25 -p100:+2500 -l0 nfiltered.sd - | me_spec   - nfiltered.spec
echo " "
echo Now filter the three sine waves with the IIR bandstop filter, and then
echo compute the post-filter spectrum based on 25th order maximum entropy
echo " "
echo "   %filter -Felli.filt sines3.sd sfiltered.sd"
filter -Felli.filt sines3.sd sfiltered.sd
echo "   %refcof -o25 -p100:+2500 -l0 sfiltered.sd -\ "
echo "     | me_spec - sfiltered.spec"
refcof -o25 -p100:+2500 -l0 sfiltered.sd - | me_spec - sfiltered.spec
echo " "
sleep 3
echo After the demo script finishes, compare the notch filter 
echo spectral response with the pre- and post-filter sine wave spectrum
echo by typing the following commands manually:
echo " "
echo "  %plotspec sines3.spec"
echo "  %plotspec nfiltered.spec"
echo " "
echo Then look at the spectral response of the band-stop filter and the
echo spectrum after band-stop filtering by manually running the following command:
echo " "
echo "  %plotspec sfiltered.spec"
echo " "
echo Here is a list of filters and their spectrum file names created in this demo
echo " "
echo "	filter file	spectral response file"
echo "	===========	======================"
echo "	notch.filt	notch.spec"
echo "	pkmc.filt	pkmc.spec"
echo "	wmse.filt	wmse.spec"
echo "	cb.filt		cb.spec"
echo "	win.filt	win.spec"
echo "	butt.filt	butt.spec"
echo "	chev1.filt	chev1.spec"
echo "	chev2.filt	chev2.spec"
echo "	elli.filt	elli.spec"
echo " "
echo " "
echo "Finally, all filter design programs can be invoked by xeparam(1-ESPS)"
echo "and eparam(1-ESPS).  For example,"
echo " "
echo "   %xeparam iir_filt my.filt"
echo " "
echo "for X-windows based interface for parameter input, and"
echo " "
echo "   %eparam iir_filt my.filt"
echo " "
echo "for command-line prompt style parameter input."
echo " "
echo "It is also possible to build customized signal processing tool interface"
echo "with ESPS using exprompt(1-ESPS), expromptrun(1-ESPS), get_param(1-ESPS),"
echo "...etc.  See the cover shell script xfir_filt(1-ESPS) as an example to"
echo "build X-windows based FIR filter design system."
echo " "
echo " "