fir_design_helper

Basic Linear Phase Digital Filter Design Helper

Copyright (c) March 2017, Mark Wickert All rights reserved.

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sk_dsp_comm.fir_design_helper.bandpass_order(f_stop1, f_pass1, f_pass2, f_stop2, dpass_dB, dstop_dB, fsamp=1)

Optimal FIR (equal ripple) Bandpass Order Determination

Text reference: Ifeachor, Digital Signal Processing a Practical Approach, second edition, Prentice Hall, 2002. Journal paper reference: F. Mintzer & B. Liu, Practical Design Rules for Optimum FIR Bandpass Digital Filters, IEEE Transactions on Acoustics and Speech, pp. 204-206, April,1979.

sk_dsp_comm.fir_design_helper.bandstop_order(f_stop1, f_pass1, f_pass2, f_stop2, dpass_dB, dstop_dB, fsamp=1)

Optimal FIR (equal ripple) Bandstop Order Determination

Text reference: Ifeachor, Digital Signal Processing a Practical Approach, second edition, Prentice Hall, 2002. Journal paper reference: F. Mintzer & B. Liu, Practical Design Rules for Optimum FIR Bandpass Digital Filters, IEEE Transactions on Acoustics and Speech, pp. 204-206, April,1979.

sk_dsp_comm.fir_design_helper.fir_remez_bpf(f_stop1, f_pass1, f_pass2, f_stop2, d_pass, d_stop, fs=1.0, n_bump=5, status=True)

Design an FIR bandpass filter using remez with order determination. The filter order is determined based on f_stop1 Hz, f_pass1 Hz, f_pass2 Hz, f_stop2 Hz, and the desired passband ripple d_pass dB and stopband attenuation d_stop dB all relative to a sampling rate of fs Hz.

Mark Wickert October 2016, updated October 2018

sk_dsp_comm.fir_design_helper.fir_remez_bsf(f_pass1, f_stop1, f_stop2, f_pass2, d_pass, d_stop, fs=1.0, n_bump=5, status=True)

Design an FIR bandstop filter using remez with order determination. The filter order is determined based on f_pass1 Hz, f_stop1 Hz, f_stop2 Hz, f_pass2 Hz, and the desired passband ripple d_pass dB and stopband attenuation d_stop dB all relative to a sampling rate of fs Hz.

Mark Wickert October 2016, updated October 2018

sk_dsp_comm.fir_design_helper.fir_remez_hpf(f_stop, f_pass, d_pass, d_stop, fs=1.0, n_bump=5, status=True)

Design an FIR highpass filter using remez with order determination. The filter order is determined based on f_pass Hz, fstop Hz, and the desired passband ripple d_pass dB and stopband attenuation d_stop dB all relative to a sampling rate of fs Hz.

Mark Wickert October 2016, updated October 2018

sk_dsp_comm.fir_design_helper.fir_remez_lpf(f_pass, f_stop, d_pass, d_stop, fs=1.0, n_bump=5, status=True)

Design an FIR lowpass filter using remez with order determination. The filter order is determined based on f_pass Hz, fstop Hz, and the desired passband ripple d_pass dB and stopband attenuation d_stop dB all relative to a sampling rate of fs Hz.

Mark Wickert October 2016, updated October 2018

sk_dsp_comm.fir_design_helper.firwin_bpf(n_taps, f1, f2, fs=1.0, pass_zero=False)

Design a windowed FIR bandpass filter in terms of passband critical frequencies f1 < f2 in Hz relative to sampling rate fs in Hz. The number of taps must be provided.

Mark Wickert October 2016

sk_dsp_comm.fir_design_helper.firwin_kaiser_bpf(f_stop1, f_pass1, f_pass2, f_stop2, d_stop, fs=1.0, n_bump=0, status=True)

Design an FIR bandpass filter using the sinc() kernel and a Kaiser window. The filter order is determined based on f_stop1 Hz, f_pass1 Hz, f_pass2 Hz, f_stop2 Hz, and the desired stopband attenuation d_stop in dB for both stopbands, all relative to a sampling rate of fs Hz. Note: the passband ripple cannot be set independent of the stopband attenuation.

Mark Wickert October 2016

sk_dsp_comm.fir_design_helper.firwin_kaiser_bsf(f_stop1, f_pass1, f_pass2, f_stop2, d_stop, fs=1.0, n_bump=0, status=True)

Design an FIR bandstop filter using the sinc() kernel and a Kaiser window. The filter order is determined based on f_stop1 Hz, f_pass1 Hz, f_pass2 Hz, f_stop2 Hz, and the desired stopband attenuation d_stop in dB for both stopbands, all relative to a sampling rate of fs Hz. Note: The passband ripple cannot be set independent of the stopband attenuation. Note: The filter order is forced to be even (odd number of taps) so there is a center tap that can be used to form 1 - H_BPF.

Mark Wickert October 2016

sk_dsp_comm.fir_design_helper.firwin_kaiser_hpf(f_stop, f_pass, d_stop, fs=1.0, n_bump=0, status=True)

Design an FIR highpass filter using the sinc() kernel and a Kaiser window. The filter order is determined based on f_pass Hz, f_stop Hz, and the desired stopband attenuation d_stop in dB, all relative to a sampling rate of fs Hz. Note: the passband ripple cannot be set independent of the stopband attenuation.

Mark Wickert October 2016

sk_dsp_comm.fir_design_helper.firwin_kaiser_lpf(f_pass, f_stop, d_stop, fs=1.0, n_bump=0, status=True)

Design an FIR lowpass filter using the sinc() kernel and a Kaiser window. The filter order is determined based on f_pass Hz, f_stop Hz, and the desired stopband attenuation d_stop in dB, all relative to a sampling rate of fs Hz. Note: the passband ripple cannot be set independent of the stopband attenuation.

Mark Wickert October 2016

sk_dsp_comm.fir_design_helper.firwin_lpf(n_taps, fc, fs=1.0)

Design a windowed FIR lowpass filter in terms of passband critical frequencies f1 < f2 in Hz relative to sampling rate fs in Hz. The number of taps must be provided.

Mark Wickert October 2016

sk_dsp_comm.fir_design_helper.freqz_resp_list(b, a=array([1]), mode='dB', fs=1.0, n_pts=1024, fsize=(6, 4))

A method for displaying digital filter frequency response magnitude, phase, and group delay. A plot is produced using matplotlib

freq_resp(self,mode = ‘dB’,Npts = 1024)

A method for displaying the filter frequency response magnitude, phase, and group delay. A plot is produced using matplotlib

freqz_resp(b,a=[1],mode = ‘dB’,Npts = 1024,fsize=(6,4))

b = ndarray of numerator coefficients a = ndarray of denominator coefficents

mode = display mode: ‘dB’ magnitude, ‘phase’ in radians, or

‘groupdelay_s’ in samples and ‘groupdelay_t’ in sec, all versus frequency in Hz

Npts = number of points to plot; default is 1024

fsize = figure size; defult is (6,4) inches

Mark Wickert, January 2015

sk_dsp_comm.fir_design_helper.lowpass_order(f_pass, f_stop, dpass_dB, dstop_dB, fsamp=1)

Optimal FIR (equal ripple) Lowpass Order Determination

Text reference: Ifeachor, Digital Signal Processing a Practical Approach, second edition, Prentice Hall, 2002. Journal paper reference: Herriman et al., Practical Design Rules for Optimum Finite Imulse Response Digitl Filters, Bell Syst. Tech. J., vol 52, pp. 769-799, July-Aug., 1973.IEEE, 1973.