Bode Plots of Digital Filters

Started by AndrewDSPdev in comp.dsp8 years ago 2 replies

Hello Everyone, I've recently created a 2-Pole Chebyshev filter and have worked on a Bode plot for it. Initially I fed in sin waves of...

Hello Everyone, I've recently created a 2-Pole Chebyshev filter and have worked on a Bode plot for it. Initially I fed in sin waves of different frequencies by hand to the filter and measured the attenution to get data points. I know the independent axis of a Bode plot is log f/fc, but I was confused when I got different attenuation of frequencies for the same ratio of f/fc in my testing. ...


Clarification of Rivlin-Shapiro theorem for FIR filters

Started by Robert Rozman in comp.dsp14 years ago 4 replies

Hi, I have problems applying Rivlin Shapiro's theorem for design of FIR filters. It says in [1] that : H(z) is best Chebyshev...

Hi, I have problems applying Rivlin Shapiro's theorem for design of FIR filters. It says in [1] that : H(z) is best Chebyshev approximation to D(z) if and only if there are r points z1,z2,....zr and r positive numbers lambda1, lambda2, ... lambdas sum to 1 ... for which : sum(k=1 to r) lambdak [D(zk)-H(zk)] fi(zk) = 0 for i=1,2,....,N ..... Main question is what are functio...


What am I missing about IIR Filter Design?

Started by FilterDan in comp.dsp4 years ago 11 replies

Every article I see regarding IIR filter design seems to make the subject far more complicated than it needs to be. For example, in this...

Every article I see regarding IIR filter design seems to make the subject far more complicated than it needs to be. For example, in this DSPRelated post "IIR Coefficient Calculation - ger_lough" the discussion goes on in great length about specific formulas for different protoypes (Butterworth, Chebyshev, etc) sampling rates, Q, pole locations, etc. I wrote an IIR Filter design program wher...


ADSP2181 IIR filter help needed please

Started by carlvonclauswitz in comp.dsp13 years ago 1 reply

Hi all, I have designed a 4th order bandpass filter using MatLab FDA tool. The filter contains 2 2nd order stages which is fine and I can...

Hi all, I have designed a 4th order bandpass filter using MatLab FDA tool. The filter contains 2 2nd order stages which is fine and I can view them in Simulink. The filter is a chebyshev type 1 with fp1=300Hz fp2=3kHz. I have the coefficients and scaling factors but have no idea how to code a cascaded (2 sos) filter in ADSP2181 assy language. If anybody could point me in the direction of a go...


Importance of phase in Audio

Started by Anonymous in comp.dsp12 years ago 12 replies

Hello all, i am designing a low pass filter and high pass filter to pass my audio samples. in matlab i checked out both butterworth...

Hello all, i am designing a low pass filter and high pass filter to pass my audio samples. in matlab i checked out both butterworth and chebyshev(cheby2) 3rd order filter. I have observed there is a lot of differance in the phase plot of both the filters. Now my query went to what actuall effect of phase in audio? please anybody help me in solving this. Looking for the repl...


Announcing ScopeIIR 5.0

Started by Grant Griffin in comp.dsp8 years ago 13 replies

Hi All, This is to announce the release of ScopeIIR 5.0, which is a comprehensive Windows tool for designing and analyzing Infinite Impulse...

Hi All, This is to announce the release of ScopeIIR 5.0, which is a comprehensive Windows tool for designing and analyzing Infinite Impulse Response (IIR) filters. The Trial Edition is free for 30 days. ScopeIIR designs high-order IIR filters based on Butterworth, Chebyshev, and Elliptic prototypes. It designs lowpass, highpass, bandpass, and bandstop filters. ScopeIIR provides a...


Linearizing phase response

Started by Anonymous in comp.dsp11 years ago 4 replies

Dear Group, I have a 16th order Chebyshev type 2 low pass IIR filter and I'd like add a couple of second order allpass stages to linearize the...

Dear Group, I have a 16th order Chebyshev type 2 low pass IIR filter and I'd like add a couple of second order allpass stages to linearize the phase response. Ideally, the resulting filter should have an equiripple reponse around an ideal linear response. I've googled quite extensively, but I can't find any information on how to design the allpass sections. Does anybody know of a techiq...


IIR filter reference designs

Started by Rune Allnor in comp.dsp13 years ago 23 replies

Hi all. I'm struggling to implement my own codes for IIR filter design by analog prototypes. The Butterworth filter works, the Chebyshev type...

Hi all. I'm struggling to implement my own codes for IIR filter design by analog prototypes. The Butterworth filter works, the Chebyshev type 1 doesn't. The books I have available are Proakis & Manolakis' 3rd edition, Oppenheim & Schafer 1975+1999, Leland B Jackson 1989. Most show, relatively crudely, the main steps in filter design. Only P&M show any examples of Cheb 1 filters in suff...


longer FFT v. shorter FFT with interpolation

Started by Gilead in comp.dsp11 years ago 2 replies

I need to analyze the magnitude spectra of some data sets. Every data vector will have 128 or fewer complex samples. I window all the...

I need to analyze the magnitude spectra of some data sets. Every data vector will have 128 or fewer complex samples. I window all the data using a Chebyshev window with a certain level of relative sidelobe attenuation. Normally, I zero pad the windowed data and take a 128-pt FFT. Now I'm experimenting with longer FFTs (256 and 512) in an attempt to get a higher resolution look at the spec...


Low Pass Reconstruction Filter

Started by dacrow in comp.dsp12 years ago 7 replies

I'm trying to build a Low Pass Reconstruction Filter for use after a DAC . The thing is it has to be a Zi = 300 Ohm input and the fc has to be...

I'm trying to build a Low Pass Reconstruction Filter for use after a DAC . The thing is it has to be a Zi = 300 Ohm input and the fc has to be 37 MHz and 50 dB attuenuation @ 118 Mhz and the passband ripple has to be < 1dB. Already tried the Butterworth but the coils were to large in fuction of the self resonant frequency of it . The Chebyshev filter has a too large ripple in th


IIR filter order

Started by Grant Griffin in comp.dsp8 years ago 7 replies

I'm finally about ready to release an IIR filter design program called - you guessed it - ScopeIIR (TM). It currently supports the basic...

I'm finally about ready to release an IIR filter design program called - you guessed it - ScopeIIR (TM). It currently supports the basic design types of Butterworth, Chebyshev, and Elliptic. I'm trying to finalize the default and maximum IIR filter order that the program will support. To help me do that, please tell me about your experiences with IIR filter order, assuming the above t...


on decimate filters

Started by SunLei in comp.dsp12 years ago 11 replies

hi, On the FPGA implementation of decimation filters, which type of decimate filters do you prefer? I am designing a IF DDC...

hi, On the FPGA implementation of decimation filters, which type of decimate filters do you prefer? I am designing a IF DDC converter, and wana use FPGA to implement the decimate filter, but I found the Half-band lowpass and the euipripple fir filters can hardly stop the out-band below -80dB. I wish to stop the outband under -90dB, and the Chebyshev filter can, but it's not s...


IIR notch filter

Started by itsh11 in comp.dsp10 years ago 18 replies

I am trying to design a second order digital IIR band stop (notch) filter with the following specs: 3dB cut off frequencies: 55Hz and 65Hz I...

I am trying to design a second order digital IIR band stop (notch) filter with the following specs: 3dB cut off frequencies: 55Hz and 65Hz I want the notch at 60Hz with atleast 90dB attenuation at the 60Hz. Sampling frequency: 200hz I tried various filter configurations like a Butterworth or Chebyshev but could not get the attenuation higher than 70 dB.I want a second order filter to accom...


using fdatool and cmsis

Started by Vl4ever in comp.dsp6 years ago 25 replies

Hi ,all I am currently trying to implement Chebyshev Type I filter on embedded microcontroller - STM32F101 (using C language).This is a...

Hi ,all I am currently trying to implement Chebyshev Type I filter on embedded microcontroller - STM32F101 (using C language).This is a microcontroller of ARM cortex M3 type.It is possible to implement this filter in IIR form using CMSIS-DSP APIs.These APIs require single-point precision (floating) input for all data,including coefficients. For determining the filter coefficients I have used Ma...


Effect of Nonlinear Group Delay on Signals

Started by JM1970 in comp.dsp9 years ago 11 replies

Hello, I am trying to model the effect of group delay of an analog filter with complex transfer function H(f) on a phase modulated signal s(t),...

Hello, I am trying to model the effect of group delay of an analog filter with complex transfer function H(f) on a phase modulated signal s(t), with a complex spectrum S(f). The analog filter I would like employ is a Chebyshev n=4, with 0.1dB ripple, but the exact filter is not important right now. In continuous time, the answer seems simple: The filtered signal is just the inverse fourier...


How spectral leakage changes the phase spectrum?

Started by bharat pathak in comp.dsp10 years ago 9 replies

Hello All, I want to understand how spectral leakage changes the phase spectrum of a sine wave? Also when I apply window...

Hello All, I want to understand how spectral leakage changes the phase spectrum of a sine wave? Also when I apply window (blackman harris 11 Term or chebyshev window with 300db attenuation), I see a significant amount of reduction in spectral leakage in the amplitude part of the spectrum. But this windowing also affects the phase part of the ...


FIR filter with arbitrary and phase responses

Started by klayman in comp.dsp7 years ago 17 replies

Hello! I am working on a project, and I have to design a optimal complex FIR filter with arbitrary amplitude and phase responses. I found a...

Hello! I am working on a project, and I have to design a optimal complex FIR filter with arbitrary amplitude and phase responses. I found a MATLAB function 'cfirpm' which looks like a algorithm from this article: "Karam, L.J., and J.H. McClellan. "Complex Chebyshev Approximation for FIR Filter Design." IEEE Trans. on Circuits and Systems II,March 1995. Pgs.207-216." But I can't realize how...


Complex FIR Filter Design - Notation in Preuss' IEEE Trans. Paper

Started by Brandon in comp.dsp12 years ago 6 replies

Is anyone familiar with the following paper? Preuss, K, "On the Design of FIR Filters by Complex Chebyshev Approximation," IEEE Trans....

Is anyone familiar with the following paper? Preuss, K, "On the Design of FIR Filters by Complex Chebyshev Approximation," IEEE Trans. Acoust., Speach, Signal Processing, vol. 37, pp. 702-712, 1989. The author uses a notation I am not familiar with. Specifically, see equation (8): | E(Omega_nu) | = delta nu = 1(1)m, where n+2


design of equiripple FIR filters with nearly linear phase in passband (complex chebyshev approximation)

Started by Robert Rozman in comp.dsp12 years ago 4 replies

Hi, I'm trying to design N=256 lowpass FIR filter with constant group delay constraint in passband (resulting filter has nearly constant...

Hi, I'm trying to design N=256 lowpass FIR filter with constant group delay constraint in passband (resulting filter has nearly constant group delay in passband). Originally Burnside and Parks described that procedure in IEEE article, but I cannot compile their MEX code for Matlab sucessfully - designs above N=250 cause Matlab crashes. I did that without problems on older computers, ...


Among all the windows which one is the best with narrower main lobe and lower side lobes?

Started by boon chun in comp.dsp10 years ago 5 replies

Hi, I'm looking for a good window which has narrower main lobe and lower side lobes. I try to use matlab to compare Blackman-Harris, Kaiser,...

Hi, I'm looking for a good window which has narrower main lobe and lower side lobes. I try to use matlab to compare Blackman-Harris, Kaiser, and Chebyshev windows. And I found the Blackman-Harris has the best main lobe width and lower side lobes. Does any one has any comments on this? Is there any other type of windows better than this available? Thanks. Regards, BC