FIR notch filters using the Windowing method

Started by Greer in comp.dsp13 years ago 41 replies

Hi, I am trying to obtain a FIR notch filter which is very narrow. For example, a 50 Hz notch filter to remove mains noise from a 1250Hz...

Hi, I am trying to obtain a FIR notch filter which is very narrow. For example, a 50 Hz notch filter to remove mains noise from a 1250Hz signal say. Doing this with an IIR filter was easy, I could specify my "notch region" as small as [49 51]Hz. I am now trying to do the same with a FIR filter. I am using Intel Peformance Primative functions to generate the taps. These use the windowing ...


Why do bandpass filters don't work like notch filters?

Started by gretzteam in comp.dsp8 years ago 2 replies

Hi, Say I generate a digital 2nd order notch filter. With the lattice structure, one coefficient controls the notch frequency and the other...

Hi, Say I generate a digital 2nd order notch filter. With the lattice structure, one coefficient controls the notch frequency and the other the bandwidth. I can get VERY good attenuation of the notch frequency, pretty much only depending on wordlength used. The overall response looks like one deep and narrow hole in a horizontal line with magnitude 1. Now, if I generate the same order bandpass...


Notch filter

Started by OZ in comp.dsp12 years ago 7 replies

Hi, I am searching a mathematical solution for a notch filter. I measured a signal with a ADC and I want to kill one frequency (50Hz) out of...

Hi, I am searching a mathematical solution for a notch filter. I measured a signal with a ADC and I want to kill one frequency (50Hz) out of the measurement data. Does anyone of you know a mathematical function for a notch filter ? best regards Oliver


Increasing Notch depth using windowing

Started by ravash in comp.dsp9 years ago 3 replies

Hello everyone, Hope no introduction for why I am here (I have a problem.....) Presently i am working on a ofdm simulink implementation...

Hello everyone, Hope no introduction for why I am here (I have a problem.....) Presently i am working on a ofdm simulink implementation where I need to increase the single carrier notch depth (notch is created by putting some carriers to zero)which at present is 13dB(because of 'no window' or default 'rectangular' window implemented). I am using a raised cosine window for the same so as to ...


Detecting if a notch filter is 'notching' something!

Started by gretzteam in comp.dsp8 years ago 10 replies

Hi, I'm receiving a signal at 100kHz and need to do two things at the same time: -notch the 2k frequency. -rough detection of the presence of...

Hi, I'm receiving a signal at 100kHz and need to do two things at the same time: -notch the 2k frequency. -rough detection of the presence of 2k frequency. So basically the notch filter is always there, but I also want to know if something is being notched. I could obviously have in parallel a bandpass filter at 2k and monitor the signal at the output. However I wonder if the answer is...


Notch comb filter coefficients

Started by ombz in comp.dsp7 years ago 4 replies

Hi all. I've found in MATLAB help that a notching comb filter has following tranfser function: H(z) = b*(1+z^(-N))/(1+a*z^(-N)) where N is...

Hi all. I've found in MATLAB help that a notching comb filter has following tranfser function: H(z) = b*(1+z^(-N))/(1+a*z^(-N)) where N is the number of notches. How to determine coefficients a and b with respect to real-world parameters such as sampling frequency, notch frequency and notch bandwidth/resp. attenuation? I don't have the filter toolbox and therefore not the 'iircomb' functio...


XSG model intermal error

Started by Yingtuo in comp.dsp8 years ago

Hi, I m making a simple PID controller with notch filters in Xilinx blocks. it always prompt the following errors for the blocks in my notch...

Hi, I m making a simple PID controller with notch filters in Xilinx blocks. it always prompt the following errors for the blocks in my notch filter. if i delete the error block or change the latency to 1, the same error will happen to another block in the notch. Is there a general guideline to determing the latency of each block or is there any other possible causes of this internal e...


IIR notch filter

Started by itsh11 in comp.dsp9 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...


Constructing frequency notch FIR filters using 5 phase sequence

Started by DSP_student in comp.dsp9 years ago

Hi all, I'm trying to find an even lengthed sequence of FIR coefficients where every coefficient will be one of the five: 1, -1, 0, j, -j. I'm...

Hi all, I'm trying to find an even lengthed sequence of FIR coefficients where every coefficient will be one of the five: 1, -1, 0, j, -j. I'm looking for a sequence whose FFT will have one notch (or at least a 20dB attenuation relative to other frequency samples) at a certain frequency. I'm hoping to find different sequences so that each sequence will have a notch (or attenuation) at a differ...


IIR Notch Filter Implementation

Started by m.nabaee in comp.dsp10 years ago 7 replies

Hi, I want to implement a digital IIR notch filter on FPGA. I used FDA tool HDL coder, but it seems not to work properly. However, can you...

Hi, I want to implement a digital IIR notch filter on FPGA. I used FDA tool HDL coder, but it seems not to work properly. However, can you give me a vhdl code or example of it? Thanks...


Complementary narrow-band peak-notch filters pair design

Started by roman rumian in comp.dsp2 years ago 8 replies

Hello, I am searching for examples (reference - papers, books) of narrow-band peak-notch filters pairs design having complementary frequency...

Hello, I am searching for examples (reference - papers, books) of narrow-band peak-notch filters pairs design having complementary frequency characteristics. By "complementary" I mean a characteristic of notch having -40..80 dB at some f0 frequency, 0dB in others, and peak filter having floor at -40..80 but 0dB at f0. Cascade connection of both should give -40..80 dB horizontal line. ...


how to get rid of ringing with IIR notch filters?

Started by Anonymous in comp.dsp14 years ago 20 replies

Hello, I have an IIR notch filter ( i.e. bandstop ), that rings like crazy whenever a transient signal comes through ... which is very...

Hello, I have an IIR notch filter ( i.e. bandstop ), that rings like crazy whenever a transient signal comes through ... which is very unwanted for my application. Anybody have any ideas how to get around this? I have to stick with IIR form filters. I've tried all the various standard design flavors, i.e. Butterworth, Bessel, Elliptic, etc ... but they all seem to ring unacceptably abou...


Best way to remove a known frequency

Started by gretzteam in comp.dsp8 years ago 22 replies

Hi, I'm having problem getting rid of a 2kHz sine wave from a digitized signal at 128kHz. I do know the exact frequency of the 2kHz (I generate...

Hi, I'm having problem getting rid of a 2kHz sine wave from a digitized signal at 128kHz. I do know the exact frequency of the 2kHz (I generate it in the first place with a DDS), but the phase/amplitude are unknown (it goes through DAC-> ADC. Now, there seems to be two approach to do this, and I don't know what would be best. 1) Simple IIR 2nd order notch filter. I can center the notch at


Notch filter

Started by y17476 in comp.dsp10 years ago 4 replies

Hi, I need to implememt a notch filter to filter 2175 Hz tone on TI C54x DSP. Does anyone know if there is source code in TI's application...

Hi, I need to implememt a notch filter to filter 2175 Hz tone on TI C54x DSP. Does anyone know if there is source code in TI's application report? or can you point me to any source code as example? Thanks in advance! Ron


DSP Riddle: Infinitely Narrow Notch Filter

Started by Andor in comp.dsp11 years ago 68 replies

Folks, is it possible to construct a causal and realizable n-th order IIR filter, where n > 1 is an integer, which acts as an infinitely...

Folks, is it possible to construct a causal and realizable n-th order IIR filter, where n > 1 is an integer, which acts as an infinitely narrow notch filter? This filter must have frequency response H(w) = 1, for w =/= w0 = 0, for w == w0, for some arbitrary 0 < w0 < pi. Assume for the moment that the filter can be computed with infinite precision. Have a nice weekend!


Re: laplace tranform convert to code

Started by Peter Nachtwey in comp.dsp11 years ago

> tim w wrote: > > Hello all, > > > > I need some guidance in programming a laplace transfer function into > > computer language --...

> tim w wrote: > > Hello all, > > > > I need some guidance in programming a laplace transfer function into > > computer language -- pseudocode for now. > > > > The transfer function is a second order function: > > > > To^2*s^2 + zeta1*To*s + 1 > > ------------------------- > > To^2*s^2 + zeta2*To*s + 1 > > That is similar to a notch filter. I posted a link to a notch filter desi


NaN issue with NOTCH filter

Started by jtp_1960 in comp.dsp4 years ago 10 replies

Hello! I have an issue with a Notch filter which works OK for certain Hz/bw/Q but after changing Hz or bw/Q sometimes a NaN value is given for...

Hello! I have an issue with a Notch filter which works OK for certain Hz/bw/Q but after changing Hz or bw/Q sometimes a NaN value is given for the sample for center frequency. http://i39.tinypic.com/32zrgk8.jpg Source code: double pi = 3.14159265358979323846f; double Fs = 96000.0; double ln = 0.69314718055994530942f; double halfsq2 = 0.707106781186547524401; for(int i = 1; i ...


notch iir implementation

Started by inna-s in comp.dsp11 years ago 6 replies

I have a similar problem described by Par in 2005. (Only different frequencies and sample size). I have signal of 10000 length that has...

I have a similar problem described by Par in 2005. (Only different frequencies and sample size). I have signal of 10000 length that has undesired frequencies: f=0.0003, 0.0006 (f \in [0 1]) I want to get rid off. I build notch IIR and apply it. To test that it works I first created a synthetic signal (linear sum of harmonics) and apply filter on this data. 1. I know that my IIR desig...


About Notch Filtering in the Frequency Domain (2D images)

Started by Javier Montoya in comp.dsp11 years ago 2 replies

Dear all: I was studying the notch filter. As far as I understood, there are 2 possible ways to accomplish this task: 1) Set the DC component...

Dear all: I was studying the notch filter. As far as I understood, there are 2 possible ways to accomplish this task: 1) Set the DC component of the spectrum to be equal to zero, i.e: F(0,0) =0. To obtain the filtered image, apply the IDFT. 2) Create a kernel (k) having the same size as the filtered image. Set all the kernel values equal to 1, except for the pixel in position (M/ 2,N/2), ...


filter notch

Started by tw in comp.dsp10 years ago 6 replies

Could you tell me how filter notch work's?

Could you tell me how filter notch work's?