## Forums Search for: Notch Filter

## FIR notch filters using the Windowing method

inHi, 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?

inHi, 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

inHi, 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

inHello 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!

inHi, 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

inHi 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...

## IIR notch filter

inI 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...

## XSG model intermal error

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...

## Constructing frequency notch FIR filters using 5 phase sequence

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

inHi, 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

inHello, 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?

inHello, 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

inHi, 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 iir implementation

inI 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...

## Notch filter

inHi, 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

## NaN issue with NOTCH filter

inHello! 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 ...

## DSP Riddle: Infinitely Narrow Notch Filter

inFolks, 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

> 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

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

inDear 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), ...

## Adaptive Notch Filter - LMS Algorithm

inHi everyone, I am working on a simple adaptive notch filter that will be used to cancel one sinusoid. Additionally, the filter coefficient is...

Hi everyone, I am working on a simple adaptive notch filter that will be used to cancel one sinusoid. Additionally, the filter coefficient is complex (I am looking after the error envelope). So what I have is one zero and one pole. The zero is fixed to the unit circle and the pole is very close to the unit circle at the same angle as the zero. The transfer function is: H(z) = (1 - (1