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# Discussion Groups > Notch Filter

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We found 278 threads matching "notch"

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## Detecting if a notch filter is 'notching' something! 0

gretzteam - 2010-01-27 16:04:00
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 para...

## FIR notch filters using the Windowing method 0

Greer - 2005-04-13 13:33:00
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 fi...

## Notch filter 0

OZ - 2005-05-10 08:22:00
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 ...

## Why do bandpass filters don't work like notch filters? 0

gretzteam - 2010-04-27 08:52:00
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 ...

## Constructing frequency notch FIR filters using 5 phase sequence 0

DSP_student - 2008-11-03 10:22:00
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 hop...

## Re: notch filter to remove 20Hz noise of ECG signal 0

Jack Ace - 2005-12-20 04:26:00
ashcroft2006 wrote: > Hey > Im a student and need help using matlab. im extremeley new to signal > processing so this is a pretty basic question, im hoping someone can help > me. > > im removing noise from an ecg signal and i need to remove this noise at > 20hz using a notch filter, ...

## Notch comb filter coefficients 0

ombz - 2010-05-21 10:18:00
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 b...

## IIR notch filter 0

itsh11 - 2008-06-26 13:30:00
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...

## Increasing Notch depth using windowing 0

ravash - 2008-05-26 10:17:00
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 ...

## IIR Notch Filter Implementation 0

m.nabaee - 2007-08-16 10:05:00
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... ...

## Best way to remove a known frequency 0

gretzteam - 2010-03-23 09:41:00
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 ...

## Frequency domain notch filter 0

skaggio - 2008-01-23 12:39:00
Hello everybody. A question from not an expert of notch filters. Suppose I have to filter out a specific frequency noise (e.g. a 50 Hz noise) from an acquired signal. Suppose my filter has not to work online, i.e. I can collect signal samples (its a digitalized signal) and then filter noise o...

## Re: Demodulating AM pulse width coding (long post) 0

Jim Thomas - 2008-04-28 10:07:00
rickman wrote: > Thanks for your comments. I appreciate it. > I was involved in an IRIG-B demod about 20 years ago. As I recall, the first thing we did was to remove DC, then square the signal, and run that through a 2KHz notch filter. Since IRIG-B is primarily a 1KHz signal, squari...

## Notch filter 0

y17476 - 2008-05-09 16:10:00
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 ...

## Notch filter design using poles and zeroes(2nd order) Newbie question 0

terrp - 2006-05-05 08:19:00
Hi all, I was given a matlab project to use a unit circle with 2poles and 2zeroes to create a notch filter. The component to be removed is 50 Hz, sampling frequency is 200 Hz. I tried putting 2 zeroes at z=1, angle= pie/2; and 2 poles at z=0.9, angle = pie/2. However, when i look at the s...

## filter notch 0

tw - 2008-04-24 14:36:00
Could you tell me how filter notch work's? ...

## Re: DSP Riddle: Infinitely Narrow Notch Filter 0

Al Clark - 2006-05-20 00:51:00
Jerry Avins wrote in news:-bmdnb3C7cUcofPZRVn-uQ@rcn.net: > Al Clark wrote: > > > Tim Wescott wrote in > > news:8KSdnUsGjuGof_DZnZ2dnUVZ_t6dnZ2d@web-ster.com: > > > > > > > Andor wrote: > > > > > > > > > > Folks, > > > > > > > > is it possible to construct a causal a...

## Re: Calculating frequency response magnitude of filter 0

HardySpicer - 2009-06-04 21:32:00
On Jun 5, 1:13=A0am, "briwel" wrote: > I have an FIR filter equation, which is > y(n) =3D 0.5x(n) + 0.5x(n - 2). > > I have to draw the magnitude of the frequency response of this filter? > Does anyone know how to do this? > > thanks in advance for any help This is an easy one si...

## how to get rid of ringing with IIR notch filters? 0

2003-12-22 02:28:00
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 desi...

## Re: Low pass filter on a PIC 0

Randy Yates - 2008-10-10 16:35:00
"Manfred" writes: > [...] Hi Manfred, I have the advantage of seeing the other posters' suggestions and your repsonse, but how about the following: y[n] = x[n] - 0.61803 * x[n-1] + x[n-2] ? This is an FIR notch filter with a notch right at 20 Hz. The 0.61803 term is 2*cos(0.4*p...

## Frequency notch filter with 5 possible coefficients 0

DSP_student - 2008-11-03 10:08:00
Hello everyone, I would like to know whether it's possible to find a sequence of FIR coefficients of even length such that each coefficient can be 1 out of 5 possibilities: 1, -1, 0, j, -j. I'm trying to create a Band-Stop filter using a sequence of coefficients like this. The literature is pa...

## books on adaptive filtering 0

Jack Ace - 2005-03-01 18:59:00
hi everybody. I'm looking for one (or more) textbook on adaptive filter theory. I'm not interesting in advanced topics, I'm interesting in a well explained book able to drive the beginner inside the matter. a book with some examples or solved exercises would be appreciated. does anyone st...

## XSG model intermal error 0

Yingtuo - 2009-06-02 00:49:00
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 guidel...

## Re: Line noise removal 0

Rune Allnor - 2010-11-28 21:56:00
On Nov 28, 9:06=A0pm, "acat" wrote: > Hi, I need some help on removing the line noise (50Hz) from my data. I kn= ow > the method conventionally adopted is to fit a sinusoidal function and > subtract from the original data No, it isn't. > --- the so called notch filter, I have two >...

## IIR phase compensator 0

itsh11 - 2008-06-18 08:34:00
I want to design an IIR notch filter with linear phase. It is pretty straight forward to design the IIR notch filter but I am not sure how to design the phase compensator(all pass IIR filter) that makes the overall phase of the system linear phase. Can someone throw a few pointers on this design? Ma...

## IIR filter on a fixed set of data points 0

ahgu - 2010-11-07 20:50:00
I have a fixed 3600 data points(samples) and I want to apply a notch 2nd order Butterworth IIR Notch filter to remove the 1/4Fs frequency, the results start to converge(or filter start to work) after about 250 or so samples. The issue is the it is a continuous stream of data and I need to remove the...

## Adaptive Notch Filter - LMS Algorithm 0

zrimkunas - 2007-02-14 21:29:00
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 clos...

## Re: laplace tranform convert to code 0

Peter Nachtwey - 2006-07-24 16:43:00
> 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 > > ----------------------...

## Re: Minimum number of partials to fit a set of points 0

Greg Berchin - 2005-04-15 09:41:00
On 15 Apr 2005 03:46:05 -0700, clemenr@wmin.ac.uk wrote: > > However, is there a simple method of finding the fewest number of > > partials required to create a waveform that passes through each of the > > points? > > > > I could "solve" this using search-based techniques such as genetic > ...

## Re: Help with THD+N calculations 0

rcoup - 2006-06-01 19:04:00
Andreas Huennebeck wrote: > Fred Marshall wrote: > > > One method might be to use the sample at 1002Hz for the reference and > > forget about a notch filter, just don't include that one sample or the rms > > value of that one sample and the two adjacent ones in the sum across > > fre...

## "Comb notch" filters missing a tooth -6

Rune Allnor - 2003-11-23 13:01:00
Hi all. I have just "made" some recordings of birds nearby (which is to say that I ripped them off a CD released by the local ornithology society, but don't tell anyone) and want to play with these sounds to make an audio DSP demo. Among the birds are the "Eagle Owl" (Bubo Bubo) and a woo...

## Ideas about removing noise/hum 0

noodle22 - 2009-04-16 22:21:00
This question gets asked all the time and I have read many of the answers and tried a number of things but I am unable to get satisfactory results. The issue is that I am recording an audio signal and processing it, however, when I use a different mic, I get a different background spectrum. One of...

## Re: Matlab implementation of adaptive noise canceler? 0

Manolis C. Tsakiris - 2008-10-07 10:38:00
Hi Fred, if you knew the exact frequency of your noise, you would remove it via an adaptive notch filter in which the input signal would be the noise and the reference signal would be the audio signal with noise. Then the adaptive filter would remove the noise from your audio signal. Since you...

## Re: Amplitude response of a Biquad Filter 0

Web Surf - 2006-02-12 11:52:00
So now my excel spreadsheet implementing R B-J's equations work fine. R B-J assisted me to build a "Master Volume Control" for the 5 band equaliser. It adds/subtracts some dB from the reponse of each filter based on the setting of the Master Volume control, by changing the coefficients ( multiply...

## Re: Elliptic filters 0

John Herman - 2005-11-24 10:33:00
In article , "Rune Allnor" wrote: > > Praveen wrote: > > Hi, > > > > I have a speech signal that has noise introduced at various > > frequencies. The FFt magnitude of the speech signal is of the order of > > 10 power 6 at these frequencies. The whole point is I have to remove > ...

## Re: Dynamic Range 0

Joerg - 2006-03-02 17:38:00
Hello Tim, > > The difference is that the first radio can handle one and only one > signal over an astounding span, but it may not be able to handle two > signals at all. The second radio can be plunked down in a busy spectral > environment and do OK -- 90dB of dynamic range is a bi...

## Re: Undersampling 0

2007-06-07 20:29:00
> My understanding is that if sampled at 2GHz a 1.1GHz signal would > appear to be a frequency of 900MHz after sampled and an FFT was > taken. A 1.9GHz signal would appear as a 100MHz signal if you took an > FFT. If you sampled a signal with two tones wouldn't you have to flip > the FFT f...

## Re: Fourier Transforms compared to FFT's [ caution -- newbie at large ;] 0

Jerry Avins - 2004-09-13 21:37:00
glen herrmannsfeldt wrote: > > > Jerry Avins wrote: > > (snip) > > > You can have a continuous function, but on a CRT, plasma display, or > > stepping-motor plotter, you can't have a continuous plot. The moirĂ© that > > troubles you is between the actual points calculated alo...

## Re: where to go? is there some body can give me advice?. 0

PARTICLEREDDY - 2006-09-06 03:59:00
hi simon based on your experience you can fit in any industry.try out for NI.i hope you should get easily into top notch postition any without trouble regards particle ...

## Re: am radio buzz filter? 0

naebad - 2006-05-16 17:50:00
An analogue notch filter will suffice. Tam ...
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