IIR filter and intermittent 50 Hz noise

Started by in comp.dsp6 years ago 3 replies

Hi all, I'm trying to filter out 50 Hz noise which intermitelly appears on the input signal, I've been trying to use a 6th order IIR filter but...

Hi all, I'm trying to filter out 50 Hz noise which intermitelly appears on the input signal, I've been trying to use a 6th order IIR filter but results are unsatisfied: http://www.jrdltd.co.uk/data/noise.png Is there any way to filter out such intermittent noise correctly without massive oscillation at transitions, please? Can you please point me to the resource where I could read about t...


Noise filter and fourier

Started by Janwillem van Dijk in comp.dsp17 years ago 3 replies

How to remove noise from a signal. I have available a zero signal mainly consisting of noise and a signal during a measurement. The real...

How to remove noise from a signal. I have available a zero signal mainly consisting of noise and a signal during a measurement. The real signal consists theoretically of one or a few (overlapping) more or less gaussian shaped peaks. In general the signal is collected in 64 time samples. The peak widths are then equal to between 20 and 40 time samples. The noise has essentially a Poisson...


two channel adaptive noise cancelling

Started by Jing in comp.dsp15 years ago 3 replies

Hi, I biult a two channel adaptive noise cancelling system. I used one microphone as a primary microphone, and the second one as noise...

Hi, I biult a two channel adaptive noise cancelling system. I used one microphone as a primary microphone, and the second one as noise microphone and picked up noise signal only. However, I found that this noise microphone also picks up a certain amount of speech, and introduce significant speech distortion after ANC. Can anybody give me some suggestions how to decrease this speech distortion?...


how to understand noise shaping of sigma_delta in time domain?

Started by lxx.helen in comp.dsp13 years ago 6 replies

let's think of the noise shaping function for sigma-delta modulators. In frequency domain, we say quantization noise is pushed to higher...

let's think of the noise shaping function for sigma-delta modulators. In frequency domain, we say quantization noise is pushed to higher frequency and then removed by lowpass filter. what I wana do is to find a time domain understanding of this noise shaping function... start from the white assumption of quantization noise. I can imagine this is because we assume the quantization error rando...


Difference between sperically isotropic noise and spatially white noise

Started by maheshwarS in comp.dsp6 years ago 4 replies

I am reading about noise reduction techniques using arrays and I came across both these terms, I tried googling it up to find the...

I am reading about noise reduction techniques using arrays and I came across both these terms, I tried googling it up to find the difference between them. It would be so nice if someone can help me with this... :) --------------------------------------- Posted through http://www.DSPRelated.com


Filtering motor moise of a DV camera

Started by Peter Mueller in comp.dsp17 years ago 5 replies

Hello, I like to get rid of the motor the motor of my DV camera introduces to the audio signal. I found out that the noise is just between...

Hello, I like to get rid of the motor the motor of my DV camera introduces to the audio signal. I found out that the noise is just between 600-1000Hz. So I can't just delete the band where the noise is. Is here a good way to filter the noise out? I thought about a filter that uses the knowlege of the raw noise signal. Any ideas? Peter


Noise Cancelling Possibilies for Bandpass Noise?

Started by westocl in comp.dsp8 years ago 13 replies

I have a signal that is the output of a real time system. The system performs 'ok' but has a a problem of what i would reduce down to...

I have a signal that is the output of a real time system. The system performs 'ok' but has a a problem of what i would reduce down to additive band limited noise. Since I know the source (but cant change it) i know that it is bandpass noise of spectral bandwith approx .2Fs. I am not the liberty to delay the signal AT ALL, so throwing a filter at the output is out of the question. My thoug...


Phase Noise

Started by ckiancho in comp.dsp16 years ago 16 replies

Hi. The simulink block Phase Noise uses noise with a spectrum characterized by a 1/f slope. I presume that means if the frequency offset is...

Hi. The simulink block Phase Noise uses noise with a spectrum characterized by a 1/f slope. I presume that means if the frequency offset is specified at F Hz, the noise spectrum is 1/f for frequency offset > = F. Then what about the noise spectrum for frequency offset < F? Is it also 1/f or simply flat? If it is 1/f, then it should not make any different to set the frequency offset at


Noise Shaping and Clipping

Started by Vladimir Vassilevsky in comp.dsp13 years ago 4 replies

Consider a requantization system with noise shaping and dithering. The question is what to do when the sum of the signal, the noise feedback...

Consider a requantization system with noise shaping and dithering. The question is what to do when the sum of the signal, the noise feedback and dither exceeds the range of the output quantizer. A differentiator of the Nth order used as a noise shaping filter has the max. feedback of ~2^N. So it is quite likely that the quantizer will run out of range at or near the peak values of the in...


Can I use FFT to calculate signal's phase noise?

Started by agump in comp.dsp10 years ago 3 replies

I have collected some datas from the ADC and want to know about the phase noise of the signal. Since the signal has phase noise ,...

I have collected some datas from the ADC and want to know about the phase noise of the signal. Since the signal has phase noise , it's time-varying signal. If I use FFT to calculate it's spectrum , I think the result can't show the phase noise of the signal. Can you give some recommends what means I can use to get the phase noise of the signal? Thanks.


Grammar on "as is the case for Gaussian observation noise"

Started by fl in comp.dsp8 years ago 1 reply

Hi, When I read a Kalman filter similar model (see below please), I am not clear what it points in the last within quotation mark (as is the case...

Hi, When I read a Kalman filter similar model (see below please), I am not clear what it points in the last within quotation mark (as is the case for Gaussian observation noise). "as is... noise" means that Gaussian density is abadoned in observation case. Thus, the probablity densities of the system is not Gaussian. "as is... noise" can be substituted as "because of the abandon of


spectral subtraction of signals other than noise

Started by adj in comp.dsp16 years ago 9 replies

i have been reading a lot of messages on spectral subtraction and how it is useful in reducing background noise. i have tried this in matlab and...

i have been reading a lot of messages on spectral subtraction and how it is useful in reducing background noise. i have tried this in matlab and i was highly successful in attenuating the noise from a sound file. but when i tried this with another sound file instead of noise the signal was not attenuated at all. in fact both of the signals could be heard perfectly well; and i can say pretty...


HELP!!!!!! effect of additive white noise

Started by THE_KILLER in comp.dsp15 years ago 1 reply

Hello i need to investigate the effect of additive white noise on the transmitted data using based-band simulation under different value...

Hello i need to investigate the effect of additive white noise on the transmitted data using based-band simulation under different value of signal-to-noise (SNR) ratio. here are the 2 programs Both files allow you to calculate the bite error rate (BER) depending on: i=2E the noise amplitude Pn & ii. the signal amplitude Ps i;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;...


Phase noise generation

Started by pchennu in comp.dsp16 years ago 4 replies

Hi, I am trying to add phase noise to a QAM signal. Can anyone tell me how to generate phase noise in matlab.Any help will be greatly...

Hi, I am trying to add phase noise to a QAM signal. Can anyone tell me how to generate phase noise in matlab.Any help will be greatly appreciated. This message was sent using the Comp.DSP web interface on www.DSPRelated.com


How to calculate SNR for signal which can only detect with noise?

Started by abracadabra in comp.dsp14 years ago 5 replies

Hi dspers, I was discussing a problem of evaluating efficiency and performance of a noise cancellation algorithm using SNR and MSE with some...

Hi dspers, I was discussing a problem of evaluating efficiency and performance of a noise cancellation algorithm using SNR and MSE with some buddies. Someone suggest that for signal which we can only detect with noise, we cannot know the exact pure source, so we have to use a known source and add some kind of synthesized noise to verify our algorithm. However, it is hard to guarantee the ...


Disguising a Reference So Others Can Test Your Filter

Started by Bret Cahill in comp.dsp10 years ago 10 replies

Say someone boasts about having a new filter that, in certain situations, can reduce noise more and faster than any other filter? Is there any...

Say someone boasts about having a new filter that, in certain situations, can reduce noise more and faster than any other filter? Is there any way to encode a reference that isn't directly identifiable but still useful as a reference? That way the reference could be posted along with the noise for the test. One way might be to make the noise in the reference the negative of the noise in...


how to calculate noise vector from Eb/No to plot a EbNo/BER graph (noise generation)

Started by Anna in comp.dsp14 years ago 6 replies

Hi, I'm doing a final project in OFDM simulation and I would like to plot a EbNo/BER graph. For a range of a specified EbNo, I I have...

Hi, I'm doing a final project in OFDM simulation and I would like to plot a EbNo/BER graph. For a range of a specified EbNo, I I have to generate a noise added to the signal. I have no idea how I could generate a noise vector from this Eb/No. supose that my signal is x = randint(1,N) some people generate noise vector by 1/sqrt*(randn(N)+jrandn(N)) do I have to multiply this with a conste...


Non-Stationary Noise

Started by Ikaro in comp.dsp14 years ago 5 replies

Hi Everyone, I am trying to derive a theoretical curve for noise reduction under non-stationary condition and see how that compare with my...

Hi Everyone, I am trying to derive a theoretical curve for noise reduction under non-stationary condition and see how that compare with my data and computer simulations. Here is the gist of the problem. I have a measured signal which is composed of a deterministic component (s) and some nonstationary noise (n(t)): x(t)= s + n(t) To simplifify things, we can assume that the no...


Noise Normalisation

Started by volkanizma2003 in comp.dsp11 years ago 7 replies

Hi, I have some problems regarding noise normalisation. I have original signal and I want to add a noise. EbN0db=...

Hi, I have some problems regarding noise normalisation. I have original signal and I want to add a noise. EbN0db= 0.00; SNRv=10^(EbN0db/10); global sigma; sigma=1/sqrt(SNRv); b=randn(1,1200); gaus=sigma*b; x= round(randn(1,1200)); % my original signal y= gaus % my noise z= x+ gauss % original signal + noise Question 1.) Do I need to normalize the noise for example multiple by 0...


generating phase noise in software.

Started by Anonymous in comp.dsp15 years ago

Hi, Is there a way to generate simulated phase noise samples starting from a arbitrary phase noise specification table that is given as pairs...

Hi, Is there a way to generate simulated phase noise samples starting from a arbitrary phase noise specification table that is given as pairs of [offset (kHz), mask (dBc/Hz)] for offsets such as 1 kHz, 10 kHz, ... upto 10 MHz + the integrated phase noise (in degrees) over a frequency range (say 1 kHz - 10 MHz) ? I would greatly appreciate if you can provide any references to papers tha...