## Phase Noise Modeling

Started by in comp.dsp16 years ago 4 replies

Hi. I am trying to model oscillator phase noise using Matlab m-code. I know there is a phase noise blockset in the simulink. I looked under...

Hi. I am trying to model oscillator phase noise using Matlab m-code. I know there is a phase noise blockset in the simulink. I looked under the blockset mask and learnt that the phase noise is modelled by passing AWGN noise through a direct form II transposed (DF2T) filter whose shape is probably 1/f. If given another type of frequency response of a phase noise model, how do I generat...

## Filtering White noise to produce desired Coloured Noise

Started by in comp.dsp14 years ago 2 replies

Hello, I am trying to produce a coloured noise from white noise in the discrete time domain. I do it by producing an FIR filter of...

Hello, I am trying to produce a coloured noise from white noise in the discrete time domain. I do it by producing an FIR filter of coefficients b,a from the Noise Floor (V/sqrt(Hz)), which filters white noise produced by the randn function. Here is the code again: %Filter coefficients of Noise floor of circuit [b,a] = invfreqz(PSD_N.^0.5,(2*pi/fs)*(nn_f_scale),70,0,[],20,0.01); %G...

## Filtering White noise to produce desired Coloured Noise

Started by in comp.dsp14 years ago

Hello, I am trying to produce a coloured noise from white noise in the discrete time domain. I do it by producing an FIR filter of...

Hello, I am trying to produce a coloured noise from white noise in the discrete time domain. I do it by producing an FIR filter of coefficients b,a from the Noise Floor (V/sqrt(Hz)), which filters white noise produced by the randn function. Here is the code again: %Filter coefficients of Noise floor of circuit [b,a] = invfreqz(PSD_N.^0.5,(2*pi/fs)*(nn_f_scale),70,0,[],20,0.01); %G...

## Noise processing

Started by in comp.dsp13 years ago 9 replies

Hi all, I am working on a project where I am trying to detect the direct path signal for ranging purposes using UWB technology. I am developing...

Hi all, I am working on a project where I am trying to detect the direct path signal for ranging purposes using UWB technology. I am developing an algorithm that accounts for noise, but am still not sure how to account for the noise. I know I can't use the noise mean because that should be zero. I am pretty sure I should be using the variance but do not exactly understand why. Can anyone explai...

## Phase Noise and 1/f noise Generation

Started by in comp.dsp13 years ago 6 replies

Hi everybody. I'm a new guy here. Nice to meet you all! Recently I am working on Phase Noise generation in Matlab/Simulink. I found so many...

Hi everybody. I'm a new guy here. Nice to meet you all! Recently I am working on Phase Noise generation in Matlab/Simulink. I found so many topics here about phase noise or 1/f. One method that seems useful to me is to pass the white noise through the 1/f shaped digital filter. Here I will give the white noise generation and filter implementation code followed by my problems. %--------------...

## noise

Started by in comp.dsp9 years ago 15 replies

Sirs, I have few questions on the characteristic of noise when it comes to processing signals with noise: 1) does it really matter what is...

Sirs, I have few questions on the characteristic of noise when it comes to processing signals with noise: 1) does it really matter what is the shape of a noise - ramp, triangle, sinusodal etc. 2) does it really matter that they very unlikely to be periodic Thanks, Manish

## Filtering Noise from a signal

Started by in comp.dsp11 years ago 8 replies

In class we analysed a signal and filtered the noise out. However the noise was in a different bandwidth to the original signal hence it was easy...

In class we analysed a signal and filtered the noise out. However the noise was in a different bandwidth to the original signal hence it was easy to filter. If noise and the signal were to overlap in freq. spectrum, are there any techniques to filter out the noise??

## Filtering Noise from a signal

Started by in comp.dsp11 years ago 9 replies

In class we analysed a signal and filtered the noise out. However the noise was in a different bandwidth to the original signal hence it was easy...

In class we analysed a signal and filtered the noise out. However the noise was in a different bandwidth to the original signal hence it was easy to filter. If noise and the signal were to overlap in freq. spectrum, are there any techniques to filter out the noise??

## Noise variance

Started by in comp.dsp13 years ago 5 replies

Hi In soft demapper, we need either value of SNR or noise variance sigma. Now in real time we do not know both of these. And lets say that...

Hi In soft demapper, we need either value of SNR or noise variance sigma. Now in real time we do not know both of these. And lets say that we know variance of white noise but as the signal passes through equaliser, we get filtered noise with different variance. So how to find variance of filtered noise. Help in this respect will be greatly appreciated. Thanks Chintan

## Noise reduction

Started by in comp.dsp15 years ago 9 replies

Hi everyone, I would like to reduce the noise in a receiver, just after the antenna (where there is just a noise floor which is "white"). Do...

Hi everyone, I would like to reduce the noise in a receiver, just after the antenna (where there is just a noise floor which is "white"). Do you know some methods or a website concerning this noise reduction? Thank you Thom

## Noise Subtraction

Started by in comp.dsp16 years ago 11 replies

My boss showed me a feature on some commercial software he wants me to incorporate into our system. Basically, you show the software a patch...

My boss showed me a feature on some commercial software he wants me to incorporate into our system. Basically, you show the software a patch of noise (samples w/o the signal). Later, the program lets you subtracts that noise from a signal contaminated by that same noise. IOW, subtract the fan noise from the voice acquired from a microphone sitting next to a fan. I'm not sure how this i...

## Mixing correlated, band-limited Noise

Started by in comp.dsp17 years ago 6 replies

If a band-limited white noise source is mixed with a non-delayed version of itself in a down-conversion process, is the noise cancelled? If the...

If a band-limited white noise source is mixed with a non-delayed version of itself in a down-conversion process, is the noise cancelled? If the noise is mixed with a version of itself, which is time delayed by greater than a 1/BW, is the noise power out of the mixer 2x one of the noise sources? I modelled this process in matalb and dont get the expected result. Thanks. This message was sent...

## regarding musical noise

Started by in comp.dsp13 years ago 9 replies

Hi everyone i am doing my project in speech processing which involves removal of musical noise after spectral subtraction for removal of noise...

Hi everyone i am doing my project in speech processing which involves removal of musical noise after spectral subtraction for removal of noise in speech signal . i have two problems. 1)i dont know how "musical noise" sounds like.if anyone could post here some link of audio files that do have musical noise then that would be great 2)spectral subtraction requires estimation of noise.can ...

## Colored Noise in Noise cancellation

Started by in comp.dsp11 years ago 6 replies

Hello, I can't seem to find references on the performance of noise cancellation algorithms namely LMS, RLS, NLMS, etc when it comes to...

Hello, I can't seem to find references on the performance of noise cancellation algorithms namely LMS, RLS, NLMS, etc when it comes to suppressing colored noise. I have read somewhere that these algorithms do not perform very well when the noise spectrum isn't flat but I can't seem to find a reference to that claim. Can somebody explain this behavior to me and why? Is this even true?...

## detection in coloured noise

Started by in comp.dsp10 years ago 1 reply

I have a signal detection problem. The observer is presented 2 waveforms r1 and r2 on every trial. One waveform contains the signal + noise, and...

I have a signal detection problem. The observer is presented 2 waveforms r1 and r2 on every trial. One waveform contains the signal + noise, and the other just noise. Eg r1 = s + n1 r2 = n2 The noise in the two waveforms is correlated Gaussian noise with covariance matrix R. Ie corr(n1,n2) is nonzero. If there were no correlation, the optimal way to make the decision would be to cross-corr...

## Noise Removal - any ideas???

Started by in comp.dsp14 years ago 5 replies

Dear All, What is the best way to extract noise from data? I have an acoustic signal, which is fairly noisy (not sure of any of the noise...

Dear All, What is the best way to extract noise from data? I have an acoustic signal, which is fairly noisy (not sure of any of the noise parameters, just the usual stuff you get on a microphone). I ask because I?m trying to tidy up the spectrogram/fft, so that it 'look's pretty' and I reckon removing the noise from the original signal would be the way to go. I've not dealt with real da...

## DC Component of White Noise?

Started by in comp.dsp17 years ago 12 replies

White noise has a PSD = No/2 for all frequencies w. Does this hold true at w = 0? In this case does that mean that white noise must have a DC...

White noise has a PSD = No/2 for all frequencies w. Does this hold true at w = 0? In this case does that mean that white noise must have a DC component. What about zero mean white noise? Does this have: PSD(w) = No/2(1 - d(0)) where d(w) is the Kronecker Delta? I am simulating a baseband OFDM system and I want to add system noise at the appropriate level for a given SNR. Do I add noise on a...

## Phase noise how to combine together with the transmitting signals

Started by in comp.dsp14 years ago 4 replies

Dear all: Now i am working on a simulation to model Phase Noise and evaluate the distortion. In many web tutorials, the definition of phase...

Dear all: Now i am working on a simulation to model Phase Noise and evaluate the distortion. In many web tutorials, the definition of phase noise is given. But who can help tell how to generate certain phase noise from AWGN and combine the phase noise with the transmitting signal? e.g. 16QAM. Many thanks.

## Re: Highly Non-Stationary Signals for Adaptive Filters

Started by in comp.dsp11 years ago

On Friday, January 21, 2011 10:38:07 AM UTC-5, pacman101 wrote: ... > I am still trying to quantify the problem. FYI I am not trying to...

On Friday, January 21, 2011 10:38:07 AM UTC-5, pacman101 wrote: ... > I am still trying to quantify the problem. FYI I am not trying to cancel > Acoustic Noise, but RF noise. The noise being generated is right on top of > my frequency band. The switch is part of a system that for some reason > generates RF noise (EMI) when it is on but not when it is off. I hope it goes without

## HIPERLAN/2 PHY layer simulator on Matlab

Started by in comp.dsp17 years ago 10 replies

Thanks Laki, ur answer could be right if I apply the effect of the channel to the signal then i add the noise, but what i do is adding the...

Thanks Laki, ur answer could be right if I apply the effect of the channel to the signal then i add the noise, but what i do is adding the noise efect first then applying the channel effect to the sum (signal+noise), to get channel*(signal+noise), so after equalization i'd have ---> (channel*(signal+noise))/channel -- > signal+noise. hope u got what i mean .! thanks alot Laki