Time domain representation of colored noise

Started by Prateek B S in comp.dsp9 years ago 9 replies

I understand that the time domain representation of white noise looks like impulses. How do colored noises like brown, pink etc. look like when we...

I understand that the time domain representation of white noise looks like impulses. How do colored noises like brown, pink etc. look like when we perform an inverse Fourier Transform on them ? What could be some sources of colored noise that may affect speech signals? I am currently working on a project that involved removing noise from speech signals. Any help would be greatly app


Noise variance estimate

Started by DWT in comp.dsp13 years ago 5 replies

I'm trying to implement a simple denoising module based on wavelet filter-banks (DWT) with VAD. Noise is white, but I'm going to use other noises...

I'm trying to implement a simple denoising module based on wavelet filter-banks (DWT) with VAD. Noise is white, but I'm going to use other noises as well (car, babble, pink,..) 1) How can one estimate the noise variance on each subband? 2) Would it be better to build VAD on the base of decomposition or as stand-alone module (energy feature)? The main problem that I'm not sure how to use stan...


Reasonablenes (NOT 'correctness') of using DCT in place of DFT

Started by Richard Owlett in comp.dsp14 years ago 2 replies

I've read ( 'have understood') that for real symmetric signals the DCT and DFT are equivalent. That got me thinking about a particular set...

I've read ( 'have understood') that for real symmetric signals the DCT and DFT are equivalent. That got me thinking about a particular set of pseudo noise signals and how information is encoded. I'm interested in things loosely associated with speech recognition. Wouldn't be reasonable to considered voiced phonemes to be nearly pink noise. Unvoiced phonemes are noise. The informatio...


PCM audio processed by custom digital filter?

Started by Anonymous in comp.dsp15 years ago 1 reply

I'm trying to create a custom-spectrum noise sample, basically 1 second of white noise but filtered with a certain response. Its not quite...

I'm trying to create a custom-spectrum noise sample, basically 1 second of white noise but filtered with a certain response. Its not quite pink or white, its got several peaks and valleys. I've been thinking about doing it like this: Step 1: Use a program like ScopeFIR to create a digital filter so that when white noise is run through it it comes out with the desired output spectrum. St...


Question regarding the validity of a SNR calculation

Started by John in comp.dsp15 years ago 19 replies

Hello, I have a question regarding the computation of SNR. The case I am working on is a speech processing algorithm which suppresses...

Hello, I have a question regarding the computation of SNR. The case I am working on is a speech processing algorithm which suppresses background noise. The input signal is a noisy speech sequence defined as x[k]=s[k]+n[k] where s is clean speech and n is quasi-stationary pink noise. I would like to know how well the algorithm performs. The SNR of the input signal is calculated as: ...


Spectral subtraction

Started by jlavrenz in comp.dsp13 years ago 6 replies

We have data that is amplitude modulated on a specific frequency. The data/amplitude of the sin wave at 50Hz is slow varying in time. There...

We have data that is amplitude modulated on a specific frequency. The data/amplitude of the sin wave at 50Hz is slow varying in time. There is stationary background noise that is white to pink in nature. Our matlab simulation only shows improvement in SNR for a SNR value below about 15 and more noticeably below 10 but after 15 it offers basically nothing. We are doing magnitude spectral subtra...


External noise generation with Matlab

Started by thom in comp.dsp15 years ago 6 replies

Hi Do you if there is a toolbox or function to generate noise which is received after a RF transmission (a model of external noise with...

Hi Do you if there is a toolbox or function to generate noise which is received after a RF transmission (a model of external noise with man-made noise, galactic noise, noise due to attenuation and noise due to lightning discharges)? Thank you


Distrubution of noise times noise

Started by spasmous in comp.dsp15 years ago 9 replies

If I have two signals that are corrupted with Gaussian random noise and I multiply them, what is the noise distribution called? x1 = s+n1 x2...

If I have two signals that are corrupted with Gaussian random noise and I multiply them, what is the noise distribution called? x1 = s+n1 x2 = s+n2 x1*x2 = s*s+(n1+n2)*s+n1*n2 Is noise times noise (n1*n2) the focus of any study? I would be interested to read about it. Thanks.


Building an approssimation of a pure-noise signal

Started by Giulio Petrucci in comp.dsp13 years ago 8 replies

Hi there I have a signal with human speech mixed with background noise. I don't have a pure-speech or pure-noise reference signal to...

Hi there I have a signal with human speech mixed with background noise. I don't have a pure-speech or pure-noise reference signal to implement an noise cancellation (using, for instance, some adaptive FIR filtering). Anyway, within my signal, I can assume some noise-only periods, like this: |--signal+noise--|--noise#1--|--signal+noise--|--noise#2--| ...and so on. Let's suppose to pr...


Noise Figure and Noise Floor

Started by Bruno DAJIN in comp.dsp14 years ago 2 replies

Hi all, I want to compute the noise figure and the noise floor for my reciever. for the NF i use the Friss equation. But for the noise...

Hi all, I want to compute the noise figure and the noise floor for my reciever. for the NF i use the Friss equation. But for the noise floor i d'ont found any formula. With an amplifier the No floor is : Noise output = Noise input + Gain + NF But with an rf attenuators the NF is equal to the attenuation value. So Noise output = Noise input + Gain + NF don't work when Noise input >


Relationship between noise dB level and sigma

Started by Ben in comp.dsp15 years ago 3 replies

I have a noise generator which gives me N(0, 1) Gaussian noise. I wish to add the noise to a signal of known dynamic range. What is the scaling...

I have a noise generator which gives me N(0, 1) Gaussian noise. I wish to add the noise to a signal of known dynamic range. What is the scaling such that the noise dB is 3. My approach was this: Since I need upto 3 dB, 3 = 10 log10(Vt/Vs)^2, which means Vt/Vs = 1.4142 where Vt is the noisy signal and Vs is the noiseless signal. The noise Vn is then 41% of Vs (approx). I scale the Vn samp...


Thermal Noise Cancelling

Started by sonofland in comp.dsp15 years ago 1 reply

Hi All, I have read some post before regarding to the adaptive white noise cancelling using simulink, it seems impossible to cancel the noise...

Hi All, I have read some post before regarding to the adaptive white noise cancelling using simulink, it seems impossible to cancel the noise unless both reference noise signal and the noise in primary signal are generated from the same source. My question is, as of the thermal noise model we have today, is it possible to perform thermal noise cancellation? I think the bottom line is how we...


Another Eb/No Question

Started by Necronomicon in comp.dsp14 years ago 13 replies

Does Eb/No, as used in digital communication calculations for signal to noise ratios, take into account the VCO/PLL/Reference phase noise of the...

Does Eb/No, as used in digital communication calculations for signal to noise ratios, take into account the VCO/PLL/Reference phase noise of the carrier(s)? I ask because the phase noise is never really flat, and the Noise Power Spectral Density, or "No", is in Watts/Hz, which is assuming that the noise is flat across all frequencies (white noise). Certainly one could use the integrated ...


1/f noise generation

Started by Yu Xiaodong in comp.dsp16 years ago 13 replies

Hi All, Is there anyone know how to generate 1/f noise for simulating the phase noise. Someone told me though passing a white noise to a FIR...

Hi All, Is there anyone know how to generate 1/f noise for simulating the phase noise. Someone told me though passing a white noise to a FIR the noise can be generated. Any clue about the FIR? Thanks alot R. Y.


Thermal Noise Tutorial and Noise Figure Tutorial

Started by brent in comp.dsp10 years ago 9 replies

I have finished two tutorials on noise. the first one is here: http://www.fourier-series.com/Noise/index.html This covers thermal noise,...

I have finished two tutorials on noise. the first one is here: http://www.fourier-series.com/Noise/index.html This covers thermal noise, and contains several interactive flash programs. included is insight into the thermal noise equation, rms voltage calculations, examples of correlation and how independent (uncorrelated) noise adds together. All the programs have extensive audio exp...


Delta Sigma modulation noise problem~! Help

Started by Leaf in comp.dsp16 years ago 5 replies

hi: We all know that DSM is good because it's abaility to push Q noise to higher frequency band. My question is does DSM only work for Q...

hi: We all know that DSM is good because it's abaility to push Q noise to higher frequency band. My question is does DSM only work for Q noise? What about if the data already corrupted by noise? therefore would DSM work if the noise is the combination of background and quantization noise.? I have done some matlab coding(first order) on it and it works a bit but i dont know if it's ...


Delta Sigma modulation noise problem~! Help

Started by Leaf in comp.dsp16 years ago

hi: We all know that DSM is good because it's abaility to push Q noise to higher frequency band. My question is does DSM only work for Q...

hi: We all know that DSM is good because it's abaility to push Q noise to higher frequency band. My question is does DSM only work for Q noise? What about if the data already corrupted by noise? therefore would DSM work if the noise is the combination of background and quantization noise.? I have done some matlab coding(first order) on it and it works a bit but i dont know if it's ...


Effect of Phase Noise & Spurious Noise on a Signal

Started by ckiancho in comp.dsp16 years ago 2 replies

Hi. Phase noise and spurious noise are impairments of PLL. The difference between phase noise and spurious noise is the latter is a pure tone...

Hi. Phase noise and spurious noise are impairments of PLL. The difference between phase noise and spurious noise is the latter is a pure tone while the former is a 'collection' of tones. Phase noise, as the name implies, changes the phase of a signal while preserving the magnitude. I am unable to visualize how this is so. Can anyone point out useful links or explain the concept behin...


Gaussian Noise Generation

Started by Chris Barrett in comp.dsp14 years ago 41 replies

I'm trying to generate noise within a certain spectral range. I believe such noise is called Gaussian noise. Is there a way I can do this...

I'm trying to generate noise within a certain spectral range. I believe such noise is called Gaussian noise. Is there a way I can do this other than by filtering white noise?


Noise Cancellation

Started by Stacy in comp.dsp14 years ago 13 replies

If you have a recording with people talking in a room and a radio playing at the same time, how do you remove the sound of the radio? I am...

If you have a recording with people talking in a room and a radio playing at the same time, how do you remove the sound of the radio? I am aware of adaptive noise cancellation with LMS. However the noise there is white noise or noise from an airplane cockpit, waterfall, etc.