complex exponential embedded in white noise

Started by ypg in comp.dsp13 years ago 3 replies

Hi all, I have a doubt regarding complex exponential in white noise. Almost all of the statistical DSP books state the following. ...

Hi all, I have a doubt regarding complex exponential in white noise. Almost all of the statistical DSP books state the following. The signal is of the form x(n) = |A|exp(j(nw + phi)) + w(n) and we have to estimate 'w' & 'A' Here 'A'(amplitude) is not a random variable nor is 'w'(freq) phi is mostly taken to be a random variable uniformly distrib...


ARMA parameter estimation from noisy observations

Started by Nick32 in comp.dsp13 years ago 7 replies

Hi I am trying to fit an (8,5) ARMA model to a time series in the presence of additive white noise. The SNR is around 10-20dB. So far I have...

Hi I am trying to fit an (8,5) ARMA model to a time series in the presence of additive white noise. The SNR is around 10-20dB. So far I have tried the armax function from the Matlab system identification toolbox, the ARMASA toolbox for Matlab and a reduced statistics algorithm. Unfortunately I have found that these methods are unreliable when the SNR is less than about 60dB, and the models p...


Phase Noise and 1/f noise Generation

Started by ctao 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. %--------------...


White noise generation in the frequency domain

Started by Michel Rouzic in comp.dsp13 years ago 28 replies

Hello all, I'd like to synthesise white noise in the frequency domain, the reason for that is that I need to make it go through a bank of...

Hello all, I'd like to synthesise white noise in the frequency domain, the reason for that is that I need to make it go through a bank of filters so it's more convenient if I don't have to perform a FFT on it. I've tried that before, unfortunately strange artifacts would appear in the form of diagonal streaks on the noise's spectrogram. I have no idea what this can be due to. The technique...


Cirrus (Crystal Semi) CS42436 codec noise problem

Started by Roman Rumian in comp.dsp13 years ago 5 replies

Hello, in a multichannel audio mixer I use two CS42436 codecs. Input and outputs are differential. When the input PGA is set to more than...

Hello, in a multichannel audio mixer I use two CS42436 codecs. Input and outputs are differential. When the input PGA is set to more than +12dB then a audible level of white noise can be heard at the outputs (codec is passing through input signals). Shorting inputs does not change this situation. Technical support has not sent the answer for more than one week (they promise to give ...


generate white noise in assembly

Started by hbarcellos in comp.dsp13 years ago 10 replies

Hi all, I'm working whit ADSP 21161 analog devices, I'm looking for a way to generate a white noise in assembly, something like a random...

Hi all, I'm working whit ADSP 21161 analog devices, I'm looking for a way to generate a white noise in assembly, something like a random function in C. kind regard's Henrique


Help! A puzzlement about noise sampling & reconstruction.

Started by Qian...@gmail.com in comp.dsp13 years ago 4 replies

a bandlimit white noise x(t) with PSD of S0 is sampled (no aliasing) to produce x[n]. The PSD of x[n] is calculated to be S0/Ts (Ts is...

a bandlimit white noise x(t) with PSD of S0 is sampled (no aliasing) to produce x[n]. The PSD of x[n] is calculated to be S0/Ts (Ts is the sample period). Now I just reconstruct the continuous noise xr(t) by passing x[n] impulses to the ideal reconstruction filter (gain=Ts, -fs


Code for generating 1/f^alpha pink noise

Started by Sampo Niskanen in comp.dsp13 years ago 12 replies

Hi, In a recent project I required a source of 1/f^(5/3) pink noise, but was unable to find any code or explanation on how to perform that. ...

Hi, In a recent project I required a source of 1/f^(5/3) pink noise, but was unable to find any code or explanation on how to perform that. The DSP Generation of Pink Noise page[1] contains extensive information on generating 1/f pink noise, but has no mention of 1/f^alpha pink noise. I therefore made my own code for the purpose. It produces pink noise by filtering white noise with...


Detecting speech obscured by loud stationary noise

Started by Silash in comp.dsp13 years ago 2 replies

Hi, I would like to detect human speech in the presence of a very loud, very stationary external sound. It doesn't require a fine-grained...

Hi, I would like to detect human speech in the presence of a very loud, very stationary external sound. It doesn't require a fine-grained detection but that would be nice. It will ultimately be implemented in an FPGA. This isn't quite a negative SNR scenario because the "external sound" isn't Gaussian white noise, but a periodic waveform. So far I've learned that; 1) energy and power sta...


Effect of Upsampling on White Noise

Started by RIMalhi in comp.dsp13 years ago 16 replies

Suppose we get a sequence by sampling a bandlimited random signal corrupted by additive White noise with PSD N_0. Noise and signal are...

Suppose we get a sequence by sampling a bandlimited random signal corrupted by additive White noise with PSD N_0. Noise and signal are independent. We upsample the sequence by factor K by inserting (K-1) zeros between two consecutive samples. The upsampling will cause the spectrum of the bandlimited signal to be amplitude scaled by factor K and frequency scaled by factor (1/K). The question is wha...


Construct noise signal with a particular SNR

Started by bsg in comp.dsp13 years ago 4 replies

hi there, My issue is as follows: consider I have a low-pass filtered version of a white noise signal (fc=300 Hz, LPF) as my signal. I would like...

hi there, My issue is as follows: consider I have a low-pass filtered version of a white noise signal (fc=300 Hz, LPF) as my signal. I would like to add different Gaussian white noise having different SNR referred to the LPF signal. I do the following. 1. I get the power of the signal using = mean(original_signal.^2) -> {say P_s} 2. standard deviation of the required noise = sqrt(P_s / SNR) -


Probability expressions of a signal

Started by Anonymous in comp.dsp13 years ago 4 replies

Folks, It has been a while since i took my course in Probability of theory and i would appreciate any help from you. I am looking to have...

Folks, It has been a while since i took my course in Probability of theory and i would appreciate any help from you. I am looking to have the symbolic expression of the expectation E and Variance V of the signal Y, where: Y=x1+x2 and x1= cst1(a)+gaussian white noise x2=cst2(a)+gaussian white noise where cst1/cst2(a) returns a real value depending on the value of a ["a" is a parameter unc...


Noise cancelling approach

Started by alexryu in comp.dsp13 years ago 1 reply

Hello I have a data vector/time-series d = s + n (where s is signal and n is noise). n is somewhat localized in frequency, with two distinct...

Hello I have a data vector/time-series d = s + n (where s is signal and n is noise). n is somewhat localized in frequency, with two distinct peaks. (in actuality of course, there is also white noise, but that's a different subject). I have around 1 second of reference noise (compared to 12 seconds of data) that was recorded before the onset of the signal. Call this reference n'. What I am doin...


How to calculate SNR of a signal

Started by raj1795 in comp.dsp13 years ago 2 replies

Hi Friends, I'm working on a project where i want to add some white noise to my signal for testing purpose. I've designed the noise...

Hi Friends, I'm working on a project where i want to add some white noise to my signal for testing purpose. I've designed the noise generator and everything is working fine. But what are the means through which i can know what exact is the noise power w.r.t signal that my signal is changing behavioral of signal on way i thought of is SNR. But I'm not quit sure how to calculate it pr...


detecting white noise... shower running?

Started by briang2000 in comp.dsp13 years ago 21 replies

Hi, We've got a safety-related application where we'd like to determine if a shower is running in the bathroom. Does anyone have any...

Hi, We've got a safety-related application where we'd like to determine if a shower is running in the bathroom. Does anyone have any suggestions on how that determination could be made by sound? Might a shower have a specific white noise characteristic that could be identified as unique from music playing, toilet flushing, talking, etc.? Kinda strange question... but just thought I'd bo...


PSD of white noise NOT flat?

Started by BreadPaPa in comp.dsp13 years ago 4 replies

Hi, all, I would like to generate a white noise whose power spectral density is 1( flat over all frequency). I used Matlab function wgn to get...

Hi, all, I would like to generate a white noise whose power spectral density is 1( flat over all frequency). I used Matlab function wgn to get it: wn=wgn(1,10000,1,'linear'); Does the function above generate a white gaussian noise whose PSD is 1? Then I did simple experiment to check its PSD. I used Matlab function periodogram without any window: [p,w]=periodogram(wn); figure; p...


Inquiry about white noise and wiener deconvolutions

Started by john917 in comp.dsp13 years ago 3 replies

I?m interested in trying a wiener deconvolution for some electro-physiology data that I have recorded, and I?m not sure how to estimate the white...

I?m interested in trying a wiener deconvolution for some electro-physiology data that I have recorded, and I?m not sure how to estimate the white noise power for use in that. According to Wikipedia, the proper terms to use are the PSD of both the noise and the true signal in the equation used for the wiener deconvolution. (As an aside question, I was going to use the recorded signal as a proxy


the spectrum of white noise

Started by HyeeWang in comp.dsp13 years ago 6 replies

How can I get a smooth straight line corrsponding with the spectra of white noise? As we know, the spectra of white noise should be a smooth...

How can I get a smooth straight line corrsponding with the spectra of white noise? As we know, the spectra of white noise should be a smooth straight line. But I ploted it using matlab and did not get the desired result,although I raised the length of DFT a lot. What is matter? Following is my matlab script to illustrate it. N = 256; x = randn(N,1); X = fft(x); X = abs(X); ...


White Noise Level in OFDM & SNR Definition

Started by PhyLyrDude in comp.dsp13 years ago

Hi All, I have this problem on the level of white noise to be added into an OFDM system. Firstly, I have series of symbols mapped to a series...

Hi All, I have this problem on the level of white noise to be added into an OFDM system. Firstly, I have series of symbols mapped to a series of subcarriers and then go through an IFFT (size 2048). For simplicity, I assumed that it goes through a 1 path channel (i.e. no change to the OFDM signal). I then added some white guassian noise. Now here is the problem, if say I want a SNR of 10 dB,...


How to design a matched filter?

Started by vimmi in comp.dsp13 years ago 4 replies

To all the members of this community, iam doing my project on ultrasonic signal processing. i need to design a matched filter,to remove the...

To all the members of this community, iam doing my project on ultrasonic signal processing. i need to design a matched filter,to remove the white noise from the received signal(it is the signal received by ultrasonic receiver sensor). as iam having very little knowledge about signal processing i dont know how to design a matched filter practically for a given frequency around 40KLHz.The only th...