In signal processing noise can be considered random unwanted data without meaning.

learn more… | top users | synonyms

-1
votes
1answer
32 views

Phase angle operator, Implemention and drawbacks

Let assume we have a signal as: $\color{blue} {x(t)=M e^{(-\beta.t)} e^{j(\sigma .t+\delta )}}$ By applying phase angle operator we have: $\color{blue} {Phase[x(t)]=Phase[M e^{-\beta.t} e^{j(\sigma ...
1
vote
1answer
31 views

How is LMS/FXLMS noise cancelling different than simple polarity inversion?

Consider a noise-cancelling headphone: If I have a noise signal from the outside world, mic it, flip the polarity by multiplying by -1 (with an op-amp or digitally), delay by the appropriate amount, ...
0
votes
0answers
73 views

why adding noise enhances the accuracy sometimes?

I am applying simple FFT to estimate the frequencies of the oscillations. The real values of frequencies are known to me as I made a synthesis signal for simulation.Thus, I can calculate the error ...
2
votes
1answer
55 views

why derivative and logarithm operators amplify the noise effects?

It is said, do not use derivative operator in a the control system. because it will amplify the noise effect. Can someone explain it and give some mathematical reference about it please? Also I heard, ...
-1
votes
0answers
16 views

what's the appropriate signal/noise ratio(SNR) if a mixed-signal(periodic signals plus noise) looks mostly like noise?

I'm new to DSP. My confusion is: if we get a mixed signal, we can use FFT or spectrum analysis to visually know the signal consists of some sin signals on low-frequency and middle-frequency, and ...
3
votes
4answers
457 views

why Gaussian noise is usually used?

Gaussian noise with different SNR levels are usually used in research works to simulate a realistic environment. How can researchers guarantee that Gaussian noise can simulate the reality of a System? ...
0
votes
2answers
79 views

what is the unit of SNR?

SNR is defined as: $$SNR=10 \log_{10}\left(\frac{\sigma_s^2}{\sigma_n^2}\right)$$ When we say SNR of 10db is 10 times higher that 20db, it is higher in what? amplitude, power or what? also tell me ...
0
votes
1answer
23 views

comb filter - attenuation

I have a signal and from 'standard information' I know the predominant frequency is at 1Hz and then there should be three harmonics at lower amplitudes. My signal however has a lower amplitude at 1Hz, ...
0
votes
1answer
46 views

Fixed SNR with unitary noise variance

I've just one question : How can I write a model like y = x + w,( with w a white gaussian noise) with a fixed SNR and a noise variance equal to 1. What coefficient may I have before x ? Thanks !
0
votes
0answers
128 views

How to estimate PSD, and time delay of a random signal?

I'm trying to estimate the power spectrum and time delay for random signals. the signals were taken from two sensors, 10 cm apart. My aim is to estimate the PSD first then estimate the time delay in ...
1
vote
1answer
58 views

Effect of noise and entropy

Relation of Entropy and SNR : Based on this question and answer, I had another question that struck me and I am curious to know, if somebody can shed some light, on the following situation: $y= ...
0
votes
1answer
46 views

white noise filtering

If I have a white noise fed into a filter what would be the output of the filter - what would you expect to see? I know that white noise has a unit power spectral density (PSD), how these thing relate ...
0
votes
1answer
43 views

Long burst of high amplitude noise removal

I have a setup with an embedded DSPIC. This is used to link multiple audio inputs to the outputs and changed between them either when told to, or when one is active. This changing takes place on a ...
0
votes
1answer
71 views

How to simulate AWGN in communication systems for specific bandwidth

I am trying to generate a AWGN waveform to add it to the signal of my simulated communication system. The operating bandwidth of the communication system is about ...
2
votes
0answers
55 views

Noise analysis with periodogram. problem with different resolutions

I don't understand what happened in my simulation. I would like to perform a trade off between 2 ways to estimate power in frequency bands. I want to detect spurious frequencies. First method: I ...
0
votes
1answer
47 views

What is best practice to remove static noise?

What is best practice/algorithms to remove static noise from speech ? static noise aka Stationary Signal/static noise due to 1.humming sound due to of telephonic line/channel, 2.moving Vehicle,or ...
0
votes
1answer
77 views

Autocorrelation of white noise

Autocorrelation of white noise should have a strong peak at '0' and absolutely zero for all other $\tau according to this. Then why is output of this code a cone shape(with the expected 'strong peak' ...
-2
votes
2answers
107 views

Denosing signal using soft and hard thresholding

Let us consider following code: fs=100; N=1000; t=0:1/fs:N-1; y=10*sin(2*pi*100*t)+0.5*randn(size(t)); plot(y) plot(t,y) I have applied following threshold ...
1
vote
1answer
92 views

Digital Gaussian White noise signal generation in C++

I am trying to generate a band limited noise signal on a Raspberry Pi. I calculate samples at every 1/48000 sec on the Pi. If I generate normally distributed random numbers as data points at every ...
-1
votes
1answer
48 views

Parameters for signal analysis

I am extremely new to signal analysis. And before posting I did a lot of reading on signal analysis, FFT and windowing. I am working on my thesis which involves comparison of speech signals lets say ...
1
vote
0answers
43 views

What is OSNR in Fiber Optics?

I have seen that the SNR is measured for optical fibers "OSNR". What is the difference? Is there any equivalent?
0
votes
2answers
64 views

noise cancellation of non-repetitive noise

There are a new noise cancellation headphones that almost fully cancel human noise. What kinds of algorithms could achieve that ? EDIT:by human noise , i mean talking. In general, previous audio ...
0
votes
1answer
44 views

simulating range-bearing sensor with Matlab with Gaussian noise

I would like to simulate a sensor that provides range and direction of a beacon. This is for EKF localization, so the noise must be Gaussian (i.e. $\mathcal{N}(0, \sigma^{2})$. Also, I would like to ...
3
votes
1answer
71 views

Maximum likelihood estimation in presence of colored noise

I am trying to test system identification in presence of measurement noise (1) A white Gaussian noise (2) Colored noise - pink, violet. When we are estimating parameters we do so in presence of iid, ...
1
vote
1answer
105 views

How to filter uniform noise in a microcontroller?

By uniform noise I mean a band of a fixed width, no spikes, etc. This has to be one of the simplest examples. I'm looking for the appropriate theoretical approach as much as something relatively ...
3
votes
1answer
136 views

What is obtained from the cross correlation plot?

Let’s assume that we have two audio signals, x(t) and y(t) affected by the noise as shown below. And we would like to cross-correlate these two signals and the cross-correlation plot is shown as ...
0
votes
1answer
49 views

How to implement simple noise filter based on the frequency domain information?

Brief introduction: I am working on my university project. My task is to develop application that captures sound from mobile phone and removes/reduces noise (this simpilied version of task). I never ...
1
vote
1answer
59 views

What is uncorrelated noise

In many applications such as estimation theory, when we need to estimate a parameter then we usually consider in presence of white gaussian noise of zero mean and some standard deviation. During ...
0
votes
0answers
44 views

Noisy Signal auto/cross-correlation

I am trying to understand the basics of the cross/auto-correlation if the noisy signal $y(t)$ which is received from the channel at the receiver. Here at receiver we want to estimate the noise in the ...
1
vote
0answers
49 views

Spectral estimation from noisy time-series data

This is the first time I'm posting a question on here so I hope I'm doing it right. I've tried searching on here for an answer but haven't found anything particularly relevant. I have some data ...
1
vote
2answers
122 views

Derivative of noisy signal

My input signal is phase vector. I want to differentiate it to get frequency vector. My input signal is somewhat noisy. Here is the input signal. This is the derivative of the input signal as ...
0
votes
1answer
43 views

Extract signal from big gaussian noise

I have signal, periodic with amplitude 10 with frequency about 10 kHz. It is hidden in Gaussian noise with standard deviation 100. Some idea how to extract periodic signal? Thanks in advance.
0
votes
2answers
46 views

Reason of circular conv in OFDM

In OFDM system, after IFFT a CP is added at the beginning of the OFDM symbol by copying it from the end of the symbol.My question is that with CP why we use cyclic convolution instead of linear ...
1
vote
2answers
69 views

A [Very] Rough Approximation to “White Noise” with Sine Waves

This might be a silly question, but I'm pretty rusty on my signals. The problem is the following: I'm using a program which does not have a random signal generator, but I can sum up sines; and I need ...
0
votes
1answer
91 views

Adding measuruments noises to kalman filter

I'm implementing navigation system for my robot. There are two ways to get data from it: odometry(encoders from motors) and camera. Both of information sources can give me estimate of robot's ...
2
votes
1answer
65 views

Determining power of white noise component of an incomplete time signal

I want to determine the power of the noise component of a time dependend signal x(t) (similar to picture below) With constant sampling rate I use Parceval's Therorem and calculate the standard ...
2
votes
1answer
102 views

Removing baseline drift from ECG signal

I am trying to design a high pass filter to remove baseline drift from an ECG signal. the baseline drift is of very low frequency like 0.3Hz or so with an amplitude of 25% of the ECG signal. But the ...
1
vote
2answers
53 views

Adaptive gaussian filter for noise image

I am looking for methods to enhance noisy images, where: some pixels in the image are very noise, some other pixels do not contain so much noise. My first thought is to build an adaptive Gaussian ...
2
votes
0answers
48 views

Performance of adaptive signal processiong algorithm in noise not working

I am taking a course on signal processing and have been looking at various algorithms performance in presence of additive noise of different SNR. I was implementing Least Mean Square (LMS) algorithm ...
0
votes
2answers
169 views

Adding white noise to complex signal (complex envelope)

Good day everyone. So, i run in to trouble - how to add white noise to signal samples? For now i'm working with MSK signal - quadrature modulator and quadrature demodulator + viterbi processor. My ...
2
votes
1answer
52 views

Forecasting noisy data with polynomials

What's the best way to incorporate polynomials or sinusoidal equations into a linear model to predict a future amplitude in this sort of data? You can see that if those polynomials continued to go on, ...
1
vote
2answers
104 views

Poisson noise and curve fitting - denoise first?

If I have an image that is severely corrupted by Poisson noise, and I want to fit a function to the image, is it "better" to attempt to denoise the signal first before fitting, or should I move ...
2
votes
1answer
70 views

Generating a time series given a transfer function

I'm trying to work my way through a paper I found online, titled "Three Models of Wind-Gust Disturbances for the Analysis of Antenna Pointing Accuracy" by W. Gawronski, 2002. ...
1
vote
2answers
272 views

How to find peaks and periods?

I am looking at data like this: Source data: http://pastebin.com/raw.php?i=L6cd8d5K The data is quasi-periodic, there is a distinct cycle but it is not an exact repeat, and the period changes ...
0
votes
2answers
189 views

Using Matlab xcorr to find a signal hidden behind noise

I am trying to develop some code to find a transient signal in a data set I have. Before I get there however I am trying to write code using simulated data. I first am creating a signal with a ...
-1
votes
1answer
154 views

How can I reduce noise errors when detecting DTMF with the Goertzel algorithm?

Thanks a lot to whoever downvoted my question for no good reason. I wrote an implementation of the Goertzel algorithm in JavaScript and made a demo that detects DTMF dial-tones. You can find the ...
0
votes
0answers
39 views

understanding 1D wavelet analysis

i would like to understand how should i use following code for code for detection of uknown frequencies?let us consider following signal ...
0
votes
0answers
30 views

Correcting outliers using the standard deviation of a two-point different function?

I recently read a research paper that discussed how to correct lightcurve data (flux vs. time) by using the method as explained below: We have considered as outliers in the datasets the individ- ...
0
votes
1answer
91 views

denosing given signal using wavelet

let us suppose that we have given following model $y(t)=A_1 \sin(\omega_1*t+\phi_1) + A_2 \sin(\omega_2*t+\phi_2) + A_3 \sin(\omega_3*t+\phi_3)+ \ldots +A_p \sin(\omega_p*t+\phi_p)+z(t)$ where ...
1
vote
0answers
58 views

Finding a signal in noisy data

I have a large data set that was collected by a 5 GHz oscilloscope, so I basically have an array of voltages with each index being a very small time step apart. I am looking for a specific signal in ...