Started by in comp.dsp15 years ago

Hi everybody, What does mean by 8db SNR for direct sequence spread spectrum signal? Where signal has 31-bit PN code multiplexed with sinusoidal...

Hi everybody, What does mean by 8db SNR for direct sequence spread spectrum signal? Where signal has 31-bit PN code multiplexed with sinusoidal wave and gaussian (additive white) noise. Thanks

Started by in comp.dsp15 years ago

Hi everybody, What does mean by 8db SNR for direct sequence spread spectrum signal? Where signal has 31-bit PN code multiplexed with sinusoidal...

Hi everybody, What does mean by 8db SNR for direct sequence spread spectrum signal? Where signal has 31-bit PN code multiplexed with sinusoidal wave and gaussian (additive white) noise. Thanks

Is a signal containing random numbers White Noise?

Started by in comp.dsp15 years ago 28 replies

Let's say my audio is represented by a series of numbers and each number has a random value. Is my audio white noise? I think it is, but I'm...

Let's say my audio is represented by a series of numbers and each number has a random value. Is my audio white noise? I think it is, but I'm having trouble proving it to my self.

Thermal Noise Cancelling

Started by 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...

White noise and the impulse function?

Started by in comp.dsp15 years ago 3 replies

I am going to learn DSP! I have been studying it for a few weeks (I have many years of RF under my belt). I note that the impule function...

I am going to learn DSP! I have been studying it for a few weeks (I have many years of RF under my belt). I note that the impule function in a given window has a frequency response that is equal at every frequency in the DFT window. I also know that white noise has a frequency response that has roughly equal magnitude across the sample frequencies in an FFT. I am trying to make s...

Frequency estimation with MUSIC for single sin wave?

Started by in comp.dsp15 years ago 9 replies

Hallo everyone, I'm new to signal processing and spectral analysis, and I want to determine freqency of one single sin wave in white...

Hallo everyone, I'm new to signal processing and spectral analysis, and I want to determine freqency of one single sin wave in white noise with MUSIC algorithm and bring it on uC and FPGA. e.g I decide to use the SVD approach(singular value decomposition) and begin with sample data length N=256. Let p = 100 then i have a data matrix of p x (N-p) = 100 x 156. (U,S,V)=SVD(A) on a matrix of th...

amplify without increase of noise

Started by in comp.dsp15 years ago 7 replies

Hi! I have a recorded file (wav) where the recorded signal is very weak. When I try to aplify the signal the signal is almost lost in all the...

Hi! I have a recorded file (wav) where the recorded signal is very weak. When I try to aplify the signal the signal is almost lost in all the noise (mostly high frequency) that also seems to be added from nowhere... maybe it is "white noise"? Are there any program (not expensive) that can can remove this unwanted noise from the file?

Diffusion using convolution

Started by in comp.dsp15 years ago 9 replies

Hi folks, I was experimenting with convolution, using the the overlap-add ideas with FFT. I was using an impulse of fading white noise to test...

Hi folks, I was experimenting with convolution, using the the overlap-add ideas with FFT. I was using an impulse of fading white noise to test the algorithm for smoothness, and I noticed to made an almost perfect diffusion sound. My question; is it possible to feed the FFT with white noise and a mixture of the previous noise or something to create a nice diffusion fall-off without us...

Low pass filtration of white noise

Started by in comp.dsp15 years ago 18 replies

Hello, The scenario: A white noise signal. (Uniformly distributed between 0 and 1) A square pulse signal in the time domain. The first zero...

Hello, The scenario: A white noise signal. (Uniformly distributed between 0 and 1) A square pulse signal in the time domain. The first zero of the sinc function in the amplitude spectrum is at 50 Hz. The result of the convolution of the two above signals is a gaussian distributed signal. How can I predict that? Thank you!

Pitch detection of speech buried under white noise

Started by in comp.dsp14 years ago 2 replies

Hi Everybody, Can anybody tell me about a pitch detection algorithm which works in noisy environment. Many Thanks in...

Hi Everybody, Can anybody tell me about a pitch detection algorithm which works in noisy environment. Many Thanks in advance. _____________________________________ Do you know a company who employs DSP engineers? Is it already listed at http://dsprelated.com/employers.php ?

Mic Modelling with Fast Convolution

Started by in comp.dsp14 years ago 9 replies

Hi, first of all hello, im new here. I have been trying to develop some microphone modelling software that uses impulse responses to apply the...

Hi, first of all hello, im new here. I have been trying to develop some microphone modelling software that uses impulse responses to apply the frequency response of a mic to a sound. I'm using fast convolution and the overlap-add method. I have developed the following code to convolve a signal with an impulse of less that 1024points. I'm presently testing using white noise as my signal. T...

wavelet based method for removing Gaussian Noise

Started by in comp.dsp14 years ago

Dearl all: Hi all, I need to use wavelet based method to remove Gaussian white noise on an image. I have some confusion and would like to ask...

Dearl all: Hi all, I need to use wavelet based method to remove Gaussian white noise on an image. I have some confusion and would like to ask you: 1. What wavelet basis I should choose for decomposing the image? I intend to use Haar , DB2, db3, db4 to test the SNR to see what is the best. However I am considering for Gaussian Noise, if there are some best wavelet bases for this task, if...

Wierner Filter implementation in Modelling Application

Started by in comp.dsp14 years ago 4 replies

Hi, If anyone has followed the book: " Adaptive Filters Theory and Applications" by B.Ferhang-Boroujeny as a text book for Adaptive...

Hi, If anyone has followed the book: " Adaptive Filters Theory and Applications" by B.Ferhang-Boroujeny as a text book for Adaptive Filters course, please let me know. I am trying to solve some problems to understand the concepts behind white noise. Could anyone please answer these questions or refer some link as resources: 1. What does white noise with zero mean and unit variance mean? 2....

LMS vs Wiener

Started by in comp.dsp14 years ago 2 replies

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise...

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise v(n) with known variance and mean x(n) = d(n) + v(n); the goal is define an optimal Wiener filter of 101 coefficients. (I call it "toy situation" because I have at the same time the value of the noisy signal and the value of the original signal) ...

LMS vs Wiener

Started by in comp.dsp14 years ago 1 reply

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise...

Hello. I have a toy situation in which, known the desired signal d(n), d(n) = sin(100*pi*n+pi/3); and a noisy signal, with white noise v(n) with known variance and mean x(n) = d(n) + v(n); the goal is define an optimal Wiener filter of 101 coefficients. (I call it "toy situation" because I have at the same time the value of the noisy signal and the value of the original signal) ...

Calculating filter coefficients from magnitude squared filter

Started by in comp.dsp14 years ago 2 replies

Good Morning, As part of my current research, I am looking into applying IIR filters to generate noise with a variety of spectra. These...

Good Morning, As part of my current research, I am looking into applying IIR filters to generate noise with a variety of spectra. These filters need to be designed at runtime. Only the magnitude of the filter's transfer function is relevant - the phase of the white noise process used to drive to filter is already random. Because of this, I can use one of the many magnitude-squared filter d...

Binary white noise signal

Started by in comp.dsp14 years ago 16 replies

Hi, I am trying to generate a random binary white noise signal such that when we take the auto spectrum of the signal it should roll of at 2Hz....

Hi, I am trying to generate a random binary white noise signal such that when we take the auto spectrum of the signal it should roll of at 2Hz. I tried to do that by PWM but wasn't close. I was wondering if there is any better way to do this? I want to use this signal as an input in other software where the time is taken as a default milliseconds(ms) and the time step is 0.01ms. Is there a w...

Started by in comp.dsp14 years ago 8 replies

Hi people, I am trying to selectively mask a speech signal with white noise.what do i mean by selectively msaking? I mean i would like...

Hi people, I am trying to selectively mask a speech signal with white noise.what do i mean by selectively msaking? I mean i would like the noise to mask when a word is spoken and to stop masking when there is a period of silence. Any ideas or code on how to do this? Best regards G.N

SNR estimation using a windowed FFT

Started by in comp.dsp14 years ago 4 replies

Hi, What is the best way to estimate the SNR of a sinusoidal signal in white noise using an FFT? For the best SNR estimate, is it better...

Hi, What is the best way to estimate the SNR of a sinusoidal signal in white noise using an FFT? For the best SNR estimate, is it better to do one long FFT or to break up into smaller FFTs to average the noise power? Also does windowing have an effect on the measured SNR? Thanks, Rizwan

Wiener Filter Implementation Question.

Started by in comp.dsp14 years ago 3 replies

Hello all, I have implemented a WIENER FILTER in the Spectral Domain for noise reduction purposes in Matlab (for speech...

Hello all, I have implemented a WIENER FILTER in the Spectral Domain for noise reduction purposes in Matlab (for speech signals). Question: Can the Wiener Filter factors in frequency domain have values above 1 or below -1? For power spectrum densities i simply used absolute values of the FFT of the signals. The noise is white noise. I use the following to calculate the Wiener Filter:...