Would this approach be possible (for analog modeling)?

Started by in comp.dsp14 years ago 12 replies

Hello, so far I didn't read anything technical about analog modeling, but I thought about some very simple and straight-forward approach and I...

Hello, so far I didn't read anything technical about analog modeling, but I thought about some very simple and straight-forward approach and I wonder if that would work (at least to a semi-satisfying level) or if this would result in a sonic catastrophy :) How about creating a white-noise sound, which gradually gains volume from 0 to 10 (or maybe to 11? :), and then running this sound throug...

Gaussian Noise Generation

Started by 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 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.

Regarding the Linear prediction

Started by in comp.dsp14 years ago 6 replies

Hi, I am currently trying to implement the linear prediction analysis in c to decorrelate the speech signal. I have implemented the livenson...

Hi, I am currently trying to implement the linear prediction analysis in c to decorrelate the speech signal. I have implemented the livenson durbin code in C. Is there any method to cross check that the linear filter coefficient are correct. And I also want to know what will be the effect of the order on decorrelation. If i want to decorrelate the speech signal and convert it as a white noise ...

LPC Question

Started by in comp.dsp14 years ago 8 replies

In LPC we estimate a 10th order all pole model of quasi-stationary speech. The predicted speech is...

In LPC we estimate a 10th order all pole model of quasi-stationary speech. The predicted speech is then y(k)=-a1y(k-1)-a2y(k-2)....-a10y(k-n) Is the 'gain' estimated at all ie the variance of the driving noise of the AR model? Also is this really a predictor? It is not a Wiener predictor in the sense there is no additive white noise and it is only predicting one step. Looks more like ...

Another Eb/No Question

Started by 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 ...

Started by in comp.dsp14 years ago 34 replies

My understanding is that when you add AWGN to a carrier, you make the amplitude a gaussian distribution, and then add white noise to this (not...

My understanding is that when you add AWGN to a carrier, you make the amplitude a gaussian distribution, and then add white noise to this (not really pure white noise, but as high a BW as your simulation can handle). However, if you amplitude modulate a carrier by any AM % modulation, then your Fourier transform will show side bands which will not be spectrally flat like the added white n...

Average Power

Started by in comp.dsp14 years ago 16 replies

Ok suppose we have an R-C network - low pass filter with tf G(s)=1/(1+sT) where T=CR. We can easily calculate the output power spectrum if...

Ok suppose we have an R-C network - low pass filter with tf G(s)=1/(1+sT) where T=CR. We can easily calculate the output power spectrum if this is driven by zero-mean white noise as Phiyy(w)=mag(G(jw))^2 x power of input noise and the area under the PSD is the total average power. Now let's do the same thing digitally...and produce an equivalent digital filter G(z) The output p...

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...

expected spectrum of aliased BW limited white noise

Started by in comp.dsp14 years ago 1 reply

I'm fairly new to DSP and am trying to see the effect of undersampling on bandwidth limited white noise in Simulink. I took the bandwidth...

I'm fairly new to DSP and am trying to see the effect of undersampling on bandwidth limited white noise in Simulink. I took the bandwidth limited white noise source (set the BW to 1kHz), put it through a zero order hold with Sampling rate set to initally 5kHz and the output of this is connected to the FFT spectrum scope block (I buffer 2048 points and take a FFT of the same length). When I...

PPM question

Started by in comp.dsp14 years ago 4 replies

Hi group, I'm looking for new ideas on the topic of efficiently determining a suitable slicing threshold for a PPM signal. What I have is a...

Hi group, I'm looking for new ideas on the topic of efficiently determining a suitable slicing threshold for a PPM signal. What I have is a signal containing short pulses in white noise. The pulse widths and repetition intervals can vary depending on the specific PPM signal. What I have tried is a long term average, as well as a block sorting procedure that extracts a percentile value near...

Started by in comp.dsp14 years ago 3 replies

Hello Dear, I'm looking for a accurate and simple way to model Rayleigh distributed sequences for modeling a wireless communication channel....

Hello Dear, I'm looking for a accurate and simple way to model Rayleigh distributed sequences for modeling a wireless communication channel. I've already made a model by filtering white noise sequence but it doesn't work well and it is not accurate. Thanks.

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

Double integrated white noise

Started by in comp.dsp14 years ago 24 replies

Hi, I am trying to generate noise with an f^-4 PSD, and am having some difficulty getting the spectrum desired. The problem is...

Hi, I am trying to generate noise with an f^-4 PSD, and am having some difficulty getting the spectrum desired. The problem is this: Applying a filter with the transfer function co-efficients b = [1] and a=[1 -1] to white noise creates noise (as expected) with an f^-2 PSD. The rolloff of this filter is 20dB per decade, so it's pretty clear why it works. The theory (as far as I can...

SNR to EbNo in OFDM scheme

Started by in comp.dsp13 years ago 1 reply

hey all, I made an ofdm simulation in matlab, I want it to output Ber/EbNo plot, and I use the awgn function in order to add white noise in...

hey all, I made an ofdm simulation in matlab, I want it to output Ber/EbNo plot, and I use the awgn function in order to add white noise in the channel, and as u know the awgn function requires SNR as input, so I need to convert from Eb/No to SNR. I know this: Es/No(dB)=10log10(Tsymb*Fs)+SNR(dB) now I need to convert the Es/No of the ofdm signal to Eb/No: Es/No(dB)=Eb/No(dB)+10log10(...

Testing FIR filter design

Started by in comp.dsp13 years ago 22 replies

Hai, To test and verify the FIR filter Wat r all the test inputs as samples x(n) ....i can apply in addition to the...

Hai, To test and verify the FIR filter Wat r all the test inputs as samples x(n) ....i can apply in addition to the following: Impulse,step,sine,triangular,sawtooth,rectangular pulse,gaussian white noise.. 1.whether the above test generation signals are sufficient?? 2.r still i have to add more??? 3.wat r the other corner test cases?? regards, faz

white noise generation

Started by in comp.dsp13 years ago 23 replies

Hello, newbie here in need of some help: I'm trying to generate white noise. I found a paper online called "Xorshift RNG's" by George...

Hello, newbie here in need of some help: I'm trying to generate white noise. I found a paper online called "Xorshift RNG's" by George Marsaglia, and found it attractive because of its simplicity, and its also supposed to generate very good random numbers that have long periods, pass the diehard randomness tests, etc. The problem is, I have a 24-bit codec so I have to shave off 8 bits when...

Lightning and Fourier transform of an impulse

Started by in comp.dsp13 years ago 44 replies

Dear list I would like to ask the group, about a certain doubt I have. In an examination, the professor asked 'why lighting causes disruptions...

Dear list I would like to ask the group, about a certain doubt I have. In an examination, the professor asked 'why lighting causes disruptions to TV and Radio signals?'. The answer supposedly is, since a lighting can be seen as an electric 'impulse' signal (on the time domain), then in the frequency domain we have white noise, thus, generating noise in all frequencies. For the time being, le...

Auto-correlation of white noise

Started by in comp.dsp13 years ago 3 replies

Im a beginner to signal processing so have that in mind. I know that the auto-covariance, c_v(k) of a white process, v(n), is: c_v(k) =...

Im a beginner to signal processing so have that in mind. I know that the auto-covariance, c_v(k) of a white process, v(n), is: c_v(k) = \$_v^2 * D(k) Where \$ is small-sigma and D is diracs deltafunction. The auto-correlation in this case i believe is the same as the auto-covariance(?) r_v(k) = \$_v^2 * D(k) Is this always true for white processes?