## How do you detect the broadband noise level?

Started by in comp.dsp19 years ago 6 replies

The traditional diode detector does not distinguish between broadband noise and narrowband signals. Is there a way to detect the overall...

The traditional diode detector does not distinguish between broadband noise and narrowband signals. Is there a way to detect the overall broadband noise level? In this coming semester, I will be working on an automatic noise cancelling device for amateur radio. The input for the feedback network will be provided by a circuit that responds to broadband noise but does not respond to narrow...

## how to calculate noise variance from noise power spectral density value

Started by in comp.dsp11 years ago 5 replies

can anyone tell me how to calculate noise variance (sigma^2/2),if noise power spectral density is -162dBm/hz. Noise is additive white circularly...

can anyone tell me how to calculate noise variance (sigma^2/2),if noise power spectral density is -162dBm/hz. Noise is additive white circularly symmetric gaussian complex noise. what is relation between noise variance and power spectral density? Thanks

## calculate noise variance of AWGN

Started by in comp.dsp12 years ago 1 reply

hello, i need to calculate the noise variance of AWGN. i have the following info Noise power at the receiver: Boltzmann?s constant ...

hello, i need to calculate the noise variance of AWGN. i have the following info Noise power at the receiver: Boltzmann?s constant -228.6 dBW/K/Hz Bandwidth = 33 MHz 74.4 dB Temperature 20 oC = 273K+20K = 293K 24.7 dB Noise figure of the LNB 1.0 dB Noise power= -128.5 dBW

## Noise

Started by in comp.dsp16 years ago 1 reply

simple question Why noise devided by two (N0/2) ? is it average value of noise +ve and -ve. gaussian channel consider zero or white?

simple question Why noise devided by two (N0/2) ? is it average value of noise +ve and -ve. gaussian channel consider zero or white?

Started by in comp.dsp17 years ago 1 reply

Hi, Is there some quick ways or software tools to add kind of noise, for example gaussian noise etc to each tuple in a...

Hi, Is there some quick ways or software tools to add kind of noise, for example gaussian noise etc to each tuple in a vector. Thanks, Richard

## What's difference between Active NC and Adaptive NC

Started by in comp.dsp19 years ago 8 replies

I am doing a project on removing noise from speech signal, but in the survey stage. I noticed that there are two kinds of subjects on ANC, which...

I am doing a project on removing noise from speech signal, but in the survey stage. I noticed that there are two kinds of subjects on ANC, which could be either Active Noise Cancellation/Control, or Adaptive Noise Cancellation. Would anybody tell me what difference is between these two? I know the adaptive noise cancellation is that the algorithm adapts to continuously cancel the noise to giv...

## Use of DSP Technology to filter ambient noise

Started by in comp.dsp13 years ago 19 replies

Hi there, I am interested in using DSP technology to filter ambient noise. That is not just headphone noise cancellation but to reduce noise in...

Hi there, I am interested in using DSP technology to filter ambient noise. That is not just headphone noise cancellation but to reduce noise in an external area. So for example to use a technology to "block" / "reduce" the noise of an aircraft/train in the garden area of a restaurant. So the device would project the inverse of the background noise and so reduce it within the given area. Doe...

## Confusion about Phase Noise vs. Jitter

Started by in comp.dsp6 years ago 18 replies

Hi, I have some confusion about phase noise and jitter. According to [1], the phase noise spectrum is identical to the spectrum of the phase...

Hi, I have some confusion about phase noise and jitter. According to [1], the phase noise spectrum is identical to the spectrum of the phase noise (because phase fluctuations <

## Oversampling technique need help...

Started by in comp.dsp11 years ago 26 replies

Hello all, I have IR preamp with a gain of 64dB, the output noise is about 50mV peak to peak for a signal of 4V peak peak (max) and the bandwidth...

Hello all, I have IR preamp with a gain of 64dB, the output noise is about 50mV peak to peak for a signal of 4V peak peak (max) and the bandwidth is 350kHz. I have a AD7626 (16 bits 10MSPS ADC) which is largly suffisient for my aplpication. I would want to know what would be the best method to filter the noise (which is white noise and 1/f noise which come from the IR detector) in my band of i...

## Calculate variance of noise

Started by in comp.dsp14 years ago 6 replies

HI All I really need your help to understand this noise concept. Can you please tell me how to calculate noise variance for...

HI All I really need your help to understand this noise concept. Can you please tell me how to calculate noise variance for bandpass simulation? And does oversampling affects noise variance calculation. Your help will be greatly appreciated. Thanks Chintan

## Noise characterization of wavelet coefficients

Started by in comp.dsp18 years ago 1 reply

Hi, I hope this question about wavelets is not too far off topic in this forum... I have some image data with noise for which the noise...

Hi, I hope this question about wavelets is not too far off topic in this forum... I have some image data with noise for which the noise statistics (mean, variance) are known : noisy image = true image + noise in image domain In my case, the mean and variance is not constant over the image (correlated noise). When I perform a wavelet transform on this noisy image, I presume I can ...

## Echo canceller

Started by in comp.dsp18 years ago 3 replies

White noise is a good, if not the best, training signal for the echo canceller. White noise has all the frequencies from 0 to fs/2. In...

White noise is a good, if not the best, training signal for the echo canceller. White noise has all the frequencies from 0 to fs/2. In telephony the range of usefull spectrum is roughly from 200Hz to 3400Hz (G712). So the output white noise will come back (echo) as a colored noise (band filtered white noise). So the echo canceller has to imitate this filtering. What is better for trainin...

## generation of noise of a particular frequency

Started by in comp.dsp12 years ago 6 replies

hello, I have generated a ecg signal in matlab. Now I want to add noise of fixed frequency of 50 Hz and a noise of 0.2-0.5 Hz. IS there any...

hello, I have generated a ecg signal in matlab. Now I want to add noise of fixed frequency of 50 Hz and a noise of 0.2-0.5 Hz. IS there any provision in matlab to generate noise of specified frequency. Plz help me with this

## Complex Data/ Complex Noise Simulation

Started by in comp.dsp13 years ago 1 reply

I have a data set that is complex that i generated by using a hilbert transform. I wanted to add guassian noise (complex) to the data and then...

I have a data set that is complex that i generated by using a hilbert transform. I wanted to add guassian noise (complex) to the data and then do some processing. When i do this, is the correct method to add the hilbert tranform of the data to the hilbert transform of the noise? Or do i use a 'different' noise sequence and create complex additive noise to keep the I and Q of the noise uncorrela...

## Burst Noise

Started by in comp.dsp15 years ago 5 replies

Hi All, How many types of busrt noise in the communication system? Is there any model for burst noise used for simulation? I tried to search...

Hi All, How many types of busrt noise in the communication system? Is there any model for burst noise used for simulation? I tried to search through the web but could not find a good source describing how to generate busrt noise that can be used for simulation. Anyone can provide me inputs? Thanks. Best Wishes, Suterrr

## SNR of Speech

Started by in comp.dsp14 years ago 8 replies

I have seen quite a lot of definitions for SNR for speech + Noise signals. Segmented SNR, noise-reduction ratio etc. Is there a way...

I have seen quite a lot of definitions for SNR for speech + Noise signals. Segmented SNR, noise-reduction ratio etc. Is there a way of automating this or do you have to manually work this out with an audio editor. eg If I have a sentence lasting say 5 secs with additive noise then I would have to look between the words to get the noise. Anotehr thing is that in a real environment (as opoosed ...

## How can I remove Background Noise Removal after FFT?

Started by in comp.dsp9 years ago 15 replies

Hi mates, I need to know somehow, the parts of overall structure setup for removing background noise and determining background noise...

Hi mates, I need to know somehow, the parts of overall structure setup for removing background noise and determining background noise sources. I am working on a problem to solve background noise emitted from test objects. Here's written all on the document, I have https://www.dropbox.com/sh/38hbzpufqiajm7n/D_vTPEP9mb What all I am looking to know , What these mathematical module...

Started by in comp.dsp11 years ago 18 replies

I have been pondering the notation for noise voltage. The noise voltage across a 50 ohm resistor is expressed as 1nV/sqrt(1Hz) As I ponder...

I have been pondering the notation for noise voltage. The noise voltage across a 50 ohm resistor is expressed as 1nV/sqrt(1Hz) As I ponder this it seems to me that one is concerned about the noise voltage period. For instance, if you have a 1Hz BW signal you would say the noise voltage on a 50 ohm resistor is 1nV. If you have a 100 Hz signal you would say that the noise voltage is 10 n...

## OPamp noise calculations

Started by in comp.dsp19 years ago 5 replies

Hi Its been a while since last I did calculations on analog circuits, maybe you can help with the following: Consider the non-inverting...

Hi Its been a while since last I did calculations on analog circuits, maybe you can help with the following: Consider the non-inverting amplifier on the drawing below (hope you can see it). When calculating the resistors' thermal noise contribution to the total noise voltage, En_total, I have seen application notes calculate each resistors thermal noise and adding them (in the sum of sq...

## removing Background Noise

Started by in comp.dsp15 years ago 10 replies

Hi Everybody, I am working on removing Background Noise from speech Since I don't have access to the reference noise and the only thing at...

Hi Everybody, I am working on removing Background Noise from speech Since I don't have access to the reference noise and the only thing at hand is speech+noise record, that's why it is a bit tricky. Can anyone help me in this regard. Many Thanks