Noise Definition and 474 Threads

This is do with wave I think but I'm intrigued with this. As with waves sometimes they can cancel each other out but what about this: Can light produce darkness? Can noise produce quietness?

Is it possible to create an active noise control stereo that works like the headphones except they are stereos used to silence noise in a a room?

I want to create an active noise stereo which works like the headphones except it's a big speaker. I need your help on how i would go about doing this? I ain't no electrical engineer or anything, in fact I have no knowledge whatsoever so try to help me using simple terms.

Hi all: I am confused about one question. When we detect signal from human brain using coil in Nuclear Magnetic Resonance, two source contribute noise to our signal. One is coil itself. The other is human brain. Why can we think the noise from human brain is white noise? Can we compare the...

Hi, Suppose you have a simple capacitor, where the potential on one side is held constant and the other is allowed to vary randomly. What is the capacitive current? thanks,

Hello, First thread on this forum! Thank you for giving me you're opinion about a question that I have. I am using a data acquisition system (ADInstruments Powerlab 16/30) to record muscular activity from electrodes. So far, everything is working properly. I recently got an approval to...

Homework Statement Explain why the noise power across a resistor in thermal equilibrium is limited in contradiction to the formula for the noise V_{RMS} = \sqrt{4RkT\Delta f} which states that if we measure with infinite bandwidth we have infinitely large power Homework Equations...

Does anyone know how to create a matrix of complex Gaussian noise (with unit power = 1 and mean of zero)? I need to define a test sample for my algorithm, but I'm stuck at defining my test bench. Any help would be appreciated, thanks!

This is what happens to roses after a night in the drizzle. I'm sure, Drizzle, that you'll think of a witty reaxion. :biggrin: Unfortunately, the day was still dull, so I had to tweak contrast to get some dynamics back in the exposure. and sure enough, -you know me- getting in...

Lease help me, I have an assignment that ask me Filter the nois of this function f(x)=cos(0.1t) + noise the noise is random number between -0.5< n < 0.5 Filter the noise out using the average noise method? ( in excel ) Thanks

Hello everyone! I have an idea of making a device that can convert noise into electrical energy. In many fields (industries, cars, construction machines,...), some used machines make much noise, then I thought as sound (noise) causes mechanical energy, why not convert that mechanical into...

Hi! I guess this thread (could) bear similarities to the discussion in the "Low noise low pass" https://www.physicsforums.com/showthread.php?t=332819" thread, but I didn't want to hijack that :) so beginning a fresh one. I find that the electronic noise gets aggravated, when I connect the...

Is a low pass with an inductance less noisy than one with a resistor due to thermal noise? Will an RC low pass between two op amps necessarily be less noisy when the C is large and the R is small? Does this matter in real life circuits?

Hi What is \delta-correlated Gaussian noise? secondly, how is it that its correlation function is given to be 2\sigma^2\delta(t)? Thanks

I've been reading through the Feynman lectures (almost done with Volume 1), and I have been trying to prove everything to myself. I have a bit of a problem now though, in Chapter 41 on Brownian motion, Feynman shows what the voltage in an LRC circuit is due to thermal noise, and then says that...

What are some ways to improve signal to noise ratio for a microphone amplifier, beyond getting low noise components. My amplifier is a single opamp.

I am observing the Sun with a small radio telescope for a research project. I am measuring the intensity of the flux and comparing it to X-ray flux data from the NOAA. I am plotting radio flux intensity against time and i get a big "hump" in the middle of the day due to less atmospheric...

Hi, Does the cosmic electromagnetic emitters, if viewed in the function of electromagnetic intensity and in the particular wave length, follow the gaussian characteristics or is the noise uniformly distributed over all wavelengths? I.e. is there "tranquility" in intensity (or least amount of...

does anyone know how i can fix this? it's really annoying and i don't want to have to bring it in seeing as it sounds like the big external fan

Does anyone have a very low noise 60 Hz notch filter circuit that will not attenuate over 100 or a low noise bandpass from 100 to 20000 hz .

I'm collecting voltage data, and I need a resolution of at least .05mV, which I think I can provide over the range of voltages with my inexpensive A/D board. The problem is, the signal fluctuates maybe 1mV up and down, and so I get a noisy signal. I've tried running a low-pass filter through it...

Hi. I'm trying to measure the milliseconds of duration of output from a little piezo speaker that is on a circuit (a freezer control unit). I tried connecting an oscilloscope across its leads, but when I apply power, I hear this resonating noise which does not sound healthy. This is only when...

I have a very small signal coming from a thermocouple \mu V \mathrm{to}\, nV range, which gets drowned in noise when I transmit it via a 2m BNC cable, even the lock in runs into problems. I am about to amplify it at the source, and while I am at it, I will try to do a few more tricks...

I have an amplification circuit where I am essentially reading a somewhat deformed square wave and I am having a lot of trouble with 60Hz noise from the walls being superimposed on my signal. The signal of interest goes from 5v - 0v, has a period of about 60ms, and I need it to be relatively...

Is noise in sensors always gaussian? I was playing with acceleromter data in matlab. I decomposed the data into high frequency and low frequency. The high frequency noise distribution looks like a gaussian. Is this common to sensors?

A machinist is in an environment where the ambient sound level is of 85 dB, i.e., corresponding to the 8 Hours/day noise level. The machinist likes to listen to music, and plays a Boom Box at an average level of 86.0 dB. A.Calculate the INCREASE in the sound level from the ambient work...

Someone just tell me that, "varnishing an inductor can reduce humming noise much better than encupsulating it", and this is what his friend told him where his friend worked in power supply field for over 10years. (But I don't know did his "encupsulating" means potting) Or did he mean varnish...

I'm stuck with an elementary thing, it must be something obvious but I can't see what's wrong. Here it goes. I was writing up some elementary course material for an instrumentation course, and wanted to quickly introduce "white noise". Now, the usual definition of white noise is something...

Does anyone know where I can download the article Mathematical Analysis of Random Noise by Stephen O Rice for free ?

i am making a tachometer which will count pulses from an inductive pikup connected to an HT lead on an engine. i am having great difficulty when measuring my signal from the pick up as there is a huge amount of noise. can anyone raccomend the best way to clean this up? someone mentioned an...

I have a circuit that is outputting a good solid analog signal which is being read by an AD converter. While the signal is good and noise free, the ADC is not and is adding a lot of gibberish to my signal which is being sent to a PC. As of now I have tried using a simple discrete kalman filter...

I have noticed that the television makes a very high pitched noise. You almost can't tell your hearing it until it is turned off. It is kind of like the ringing of the ear in a way. Then When I turn on the DTV box, the sound becomes a little louder and changes frequency. Does anyone know...

Hi guys, I understand that in the Sun electrons are released upper chromosphere and corona which causes synchotron radiation when they spiral through its magnetic field, but how does it work in the galactic centre? Could anyone shed some light on this? What I mean is what's the constant...

hello well I have 2 vectors in MATLAB each representing a signal+shot noise. I have to add them. Can anyone tell me what the signal noise ratio will be when they are added? thanks MB

I'm working on a 'Fuzz box' for a bass guitar, ckt diagram below. With fuzz on and gains up, I'm getting a strange (to me) AC artifact -- Oscope images below (AC waveform from isolation xfmr at 10V/div, signal out at 2V/div). With fuzz on, and the input shorted to ground, the artifact is...

From the PC game doom, one of the characters make an insane screaming noise that is reused in some movie, i can't think of it now. I haven't played doom in a while, but i really need to know where i can find this scream noise because it is the single most disgusting noise in the world. if anyone...

Dear all, I'm trying to implement an Extended Kalman Filter for position, velocity and orientation tracking of a rigid body and I am using quaternions for representing the orientation in the state vector. As this is the first time I have to work with a Kalman Filter, and the project is on a...

I don't mean to violate any rules or conventions; these are questions pertaining to labs I'm doing as part of an undergrad degree. It's not homework, as such, so I've not put it in one of those forums But my apologies if this is incorrect. Anyhow; the experiment that bothers me is a...

Could someone explain the equation describing Thermal Noise? The equation is given by \overline{\left(\delta U\right)^{2}_{kT}} = 4RkT\Delta f Specifically I don't understand what the \Delta f is. Some online resources describe \Delta f as: - "frequency bandwidth within which...

does anyone know what causes noise in photomultipliers or where it comes from?

hi i want to know why while dealing with any noise based application noise is assumed to be gaussian distributed? give me the explanation clearly please

Hi PF Designers, Wasn't too sure if this would belong in the Electrical engineering forum but here goes. I'm designing a prototype for my thesis that will read in sensory data wirelessly to a MATLAB script. This sensory data is riddled with noise, however important data is contained in...

What makes the noise when atoms rub each other. E.g a different noise is made from scratching wood than a noise from scratching glass.

Hello, I'm a newbie for this forum, and I don't have much practical experience on SMPS too. I found this forum when I'm searching for my solution from internet. My Circuit: I'm using a simple buck converter: Vin: 24V Vout:3.3V Iout: 1.5A (dynamic load) The loading is running in PWM...

my professor gave me this equation to compute the distribution of the noise signal but I have no ideal what it is, so can someone explain this for me 1/√(2πσ)*e^((x-μ)^2/2σ^2 ) thanks

Hi there, For a personal project of mine, I have been designing a low-noise linear power supply to provide power to guitar effects pedals. A couple guitarists I know use a hodge-podge of AC adapters and switched PSU's to run their various pedals (sometimes 8 at a time). This mixture of...

What is the best way to filter out Gaussian noise from points in a data curve? (i.e. each point of the x-y-graph is displaced in y by a random amount) A simple running mean does it, but on the other hand it also changes the shape of the underlying real curve. Is it possible to use the...

Is there any way I can build/make something that I can wear that prevents me from hearing what's going on around me? When I study, there are so many noises because of vehicles moving downstairs, TV on loud etc. What can I do to cancel the noise?

I have a problem with my switch mode power supply, smps. It creates audio sound when I power it up, especially at minimum load. As I increase the load then sound disappears and in some designs it is still there. I don't know what to do. It is a bottleneck for me. Anyone who knows what to do...

Muscle noise is a big problem with our EKG machines at work. Even the slightest movement will overwhelm the waveform being studied; however, EKGs are done during stress tests which involve quite a bit of vigorous exercise. Muscle noise has a different waveform, but it's basically the same...