Noise Definition and 474 Threads

I have a sense resistor connected in series with the neutral wire. From the oscilloscope i detect noise of around 500mV - 1V across the sense resistor at high frequencies 60khz- 100khz. I see the noise once the power plug is inserted to the socket, although not switched on(live wire not...

I have a ccd camera that I put a peltier element into, and there is noise from the power supply, even when it isn't plugged in. Just plugging the jack in gives noise, I tried the bypassing thing with a capacitor with no effect. Plugging the PSU in gives no change. I tried moving the power supply...

analyze please? Our neighbor has a noisy dog and a Sportster. Niether is louder than the other or actually very loud at all. I don't mind the bike but the dog really gets me upset because there is a history of her and the dog being much worse and I've had to call the police. I like...

what is the advantage of using a gaussian distribution of noise (white/colored) in a system over any other distribution ??

I am a bit confused over the frequency term that appears in Johnson and Shot noise formulae. What is this term? Is it bandwidth? Of what? In relation to say a photodiode, is it the range of frequencies being detected? And how would this relate to say a DC circuit which no frequency terms...

Hey, I figured you physics geniuses might have an idea regarding what's happening to my headphones: When under certain conditions (some of which I've nailed down, but others I can't figure out) the headphones will start making insanely loud "electric" noises that resemble the "zzzz" sound...

No is the one sided noise spectral density in communication systems. N is the double sided noise spectral density. The relationship between them is given by 2N = No but I don't understand why it is like that. Why isn't it N = 2No instead?!

Help!~ Calculate the maximum noise voltage Homework Statement Two conductors, each 10-cm long and space 1-cm apart, form a circuit. This circuit is located where there is a 10-gauss magnetic field at 60 Hz. What is the maximum noise voltage coupled into the circuit from the magnetic...

Hi, I would like to measure the signal noise in a tv cable after introducing a splitter and compare it with the original signal. Keeping in mind the bandwidth frequency of the tv cable signal transmission, what kind of instrument do I need? Oscilloscope perhaps? At what speed? I don't know...

I have a roommate who blasts his music and bass below me till 5 am every night. It makes it very difficult to sleep and I have asked him to turn it down many times and every time he just curses me out. I would like to make it so his speakers don't play as loud or even that the bass is softer...

How is the noise sheilding provided by the fuselage when the engines are mounted at the rear end of the aircraft ? for example-SAX 40

I am trying to invert the the output of a battery so I can run an op-amp double ended with 5 volts and -5 volts. The battery itself produces 7.5 volts so I am passing it through a linear regulator to drop it down to 5 volts with low noise, at the expense of heat/efficiency. This is all great...

Hello, I am using stepper motors for some neuroscience experiments on rats. The problem is that our experiments are being corrupted by high-frequency noise. The acoustic frequency of the noise is high enough that humans can't hear it, but rats can (humans can hear up to 20 kHz, whereas rats...

Hello all :smile: I am currently doing some experiments in combustion where the pressure inside of a closed vessel is recorded while a mixture of fuel/air are ignited. It's obvious from a physical standpoint that the plot of the recorded pressure data against time should resemble a...

I have an Antenna system using two patch antennas, and I'm trying to determine the SNRin and SNRout of the system. I'm trying to determine the noise figure - is there a way to do it using scattering parameters? Thanks!

Hi, I am new to circuit design. Although, I am designing CSA&SA(charge sensitive @ shaping amplifier) for our detector system to detect the radon gas emission. We soldered every thing and we observe the output that is bit noisy. I learned some concepts in my course about...

I am trying to get an understanding of what a good signal to noise ratio in terms of decibels. My SNR is roughly 20 dB, and am concerned about being able to resolve the signal from this.

A battery of emf 9V, and negligible internal resistance, has a 100Kohm resistor connected across its terminals. What are the values of johnson and shot noise at a temperature of 20*C if the measurement bandwidth is 10KHz? At what temperature would the johnson and shot noise contributions to...

We need a very-low-noise amplifier for a special application, and we buy such an amplifier with a noise bandwidth of 2.4 MHz and an amplification of 1000. To test it, we take a set of "perfectly" shielded standard resistors, connect each if these to the amplifier input, and measure the rms...

I am really new to this and so I am trying to understand some basic stuff here. Autocorrelation of a univariate white noise is 0. Am I correct?

hello, i have a signal current I(t)=Acos(wt+theta) How can i calculate the signal power and noise power individually? thanks Reza

I keep having to call the police on my neighbors for them playing their bass music too loud. Will these sub-humans eventually get a ticket, or will the cops just keep showing up and saying the same thing over and over again to them? I had to call twice yesterday and just called again this...

Hello, I have the following question which I'm not quite sure about. I have the following Transfer Characteristic for a buffer. You can see the graph breaks at the points (2,0),(3.5,4),(5,5) http://img521.imageshack.us/img521/5052/captureen.jpg I need to set the appropriate values...

I wonder if anyone could tell me how and why the noise is created by the any electronic circuit or clipping circuit? thanks

Homework Statement If the received signal level for a particular digital system is -151dBw and the receiver system effective noise temperatyre is 1500K, what is E_b/N_o for a link transmitting 2400bps? solution says: (Eb/N0) = –151 dBW – 10 log 2400 – 10 log 1500 + 228.6 dBW = 12 dBW My...

Sampling theorem says that we should sample at least at a double rate than the bandwidth of the signal : Fs>=2B. Ideally Fs==2B e.i. oversampling is unnecessary. However, there's always noise present in the signal. Hartley's theorem connects the SNR with the bandwidth and the sampling rate for...

dears I study nuclear engineering (medical radiation ,MS) , my proposal for graduation is (Modeling of Acoustical Noise in MRI and It Is Validation Through Measurements). I want to make and deliver a mathematical model for reducing noise in mri,would you please tell me what should i do? and...

Hello everyone, I'm new to this forum, and though this question may be addressed already in another thread somewhere, I'm hoping to get some focused discussion about solutions going here. Problem: HVAC noise is propagating down the HVAC duct, entering a meeting room / boardroom. The...

I am responsible for investigating excessive noise problems in the cabin of an aluminum fireboat. I have no idea if the problems are with structure borne noise or airborne noise, so here is what I was thinking about doing, please let me know if there are any problems with this method. I was...

It's very hot in the UK at the moment, and so I went out and bought a semi-industrial 20" pedestal fan for my living room. It certainly does its job in cooling, but unfortunately, it also sounds like a jet engine. This got me wondering. I assume it uses a standard brushless electric motor to...

Homework Statement Consider the random process X(t)=A+N(t), where A is a constant and N(t) is a white Gaussian noise with spectral density equal to 1. The process X(t) is filtered with a system with impulse response h(t)=u(t)exp(‐t/T). Compute the probability that X(t), once filtered, is...

Hello all. I'm not a regular from the forum or nothing, I've been looking for a solution for a problem with static noise in a speaker system and got to this post in the forum https://www.physicsforums.com/showthread.php?t=201439 is not what i was looking for but from what i read someone...

I am using an electric motor to impose displacements on a specimen, but when the motor is on, there is too much noise in the displacement and force signal. Everything seems to be nice when the motor is off. The frequencies of the noise are less than 10Hz, too low to be filtered. In...

Question one Homework Statement x[n] = 5sin(0.22*pi) The root mean square (RMS) value eof a sin wave is known to be A/root(2) where A is the amplitude. If the noise in a system is known to have an RMS value of 0.5, what si the signal to noise ration (in dB) of the x[n] in this syetem...

Hi, I've got a square wave: x = square(2*pi*10*t); with time vector: t=0:0.001:2; I've also got a random noise signal: r=randn(1,10000); I want to add the noise signal to the square wave, but I can't add them because they aren't of the same dimensions. I know I can use awgn(x,snr) but I...

First I thought of posting this on the random thoughts thread, but I need an answer to this bugging question. Why the hell a microwave (the cooking device) makes that fanlike noise? While an infrared device (electric heater), visible light device (a flashlight), x-ray machine do not make any...

A few questions about noise. I am doing a noise budget and I am not sure if everything is correct... 1/f flicker noise Resistors show this noise. Horowitz specifies microvolt per decade frequency per applied volt. This would give me a false reading on a four point measurement, at least...

Hello, I've got a problem where a recording signal is a signal + gaussian white noise (quite classic). I derive this signal and while I know the theoretical result of the derivative of the noiseless signal, but I can't figure out what happens to the noise after the operation. So...

First of all, new to the forums, so HELLO! I am currently working on a project and cannot catch a break on what I need to be looking for. The project consists of calibrating antennas based on the radio noise from the Milky Way. We would like to point the antenna at the center of the milky way...

I read an account of this incident years ago and have often wondered about it. Here's the short version: http://soultherapynow.com/articles/carl-jung.html A longer version is available at this separate source (which does not allow for copy and paste)...

I am currently doing an acoustic experiment, testing the sloshing noise made by the fluid content in a tank. My software and microphone gives me all the outputs from the sloshing noise but not the loudness calculation. I am needing a figure for every test to key into my statistical software and...

I'm trying to find how simple electric circuits behave when the input is a random signal or noise. I'm wondering if anyone is familiar with this area or know of any resources they can point me to. Thanks in advance,

I am doing satellite attitude determination simulation using sun Earth sensors and Gyro modelling .I am using extended kalman filtering for attitude determination. the sequence of operations I am doing are % Simulation data % Spacecraft data % Gyro data % Sensor data. % Control system...

I have the intrinsic noise PSD spec for Honeywell's QA3000 accels, and I need to find the velocity random walk due to noise to show that I'm within my allowable. The PSD is given in units of g^2/Hz vs Hz. I'm given a velocity random walk due to noise spec of 15 (micro-m/s)/rt(s) that I must be...

Does anyone know how to plot noise in mathematica? I want to plot a normal distribution which is white noise in the time domain. This is because I want a constant power spectral density but Gaussian spread of values. Anyway I can plot a list of normal distributed numbers but want to know how to...

I am making a noise level meter, that would trigger an alarm, if the noise level has reached hazardous levels. However, one problem with noise is that it'd intensity decreases with distance, so that the meter would percieve a low sound near the meter and a high sound far away as equal. So does...

Given a power spectral density Sn(f) (or alternatively the autocorrelation function), is there a way to output random noise in Mathematica? Not sure if anyone here will know this but it's worth a try.

Hello, I am trying to understand how noise affects the potential measured across a certain point of a circuit. If we have two alternating voltage sources in a circuit, I understand that the "sum" of the potentials provided can affect the potential at the point of interest. However, I am...

Too much noise in "Embedded" system? Hey everyone. I'm working on putting a circuit board (with microprocessor, eventually) into a car for electro-pneumatic shifting on a manual transmission. This means that the circuit has to run on a 12V source being charged by an alternator. I have a...

The noise power in a conductor is given by P = k.t.B Does this mean the noise power is independant of the conductor length? Also, does this only apply for a conductor with no resistance? Thnks, Rudi