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Topic: Signal noise


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In the News (Mon 11 Dec 17)

  
  Signal-to-noise ratio - Wikipedia, the free encyclopedia
With an interferometric system, however, where interest lies in the signal from one arm only, the field of the electromagnetic wave is proportional to the voltage (assuming that the intensity in the second, the reference arm is constant).
In this case the noise is the error signal caused by the quantization of the signal, taking place in the analog-to-digital conversion.
Assuming a full-scale sine wave signal, the quantization noise approximates a sawtooth wave with peak-to-peak amplitude of one quantization level.
en.wikipedia.org /wiki/Signal-to-noise_ratio   (1077 words)

  
 Signal noise - Wikipedia, the free encyclopedia
In science, and especially in physics and telecommunication, noise is fluctuations in and the addition of external factors to the stream of target information (signal) being received at a detector.
In communications, it may be deliberate as for instance jamming of a radio or TV signal, but in most cases it is assumed to be merely undesired interference with intended operations.
In some cases a little noise may be considered advantageous, allowing a dithered representation of signals below the minimum strength, or between two quantization levels.
en.wikipedia.org /wiki/Signal_noise   (399 words)

  
 2002_August_techbrief   (Site not responding. Last check: 2007-11-06)
The signal (voltage) from a typical thermocouple is low, of order 10 mV, and the signal-to-noise ratio may degrade rapidly in the presence of signal noise, inherently raising the uncertainty of the temperature measurement.
The amplitude of the noise signal generated is directly proportional to the magnitude of the current in the offending power line, and inversely proportional to the distance between the thermocouple pair and the power line [1].
Because the signal noise is generated in a relatively narrow bandwidth around 60 Hz, a low pass filter can be used to pass the much lower frequency or DC thermocouple signal and reject or attenuate the signal components at frequencies above 60 Hz.
www.electronics-cooling.com /html/2002_august_techbrief.html   (522 words)

  
 Intro. to Signal Processing:Signals and noise   (Site not responding. Last check: 2007-11-06)
There are many sources of noise in physical measurements, such as building vibrations, air currents, electric power fluctuations, stray radiation from nearby electrical apparatus, interference from radio and TV transmissions, random thermal motion of molecules, and even the basic quantum nature of matter and energy itself.
One of the fundamental problems in signal measurement is distinguishing the noise from the signal.
The thing that really distinguishes signal from noise is that the noise is not reproducible, that is, it is not the same from one measurement of the signal to the next, whereas the genuine signal is at least partially reproducible.
www.wam.umd.edu /~toh/spectrum/SignalsAndNoise.html   (431 words)

  
 Remote Viewing and Signal-To-Noise Ration
Noise is also accidental or random fluctuation in electric circuits due to motion of the current carriers.
From this concept of noise, the term is used as an adjective to denote unwanted fluctuations in quantities that are desired to remain constant (or clear and not interfered with.)
"Noise" is whatever distorts, deforms, prevents, interferes with, disorganizes, changes or aborts the signal down to the point where the signal might not be locatable or received at all.
www.biomindsuperpowers.com /Pages/RVandSignalToNoise.html   (4370 words)

  
 Satellite Footprints by Dish Size - Noise Discussion, Terrestrial Interference (TI), Rain Fade, Free Space Loss, Earth ...
Signal can always be amplified above the noise floor but once it gets buried in background noise (falls into the signal floor) it can not be retrieved; this is why the LNB amplifies the weak satellite signals as soon as they are received before passing them on into the cable and to your receiver.
Interference is noise that comes in on the same frequency(ies) as signal and masks (overwhelms) parts or all of the desired signal (see diagram).
The test signal is aimed at the stationary dish and at regular intervals, as the test microwave source is physically rotated around the dish a full three hundred sixty degrees, its per cent reception by the dish, as compared to the known test signal generated by the test source, is monitored and recorded.
www.geo-orbit.org /sizepgs/Noise.html   (4779 words)

  
 Notes on signal to noise ratio.
There are several sources of noise; poor circuit design, heat, over-amplification, external influences, automatic gain control, transmission systems such as microwave, infrared etc. The important factor that determines the tolerance of noise is the amount of noise in the video signal, the signal to noise ratio.
Signal to noise ratios are calculated from the peak to peak value of the video signal.
Where R is the signal to noise ratio and the signal and noise are measured in millivolts.
www.cctv-information.co.uk /constant2/sn_ratio.html   (1276 words)

  
 Nikon MicroscopyU: Interactive Java Tutorials - CCD Signal-To-Noise Ratio
The measured signal from a CCD imaging system, utilized in calculating SNR, depends upon the photon flux incident on the CCD (expressed as photons per pixel per second), the quantum efficiency of the device (where 1 represents 100 percent efficiency), and the integration (exposure) time over which the signal is collected (seconds).
Because photon noise is an inherent property of CCD signal detection, which cannot be reduced by camera design factors, it essentially represents a "noise floor" that is the minimum achievable noise level, diminishing in relative effect as photon flux increases.
Because of the square-root relationship of photon noise to signal, this division between the two regions occurs at an exposure time for which the total detected signal per pixel is approximately the square of the read noise value.
www.microscopyu.com /tutorials/java/digitalimaging/signaltonoise   (2511 words)

  
 Analog Signal Transmission
While internal noise is generated by components associated with the signal itself, external noise results when natural or man-made electrical or magnetic phenomena influence the signal as it is being transmitted.
Normal mode noise enters the signal path as a differential voltage and cannot be distinguished from the transducer signal.
By increasing the signal, nonlinear effects become dominant, as the signal amplitude is increased-it enhances the signal and the noise in the same proportion.
www.omega.com /literature/transactions/volume2/analogsignal2.html   (949 words)

  
 SIGNAL TO NOISE: JAN/FEB 2002
The factory speaker wires were replaced with the standard aftermarket “zip cord,” and the multichannel signal outputs of the “brain” were connected to the amps via four-channel and two-channel UTP (Unshielded Twisted Pair) signal cables.
The signal cables were routed on the right side of the car, through the fold-down rear seat, and into the amp rack.
This means that a signal level of zero volts, with a source impedance of zero ohms, is fed into the amp channels.
www.carsound.com /columns/navone/nav0013.shtml   (1231 words)

  
 SIGNAL TO NOISE: Sept/Oct 2001
This is because the noise lies in the same low frequency bandwidth as the signal.
Simply laying the signal cables near the car’s chassis is enough to permit inductive coupling of the interference into the signal.
With a simple mono signal cable, the width of the loop is the distance between the conductors times the length of the cable run.
www.carsound.com /columns/navone/nav0011.shtml   (1102 words)

  
 ENGnetBASE: Engineering Handbooks Online
Additive and multiplicative noise in the information signal can significantly limit the potential of complex signal processing systems, especially when those systems use signals with complex phase structure.
Signal Processing Noise sets forth a generalized approach to signal processing in multiplicative and additive noise that represents a remarkable advance in signal processing and detection theory.
This approach extends the boundaries of the noise immunity set by classical and modern signal processing theories, and systems constructed on this basis achieve better detection performance than that of systems currently in use.
www.engnetbase.com /ejournals/books/book_summary/summary.asp?id=913   (201 words)

  
 Spectrofluorometer signal to noise ratio explained   (Site not responding. Last check: 2007-11-06)
The peak signal is measured at the water Raman peak (397 nm for 350 nm excitation) and the noise in a region (450 nm) where no Raman signal is present, and an "ideal" system would give a signal value of zero.
Another commonly used method is to divide the difference (Peak signal - Background signal) by the rms value of the noise on the background signal.
On the other hand, by using the background total intensity as a measure of noise, the JY method is more representative of a real "live" experiment where noise is also influenced by factors like the quality of the optics and scattered light in the system.
www.jobinyvon.com /Spain/esdivisions/Fluorescence/signal_to_noise.htm   (438 words)

  
 Signal-to-Noise Ratio of an Amplitude-Modulated Signal   (Site not responding. Last check: 2007-11-06)
As shown in the triangular-shaped signal spectrum, we apply coherent receiver to this filtered signal, with the result that the demodulated output contains noise that cannot be removed: It lies in the same spectral band as the signal.
Signal amplitude essentially equals the integral of the magnitude of the signal's spectrum.
Enforcing the signal amplitude specification means that as the signal's bandwidth increases we must decrease the spectral amplitude, with the result that the signal power remains constant.
cnx.org /content/m0541/latest   (913 words)

  
 Signal-to-noise ratio - Tutorial - Development Library - National Instruments   (Site not responding. Last check: 2007-11-06)
Internal noise is the noise component contributed by the amplifier under consideration.
When noise, or S/N ratio, is measured at both input and output of an amplifier, the output noise is greater.
The internal noise of the device is the difference between output noise level and input noise level.
zone.ni.com /devzone/conceptd.nsf/webmain/A76A4DFCDDBBACAF86256811004E677C   (632 words)

  
 Encyclopedia Obscura: Signal to Noise
Signal to Noise is one of these works, and I'm sure it won't be the last of Gaiman's smaller triumphs to be featured here at Encyclopedia Obscura.
Back to the subject: Signal to Noise concerns a film director who's working on the one film he knows will turn out the way he imagines it.
No matter how vivid and clear his ideas are, they always seem to mutate into a shadow of their intended form when the product is finished, but this time he knows he'll get it right.
www.encyclopedia-obscura.com /comicssignal.html   (493 words)

  
 Eigendecomposition Signal-Noise Threshold
The retained eigenmodes should represent the signal or principal components since these are used for the procedure's solution or reconstruction.
Red noise, which decreases in power as frequency increases, is not as readily partitioned using the SVD.
When noise is present at levels that start to approach that of the signal, the characteristic transition may be impossible to achieve.
clecom.co.uk /science/autosignal/help/Eigendecomposition_Signal-N.htm   (559 words)

  
 Photometrics - Encyclopedia   (Site not responding. Last check: 2007-11-06)
Specifically, it is the ratio of the measured signal to the overall measured noise (frame-to-frame) at that pixel.
Dark noise, which also follows a Poisson relationship, is the square root of the number of thermal electrons generated within a given exposure.
Under low-light-level conditions, read noise exceeds photon noise and the image data is said to be "read-noise limited." The integration time can be increased until photon noise exceeds both read noise and dark noise.
www.photomet.com /library_enc_signal.shtml   (470 words)

  
 Turn Signal Noise on AM Band   (Site not responding. Last check: 2007-11-06)
There's also a static noise through the speakers when using the passenger window switch from the driver's side (but not the driver's window switch), or if I turn the headlight switch, I also get static noise through the speakers.
the noise from the turn signal wil be there on and off.......seems to me it depends on the weather too when it rains i gets really bad.
That noise is normally caused by an improper or loose ground connection.
forums.pickuptruck.com /printthread.php?Cat=&Board=interior&main=270968&type=thread   (433 words)

  
 Comparative Analysis of the Ways to Increase Signal to Noise Ratio at NDT Inspection of Austenitic Welds
To increase signal/structure noise ratio by austenitic weld inspection the multifrequency testing method was developed and implemented in Russian atomic energy industry [2, 3].
Its essence is that the weld is tested by the pulses of different frequencies, received echo-signals are compared by time of reception and amplitude; the signals with equal time of reception and amplitude exceeding determined level of cut-off are selected.
The ratio of the useful signals from notches to the mean level of structure noises is increased more than 6 dB when using the same shear wave probes and holographic method.
www.ndt.net /article/wcndt00/papers/idn694/idn694.htm   (2205 words)

  
 Antenna earthing - Digital Broadcasting Australia - DBA Forums   (Site not responding. Last check: 2007-11-06)
The signal modulation is different but it is analogue all the same, and it is susceptible to interference if an installation does not meet the requirements for its reception, in any location.
Since the signal from the antenna is between micro and millivolts not hundreds of volts the effect of mains noise through the power cable is minimal.
The impedance of the cable at signal frequencies is the diameter of the centre conductor, the volume of and type of dielectric and the inner shield on RG6 cable.
www.dtvforum.info /index.php?showtopic=12444   (3433 words)

  
 Amazon.com: Signal to Noise: Books: Eric S. Nylund   (Site not responding. Last check: 2007-11-06)
While Signal to Noise introduces some fascinating virtual sleights of hand, the overall impression is of a continuation of the nano-techno-cyberpunk genre rather than a leap in evolution to a new form of fiction.
The brilliance of Signal to Noise is in the science: the idea of looking out into the swirling sea of the cosmos and finding patterns hidden amongst the static hiss of the births and deaths of stars.
Signal to Noise is not like anything I've read before and part of the reason for that is because I have not read any books from this sort of "cyberpunk/hyper punk" genre before, but after reading this book that may change.
www.amazon.com /exec/obidos/tg/detail/-/0380792923?v=glance   (2304 words)

  
 BBC NEWS | Science/Nature | Astronomers deny ET signal report
It was reported on the internet that the signal had been found using the Seti@home screensaver that uses computer downtime to analyse sky data from telescopes.
About 150 signals survived the process and were subjected to further scrutiny but none passed the final test to be classed as a potential signal from ET.
The "signal" that kicked off furious media excitement on Thursday is called SHGb02+14a and was first detected by computers running Seti@home software in Germany and the US.
news.bbc.co.uk /1/hi/sci/tech/3621608.stm   (422 words)

  
 Clarkvision: Signal-to-noise of Digital Cameras   (Site not responding. Last check: 2007-11-06)
Each level was analyzed for signal and noise as a function of multiple exposures at each ISO setting, and at multiple ISO settings as a function of intensity of the scene.
The signal-to-noise ratio is the linear signal calibrated from the linear output of a digital sensor divided by the standard deviation at that intensity.
Read noise, and other factors can only degrade this number (read noise is insignificant for the maximum possible and 18% gray card signal-to-noise ratios for the cases shown here).
www.clarkvision.com /imagedetail/digital.signal.to.noise   (1799 words)

  
 USS Clueless - Fault tolerant distributed computing
The noise is rejected, leaving only the clean signal in the form of an electoral result, and the system acts on that.
One reason a more complicated encoding has the potential for increasing noise is that the voters may become confused, or they may deliberately manipulate the information to try to subvert the system result.
One is the signal strength, the other is the noise floor, which represents the amount of the total signal which was being used to send data to phones other than us (plus a small contribution by naturally-occurring interference).
www.denbeste.nu /cd_log_entries/2002/08/Faulttolerantdistributedc.shtml   (5684 words)

  
 Signal, Noise, & Silence
Whereas telephones at least direct their signals, and messages received through them cannot be entirely dismissed as unintentional or random, television is without direction, and therefore without intent.
Pynchon seems to be suggesting that modern Americans derive their responses to most situations largely from the fantasies broadcast to them willy-nilly by radio and TV and movies; that they have become so lost in these fantasies they donít feel the ìactualî people slipping away.
Yet, the silent belief in the possibility of redemption, of individual, anarchic freedom from the isolated, paranoid, hellish desert of Noise uninhabited by the Mucho Maases--perhaps a personal, apolitical belief in such a freedom, is transcendent and redemptive in and of itself.
www.towson.edu /users/sallen/MyEssays/Lot49.html   (3076 words)

  
 Signal noise
Signal processing consultants specializing in signal and image processing, geolocation, DSP and other signal noise reduction techniques.
Long-running set of two courses which provide an understanding of the mechanisms of gear noise generation, of methods by which gear noise is measured and predicted, and of techniques employed in gear noise and vibration reduction.
The aim is to clearly identify links and gaps between current noise abatement technology and future EU noise reduction and regulation goals in the fields of air traffic, road and rail transport, marine technologies and outdoor equipment.
www.omniknow.com /common/wiki.php?in=en&term=Random_noise   (1942 words)

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