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Topic: Noise current

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Thermal noise

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	Shot noise - Wikipedia, the free encyclopedia
		Shot noise consists of random fluctuations of the electric current in an electrical conductor, which are caused by the fact that the current is carried by discrete charges (electrons).
		Shot noise is to be distinguished from current fluctuations in equilibrium, which happen without any applied voltage and without any average current flowing.
		Therefore, a more fundamental quantity is the noise power, which is essentially obtained by dividing through the bandwidth (and, therefore, has the dimension ampere squared divided by Hertz).
	en.wikipedia.org /wiki/Shot_noise (318 words)

	Finesse Voltage Regulator Noise!
		By amplifying the noise with an inverting transconductance amplifier with the right amount of gain, the required current sink may be realized.
		The regulator's noise voltage appears across this resistor so the noise current is shunted to ground through the transistor's collector.
		The regulator's noise is 330 nV per root-hertz at 100 hertz and the circuit reduces this noise to 20 nV.
	www.wenzel.com /documents/finesse.html (1272 words)

	Electrochemical Noise (Site not responding. Last check: 2007-10-15)
		Electrochemical noise is a general term for the `random' fluctuations in current or potential which occur as an electrochemical process proceeds.
		It is also possible to combine both of these techniques by measuring the current noise between two identical electrodes while at the same time monitoring the potential noise of the coupled electrodes relative to a low-noise reference electrode or to a third identical electrode.
		Noise due to instrumentation is more likely at higher frequencies (and correspondingly lower amplitudes) and you should check for instrumental noise by replacing the electrochemical cell by a dummy cell of comparable impedance to that of the electrochemical cell.
	www.cp.umist.ac.uk /lecturenotes/Echem/Noisefile.html (3352 words)

	Patent 4963764: Low noise current mirror active load circuit (Site not responding. Last check: 2007-10-15)
		The low noise integrated active load circuit according to claim 1 wherein the transconductance of the first transistor is increased to a larger value than the transconductance of the second transistors by a second bias resistor coupled between said first emitter and said voltage supply terminal.
		The low noise integrated active load circuit according to claim 3 wherein the transconductance of the first transistor is increased to a larger value than the transconductance of the second transistors by a second bias resistor coupled between said first emitter and said voltage supply terminal.
		The noise current for the circuit of FIG.
	www.freepatentsonline.com /4963764.html (3528 words)

	米国特許公開公報 20040041534 - Active EMI filter with magnetoresistive sensor for common mode noise current (Site not responding. Last check: 2007-10-15)
		A motor drive including an input for alternating current, a rectifier circuit, an inverter, an output which provides the controlled alternating current to drive a motor; and an active EMI filter for eliminating common mode noise in the motor drive which employs a magneto-resistive sensor.
		In the filter, a pair of lead frame bars which are connectable to the current path of the motor drive and an MR sensor in the form of a Wheatstone bridge are fabricated on a semiconductor die, with the bridge in contact with and straddling the lead frame bars.
		This allows the lead frame bars to be connected in such a manner that the common mode noise signals in the motor drive current path cause flux variations which reinforce the sensor output, while flux variations associated with other signals tend to cancel.
	cxp.paterra.com /jp/uspregrant20040041534.html (172 words)

	Andrei G. Chakhovskoi: selected publications
		Noise measurements were done using 50x50 arrays of gold gated silicon field emission devices fabricated using the method previously described.
		Currents measured from the devices ranged from about 0.5 to 4 =B5A depending on the bias and most likely the number of tips on the device that were emitting.
		Signal to noise ratios measured at pressures from 2x10-6 to the current cutoff threshold are similar and seem to improve over time at the expense of overall current.
	www.ece.ucdavis.edu /~chakhovs/Papers/ref16.html (1441 words)

	Patent 4577160: Method of and apparatus for low noise current amplification (Site not responding. Last check: 2007-10-15)
		A method is claimed in claim 1 and in which said passing of equal but opposite currents through the switching device comprises passing through the switching device current that is generated by said source and current that is inverted by said differencing amplifier circuit and fed back to said switching device.
		The conventional approach to low noise circuitry is to use, for example, a single transistor with grounded emitter, and to introduce the signal by means of a voltage at the base.
		This provides for the collector current of T.sub.1 to be applied through the emitter of T.sub.3 and the resulting collector current T.sub.3 to be pitted against a reflected or inverted current from the same constant current source.
	www.freepatentsonline.com /4577160.html (3633 words)

	美国专利申请公开说明书 20040095188 - Current source circuit for generating a low-noise current and method of ... (Site not responding. Last check: 2007-10-15)
		A current source circuit for generating a low-noise current has a current mirror circuit with a first and a second transistor.
		The current mirror circuit contains a capacitor connected between a source connection and a gate connection of the second transistor.
		The current mirror circuit likewise contains a switching element disposed between a drain connection of the first transistor and the gate connection of the second transistor.
	cxp.paterra.com /uspregrant20040095188cn.html (136 words)

	Thermal noise; dark current (Site not responding. Last check: 2007-10-15)
		This offset is termed the dark current because it is present whether the shutter is open or closed.
		The dark current response is then scaled to the exposure time of each target image and subtracted from the target image.
		However, the dark current is usually insignificant (and ignored) for visible light CCDs, but is important for infrared arrays.
	star-www.rl.ac.uk /star/dvi/sc5.htx/node14.html (161 words)

	NPC Action Alert: Abandon the Current Aircraft Noise Standard
		The 65 decibel level is derived from the “Schultz Curve,” which correlated people reporting being “highly annoyed” by noise with noise levels.
		A standard that accounts for low frequency noise using the “C” weighting is necessary to reflect the impact of low frequency noise, such as 65 dBC DNL.
		Abandon the current day-night level noise standard of 65 dBA DNL and replace it with a 65 dBC DNL standard.
	www.nonoise.org /action/dnlstd.htm (435 words)

	Thermal noise
		In telecommunication or other systems, thermal noise (Johnson noise) is the noise generated by thermal agitation of electrons in a conductor.
		The noise power, P, in watts, is given by P = 4kT Δf, where k is Boltzmann's constant in joules per kelvin, T is the conductor temperature in kelvins, and Δf is the bandwidth in hertz.
		Thermal noise is intrinsic to all resistors and is not a sign of poor design or manufacture, although resistors may also have excess noise.
	www.sciencedaily.com /encyclopedia/thermal_noise (205 words)

	CCD Analysis (Site not responding. Last check: 2007-10-15)
		The plots indicate that the dark current is 2484 and 2267 ADU/pixel/s for K1 and K2 respectively when the analogue gain is set to two.
		In order to compute the Poisson noise, it is necessary to know the ADU to electron conversion: The variance of the intensity measurement obeys Poisson statistics and is equal to the number of electrons, not the number of counts measured.
		For Keck 2 AO operating at 55 Hz, the variance of the measurement is the sum of the Poisson noise, the read noise and the dark current.
	www2.keck.hawaii.edu /optics/aochar/ccdanalysis.html (1135 words)

	5.4 Detector Noise & Dark Current (Site not responding. Last check: 2007-10-15)
		Detector dark noise and dark current values for individual detectors are stored in calibration G files 21_1, 21_2, 21_4 and 21_8, corresponding to the 1, 2, 4 and 8 second reset interval.
		The dark currents were higher at the start of a revolution for all bands, decaying with time so that after about four hours they had reached their nominal values.
		Cases where the continuum is weak can cause problems for dark current subtraction in the OLP pipeline, especially when memory effects are included.
	isowww.estec.esa.nl /manuals/sws_idum4/sidm/node34.html (465 words)

	Quantum 1/f Proximity Effect in Nanotechnology
		The effect is proportional to the mutual inductance L between the two parallel halves, or between two parallel currents at a distance d, in general.
		The total magnetic energy is not a sum of the contributions of individual carriers, but rather proportional to the square of such a coherent sum, i.e., to the squared magnetic field.
		In conclusion, we expect the induced 1/f noise effect to vary with the distance d between two parallel elements of current proportional to the mutual induction coefficient.
	www.foresight.org /Conferences/MNT8/Abstracts/Handel/index.html (357 words)

	Noise News for Week of July 4, 1999
		Noise reduction advocate Richard Mill, who is general secretary of the National Society for Clean Air, asked for a national noise reduction strategy that will strengthen the existing noise policy in the UK.
		The noise is so bad at times, according to Judy Moskop an Arroyo Springs resident whose back yard is only yards from the loop that her family is unable to sit on their patio.
		Wong said the county defines noise as that which "endangers or injures the welfare, safety or health of a human being or disturbs a reasonable person of normal sensibilities," and adds that a specific decibel does not need to be listed to define noise.
	www.nonoise.org /news/1999/jul4.htm (13180 words)

	5.2 Detector Noise & Dark Current
		Detector dark noise and dark current are kept in calibration G files 21_1, 21_2, 21_4 and 21_8 , corresponding to the 1, 2, 4 and 8 second reset times.
		The detector noise given is that if some processing has been carried out on the data, namely throwing away samples affected by glitches .
		When the amount of flux falling on the detector is small, there may be cases where the output of the detector from (incident flux plus dark current plus noise) is less than the detector from (dark current plus noise), the end result being negative fluxes in the AAR product.
	www.ipac.caltech.edu /iso/sws/idum/node33.html (293 words)

	Product Category Results (Site not responding. Last check: 2007-10-15)
		Current Transformers (55 companies) Current transformers are used to step down current in a very predictable fashion with respect to current and phase.
		Noise Meters (9 companies) Noise meters are used to measure and/or monitor noise produced by RF equipment.
		Current Loop Converters (62 companies) Current loop converters convert an analog or digital signal to a current loop output such as 4-20 mA or 0-20 mA.
	globalspec.com /ProductFinder/FindProducts?query=low+noise+current/... (492 words)

	Low Noise Current Preamplifier - SR570 (Site not responding. Last check: 2007-10-15)
		The SR570 is a low-noise current preamplifier capable of current gains as large as 1 pA/V. High gain and bandwidth, low noise, and many convenient features make the SR570 ideal for a variety of photonic, low temperature and other measurements.
		The low noise mode places gain in the front end of the amplifier for the best noise performance.
		Low bias current amplifier is used for reduced drift at high sensitivity.
	www.srsys.com /products/SR570.htm (724 words)

	diyAudio Forums Archive - Question on input noise current
		As base shot noise and 1/f noise usually dominate in bipolar op-amps without base current compensation, you should also be able to calculate the white part of the input noise current in A/sqrt(Hz) from sqrt(2q times the input bias current), where q is the electron charge (1.6022E-19 C).
		With a typical high open loop gain op amp circuit, the noise the noise currents are in parallel with the both input terminals and the voltage noise source in series with one.
		The theoretical noise is:.67/Gm, which is a noise eq resistance of 45 ohms at 1 ma and 12 ohms at 10 ma, so both conditions have added noise or the specified measurement are conservative.
	www.diyaudio.com /forums/showthread/t-20567.html (8405 words)

	Shot noise - Encyclopedia.WorldSearch (Site not responding. Last check: 2007-10-15)
		Shot noise generated by a Semi-Markov process (Institute of Statistics mimeo series)
		The effects of transit angle on shot noise in vacuum tubes (Massachusetts Institute of Technology.
		Shot noise in beam type traveling-wave amplifiers [by] L.D. Smullin (Massachusetts Institute of Technology.
	encyclopedia.worldsearch.com /shot_noise.htm (390 words)

	Noise Current Correlation Matrix
		This section describes the noise current correlation matrices of noisy components.
		The equations are built for RMS noise currents with
		Noise current source with a current power spectral density of
	qucs.sourceforge.net /tech/node25.html (115 words)

	Noise Wave Correlation Matrix in CAE
		Due to the similar concept of S parameters and noise correlation coefficients, the CAE noise analysis can be performed quite alike the S parameter analysis (section 1.2.2).
		As each step uses the S parameters to calculate the noise correlation matrix, the noise analysis is best done step by step in parallel with the S parameter analysis.
		The noise waves of different circuits are uncorrelated and therefore their time average product equals zero (e.g.
	qucs.sourceforge.net /tech/node11.html (301 words)

	Signal + Noise: Current Affairs
		The day Baghdad fell, I wrote that we should make rapid and salient improvement in the Iraqis' quality of life our immediate priority, even before the security situation was resolved.
		First, the threat is dire, more dire than is reflected in our current mindset or political rhetoric.
		UPDATE: Brian Weatherson at Crooked Timber argues that Bush's SOTU claim was not technically accurate because they claimed the British "learned" rather than believed that the deal had taken place.
	signalplusnoise.typepad.com /signal/current_affairs/index.html (4383 words)

	E-A-R® Hearing Conservation : Noise Regulations, Current Events (Site not responding. Last check: 2007-10-15)
		It modifies current noise level standards, which were established in 1980, and also sets out additional requirements.
		The new rule would require railroads to conduct noise monitoring and to implement a hearing conservation program for railroad operating employees whose noise exposure equals or exceeds an 8-hour time-weighted average of 85 decibels.
		The Noise Reduction Ratings (NRRs) that are emblazoned on all hearing protection devices that we buy and recommend are governed by a 1979 Hearing Protector Labeling Regulation promulgated under the auspices of the Environmental Protection Agency (EPA).
	www.gearupforsafety.com /e-a-r.com/hearingconservation/noise_main.cfm (598 words)

	Quantization Noise Current Spectral Density (Site not responding. Last check: 2007-10-15)
		The r.m.s quantisation noise is given for rounding as sigma = delta/sqrt(12) where delta = dynamic range/ no of quantisation levels no of quantisation levels = 2^B where B = no of bits.
		Your quantization noise will be at the ADCs and DACs, the quantization noise will be negligible on the 32bit floating point processor.
		I think I'm right in saying that the formula for Quantization Noise Current Spectral Density is given by - ((V/2^Q)^2)/6TR^2 where V is the voltage range at the ADC, Q is the number of bits - quatization, T is the sampling time, and R is the load resistance.
	www.seriousliving.net /new-1298754-1134.html (541 words)

	STMicroelectronics \| 550 MHz, Low Noise Current Feedback Amplifier - TSH350
		The input noise of the instrumentation must be extracted from the measured noise value.
		The input noise is called the Equivalent Input Noise as it is not directly measured but is evaluated from the measurement of the output divided by the closed loop gain (eNo/g).
		The aim is to compensate for the offset bias current, which could affect the input offset voltage and the output DC component.
	www.st.com /stonline/products/literature/ds/10961/tsh350.htm (2820 words)

	I_NoiseBD (Bias-Dependent Noise Current Source)
		The noise spectral density of this source is given by
		The dc current is that flowing into the Pin of Elem.
		summarizes the values to which the parameters must be set to realize the types of noise sources.
	eesof.tm.agilent.com /docs/adsdoc2002C/ccsrc/ccsrc043.html (177 words)

	vlsid,17th International Conference on VLSI Design
		A major obstacle in current-mode CMOS image sensors is the transconductance gain mismatch across pixels, which translates to Fixed Pattern Noise (FPN), degrading the image quality.
		In this paper, we propose a highly linear and compact current-mode readout circuit that eliminates this mismatch by performing the voltage to current conversion within a unity gain feedback loop.
		It is further proposed that by using the Active Column Sensor (ACS) architecture [4], only two transistors from the readout circuit are required to be present at the pixel site, while the rest of the circuitry resides common to an entire column.
	csdl.computer.org /comp/proceedings/vlsid/2004/2072/00/20720635abs.htm (204 words)

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