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Topic: Equivalent noise resistance

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	Noise Parameter Extraction using Source Pull - Microwave Encyclopedia - Microwaves101.com
		In the case of a low noise device, source pull is used in a noise parameter extraction setup to evaluate how signal-to-noise ratio (noise figure) varies with source impedance.
		In noise parameter extraction, the output is load-pulled to an impedance that provides good gain, then the input is swept all over the Smith chart.
		Measuring noise parameters using source pull is what is used to empirically gather all of the data you need to design a low noise amplifier, starting from the device level.
	www.microwaves101.com /encyclopedia/sourcepull.cfm (665 words)

	Equivalent noise resistance - Wikipedia, the free encyclopedia
		In telecommunication, an equivalent noise resistance is a quantitative representation in resistance units of the spectral density of a noise-voltage generator, given by
		is the standard noise temperature (290 K), so
		Note: The equivalent noise resistance in terms of the mean-square noise-generator voltage, e
	en.wikipedia.org /wiki/Equivalent_noise_resistance (126 words)

	Printer Friendly Version
		Amplifier noise is increased by the resistive two-ports as a result of signal attenuation and the impedance mismatch between the cascade-connected ports.
		The ripple in the noise figure meter data is attributed to the slight impedance mismatches between the cables and connectors that are necessary to insert the noise figure meter.
		The predicted noise figure was obtained by applying the procedure discussed in the previous section to the measured scattering parameters for the amplifier obtained here, along with manufacturer provided transistor noise parameters.
	www.mwrf.com /Articles/Print.cfm?ArticleID=11710 (2872 words)

	Noise- Developer Zone - National Instruments
		Noise comes from both external sources -- such as the AC power line, motors, generators, transformers, fluorescent lights, soldering irons, CRT displays, computers, electrical storms, welders, and radio transmitters -- and internal sources, such as digital clocks, microprocessors, and switched mode power supplies.
		Noise may either be transient in nature, have fixed frequencies such as harmonic or mixer products, or be broadband random noise.
		First, although the noise of space is highly variable, depending on both man-made and galactic factors (for some systems, sun spots are often one variable), theory and experience have coupled to give useful approximations.
	zone.ni.com /devzone/cda/tut/p/id/5491 (1399 words)

	Noise in Audio Amplifiers
		Thermal noise is "white" in character (has a constant energy per unit bandwidth) and is generated by the thermal agitation of electrons in a conductor.
		This is the equivalent of 80dB Signal to Noise ratio (S/N) relative to 0dBu.
		A common technique for low noise is to select transistors based on their noise data, which will indicate the optimum collector current for a given source impedance.
	sound.westhost.com /noise.htm (2366 words)

	Circuit Design-Chapter 3
		The equivalent circuit for a junction diode the equivalent circuit is shown in Fig.
		The noise voltage spectral density is shown in the Fig.
		Flicker noise varies inversely with the gate capacitance because trapping and detrapping lead to variation of the threshold voltage which is inversely proportional to the gate capacitance.
	www.eie.polyu.edu.hk /~ensurya/lect_notes/commun_cir/Ch3/Chapter3.htm (3479 words)

	Noise Parameters
		Calculating the noise wave correlation coefficients from the noise parameters is straightforward as well.
		are the signal to noise ratios at the input and output, respectively,
		All curves with constant noise figures are circles (in all planes, i.e.
	qucs.sourceforge.net /tech/node9.html (161 words)

	Amplifier Design 1.
		It is known that for a bjt there is an extra equivalent noise resistance in series with the emitter with value 0.5/gm.
		The increase appears to be equivalent to a resistance of around 0.8/gm, which if correct suggests that this fet has more noise added by the gm effect than a bjt with the same gm.
		Using a bjt with series resistor may add more noise resistance than a fet without series resistor and the same total gm, but the difference can be expected to be small.
	www.angelfire.com /ab3/mjramp/ampdes1.html (1660 words)

	transmissionII: airborne
		Ambient noise level is the level of acoustic noise existing at a given location, such as in a room, in a compartment, or at a place out of doors.
		Antenna noise temperature is the temperature of a hypothetical resistor at the input of an ideal noise-free receiver that would generate the same output noise power per unit bandwidth as that at the antenna output at a specified frequency.
		In telecommunications, effective input noise temperature is the source noise temperature in a two-port network or amplifier that will result in the same output noise power, when connected to a noise-free network or amplifier, as that of the actual network or amplifier connected to a noise-free source.
	www.newmuseum.org /airborne/glossary.html (3952 words)

	Definition: equivalent noise resistance (Site not responding. Last check: 2007-09-10)
		equivalent noise resistance: A quantitative representation in resistance units of the spectral density of a noise-voltage generator, given by R
		is the standard noise temperature (290 K), and kT
		Note: The equivalent noise resistance in terms of the mean-square noise-generator voltage, e
	glossary.its.bldrdoc.gov /fs-1037/dir-014/_2062.htm (66 words)

	Equivalent Noise Generators
		may be characterized using either an equivalent e.m.f.
		The equivalent circuit for a detector and amplifier system is shown in figure 1 and the noise components for an FET amplifier input stage are given below.
		The minimum obtainable equivalent noise charge may be limited by the 1/f noise if this term is large.
	ppewww.ph.gla.ac.uk /preprints/95/06/rbates/node2.html (142 words)

	New England Photoconductor: Terminology
		The square areas resistance of a thin film detector, where L and W are equal; L being the separation between the electrodes and W is the length of the detector active area.
		Resistivity is a function of the detector element temperature and the level of irradiance.
		A resistance element that is in series with the detector element and bias voltage; typically matched to the detector's dark resistance.
	www.nepcorp.com /info/terms.htm (573 words)

	NPC Library: Noise Effects Handbook
		It is felt that excessive exposure to noise might be considered a health risk in that noise may contribute to the development and aggravation of stress related conditions such as high blood pressure, coronary disease, ulcers, colitis, and migraine headaches.
		Noises that are unpredictable or randomly intermittent tend to be associated with greater decrements in performance than in continuous noise.
		Noise may interfere with a broad range of human activities, the overall effect of which is to cause annoyance.
	www.nonoise.org /library/handbook/handbook.htm (15548 words)

	LNA Matching Techniques for Optimizing Noise Figures
		The first part of this article is a refresher addressing the theoretical noise figure for a two-port RF network, and the optimum reflection coefficient for the minimum noise figure.
		For LNA input matching, a noise circle is positioned on the Smith chart's center and radius.
		To design an amplifier for minimum noise figure, determine (experimentally or from the data sheet) the source resistance and bias point that produce the minimum noise figure for that device.
	rfdesign.com /mag/radio_lna_matching_techniques (1793 words)

	Noise
		In telecommunication, antenna noise temperature is the temperature of a hypothetical resistor at the input of an ideal noise-free receiver that would generate the same output noise power per unit bandwidth as that at the antenna output at a specified frequency.
		Car noise is generated by the engine and friction of the tyres as they move across the road surface as well as voluntary sources of noise a car might make, such as a music centre or its horn.
		In telecommunications, effective input noise temperature is the source noise temperature in a two- port network or amplifier that will result in the same output noise power, when connected to a noise-free network or amplifier, as that of the actual network or amplifier connected to a noise-free source.
	www.shortopedia.com /N/O/Noise (1207 words)

	Equivalent Noise Generators (Site not responding. Last check: 2007-09-10)
		may be characterized using either an equivalent e.m.f.
		Figure 1: Equivalent circuit of the detector and amplifier for noise considerations
		The equivalent circuit for a detector and amplifier system is shown in figure 1 and the noise components for an FET amplifier input stage are given below.
	ppewww.physics.gla.ac.uk /preprints/1995/06/rbates/node2.html (142 words)

	[No title] (Site not responding. Last check: 2007-09-10)
		Note that the available noise power at the output of the source is due to thermal noise source to the left of input terminals and not the noise generated by the input devices of the terminal.
		Receiver noise figure calculations and specifications for different blocks are easily performed when we have a knowledge of the impedances as we move down the receiver chain.
		One method to perform the phase noise calculation is to assume that the receiver channel is noiseless and the only interference within the signal band is due to the phase noise mixing with out-of-signal band blockers [5].
	kabuki.eecs.berkeley.edu /~jrudell/papers/specs2 (6906 words)

	ko #46041 #52824 #44288 #44228 In mathematics...
		The relation "has a common factor with" between natural numbers is "not" an equivalence relation, because although it is reflexive and symmetric, it is not transitive (2 and 6 have a common factor, and 6 and 3 have a common factor, but 2 and 3 do not have a common factor).
		Every equivalence relation on "X" defines a partition of "X" into subsets called equivalence classes: all elements equivalent to each other are put into one class.
		The equivalence classes of this relation are the right cosets of "H" in "G".
	www.geodatabase.de /Equivalent (673 words)

	EIS - Noise Processes (Site not responding. Last check: 2007-09-10)
		To give a brief introduction to noise sources and the way in which they can be modelled.
		To be able to interpret noise contour plots and noise figures for amplifier systems.
		Noise figure, noise in amplifiers, equivalent noise resistance.
	people.man.ac.uk /~mbhesch/Noise.htm (164 words)

	diyAudio Forums - Working with Current O/P DAC Chips
		The problem is that the input resistance (the cathode) is still pretty high because he doesn’t use feedback.
		Oh yeah, since noise is an issue, expensive Vishay S102s in the 4.99 Ohm I/V positions may be a rational selection.
		This 5-ohm noise resistance will be dwarfed by the first stage triode's noise resistance.
	www.diyaudio.com /forums/showthread.php?threadid=100844 (1450 words)

	Thevenin Equivalent Circuits
		A source has an open circuit voltage of 24 volts and an internal resistance of 600 W. Determine the voltage at the terminals of this source when a 1200 W load resistor is attached to the source.
		This is the Norton equivalent circuit for the voltage divider.
		The internal resistance has a formula for a parallel resistance even though the two resistors would appear to be in series in the original voltage divider.
	www.facstaff.bucknell.edu /mastascu/eLessonsHTML/Source/Source2.html (3332 words)

	Thiel_small_analysis
		The driver parameters, which determine several of the equivalent circuit elements, are known as "Thiele parameters," and are fairly standardized; a table given here[13.5kb] provides precise definitions and units, and also points out some potential pitfalls in using published values.
		The goal of the equivalent circuit analysis is to solve for the velocity of the cone, and velocity of the air in the vent.
		The resistive force in the vent is proportional to velocity for laminar air flow, but proportional to the square of velocity for turbulent flow.
	www.silcom.com /~aludwig/Sysdes/Thiel_small_analysis.htm (4158 words)

	IK1ODO_SDR1
		The noise in an operational amplifier is modelled with a voltage source (En) in parallel to the inputs and a current source (In) in series.
		Three dBs are lost in the diplexer resistors, about one dB is the opamp noise contribution, something (another dB?) is contributed by the audio board and from input transformer losses, another dB is lost in the 90° sampling process.
		My extimate of the mixer ENR is about 8dB; so there is still room for improvement, and indeed tweaking with parameters on a slightly different circuit I arrived at -132 dBm at 14MHz (always in 2.4kHz).
	www.spin-it.com /sdr/IK1ODO_SDR1.html (1494 words)

	Types of noise sources
		Shot noise is due to the discreteness of the charge carriers and is related to the statistical nature of their injection into the semiconductor over a Schottky barrier.
		The second is that each current pulse should be able to displace a charge equivalent to that of one electron in the external circuit, that is to say a low trap density is required at the metal-semiconductor interface.
		If the current that flows through a device is due to generation then the expression for the noise present will be the generation-recombination one rather than the expression for the shot noise defined in equation (9).
	ppewww.physics.gla.ac.uk /preprints/95/06/rbates/node3.html (524 words)

	diyAudio Forums - A Heretical Unity Gain Line Stage part II
		The principle sources will be the tube’s noise, noise from the cathode load current source, and thermal noise from the input circuit.
		Ignoring the favorable shunting action of whatever load the cathode follower is driving, the noise from the current source is divided down by its source impedance (on the order of 10 megohm) and the looking-in impedance.
		The prevalent source of noise is from the modulation of the LED reference voltage via noise on the 12-volt rails.
	www.diyaudio.com /forums/showthread.php?s=&threadid=59244 (4423 words)

	Intermodulation Distortion and Adjacent Channel Power Application - MT993D Option
		Knowledge of a device's noise parameters is valuable to receiver/amplifier designers, saving hours of design time and reducing, or eliminating, "cut-and-try" iterations.
		Maury noise application software enables an automated tuner system to make fast, accurate measurements of minimum noise figure, optimum source reflection coefficient, and equivalent noise resistance.
		Noise parameters as well as maximum gain, associated gain and stability factor (k) are tabulated and available for printout below the plots.
	www.maurymw.com /products/rfdcs/mt993b.htm (738 words)

	Low-Noise Amplifier (LNA) Matching Techniques for Optimizing Noise Figures - Maxim/Dallas
		SC\) at the input port of the noise-free amplifier; and noise power due to the source alone is proportional to the mean square of the source current (/I
		When the noise figure (F in equation 46) is expressed as a function of a circle, it can be used with a Smith chart for optimum noise-figure matching in specific applications:
		In most circuit designs, however, the noise contribution of each two-port network can be minimized through a judicious choice of operating point and source resistance.
	www.maxim-ic.com /appnotes.cfm/appnote_number/3169 (1792 words)

	Tubes 201 - How Vacuum Tubes Really Work
		One is the noise diode, which is deliberately operated with a low heater voltage so that emission is low, and saturation occurs continuously.
		The noise produced by the tube is equivalent to a resistor in series with the grid, at room temperature, whose value is given by:
		Flicker noise is caused by variations in cathode emission due to movement of atoms within the cathode structure.
	www.john-a-harper.com /tubes201 (10896 words)

	A Practical Design of a Low Phase Noise Airborne X-band Frequency Synthesizer \| October 12, ...
		The choice of an optimal architecture for minimum phase noise, rejection of spurs from different sources, and achieving high efficiency and small volume are the key steps in an airborne synthesizer design.
		The phase noise is —80 dBc/Hz at 100 Hz and —97 dBc/Hz at 10 to 600 kHz frequency offset.
		There are two different ways to design a synthesizer—use a VCO at half the output frequency to produce the input signal to the PLL and then double it or use a VCO at the output frequency and then divide by 2 to produce the input signal to the PLL.
	www.mwjournal.com /Journal/article.asp?HH_ID=AR_3450 (527 words)

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