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Topic: Noise figure

	Definition: noise figure (Site not responding. Last check: 2007-10-19)
		noise figure (NF): Of an active device, over the bandwidth of interest, the contribution by the device itself to thermal noise at its output.
		It is determined by (a) measuring (determining) the ratio, usually expressed in dB, of the thermal noise power at the output, to that at the input, and (b) subtracting from that result, the gain, in dB, of the system.
		In this example, the noise figure is determined only with respect to that noise that appears in the output via the principal frequency transformation of the system, and excludes noise that appears via the image frequency transformation.
	www.atis.org /tg2k/_noise_figure.html (227 words)

	NPC Library: Noise Effects Handbook
		Figure 1-3 hypothetically depicts an example of what might be considered a typical daily noise exposure of a homemaker, students, and workers.
		Noises that are unpredictable or randomly intermittent tend to be associated with greater decrements in performance than in continuous noise.
		These figures, which were adapted from a summary and analysis of recent experimental sleep data as related to noise exposure (3), show a relationship between frequency of response (disruption or awakening) and the sound level of an intrusive noise.
	www.nonoise.org /library/handbook/handbook.htm (15548 words)

	RF Cafe - Noise Figure Calculation Equation Formula
		Noise figure is the increase in noise power of a device from the input to the output that is greater that the signal gain.
		Cascade noise figure calculation is carried out by dealing with gain and noise figure as a ratio rather than decibels, and then converting back to decibels at the end.
		As the following equation shows, cascaded noise figure is effected most profoundly by the noise figure of components closest to the input of the system as long as some positive gain exists in the cascade.
	www.rfcafe.com /references/electrical/noise_figure.htm (237 words)

	Noise Figure
		The system noise figure is an important factor in determining the NMR instrument's overall signal to noise.
		As a rule of thumb, a 1 dB increase in the noise figure decreases the signal to noise by 10-15%.
		If the noise level increases or decreases when the lock cable is disconnected from the probe, then the lock is adding noise (meter increases) to the overall system or the lock may be overloading the preamp (meter increases or decreases).
	www.acornnmr.com /appnotes/noise.htm (1410 words)

	Noise Source Applications
		Perhaps the highest visibility noise application is simply using a calibrated noise source in conjunction with a benchtop test instrument to measure noise figure of an LNA, mixer or receiver front end.
		Noise sources are mounted in the unit and automatically switched in to make the noise figure measurement.
		Noise sources employed in these live, outdoor applications should have isolators on the output which serve a dual purpose; to protect the noise source and other circuitry from possible incident power surges from the antenna and to ensure a low VSWR for lower noise figure measurement uncertainty.
	www.micronetics.com /Noise/Sources.html (1081 words)

	MMS Noise Figure
		This may be summarized by saying that the contribution made by a given stage to the overall system noise is the noise temperature of that stage divided by the total gain leading up to that stage.
		Figure 1 - Noise contribution due to a follow-on stage as a function of the gain leading up to that stage, for various values of the noise figure of that stage.
		Figure 2 - Stage noise temperature, as a function of gain leading up to that stage, for various values of the contribution that would be made by that stage to the total system noise.
	dsnra.jpl.nasa.gov /technical/mms_nf.html (1295 words)

	Noise Figure 3/2003
		Applying this general rule to a receiver with a 1 db noise figure and compare it to a receiver with a 4 db nose figure we would expect for the latter to produce twice as much noise.
		In the 1930s noise figure was associated to our room temperature, which was, at the time, a choice as good as any.
		Noise factor, by the way, is the number which the noise figure represents: e.g.
	www.ceitron.com /mvus/noise303.html (718 words)

	Noise Figure Notes
		From the diagram, it can be seen that the total noise at the output is the sum of two contributions: (1) the amplified noise which accompanied the signal, and (2) the noise added by the stage and amplified by it.
		Thus the signal to noise ratio at the output is equal to the signal to noise ratio at the input divided by NR, or decreased (degraded) by NF if dB are being used.
		The most likely interpretation is that the specification is implying excess noise, and that the value for noise figure used in computing stage noise contribution should be the specified noise figure plus the loss (in dB).
	moon.pr.erau.edu /~lyallj/ee410/noise_fig.html (688 words)

	How Quantization and Thermal Noise Determine an ADC's Effective Noise Figure - Maxim/Dallas
		The following discussion assumes that the noise is flat across the converter's Nyquist band and provides a designer with the means to determine an estimate for the ADC effective noise figure.
		Figure 2 shows a direct comparison of the effective noise figure for a Nyquist ADC and an oversampled ADC.
		The noise density for the oversampled converter is defined in the frequency bandwidth for which the converter is designed, and the SNR is normalized to that particular bandwidth to obtain the spot noise in dBc/Hz.
	www.maxim-ic.com /appnotes.cfm/appnote_number/1197 (1232 words)

	Noise Figure Uncertainty Calculator Instructions
		The noise figure and gain values are the values that are read from the display on the measurement instrument after a calibrated measurement is made.
		The values of instrument noise figure and match should be obtained from calibration reports; otherwise typical instrument default values are available.
		If values for the NFA instrument noise figure and match versus frequency are required, typical values can be found on the data sheet (5980-0164E - page 3 to 5) available in the "Download" section of the Noise Figure Uncertainty Overview page.
	contact.tm.agilent.com /Agilent/tmo/Format/K2Pages/NFUcalc.html (554 words)

	Figure - Wikipedia, the free encyclopedia
		A figure is a synonym for a number.
		Figure of speech, also called a rhetorical figure.
		This is a disambiguation page, a list of pages that otherwise might share the same title.
	en.wikipedia.org /wiki/Figure (91 words)

	Making Noise Figure Measurements Using a Spectrum Analyzer - Tutorial - Development Library - National Instruments
		It is equivalent to say that this noise comes from the input of the system and that the system itself is noiseless.
		Combining equations 6 and 7 or equations 6 and 4, we determine the noise factor, and hence determine the noise figure of the device to be:
		Choose the frequency you want to determine the noise figure at; noise figure varies with frequency in both the spectrum analyzer and device under test (DUT).
	zone.ni.com /devzone/conceptd.nsf/webmain/78A610B94390680486256D0B005403E8 (681 words)

	Figure article - Figure figure synonym number Figure speech Figure skating Miniature - What-Means.com (Site not responding. Last check: 2007-10-19)
		Figure article - Figure figure synonym number Figure speech Figure skating Miniature - What-Means.com
		This is a disambiguation page; that is, one that points to other pages that might otherwise have the same name.
		Figure article - Figure definition - what means Figure
	www.what-means.com /encyclopedia/Figure (95 words)

	Noise Figure Measurement using Standard Antennas
		Besides using noise figure measurement equipment for adjusting a homebrew receive system there is another and cheaper method to measure the noise figure of preamps for 70cm and 23cm (and up).
		The method is to measure the ratio of noise output, when turning the test antenna from the warm earth to the cold sky.
		This implies a correction figure of 0.35 dB for the Y-factor as the noise contribution by the second stage, cable and converter are not negligible.
	www.qsl.net /oe5jfl/noisefig.htm (658 words)

	Noise temperature, Noise Figure and Noise Factor
		Noise temperature is measured in units called Kelvin (K) and these are like Celsius (C) temperature degrees but start at zero for absolute zero temperature so 0 K = -273 deg C 273 K = 0 deg C (ice melts) 290 K = 17 deg C (ambient temperature of a waveguide, for example)
		The noise temperature of the cable after the LNA refers to the input of the cable.
		The noise temperature of the receiver refers to the input of the receiver.
	www.satsig.net /noise.htm (636 words)

	Amplifier noise temperatures (Site not responding. Last check: 2007-10-19)
		This noise temperature Tn is found by toggling a source with known on and off temperatures T, and measuring the two resulting levels of output power.
		Summary: The noise temperature Tn of the two amplifiers in cascade is the noise temperature of the first plus the noise temperature of the second divided by the gain of the first:
		Assuming the coax is more or less at room temperature 290 K, attach an infinitely long piece of the same type coax also at room temperature to the input of this `amplifier.' The output and input temperatures must both be 290 K since they are both infinite lines.
	www.mth.msu.edu /~maccluer/Lna/noisetemp.html (520 words)

	Chris Trask: Noise Figure References (Site not responding. Last check: 2007-10-19)
		Coffey, W.N., "Behavior of Noise Figure in Junction Transistors," Proceedings of the IEEE, Feb 1958, pp.
		Nielsen, E.G., "Behavior of Noise Figure in Junction Transistors," Proceedings of the IRE, Jul 1957, pp.
		Okamoto, M. and A. van der Ziel, "Noise Figure of FET Mixers with HF Feedback from Output to Input," IEEE Journal of Solid-State Circuits, Vol.
	home.earthlink.net /~christrask/noisefig.html (2876 words)

	Noise temperature, Noise Figure and Noise Factor
		Noise temperature is measured in units called Kelvin (K) and these are like Celsius (C) temperature degrees but start at zero for absolute zero temperature so
		T (K) This table is useful for working out LNA or LNB noise temperatures from advertised Noise Figures.
		Note that LNA noise temperature, the antenna noise temperature and waveguide loss are the main factors.
	www.sasltd.com /T/faq/noise.html (294 words)

	Noise_Figure
		A spectrum analyzer is a receiver, and we shall examine noise
		figure on the basis of a sinusoidal input.
		Noise figure can be defined as the degradation of signal-to-noise ratio as a
	www.spectrum-analyzer.info /Spectrum_Noise_figure.aspx (239 words)

	Noise Com Sources for your Diodes, C/N Generators, Noise Generators & RF Test Equipment
		Noise Com Sources for your Diodes, C/N Generators, Noise Generators & RF Test Equipment
		Otherwise please call Noise Com at +1 (201) 261-8797 for information about noise sources, noise diodes, noise modules, noise generators, Eb/No and C/N generators for noise figure measurement, NPR or BER testing.
		Noise/Com is a source for your noise diode, noise source, noise module and noise generator RF and microwave test equipment.
	www.noisecom.com (78 words)

	Low-noise amplifier boosts GPS performance: News from Agilent Technologies
		The industry's lowest noise figure 0.9 to 3.5GHz MMIC low-noise amplifier module with integrated shutdown capability enhances the performance of GPS handsets.
		The Agilent ALM-1106's combination of low noise figure to improve sensitivity, miniature size, low-voltage operation, and battery-saving features makes the amplifier module an ideal choice for GPS receivers incorporated in mobile phone handsets.
		Among the performance features of the ALM-1106 LNA module are very low 0.85dB noise figure; high 14.8dB gain; 0dBm output power (1dB gain compression); and wide dynamic range, with an input third-order intercept point of +5dBm (all typical).
	www.electronicstalk.com /news/agi/agi313.html (531 words)

	noise figure
		It will have graphs of noise figure vs source impedance.
		It will be larger at the extremes of source impedance.
		If the LNA is designed for 50 ohms normally the best noise figure will be achieved close to 50ohms but not exactly.
	www.edaboard.com /ftopic65029.html (134 words)

	HP / Agilent 8970B Noise Figure Meter - TestEquity
		Used with 346 or 347 family noise sources, the 8970B noise figure meter takes the mystery out of noise figure measurements, making them easy, accurate and repeatable.
		Low instrument uncertainty and automatic second-stage correction make it possible to make accurate noise figure readings, even for low-gain devices.
		The instrument has special measurement modes for mixer measurement and is capable of controlling external local oscillators and the 8971C noise figure test set.
	www.testequity.com /products/765 (174 words)

	CSVHFS Noise Figure Measurements index (Site not responding. Last check: 2007-10-19)
		The Central States VHF Society has conducted Noise Figure Measurements since the late 1970's.
		In recent years the equipment used to measure noise figure has been the HP8970 Noise Figure Meter and HP346A Noise Source.
		The Noise Figure Measurements are currently (and have been for many years) conducted under the diligent guidance of Al Ward, WB5LUA.
	www.csvhfs.org /CSVHFNF.HTML (164 words)

	How Quantization and Thermal Noise Determine an ADC's Effective Noise Figure - Maxim/Dallas
		It concludes by comparing their impact on the effective noise figure for a Nyquist and oversampling ADC.
		These factors include thermal noise, clock jitter (especially for higher input frequencies having high slew rates), and subranging errors.
		The data sheet will provide the conditions from which the SNR value was determined.
	www.maxim-ic.com /tarticle/view_article.cfm/article_id/1197 (1232 words)

	Image Rejection Mixers - Microwave Encyclopedia - Microwaves101.com
		The typical reason for this is noise figure: image noise from the unwanted sideband can easily pollute the noise figure of your receiver by 3 dB.
		because this will keep the noise figure contribution of the image frequency down below 0.1 dB.
		Referring to the figure, you can trade perfect phase balance for 1.7 dB amplitude imbalance and get 20 dB rejection, or perfect amplitude balance for about 11 degrees phase error and still get 20 dB rejection.
	www.microwaves101.com /encyclopedia/mixersimagereject.cfm (192 words)

	Noise Source and Noise Diode products from Micronetics for microwave and RF systems
		Noise Source and Noise Diode products from Micronetics for microwave and RF systems
		Applications include: Broadband calibrated output for use with noise figure meters.
		Micronetics, Inc. acquired the Solid State Noise Source line of Densitron Microwave Limited (DML) in March, 2003.
	www.micronetics.com /Noise/Source.html (350 words)

	Noise Figure Meter with a Spectrum Analyser - L. Cupido (Site not responding. Last check: 2007-10-19)
		Noise Figure Meter with a Spectrum Analyser - L. Cupido
		A relatively simple automatic Noise Figure (NF) meter was developed which is using a spectrum analyser as the receiver and logarithmic power detector.
		It processes these signals to control a noise head and obtain Y, Gain and NF values that are displayed on digital or analogue meters.
	gref.cfn.ist.utl.pt /cupido/nfsa.html (267 words)

	ARTICLE: Lawyers prepare to argue that Navy-jet noise has devalued homes (The Virginian-Pilot - ... (Site not responding. Last check: 2007-10-19)
		The lawsuits stem from the 1998 and 1999 arrival of the Navy’s F/A-18 Hornets at Oceana Naval Air Station in Virginia Beach.
		Property owners will ask the judge to determine a dollar value of their losses as a result of jet noise, a figure that Ferrebee said could run into the millions.
		The cases involve properties that were not in a jet-noise zone or were pushed into a higher noise zone after the Hornets arrived, Ferrebee said.
	home.hamptonroads.com /stories/story.cfm?story=75665&ran=206364 (667 words)

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