about attenuation in physics other uses Attenuation disambiguation In physics , attenuation in some contexts ... are attenuated by water. In electrical engineering and telecommunications , attenuation affects ... radio waves . Background In many cases, attenuation is an exponential function of the path length ..., attenuation is usually measured in units of decibels per unit length of medium dB cm, dB km, etc. and is represented by the attenuation coefficient of the medium in question. ref name Zagzebski Essentials ... Frequency dependent attenuation of electromagnetic radiation in standard atmosphere. Attenuation also ... as they are attenuated by the Earth ground . Ultrasound One area of research in which attenuation figures strongly is in ultrasound physics. Attenuation in ultrasound is the reduction in amplitude of the ultrasound beam as a function of distance through the imaging medium. Accounting for attenuation ... produced. By knowing the attenuation that an ultrasound beam experiences traveling through ..., Mosby Inc., 1991. ref Ultrasound attenuation measurement in heterogeneous systems, like emulsion ... Ultrasound attenuation can be used for extensional rheology measurement. There are acoustic rheometer s that employ Stokes law for measuring extensional viscosity and volume viscosity . Attenuation coefficient Attenuation coefficient s are used to quantify different media according to how strongly the transmitted ultrasound amplitude decreases as a function of frequency. The attenuation coefficient math alpha math can be used to determine total attenuation in decibel dB in the medium using the following formula math text Attenuation alpha text dB text MHz cm cdot ell text cm cdot text f text MHz math As this equation shows, besides the medium length and attenuation coefficient, attenuation is also linearly dependent on the frequency of the incident ultrasound beam. Attenuation coefficients ... and water are the most commonly used media. The attenuation coefficients of common biological materials ... more details
Attenuation is the gradual loss in intensity of any kind of flux through a medium. Attenuation may also refer to Attenuation brewing , the percent of sugar converted to alcohol and carbon dioxide by the yeast in brewing Attenuation coefficient , a basic quantity used in calculations of the penetration of materials by quantum particles or other energy beams Mass attenuation coefficient , a measurement of how strongly a chemical species or substance absorbs or scatters light at a given wavelength, per unit mass Regression dilution , a cause of statistical bias The process of producing an attenuated vaccine by reducing the virulence of a pathogen Attenuation constant, the real part of the propagation constant Attenuator genetics , form of regulation in prokaryotic cells. See also Attenuator disambiguation disambig ... more details
In brewing attenuation is the percentage that measures the conversion of sugar s into ethanol alcohol and carbon dioxide by the Ethanol fermentation fermentation process. The percentage is calculated by comparing weight or specific gravity of the extract before and after fermentation. Attenuation 100 starting extract current extract starting extract This formula works with extract given in weight percentages or degree Plato. Extract refers to all the non water substances sugars, dextrins, proteins, vitamins, minerals, etc. that are present in the wort. The percent extract or Plato scale is a measure in percent of how much of the wort s weight is extract. Since, at least in the wort and beer gravities that most brewers work with, an almost linear relationship between specific gravity 1 and extract percentages exists, the above formula can also be expressed as Attenuation 100 starting gravity current gravity starting gravity 1 for brewers who prefer to work with specific gravity. Sources div class references small braukaiser.com http braukaiser.com wiki index.php?title Understanding Attenuation Understanding Attenuation div DEFAULTSORT Attenuation Category Brewing beer stub ... more details
For attenuation coefficient as it applies to electromagnetic theory and telecommunications see Attenuation constant propagation constant . For the mass attenuation coefficient , see the article mass attenuation coefficient . The attenuation coefficient is a quantity that characterizes how easily a material ... energy or matter . A large attenuation coefficient means that the beam is quickly attenuated weakened as it passes through the medium, and a small attenuation coefficient means that the medium is relatively transparency and translucency transparent to the beam. Attenuation coefficient is measured using units of reciprocal length . The attenuation coefficient is also called linear attenuation coefficient , pencil beam narrow beam attenuation coefficient , or absorption coefficient . Although ... Attenuation versus absorption below . Overview The attenuation coefficient describes the extent ... paths . In the case of ultrasound attenuation it is usually denoted as math alpha math and measured ... colloids , Elsevier, 2002 ref The attenuation coefficient is widely used in acoustics ... ref Note that the sabin is not a unit of attenuation coefficient rather, it is the unit of a related quantity. A small linear attenuation coefficient indicates that the material in question is relatively ... opacity . The linear attenuation coefficient is dependent upon the type of material and the energy ... photons and the less dense the material in question, the lower the corresponding linear attenuation ... I I 0 , e alpha , x , math where math x math denotes the path length. The attenuation coefficient or linear attenuation coefficient is math alpha math . The Half Value Layer HVL signifies the thickness ... potentially harmful radiation. The attenuation factor of a material is obtained by the ratio of the emergent and incident radiation intensities math I I 0 math . The linear attenuation coefficient and mass attenuation coefficient are related such that the mass attenuation coefficient is simply math ... more details
Attenuation distortion ref Rowe, Standord H. II, Network Technology & Service Integration 5th Edition , 2002, Prentice Hall, Inc., 2002 ref is the distortion of an analog signal that occurs during Transmission telecommunications transmission when the transmission medium does not have a flat frequency response across the Bandwidth signal processing bandwidth of the medium or the frequency spectrum of the signal. Attenuation distortion occurs when some frequencies are attenuate d more than other frequencies. When an analog signal of constant amplitude across its frequency spectrum suffers attenuation distortion, some frequencies of the received signal arrive being greater in amplitude louder , relative to other frequencies. To overcome the effects of attenuation distortion, communications circuit s have special equalization equipment attached at the ends of the circuit or in between, designed to attenuate the signal evenly across the frequency spectrum, or to allow the signal to be received at equal amplitude for all frequencies. Attenuation distortion can still occur in a properly equipped circuit if this equalization filter is not properly maintained or adjusted. In DSL circuits, reflection electrical echoes due to Impedance matching impedance mismatch often cause attenuation distortion so severe that some frequencies must be automatically mapped out and not used. References references Category Audio effects ... more details
No footnotes date January 2010 In physics , the attenuation length or absorption length is the distance math lambda math into a material when the probability has dropped to math 1 e math that a Elementary particle particle has not been Absorption electromagnetic radiation absorbed . Alternatively, if there is a beam of particles incident on the material, the attenuation length is the distance where the intensity physics intensity of the beam has dropped to math 1 e math , or about 63 of the particles have been stopped. Mathematically, the probability of finding a particle at depth x into the material is calculated by Beer Lambert law math P x e x lambda , math . In general math lambda math is material dependent. See also Beer s Law Mean free path Attenuation coefficient Attenuation electromagnetic radiation Radiation length References S. Eidelman et al. Particle Data Group , Review of particle physics , Phys. Lett. B 592 2004 http pdg.lbl.gov http www.ct.infn.it rivel Glossario node2.html External links http henke.lbl.gov optical constants atten2.html Category Particle physics Category Experimental particle physics particle stub de Absorptionsl nge it Lunghezza di attenuazione ... more details
Growth attenuation is an elective medical treatment which involves administering estrogen to cause closure of the epiphysis epiphyses of the bone s Epiphyseal plate s , resulting in a reduced adult height. Since the 1960s this treatment has been performed primarily on children growing toward an adult height considered unacceptably excessive by their parents and doctors. The cultural consensus of what is considered an excessive height justifying treatment has differed in Europe and North America and has risen over the last 4 decades. ref Joyce M. Lee and Joel D. Howell. http archpedi.ama assn.org cgi content abstract 160 10 1035 Tall Girls The Social Shaping of a Medical Therapy Archives of Pediatrics & Adolescent Medicine , Vol. 160 No. 10, October 2006. ref Most of the children treated have been girls, with larger numbers treated in Europe than in North America. The height considered unacceptable by parents and doctors has become substantially taller over the last few decades. Very few boys have ever been treated for excessive tallness in North America, but this also has been done more often in Europe. More recently, growth attenuation treatment has been in the news as part of the controversial Ashley Treatment administered to a developmentally disabled girl. References references DEFAULTSORT Growth Attenuation Category Medical ethics Category Medical treatments Category Pediatrics medical stub ... more details
orphan date March 2012 refimprove date March 2012 confusing date December 2011 context date December 2011 Attenuation theory is part of the cognitive topic of attention and is Anne Treisman s modified version of the filter theory proposed by Broadbent in 1958. ref http www.simplypsychology.org attention models.html Broadbent s filter theory ref Broadbent s filter theory proposed that unattended messages are completely blocked before they are processed for meaning. Anne Treisman believed that some meaningful information in unattended messages might still be available, but may be hard to recover. She compared this theory to volume control in saying that our volume can be turned down. The attenuation model therefore proposes that there is a decrease in the perceived loudness of an unattended message. Differential recognition of words Meaningful units, such as words or phrases, are processed quite easily. Words that have subjective importance like one s name or that signal danger someone shouting the words fire or watch out have lowered thresholds, which means they are easily recognizable at lower volumes. Example You hear people behind you whispering and you re not positive of what was said but you know you heard your name in the midst of their conversation. The reason your name is so easily heard is because it requires little mental effort. Treisman s Experiments Treisman suggested messages are processed in a systematic way, beginning with analysis of physical characteristics, syllabic pattern, and individual words. After that, grammatical structure and meaning are processed. Treisman carried out experiments to prove the Attenuation Theory valid, using the speech shadowing method . Under the speech shadowing method, participants are asked to simultaneously repeat aloud speech played into one ear called the attended ear while another message is spoken into the other ear. In one of her experiments, identical messages were played into both ears but with a slight delay be ... more details
Correction for attenuation is a statistical procedure, due to Charles Spearman Spearman 1904 , to rid a correlation coefficient from the weakening effect of measurement error Jensen, 1998 , a phenomenon also known as regression dilution . In measurement and statistics , it is also called disattenuation . The correlation between two sets of parameters or measurements is the estimated a manner that accounts for measurement error contained within the estimator estimates of those parameters. Background Correlations between parameters are diluted or weakened by measurement error. Disattenuation provides for a more accurate estimate of the correlation between the parameters by accounting for this effect. Derivation of the formula Let math beta math and math theta math be the true values of two attributes of some person or statistical unit . These values are regarded as random variables by virtue of the statistical unit being selected randomly from some statistical population population . Let math hat beta math and math hat theta math be estimates of math beta math and math theta math derived either directly by observation with error or from application of a measurement model, such as the Rasch model . Also, let math hat beta beta epsilon beta , quad quad hat theta theta epsilon theta, math where math epsilon beta math and math epsilon theta math are the measurement errors associated with the estimates math hat beta math and math hat theta math . The correlation between two sets of estimates is math operatorname corr hat beta , hat theta frac operatorname cov hat beta , hat theta sqrt operatorname var hat beta operatorname var hat theta math math frac operatorname cov beta epsilon ... for attenuation is math r x y frac r xy sqrt r xx r yy math . How well the variables are measured affects the correlation of X and Y . The correction for attenuation tells you what the correlation ... and regression coefficients Jason W. Osborne DEFAULTSORT Correction For Attenuation Category ... more details
The mass attenuation coefficient is a measurement of how strongly a chemical species or substance absorbance ... light, mass attenuation coefficients can be defined for other electromagnetic radiation such as X ray s , sound , or any other beam that attenuates. The mass attenuation coefficient is also called ... used interchangeably, they can occasionally have a subtle distinction, as explained Attenuation versus ... Beer Lambert law The defining equation for the mass attenuation coefficient is essentially a different ..., math mu math is the attenuation coefficient . When discussing the mass attenuation coefficient, this equation ... mu rho math is the mass attenuation coefficient and math rho ell math is the area density known also as mass thickness. In accordance with the above, the mass attenuation coefficient is equal to the attenuation coefficient divided by the density. In solutions In chemistry, mass attenuation coefficients are often used for a chemical species dissolved in a solution . In that case, the mass attenuation ... chemical species, and the attenuation is the attenuation due to only that one chemical species. The actual attenuation coefficient is computed by math mu mu rho 1 rho 1 mu rho 2 rho 2 cdots math where each term in the sum is the mass attenuation coefficient and density of a different component of the solution the solvent must also be included . This is a convenient concept because the mass attenuation ... . They are quantitatively related by Mass attenuation coefficient Molar mass Molar absorptivity . Units The attenuation coefficient has units of inverse length , while density has units of mass per volume. Since the mass attenuation coefficient is the ratio of these two, we find that it has ... cm sup 2 sup g sup 1 sup the most common unit for X ray mass attenuation coefficients and mL g sup 1 sup cm sup 1 sup sometimes used in solution chemistry . Mass attenuation coefficients for X rays Image Attenuation Coefficient Iron.svg thumb right 400px Mass Attenuation Coefficient of Iron with contributing ... more details
Cleanup date May 2011 Attenuation to crosstalk ratio , ACR, is the most important result Peacock term date May 2011 when testing a link because it represents the overall performance of the cable. ref http whatis.techtarget.com definition 0,,sid9 gci1059969,00.html , Learning Path Testing network cable. ref ACR is a mathematical formula that calculates the ratio of attenuation to near end crosstalk for each combination of cable pairs. ref http ecmweb.com mag electric testing copper cabling 2 , Testing Copper Cabling the Right Way. ref ACR is expressed as a figure in decibels dB , between the Signalling telecommunication signal attenuation produced by a wire or Communications channel cable transmission medium and the near end crosstalk NEXT . ref name SearchNetworking http searchnetworking.techtarget.com definition attenuation to crosstalk ratio , attenuation to crosstalk ratio ACR or headroom. ref In order for a signal to be received with an acceptable bit error rate, the attenuation and the crosstalk must both be minimized. ref name SearchNetworking Crosstalk can be reduced by ensuring that twisted pair wiring is tightly twisted and is not crushed, and by ensuring that connectors between wire and cable media are properly rated and installed. ref name SearchNetworking Positive ACR calculations mean that transmitted signal strength is stronger than that of near end crosstalk. ref name inet http inetco.com.vn list.aspx?cat 014 , De Mystifying Cabling Specifications Important Definitions. ref ACR can be used to define a signal bandwidth i.e. 200 MHz for category 6 where signal to noise ratios are sufficient to support certain applications. ref name inet The maximum frequency for which positive ACR is assured provides a benchmark to assess the usable bandwidth of twisted ... electronics References Reflist DEFAULTSORT Attenuation To Crosstalk Ratio Category Telecommunications terms Telecomm term stub de Attenuation To Crosstalk Ratio fr Attenuation to crosstalk ratio ... more details
Ultrasound attenuation spectroscopy is a method for characterizing properties of fluids and dispersed particles . It is also known as acoustic spectroscopy There is an international standard for this method. ref ISO 20998 1 2006 Measurement and characterization of particles by acoustic methods ref ref Dukhin, A.S. and Goetz, P.J. Ultrasound for characterizing colloids , Elsevier, 2002 ref Measurement of attenuation coefficient versus ultrasound frequency yields raw data for further calculation of various system properties. Such raw data are often used in the calculation of the particle size distribution in heterogeneous systems such as emulsion s and colloid s. In the case of acoustic rheometer s, the raw data are converted into extensional viscosity or volume viscosity . Instruments that employ ultrasound attenuation spectroscopy are referred to as Acoustic spectrometers. References references External links http www.iop.org EJ abstract 0957 0233 1 6 008 Ultrasonic Spectrometer DEFAULTSORT Ultrasound Attenuation Spectroscopy Category Acoustics Category Colloidal chemistry Category Spectroscopy chem stub de Ultraschalld mpfungsspektroskopie ... more details
About sound attenuation in fluids Stokes disambiguation Stokes Stokes derived a law for the attenuation of sound in a Newtonian fluid ref Stokes, G.G. On the theories of the internal friction in fluids in motion, and of the equilibrium and motion of elastic solids , Transaction of the Cambridge Philosophical Society , vol.8, 22, pp. 287 342 1845 ref . According to this law attenuation of sound is proportional to the dynamic viscosity , square of the sound frequency , and reciprocally proportional to the fluid density and cubic power of sound speed V math alpha frac 2 eta omega 2 3 rho V 3 math Attenuation is expressed in neper per meter in this equation. The author of this law is the same famous George Gabriel Stokes who derived the well known Stokes law for the friction force in fluids. It is 160 years old. This remarkable law does not contain unknown or unmeasurable parameters. It is convenient to convert attenuation into other units, by normalizing attenuation with respect to frequency, because the attenuation typically increases rapidly with frequency. These new units make more adequate presentation of attenuation within a wide frequency range. It is seen that attenuation of the Newtonian fluid, presented in these units, becomes a linear function of frequency. There has been substantial theoretical development in this field since Stokes pioneering work. It has brought one important correction to the Stokes law. It turns out that in addition to the dynamic viscosity the parameter of volume viscosity sup v sup also affects the total attenuation according to the following relationship math alpha frac 2 eta eta v omega 2 3 rho V 3 math The parameter volume viscosity is surprisingly little known despite its fundamental role for fluid dynamics at high frequencies . This parameter ... sound attenuation at very high frequencies math 2 left frac alpha V omega right 2 frac 1 sqrt ... practical purposes of describing sound attenuation in Newtonian fluids Stokes law is clearly sufficient ... more details
In reflection seismology , the anelastic attenuation factor or the seismic quality factor or Q quantifies the effects of anelastic attenuation on the seismic wave seismic wavelet caused by fluid movement and grain boundary friction. It is defined as math Q 2 pi left frac E delta E right math where math frac E delta E math is the fraction of energy lost per cycle. ref Sheriff, R. E., Geldart, L. P., 1995 , 2nd Edition. Exploration Seismology. Cambridge University Press. ref Its behaviour said to be dispersive because the rate of attentuation increases with frequency. Introduction As a seismic wave propagates through a medium, the elastic wave elastic energy associated with the wave is gradually absorbed by the medium, eventually ending up as heat energy . This is known as Absorption electromagnetic radiation absorption or anelastic attenuation and will eventually cause the total disappearance of the seismic wave. ref Toksoz, W.M., & Johnston, D.H. 1981. Seismic Wave Attenuation. SEG. ref Why Measure Q? Q preferentially attenuates higher frequencies, resulting in the loss of signal resolution as the seismic wave propagates. Quantitative seismic attribute analysis of amplitude versus offset effects is complicated by anelastic attenuation because it is superimposed upon the AVO effects. ref Dasgupta, R., & Clark, R.A. 1998 Estimation of Q from surface seismic reflection data. Geophysics, 63, 2120 2128 ref The rate of anelastic attenuation itself also contains additional information about the lithology and reservoir conditions such as porosity , saturation and pore pressure so it can be used as a useful reservoir characterization tool. ref Enhanced seismic Q compensation, Raji, W.O., Rietbrock, A. 2011. SEG Expanded Abstracts 30, 2737 ref Therefore if Q can be accurately measured then it can be used for both compensation for the loss of information in the data and for seismic ... will have experienced different attenuation effects. ref Dasgupta, R., & Clark, R.A. 1998 ... more details
Multiple issues notability October 2010 original research October 2010 One of the causes of attenuation of radio propagation is the absorption by the atmosphere . There are many well known facts on the phenomenon and qualitative treatments in textbook s. ref name ReferenceA Antennas and radiowave propagation . R. E. Collin. Mc Graw Hill, 1985 ref A document published by the International Telecommunication Union ITU ref name ReferenceC ITU recommendation ITU R pp. 676 8, 2009 ref provides some basis for a quantitative assessment of the attenuation. That document describes a simplified model along with semi empirical formulas based on data fitting . It also recommended an algorithm to compute the attenuation of radiowave propagation in the atmosphere. NASA also published a study on a related subject. ref name ReferenceD http trs new.jpl.nasa.gov dspace handle 2014 41145 . NASA progress report ref Free software based on ITU R recommendations of the French Spatial Reasearches Institute http logiciels.cnes.fr PROPA fr logiciel.htm CNES for download is also available to the public. The model ... is multiplied by a specific attenuation coefficient g expressed in dB km. All the increments g dL are added to provide the total attenuation. Note that the algorithm does not guaranty that the target ..., the attenuation is negligible. The paths of the three are plotted File The3methods.png The linear ... 0.5 degree and the target is at 30 km altitude the attenuation found by the boundary value method ... and an attenuation of 170.77 dB. With this kind of attenuation, every system would be unusable It was found ... in the Wikipedia List of numerical analysis software and it offers a higher precision order. The attenuation ... Reflist Use dmy dates date October 2010 External links http pediaview.com openpedia AttenuationAttenuation http www.itu.int publications sector.aspx?lang en§or 1 ITU Publications http trs new.jpl.nasa.gov dspace handle 2014 41145 JPL Publication 09 14 Categories DEFAULTSORT Radiowave Attenuation ... more details
The ITU Indoor Propagation Model , also known as ITU Model for Indoor Attenuation , is a radio propagation model that estimates the path loss inside a room or a closed area inside a building delimited by walls of any form. Suitable for appliances designed for indoor use, this model approximates the total path loss an indoor link may experience. Applicable to under conditions This model is applicable to only the indoor environments. Typically, such appliances use the lower microwave bands around 2.4 GHz. However, the model applies to a much wider range. Coverage Frequency 900 MHz to 5.2 GHz Floors 1 to 3 Mathematical formulations The model The ITU indoor path loss model is formally expressed as math L 20 log f N log d P f n 28 math where, L the total path loss . Unit decibel dB . f Frequency of transmission. Unit megahertz MHz . d Distance. Unit metre m . N The distance power loss coefficient. n Number of floors between the transmitter and receiver. P sub f sub n the floor loss penetration factor. Calculation of distance power loss coefficient The distance power loss coefficient, N is the quantity that expresses the loss of signal power with distance. This coefficient is an empirical one. Some values are provided in Table 1. ref name ITU 2 Propagation data and prediction methods for the planning of indoor radio communication systems and the radio local area networks in the frequency range 900 MHz to 100 GHz, ITU R Recommendations, Geneva, 2001 ref class wikitable Frequency Band Residential Area Office Area Commercial Area 900 MHz N A 33 20 1.2 GHz N A 32 22 1.3 GHz N A 32 22 1.8 GHz 28 30 22 4 GHz N A 28 22 5.2 GHz N A 31 N A Calculation of floor penetration loss factor The floor penetration loss factor is an empirical constant dependent on the number of floors the waves need to penetrate. Some values are tabulated in Table 2. ref name ITU 2 class wikitable Frequency Band Number of Floors Residential Area Office Area Commercial Area ... more details
Stokes law can refer to Stokes law for friction force Stokes law sound attenuation law describing attenuation of sound in Newtonian liquids For integration, see Stokes theorem . dab ... more details
Acoustic spectroscopy may refer to Spectrogram metry plotting the energy versus frequency over time Ultrasound attenuation spectroscopy , instead of energy, the attenuation coefficient is measured versus frequency disambig ... more details
Stokes formula can refer to Stokes law for friction force in a viscous fluid. Stokes law sound attenuation law describing attenuation of sound in Newtonian liquids. Stokes theorem on the integration of differential forms. dab ... more details
seealso AttenuationAttenuation disambiguation An attenuator could mean Attenuator electronics , an electronic device that reduces the amplitude of a signal Optical attenuator , a device or instrument to reduce light power Attenuator genetics , a specific regulatory sequence transcribed into RNA Impact attenuator , used on highways as a crumple zone in case of a car crash disambig es Atenuador ... more details
ND4 can mean several things Neutral density filter ND with an attenuation factor of 4, or simply ND4 MT ND4 , NADH dehydrogenase subunit 4, or simply ND4 Letter NumberCombDisambig ... more details
In telecommunication , the term shadow loss has the following meanings The attenuation electromagnetic radiation attenuation caused to a radio signal by obstructions in the propagation path . In a reflector antenna reflector antenna , the relative reduction in the effective aperture antenna aperture of the antenna caused by the masking effect of other antenna parts, such as a feed horn or a secondary reflector, which parts obstruct the radiation path. References FS1037C MS188 Category Radio frequency propagation telecomm term stub ... more details
ND2 can mean several things Neutral density filter ND with an attenuation factor of 2, or simply ND2 MT ND2 , NADH dehydrogenase subunit 2, or simply ND2 China Railways ND2 diesel electric locomotive Letter NumberCombDisambig ... more details
Multiple issues orphan January 2011 date January 2011 ITU R P.525 is the International Telecommunications Union radiocommunication s standard for the calculation of free space attenuation . See also Free space loss DEFAULTSORT Itu R P.525 Category ITU R recommendations Category Standards Wireless stub ... more details
The ITU Terrestrial Model for One Terminal in Woodland is a Radio propagation model belonging to the class of Foliage models. This model is a successor of the Early ITU Model . Applicable To Under Conditions Applicable to the scenario where one terminal of a link is inside foliage and the other end is free. Coverage Frequency Below 5 GHz Depth of Foliage Unspecified Mathematical Formulation The mathematical formulation of the model is math A v A 1 e frac d gamma A math Where, A sub v sub Attenuation due to Vegetation. Unit Decibel dB A Maximum Attenuation for one terminal caused by a certain foliage. Unit Decibel dB d Depth of Foliage along the path. Unit Meter m math gamma math Specific Attenuation for short vegetations. Unit Decibel meter dB m Points to Note The value of math gamma math is dependent on frequency and is an empirical constant. The model assumes that exactly one of the terminals is located inside some forest or plantation and the term depth applies to the distance from the terminal inside the plantation to the end of plantation along the link. Further reading Introduction to RF propagation, John S. Seybold, 2005, John Wiley and Sons. See also Early ITU Model Weissberger s Model Single Vegetative Obstruction Model Category Radio frequency propagation ... more details
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