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	Vector Signal Analyzers \| IEEE 802.11 Spectral Measurements Using Vector Signal Analyzers - vector signal analyzers
		Spectral mask measurement is a test method used by regulatory agencies (i.e., FCC, ETSI) to ensure that the RF signal produced by the transmitter provides minimal interference to other systems that are not on the same RF frequency.
		The spectral mask generally has a flat top representing the power level of the carrier, and outside the band the mask shows the limits that a transmitter should not exceed.
		For the spectral mask, measurements on digital modulation signals the smoothing of the PSD (or lack of it) as the VBW setting changes will alter the placement of the spectral mask relative to the actual average signal power.
	rfdesign.com /mag/radio_ieee_spectral_measurements (3058 words)

	Spectral mask - Wikipedia, the free encyclopedia
		In telecommunications, a spectral mask is a mathematically-defined set of lines applied to the levels of radio (or optical) transmissions.
		The spectral mask is generally intended to reduce interference by limiting excessive radiation at frequencies beyond the necessary bandwidth.
		The spectral mask is usually one of the things defined in a bandplan for each particular band.
	en.wikipedia.org /wiki/Spectral_mask (341 words)

	Spectral mask -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-10-26)
		The spectral mask is usually one of the things defined in a (Click link for more info and facts about bandplan) bandplan for each particular (Something elongated that is worn around the body or one of the limbs) band.
		It is essential in assuring that a transmission stays within its (A deep and relatively narrow body of water (as in a river or a harbor or a strait linking two larger bodies) that allows the best passage for vessels) channel.
		Other types of ((electronics) the transmission of a signal by using it to vary a carrier wave; changing the carrier's amplitude or frequency or phase) modulation have different spectral masks for the same purpose.
	www.absoluteastronomy.com /encyclopedia/s/sp/spectral_mask.htm (279 words)

	Latex Mask Central
		World famous mask collector Rhonda Underwood is running a marathon (yes, a marathon) to raise money for the Leukemia and Lymphoma Society.
		She is putting up one of her prized masks for auction to help the cause.
		This is a beginners class that will teach you everything you need to know about mask making so you can do it on your own, as well as pick up alot of mask making supplies (and fun free stuff).
	www.latexmaskcentral.com (1267 words)

	Encyclopedia: IEEE 802.11
		The 802.11b and 802.11g standards do not specify the width of a channel; rather, they specify the center frequency of the channel and a spectral mask for that channel.
		The spectral mask for 802.11b requires that the signal be attenuated by at least 30 dB from its peak energy at Â±11 MHz from the center frequency, and attenuated by at least 50 dB from its peak energy at Â±22 MHz from the center frequency.
		Since the spectral mask only defines power output restrictions up to Â±22 MHz from the center frequency, it is often assumed that the energy of the channel extends no further than these limits.
	www.nationmaster.com /encyclopedia/IEEE-802.11 (4692 words)

	White Papers (Site not responding. Last check: 2007-10-26)
		Considering that a typical analog FM transmitter is not capable of meeting the new spectral emissions mask while passing the new IBOC digital signal, external equipment such as high-level and mid-level combiners, or separate radiation systems needed to be employed, or new transmitter designs needed to be developed.
		Tests were conducted by lowering the filament voltage of the tube below the nominal operating point of 10.0 V to as low as 7.0 V to quantify the effect of having reduced the number of free electrons available from the thoriated tungsten filament to simulate the effects of tube aging.
		Spectral plot of 816HD at 18 KW TPO with IBOC mask overlay.
	www.contelec.com /fm_white_papers.php (2259 words)

	[No title]
		With respect to the spectral mask, petitioners sought, and the Commission granted on an interim basis, an amendment to the emission mask for MDS and ITFS stations using VSB and QAM to account for the significant difference between the spectral occupancy pattern of these emissions and the spectral occupancy of the NTSC analog video emission.
		Additionally, with respect to the spectral occupancy of these digital emissions, the Commission set out a requirement in the Digital Declaratory Ruling that the power spectral density be "substantially uniform" across the occupied bandwidth, including at times when no data (input signal) is applied to the transmitter.
		The amplitudes and spacings of the carriers are configured such that the spectral energy of each carrier is significantly attenuated at the frequencies of each of the two adjacent carriers.
	wireless.fcc.gov /services/brsebs/releases/da990554.txt (1079 words)

	[No title]
		The spectral mask and its impact on the performance of 802.11 networks has been investigated and extensively discussed in previous meetings.
		An explicit indication of the fact that it is indeed barker short preamble is required to avoid this possible confusion.bStrongly object to the removal of the requirement that all control frames be sent at a basic rate.
		The response from the TG indicated that "it has never been demonstrated that the relaxed mask used for 802.11g will create noticeable interference.", yet it is clear that the effect will be non-negligible.
	www.ieee802.org /secmail/xls00040.xls (984 words)

	[No title]
		The spectral mask discussion refers to the "output spectrum" which is considered to reference the Improved Test Transmitter output.
		It is also agreed that the existence of spurious spectral lines indicates non-linearities with one possible cause being phase distortion with a non-linear characteristic.
		The reference to a “cake layer” apparently is directed towards a concept of a possible method to specify a spectral mask.
	water.usgs.gov /datarelay/hdr/hdr_ncar.html (4912 words)

	Cloud Detection Over Snow and Ice Surfaces: Summit Camp, Greenland
		Spectral tests specific to snow and ice surfaces within the MODIS cloud mask algorithm will then be investigated in closer detail.
		The full title of the MODIS cloud mask data set for the Terra satellite is the "MODIS/Terra Cloud Mask And Spectral Test Results 5-min L2 Swath 250 m and 1 km." The short-name for this data set is "MOD35_L2." Each data file is a 48-bit word, or six 8-bit bytes, of information, totaling 47.6 MB.
		Perhaps the deployment of several ceilometers could be deployed for cloud detection over a given geographic region, or a ceilometer that is light enough could be attached to a UAV (unpiloted aerial vehicle) and flown over this region.
	cires.colorado.edu /~maurerj/clouds/cloud_detection.htm (5775 words)

	IDL Help
		This option is most ; often used when the bad pixel mask does not yet exist.
		In this case, the gaussian ; profile is used to help with locating the centerline but not ; for the spectral extraction.
		Ideally this ; should be set for each and every spectrum but this has not yet ; proved tractable.) ; NONEG - Flag, if true will inhibit all treatment of the negative image.
	www.astro.washington.edu /deutsch-bin/getpro/library30.html?OPTSPEC (1822 words)

	September 26, 2002 News Announcements (Site not responding. Last check: 2007-10-26)
		The provisional cloud mask data exist for August 23, 2002 to the present.
		This data product consists of cloud mask, quality assurance, and other ancillary parameters.The visible and infrared threshold and consistency tests are used to specify confidence levels that an unobstructed view of the Earth's surface is observed.
		The cloud mask is produced at spatial resolution of 250 and 1-km.
	daac.gsfc.nasa.gov /MODIS/news/09262002.shtml (723 words)

	BBC - R&D - Publications - WHP023
		The revised spectral mask for PAL - transmitters and its effect on PAL-I reception
		There are potential engineering problems resulting from this, one of the most serious of which is posed by the high level of PAL-I sidebands radiated within the lower adjacent channel.
		(In effect, the new mask reduces the width of the vestige from 1.25 MHz to 0.75 MHz.) However, PAL-I receivers are designed to make full use of the 1.25 MHz vestige, and modification of the mask must lead to some distortion of the demodulated signal.
	www.bbc.co.uk /rd/pubs/whp/whp023.shtml (194 words)

	GeoConnections - Data - Data Details (Site not responding. Last check: 2007-10-26)
		It acquires data in 36 high spectral resolution bands between 0.415 to 14.235 micron with spatial resolutions of 250m(2 bands), 500m(5 bands), and 1000m (29 bands).
		The MODIS level-2 cloud mask product is a global product generated for both daytime & nighttime conditions at 1-km spatial resolution (at nadir) and for daytime at 250-m resolution.
		The 250-m cloud mask flags are based on the visible channel data only.
	cgdi.gc.ca /CGDI.cfm/fuseaction/data.details/id/9400/gcs.cfm (639 words)

	ISMP 2000 - Meeting Topics (Site not responding. Last check: 2007-10-26)
		We consider the problem of designing a pulse shaping filter for a digital communication system where some spectral mask constraints must be satisfied.
		Since the constraints are nonconvex in the filter tap weights and are semi-infinite (each corresponding to a frequency point), the pulse shaping filter design problem has long been considered a difficult task.
		In this work, we provide a convex reformulation of the spectral mask constraints using linear matrix inequalities.
	www.isye.gatech.edu /ismp2000/schedule/session_pages/WEC-30-IC111.html (392 words)

	Fluid Mask 3 - $10 DISCOUNT - Vertus Fluid Mask Photoshop Plugin \| PhotoshopSupport.com
		Fluid Mask is a powerful new plugin for Photoshop that lets you perform precise cutouts with little effort.
		Then straight after that is Fluid Color enabling you to re-color all or separate bits of an object (stripes in a shirt – colors elements within skin) within the image (not having to go to layers) and blend those changes seamlessly in.
		I have to be careful here because cutting out a cornflakes packet would be better accomplished using 6 points on a vector path in Photoshop or a simple object contrasted against the background without much edge anomaly could be just as well picked out by filtering the RGB channel.
	www.photoshopsupport.com /tools/plugins/fluid-mask.html (2945 words)

	Handling Nonnegative Constraints in Spectral Estimation - ALKIRE, VANDENBERGHE (ResearchIndex) (Site not responding. Last check: 2007-10-26)
		Abstract: We consider convex optimization problems with the constraint that the variables form a finite autocorrelation sequence, or equivalently, that the corresponding power spectral density is nonnegative.
		This constraint is often approximated by sampling the power spectral density, which results in a set of linear inequalities.
		ALKIRE and L. Handling nonnegative constraints in spectral estimation.
	citeseer.ist.psu.edu /alkire00handling.html (365 words)

	Printer Friendly Version
		The final installment of this four-part article series will examine the use of fixed-point filtering and provide a practical example of DSP-based FIR filtering to meet the spectral mask requirements of a Global System for Mobile Communications (GSM) cellular system.
		It also permits the filter order to be specified, and allows for a slope in the stopband, which can be used to attenuate spectral replicas of the PFIR filter that follows.
		As the combination response shows, the GSM spectral mask requirements are easily met.
	www.mwrf.com /Articles/Print.cfm?ArticleID=7965 (2502 words)

	Residual Spectra mean values and standard deviation data ADS (Site not responding. Last check: 2007-10-26)
		Mean value of residual spectra for spectral grid points in p,T retrieval microwindows [Ntot_grid(pT) = Si nspec_pT (i)]
		Mean value of residual spectra for spectral grid points in species VMR retrieval microwindows.
		Standard deviation of residual spectra for spectral grid points in species VMR retrieval microwindows.
	earth.esa.int /envisat/dataproducts/mipas/CNTR6-5-44.htm (805 words)

	SeaSolve - WiLANTA LVSA11bg : Overview (Site not responding. Last check: 2007-10-26)
		The advantage of having an I/Q view available while in the waveform measurement is that it allows you to view complex components of the same signal without changing settings or measurements.
		One of the most important measurements in RF communications is the spectral mask measurement.
		By just looking at the PSD plot generated by WiLANTA LVSA 11bg which is self explanatory the designer gets the clear idea of the RF signal falling within the mask (channel limits) or not.
	www.seasolve.com /products/wilanta_lvsa (609 words)

	MATLAB Central File Exchange - Spectral Mask Tests
		MATLAB Central > File Exchange > Signal Processing > General DSP > Spectral Mask Tests
		Test whether a filter's magnitude response fits within a spectral mask.
		FilerMaskFigure.m overlays a spectral mask on a filter's magnitude response.
	www.mathworks.com /matlabcentral/fileexchange/loadFile.do?objectId=5890 (217 words)

	Articles - Ultra wideband (Site not responding. Last check: 2007-10-26)
		There is at least one company successfully using this approach for its first-generation silicon.
		On February 14, 2002 [FCC15 2002] the FCC approved a spectral mask for operation of UWB devices.
		The major part of it lies between 3.1 and 10.6 GHz (from the middle of S band through to the middle of X band) with allowed effective isotropically radiated power (EIRP) of -41.3 dBm/MHz.
	www.kingj.com /articles/Ultra_wideband (717 words)

	Panels - WPMC 2006 : September 17-20, 2006
		In recent years, UWB have attracted increasing interests, thanks to its unique features, which led FCC to grant a license for commercial deployment under a much discussed spectral mask, which is not accepted in Europe and Asia.
		The panel will look into a much wider range of future applications, going from very high data rate, guaranteed- QoS multimedia applications for entertainment purposes, to pervasive localization for security and emergency purposes, to low-power, low- to medium data rate communications for sensors and actuators, to body area networking (BAN) for medical purposes.
		It will also discuss the role, potential, and limitations of standardization will be discussed in light of regionally-set spectral masks.
	www.wpmc2006.org /panels.aspx (691 words)

	MERL – TR2003-066 – On the Spectral and Power Requirements for Ultra-Wideband Transmission (Site not responding. Last check: 2007-10-26)
		Sheng, H.; Orlik, P.V.; Hiamovich, A.M.; Cimini, L.J.; Zhang, J., "On the Spectral and Power Requirements for Ultra-Wideband Transmission", IEEE International Conference on Communications (ICC), Vol.
		In this paper, a new pulse shape is presented that satisfies the FCC spectral mask.
		Using this pulse, the link budget is calculated to quantify the relationship between data rate and distance.
	www.merl.com /publications/TR2003-066 (145 words)

	CommsDesign - UWB Chip Set Meets FCC Spectral Mask
		CommsDesign - UWB Chip Set Meets FCC Spectral Mask
		Based on Xtreme Spectrum's biphase monocycle technology, the device is billed as the first UWB RF transceiver and media-access controller (MAC) to meet the FCC's recently defined spectral mask in the 3.1- to 10.6-GHz range for such radios.
		Trinity consists of the XSI141 MAC, based on the emerging TDMA-based IEEE 802.15.3 protocol; the XSI122 baseband processor with integrated analog-to-digital converter; the XSI102 transceiver; the XSI112 low-noise amplifier (LNA); and a 1 x 1-inch flat planar antenna etched on an FR4 pc board.
	www.commsdesign.com /showArticle.jhtml?articleID=16505234 (279 words)

	Optimization Online - Semidefinite descriptions of cones defining spectral mask constraints
		Semidefinite descriptions of cones defining spectral mask constraints
		Abstract: We discuss in detail an additive structure of cones of trigonometric polynomials nonnegative on the union of finite number of pairwise disjoint segments of the unit circle.
		Citation: Research Report,March 2004, University of Notre Dame
	www.optimization-online.org /DB_HTML/2004/04/857.html (100 words)

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