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This term is used when buying and selling Internet advertising banners, buttons, or text ads. CPM refers to the cost of displaying an ad impression 1,000 times. Buyers and sellers will typically list costs between US$0.20-$100 CPM, depending on how targeted the traffic is. The "M" refers to the Roman Numeral for thousand.
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CPM - NEWINGTON, CT.A subcommittee of an International Telecommunication Union (ITUhttp://www.itu.org/) panel of technical experts responsible forterrestrial broadcasting issues has joined a growing chorus of concernabout the interference potential of power line telecommunication (PLT)-- better known in the US as Broadband over Power Line (BPL). ITURadiocommunication Sector (ITU-R) Sub Working Group (SWG) 6E1expressedthe view that interference produced by systems employing PLTas well as by Industrial, Scientific and Medical (ISM) equipment andshort-range devices, would compromise broadcast reception."SWG 6E1 is of the opinion that any increase in the amount of noisedue to these systems is unacceptable," said a statement from thegroup's chairman to the chairman of Working Party 6E (WP 6E). "Inparticular, broadcast services should be protected from unwantedemissions from PLT systems," the panel asserted, "as these emissionsare a byproduct of a system that is not itself a user of the radiospectrum." The panel recommended the formation of a group representingall users of the radio spectrum "to coordinate development of limitsto be imposed on the radiation from these systems."WP 6E says it will continue to study the effects of PLT/BPL, ISMequipment and short-range devices on terrestrial broadcasting and sendthe results to ITU-R Working Party 1A, which is responsible forspectrum engineering techniques. WP 1A is scheduled to meet in GenevaOctober 30 to November 5.ARRL Chief Executive Officer David Sumner, K1ZZ, expressed strongsupport and appreciation for the SWG's conclusions and the ongoingefforts of parent Working Party 6E to study the issue. "Our studieshave shown that the broadcasters' concerns are fully justified,"Sumner said. "If BPL is a problem for broadcasters, it's easy to seethat it would be a disaster for us," he added, noting thatbroadcasters' signal strengths typically far exceed those of radioamateurs.Broadcasters themselves also have exhibited increased concern aboutthe potential of PLT/BPL to prevent their signals from reachinglisteners. The Research and Development branch of the highly regardedBritish Broadcasting Corporation (BBC) has released a White Paperreporting on a brief trial in Scotland(http://www.bbc.co.uk/rd/pubs/whp/whp067.html). The two competingPLT/BPL systems in operation in the town of Crieff both interferedwith HF reception. Tests were conducted at four locations."The forms of access PLT that were tested in Crieff were found to havedemonstrable potential to cause interference to indoor reception ofbroadcasting in relevant bands," the White Paper concluded. Beforecommercially licensing PLT, the report advised, regulators need toundertake further study of other PLT systems and, among other issues,look into possible ways to make the PLT systems compatible with radioreception.At the first location, a residence, interference from a Main.Net modemwas audible even on very strong broadcast signals. Reception was alsosignificantly impaired at a neighbor's house as well as at variouslocations in the street between the residence and the substationserving it. This was despite the fact that the main distributor cablewas underground.The BBC engineers described the interference as varying between"'annoying' and a level sufficient to make the broadcast completelyunintelligible."At a retail shop where another Main.Net modem was in use, "receptionof an apparently strong broadcast signal was badly impaired when thePLT modem was busy," the report said.Ascom systems were in use at the other two locations. The BBCengineers observed interference to HF broadcasting signals despite thesystem designers' efforts to reduce emissions in the broadcastingbands.Field strength measurements taken at three of the four locationsshowed PLT/BPL emissions far in excess -- by as much as 50 dB -- ofvarious proposals for limits intended to restrict the degree ofinterference.A report prepared by the Australian Communications Authority (ACA),Broadband Powerline Communications Systems --
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