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9C <br /> Page 20 <br /> Appendix A <br /> Gtossary of 7erms <br /> Analog An automobile fuel gauge with a needle is an analog device; it displays fu11, <br /> empty,and aIl points in b�tween.The value displayed is variable and continuous. <br /> An analog radio e�nits a continuous electromagnetic carrier wave,and informarion <br /> is tzansmitted by modulating(chaziging)either the amplitude(hence AM)or <br /> frequency(FM)of the,carrier wave. <br /> Digital An autamobile fuel waming liglat is a digital device; it has only iwo sfiates, <br /> on or off.If the light is off there is fuel in the tank;if the light is on the tank is <br /> alrnost em.pty.The warning light cannot inriicate tba.t the tank is one-half or <br /> one-quarter full. <br /> A digitai radio also emits an.electromagnetic wave,but instead of the continuous, <br /> varying wave used in analog radio,the digital wave is intexntptect. Informalion is <br /> transmitted by timing the in'terrupfiions or breaks in the carrier wave. <br /> FCC-Mandated Changes The PCC requixes that Puhlic Safety Radio Pool licensees - <br /> aperatin�.g in the 1�0-174 MHz and 421-512 MHz bands migrate to narrowband <br /> (12.5 kHz)technology by January 1,2013.Additionally, applications for new <br /> licenses or expansion of existing licenses using widehand(25 kHz)technology <br /> will not be accepted after January 1,2011.Manufacture ar importa.tion of wid� <br /> band equipment wilt be prohibited on January I,2a11. <br /> ISD The Fnformation Services Depar�ient provides a variety of information <br /> t�c�nalc�gy and computer application ser�c€�ta County d�partments.The <br /> Communication Services Division of ISD plans,designs, and sapports tlze County <br /> digital radio network. (The digital radio network is actually owned by the Joint <br /> Powers Authority camposed of San Mateo County and all the cities in the <br /> county.) . <br /> Public Safety Radio This term,as used by the�CC,includes law enfarcement,fire, <br /> arnbulance,and other first response services.In San Mateo County,aIl fire <br /> deparh�ients use rad'zo frequencies in the 154-155 MHz range,lmown as high <br /> band VHF. The emergency response ambulance service uses the coun�y's digital <br /> rad.io network,as does the PubIic Works Department. The Sheriff's Department <br /> uses the county digital radio network while the local police deparbments vse <br /> anaiog radios,all of which operate in ttxe 470-512 MHz frec�uency z�ange known <br /> �T-b�a vz-�. <br /> 33 <br />