| 单词 | SS |
| 释义 | SS 1. Spread Spectrum. A wideband radio transmission technology that spreads the bandwidth of the transmitted signal over a spectrum of radio frequencies that is much wider than that required to support the native narrowband transmission.Thereby, multiple transmissions can simultaneously use the entire system wideband, rather than just individual time slots or frequency channels. Direct sequence spread spectrum (DSSS) is a radio technique in which the narrowband signal is spread across a wider carrier frequency band. Frequency hopping spread spectrum (FHSS) transmits short bursts of data over a range of frequency channels within the wideband carrier, with the transmitter and receiver hopping from one frequency to another in a carefully choreographed hop sequence under the control of the centralized base station. Hedy Lamarr, the famous actress and dancer of pre-war (WWII) fame, and George Antheil, a composer of music, invented spread spectrum and were granted a U.S. patent in 1942. As the story goes, Lamarr developed spread spectrum radio in order to remotely synchronize multiple player pianos in radio-controlled piano concerts. Spread spectrum is the basis of code division multiple access (CDMA), which is employed in cellular radio and other networks. See also Antheil, George; bandwidth; carrier; CDMA; channel; DSSS; FHSS; frequency; Lamarr, Hedy; narrowband; radio; signal; spectrum; time slot; and wideband. 2. Single Sideband. See SSB. |
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