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In telecommunication and electronics, baud (, unit symbol Bd) is the unit for symbol rate or modulation rate in ''symbols per second'' or ''pulses per second''. It is the number of distinct symbol changes (signaling events) made to the transmission medium per second in a digitally modulated signal or a line code. Digital data modem manufacturers commonly define the baud as the modulation rate of data transmission and express it as bits per second.〔AT&T, Bell System Data Communications Technical Reference, ''Data Set 103F Interface Specification'', May 1964〕 Baud is related to gross bit rate expressed as bits per second. ==Definitions== The symbol duration time, also known as unit interval, can be directly measured as the time between transitions by looking into an eye diagram of an oscilloscope. The symbol duration time ''T''s can be calculated as: : where ''f''s is the symbol rate. There is also a chance of miscommunication which leads to ambiguity. :A simple example: A baud of 1 kBd = 1,000 Bd is synonymous to a symbol rate of 1,000 symbols per second. In case of a modem, this corresponds to 1,000 tones per second, and in case of a line code, this corresponds to 1,000 pulses per second. The symbol duration time is 1/1,000 second = 1 millisecond. In digital systems (i.e., using discrete/discontinuous values) with binary code, 1 Bd = 1 bit/s. By contrast, non-digital (or analog) systems use a continuous range of values to represent information and in these systems the exact informational size of 1 Bd varies. The baud unit is named after Émile Baudot, the inventor of the Baudot code for telegraphy, and is represented in accordance with the rules for SI units. That is, the first letter of its symbol is uppercase (Bd), but when the unit is spelled out, it should be written in lowercase (baud) except when it begins a sentence. The baud is scaled using standard decimal prefixes, so that for example *1 kBd (kilobaud) = 1000 Bd *1 MBd (megabaud) = 1000 kBd *1 GBd (gigabaud) = 1000 MBd. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Baud」の詳細全文を読む スポンサード リンク
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