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Hydrology measures newspaper chain tube-shaped part automatically
From;    Author:Stand originally

   Information transmits a passagewayAbbreviation channel, it is the electric wave transmission line between join telemetering station and central station, cent is wired and wireless two kinds: ① wired passageway uses special railway line or common line means. Its advantage is interference rejection sex strong, use more convenient and reliable. Defect is facility cost raises along with the distance, if use trolly wire, easy damage is allowed when fresh gale rainstorm. ② radio passageway is commonly used ultrashort frequency paragraph, power 10 tile of 1 ~ , when communication the distance exceeds 50 kilometers, or when the high mountain is held back, often install relay station, increase the signal that receives after power, another frequency launchs reoccupy go out. Measure a station to use directional antenna, relay station can use the omnidirectional antenna of tall gain, in order to satisfy the need that each direction correspond. Power source uses power supply of alkaline secondary battery commonly. Radio passageway is applied to remote transmit, facility cost is inferior, but suffer interference easily, pile up machine rate by accident wiredder passageway is tall. Satellitic radio passageway, serve as relay station with the satellite, use microwave wave band commonly, the advantage is observation station position does not accept landform restriction, communication distance is farther, cover an area bigger. Still have the kind such as slash scattering of shortwave, shooting star beyond, can make a telecommunication use.

Information transmits means to use communication of pulse modulation number, abbreviation PCM. “0” and “1” are the basic message that the number corresponds, call bit, every second transmits basic information content to weigh baud. Because the data bulk of hydrology remote supervising system is less, use normally 25, 50, 100 baud, useful also 300, of 1000 baud. Send every time with receive must make information synchronous, ability undertakes decipher. Of respondent type anthology breathe out the method is commonly used the address code that signal of two frequency modulation stands as each.

   The center controls a stationIts function is to center the hydrology data that each telemetering stands inside remote supervising system, undertake computational arranging, make pluvial forecast in time, controallable gate is opened shut, undertake irrigation works attempers. The need that reachs a section according to drainage area can configure multistage to control a center. Central station basically sets stock communication broadcasting station and computer to wait. According to the function requirement and data bulk choose model, in be being used commonly small personal computer, configure printer of monitor, wide travel and the peripheral equipment such as disk drive. Control means basis of the system send make type and decide, from the newspaper type has the power comsumption that measure a station humble, equipment is simple and reliable, fare is low, data is businesslike advanced advantage, more agree with outlying area uses the high mountain. The country such as the United States and Canada basically uses this kind to make type. The function of respondent type more, control is quick, receive a center to be able to time automatic make one's rounds is measured, also can dictate make one's rounds is measured at any time or choose measure, and can communicate, use convenient. The country such as Japan and Italy basically uses this kind to make type. China makes type two kinds this be used, or compatible in the system.
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