The Design And Realization For The Decoding Of Electric Wave Clock Based On Radio Singnal

With the development of the time,the need of people for accurate time is higher and higher,such as the launch of satellite and missile,the need of witch to time precision is microsecond.We may get time by radio or television,and adjust our clock by hand,but it is very difficult to keep the clock accurate.The mode that we can get accurate time is impossible,so many sides of the socity are influenced,such as the charge of ammeter or water meter at different time and the leave of the bus,cheking on work attendance of company.How can people get accurate time by conveniency and cheap way?This accelerate the development of the electric wave clock.It is a clock that can receive time code took by Electric wave.The China Nation Radio'singnal may cover all area of China,so we put the time code in he China Nation Radio's signal,then the cost is cheap,the singnal receiving equipment and decoding equipment is simple,the usement is convient,then the China Nation Radio transmitter the standard time code each hour, witch can send the standard time to everyone and the time synchronization is realized.I design the project that the time code decoded from the China Nation Radio's singnal in This article.The radio can receive six segments sine wave audio signal at integral point,that the front five is standard frequency of 800hz,and the last is 1600hz.The way of time code encoding is that 1600hz sine wave embeded in 800hz sine wave,and half period of 800 hz sine wave represent 0,A period of 1600 hz sine wave represent 1.It contains 5 binary numbers in every broadcasting time signals of 800hz sine wave.It has the time code 'year','month','date','hour'and'hour'in front five segment 800hz sine waves.800 hz of time signal and 1600 hz sine waves signals is enlarged by enlarging and reshaping circuit which can transform the sine wave into similar Rectangular wave,then we use singlechip machine to read 0 and 1 by judging the pulse width,so we can receive time code:'year','month"date', 'hour'.I analysed an audible signal amplification reshaping circuit detailedly in culture,and discussed an audible signal with opposed phase problem,and the sign bit losing problem when the opposed phased signal is Shaped and amplified,and the method to eliminate the error time code,the Anti-interference designs of software and hardware,and the method to deal with the time signal that was disturbed gravely.