| 摘要 |
PURPOSE: A frequency hopping synchronism deviation control method is provided to implement a synchronization function simply at a low cost by using a system controlling processor built-in timer and a general crystal oscillator, and implement an accurate and reliable synchronizing method even in a communication environment that a synchronous signal is lost. CONSTITUTION: There is a frame of a transmission terminal providing a hopping synchronization and a frame structure of a receiving terminal for receiving a synchronization. Each frame length is the same and synchronous areas having a certain length exist in one frame. A position and a length in a frame of a synchronous area of the transmission terminal frame and the receiving terminal frame are set the same, and the transmission terminal is set as a transmission mode and the receiving terminal is set as a receiving mode in the synchronization area. The transmission terminal transmits a synchronous code to a synchronous time previously set in the synchronization area, and the receiving terminal is in a standby state to receive the synchronous code in entering into the synchronous area. When the receiving terminal receives an accurate synchronous code without an error, it compares the receiving time with a previously set synchronous time. If there is a deviation therebetween, the receiving terminal adjusts a receiving terminal timer(323) to correspond the previously set synchronous signal receiving time to an actual synchronous code receiving time. Oscillators(314,324) drive the timer. Timers(313,323) inform a processor of a time last for every certain period. Processors(312,322) record the number of receiving a signal in an internal register whenever it receives the signal from the timer, determines whether an operation mode of a system is in a communication mode or in a synchronous mode by using the number, to thereby control demodulating/modulating units(311,321). |
