【摘要】：
本文主要介紹以AT89S51單片機(jī)為核心的一個(gè)具有單工語(yǔ)音和英文數(shù)據(jù)傳輸功能無(wú)線呼叫系統(tǒng)。該系統(tǒng)的主站主要由單片機(jī)與雙音頻（DTMF）信號(hào)編碼器以及鎖相頻率發(fā)射機(jī)組成；從站主要由由單片機(jī)與高保真調(diào)頻接收機(jī)以及雙音頻信號(hào)解碼器組成。主站與從站通過(guò)鎖相頻率發(fā)射機(jī)與高保真調(diào)頻接收機(jī)進(jìn)行通訊。雙音頻（DTMF）信號(hào)編碼器與雙音頻信號(hào)解碼器能對(duì)調(diào)頻信號(hào)中的雙音頻（DTMF）信號(hào)進(jìn)行調(diào)制與解調(diào)。雙音頻（DTMF）信號(hào)編碼器與雙音頻信號(hào)解碼器使得本系統(tǒng)具有數(shù)據(jù)傳輸能力。在傳輸語(yǔ)音信號(hào)的同時(shí)也能傳輸一定的數(shù)據(jù)信息，對(duì)于小型的通訊系統(tǒng)具有一定的適用性。

【關(guān)鍵詞】：?jiǎn)纹瑱C(jī) 雙音頻（DTMF） 鎖相環(huán) 數(shù)據(jù)傳輸

【Abstract】：
This article describes a radio calling system with the functions of single direction voice and data transmission which is based on the AT89S51 single chip microcomputer. The system’s master station mainly consists of the single chip, DTMF signal encoder and PLL frequency transmitter. The slave stations mainly consist of single chip, Hi-Fi FM receiver and DTMF signal decoder. The master and slave stations communicate with each other through the PLL frequency transmitter and Hi-Fi FM receiver . Both of them make the system capable of transmitting the data. The system is suitable for using in small communications systems due to the ability of its transmitting voice as well as the data in the same time.

【Key Words】：Single chip microcomputer, DTMF PLL Data transmission