Digital two-way radio-communication system using single frequency

A digital two-way radio communication system comprising:

• a first radio station including:
• a first antenna;
• first data transmission means;
• first data reception means including a first clock reproduction circuit for supplying a first clock for recovering a first reception signal, said first clock being generated by a first local clock generator when said first radio station initiates a data transmission;
• first switching means provided between said first antenna, said first data reception means and said first data transmission means to form one of a first transmission path between said first data transmission means and said first antenna and a first reception path between said first antenna and said first data reception means;
• first voice signal generation means, operatively connected to said first data transmission means, for supplying a first voice signal to said first data transmission means;
• first voice signal reproduction means, operatively connected to said first data reception means, for reproducing a second voice signal;
• first speed converter means, operatively connected between said first voice signal generation means and said first data transmission means, for receiving said first voice signal, converting said first voice signal into a digital signal, and raising the bit rate of said first voice digital signal from said first data transmission means by at least two times;
• and
• second speed converter means, operatively connected between said first data reception means and said first voice signal reproduction means, for lowering the bit rate of said first voice digital signal from said first data reception means by at least half speed;
• a second radio station including:
• a second antenna;
• second data transmission means;
• second data reception means, including a second clock reproduction circuit for supplying a second clock for recovering the reception signal, said second clock being reproduced from said second data reception means output when said first radio station initiates a data transmission and generated by a second local clock generator when said second radio station initiates a data transmission;
• third speed converter means, operatively connected between said second voice signal generation means and said second data transmission means, for receiving said second voice signal, converting said second voice signal into a digital signal and for raising the bit rate of said second voice digital signal from said second data transmission means by at least two times;
• fourth speed converter means, operatively connected between said second data reception means and said second voice signal reproduction means, for lowering the bit rate of said second voice digital signal from said second data reception means by at least half speed;
• second switching means provided between said second antenna, said second data reception means and said second data transmission means to form one of a second transmission path between said second data transmission means and said second antenna, and a second reception path between said second antenna and said second data reception means,
• said first and second radio stations being radio-connected by passing a single frequency through said first and second antennas,
• when said first data transmission means transmits data to said second radio station through said first antenna, said first switching means forming said first transmission path, and said second switching means forming said second reception path, and
• when said second data transmission means transmits data to said first radio station through said second antenna, said second switching means forming said second transmission path, and said first switching means forming said first reception path;
• second voice signal generation means, operatively connected to said second data transmission means, for supplying said second voice signal to said second data transmission means;
• and
• second voice signal reproduction means, operatively connected to said second data reception means, for reproducing said first voice signal from said first radio station;
• said first and second voice signal generation means each comprising:
• a microphone;
• and
• a voice coder connected to said microphone;
• and
• said first and second voice signal reproduction means each comprising:
• a voice decoder;
• and
• a speaker connected to said voice decoder.