Nec Corporation

Yasunori Yoshizawa

Toshinori Hotta

Shinichi Ohmagari

The invention provides a radio station apparatus which converts a plurality of inputs digital transmission signals whose data transmission rates are different into an analog signal, modulates the analog signal with a radio carrier frequency and transmits the modulated signal, and a signal transmission method through radio station apparatus. The radio station apparatus of the present invention includes indoor unit 10, outdoor unit 20, and coaxial cable 60 which connects indoor unit 10 and outdoor unit 20 to each other. An inputted first binary digital signal is converted into a serial second binary digital signal by parallel/serial converter 2 and modulated by amplitude shift keying (ASK) into a third binary digital signal by modulator 13 with carrier f.sub.3 (Hz) whose frequency is a common multiple of respective value of n (sampling number).times.m (quantization bit number) times the data rate of all inputted data. The third binary digital signal is multiplexed by frequency division multiplexing with another signal or signals by multiplexer 3 and transferred to outdoor unit 20 through coaxial cable 60. In outdoor unit 20, transferred third binary digital signal is demultiplexed and converted into an analog signal by a D/A converter.

Radio station apparatus and signal transmission method thereof

In a satellite business communication system comprising a plurality of aperture terminals, a supervising station is coupled to the aperture terminals through a public communication network to centralize a monitoring operation of each aperture terminal. Each of the aperture terminals has a terminal directory number and a terminal indentification address while the supervising station has a primary directory number. A monitoring item is transmitting from the superivising station to a selected aperture terminal along with the terminal identification address of the selected aperture terminal and the primary directory number after a transmission path is formed by the terminal directory number through the public communcation network. A result of monitor in the selected aperture terminal is sent as a response signal back to the supervising station through a return path formed by the use of the primary directory number. The result of monitor may be stored in a status memory or be transmitted through a different path to the supervising station, if the return path is busy.

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Tokyo, Japan

Yasunori Yoshizawa