| 摘要 |
PURPOSE:To enlarge communication coverage, to prevent wire tapping, and to improve a data quality by making it difficult to be affected by a transmission disturbance or interference due to other transmission signals or the like, and reducing the interference given to other transmission signals. CONSTITUTION:In a transmission side 11, a data signal is spread spectrum- processed by a direct sequence system by a spread spectrum processing circuit 12, FSK modulated by an FSK modulating circuit 13, and a weak radio wave signal suitable to an electric wave modulus is transmitted. In a reception side 21, the received weak radio wave signal is FSK-demodulated by an FSK demodulating circuit 23, then inverse spread spectrum-processed by the direct sequence system by an inverse spread spectrum processing circuit 24, and extracted as the data signal. |
