| 摘要 |
PURPOSE:To attain high speed data transmission and high reliability by injecting a signal subject to spread spectrum modulation to a distribution line at a sender side, and applying frequency shift demodulation to a spread spectrum inverse modulation signal at a receiver side. CONSTITUTION:A narrow band FSK modulation signal is inputted to a spread spectrum SS modulator 3 at a sender side, and the modulator 3 applies PSK modulation and broad band SS modulation to the signal via a sender side clock generator 33, a PN code generator 32 and a sender side multiplier 31. Then the signal subject to SS modulation is amplified by an injection amplifier 4 and the result is injected to a distribution line through a sender side coupler 5. Moreover, a reception signal is inputted to an inverse spread spectrum modulator 8 at a receiver side, in which the signal is subject to spread spectrum inverse modulation and the result is demodulated by an FSK demodulator 9. Thus, high speed transmission with excellent noise immunity and high reliability is attained. |
