| 摘要 |
PURPOSE:To improve the privacy of a transmission signal, to reduce the effect by radio wave disturbance and to attain high quality communication by providing a first 2 phase modulator, a second 2 phase modulator, a power synthesizer and plural intermediate frequency amplifiers or the like. CONSTITUTION:A transmission signal 11 sent from a transmitter results from power synthesis by a power synthesizer 20 given an orthogonal signal in an output 31 of the first 2 phase modulator 30 and an output 33 of the second 2 phase modulator 32. In this case, 2 kinds of code series are used, the frequency is spread over a wide band width in 4-phase and the recovery of a carrier is difficult, then the possibility of the code series of the signal 11 to be decoded is less and the privacy is improved. Effective disturbance is difficult in an output of an intermediate frequency amplifier (such as 1st intermediate frequency amplifier output 63, 2nd intermediate frequency amplifier output 65, and 3rd intermediate frequency amplifier output 67 or the like) in a receiver so long as the cryptograph of the signal 11 is not decoded. Thus, the privacy of the transmission signal is improved and the effect in the demodulation in the case of a disturbing radio wave in the reception signal is decreased to attain high quality communication. |
