| 摘要 |
PURPOSE:To reduce distortion noises generated by respective repeaters by attaining alternate frequency converter using upper side-band waves and frequency conversion using lower side band waves on heterodyne repeating communication at a long distance requiring several repeaters. CONSTITUTION:On the heterodyne repeating communication system transmitting information signals at a long distance using a frequency-converter and several repeaters composed of an amplifier, up-converter 4 at the transmission side uses upper side- band waves to send out power to antenna 7 via power amplifier 5. Then, frequencies are converted by down-converter 2 via sntenna 1 at the reception side, and applied to up-converter 8 via IF amplifier 3, thereby attaining frquency conversion. For this frequency conversion by converter 8, lower side-band waves are used to cancel distortion noises outputted from power amplifier 5, so that the distortion noises of the power transmitted from antenna 7 will be reduced. |
