| 摘要 |
PURPOSE:To transmit and AM-DBS (amplitude-modulated double side-band wave) in the double speed without transmission distortion, by using the orthogonal modulation method, where two independent channels are secured, after time base expansion and compression of the frequency band, in transmission of the unipolar signal train such as a facsimile signal. CONSTITUTION:Unipolar signal train Ln where a fixed value and an arbitrary amplitude value of one of values larger and smaller than the fixed value are alternate in respect to time is written in memory circuits 13a-13c, and this signal train is read and is divided into two signal series C1 and C2 which have the time base expanded, and the first and the second carrier signals of the same frequency and of phases different by 90 deg. are subjected to two-phase AM-PM modulation in 15a and 15b by respective signal series, and these modulation outputs are synthesized and transmitted. Then, the transmitted signal is received by 19 and is subjected to orthogonal modulation in 22a and 22b to take out two signal series C1 and C2, and these signals are written to memory circuits 25a-25c and are read and have the time base compressed, thus obtaining the original unipolar signal. |
