| 摘要 |
1,160,613. Multiplex carrier system. SIEMENS A.G. 22 June, 1967 [23 June, 1966] No.28855/67. Headings H4L and H4R. In a carrier transmission system for stereophonic signals, the two stereo audio channels are each included in the same primary group of channels of a frequency-division multiplex carrier telephony system as a suppressed carrier single-sideband signal, one of said single sideband signals being transmitted with frequency inversion and the other without frequency inversion, the two frequency bands corresponding to said single-sideband signals being situated symmetrically on opposite sides of the centre frequency of said primary group of channels. This equalizes the transit-time distortion in the two related channels. The system may be arranged so that the audio band in the lower frequency region of the primary group of channels is transmitted with frequency inversion. This ensures that the transit-time distortion, which becomes greater towards the edges of the primary group of channels, is effective only at the higher audio frequencies where it is less objectionable. Pilot frequencies may be transmitted with each channel for purposes of gain control and compandor equipment may be introduced. |
