Optical fiber digital transmission of multiplexed video and audio signals suitable for multimedia applications

摘要

This paper describes a new digital NTSC TV and audio signal transmission system in which circuit configurations are simplified and made more inexpensive than MPEG 2 on the basis of the subjective evaluation of the picture quality. An NTSC TV signal and an audio signal can easily be transmitted to the receiver at the same time, since the transmission rate is kept unchanged due to the insertion of the digital audio signal into the horizontal sync pulse of the digital NTSC TV signal. The proposed system has three features. Firstly, the system could give a satisfactory picture quality for consumer-use visual appliances even though the quality of the reproduced pictures is lower than that of the normal digital NTSC TV picture codes obtained at a sampling frequency of 4.00/spl times/fsc with a quantisation level of 8 bits. Secondly, the system can satisfactorily transmit NTSC TV picture codes at a low transmission rate of 50 Mbps even if such an advanced compression technique as MPEG 2 has not been used. Thirdly, the system is used for transmission of the digital audio signals which are inserted into the horizontal sync pulse of the digital NTSC TV signal. A combination of edge-emitting LEDs (ELEDs) and single-mode (SM) optical fibers enables the system to easily transmit a digital NTSC TV picture signal together with digital audio signals over a distance of 10 km through the SM optical fibers.