Matsushita Electric Industrial Co., Ltd.

Seiho Kitaji

Noboru Mizuguchi

Kiyoshi Uchimura

Kazuhiro Nojima

Masatoshi Tanaka

Yoshiharu Ohsaki

Hiromasa Kimura

Susumu Unosawa

In a multi-channel video optical transmission system comprising an optical transmitter and an optical receiver, a frequency modulation function incorporated pilot signal generating unit is provided in the optical transmitter to generate a pilot signal frequency-modulated. This frequency-modulated pilot signal is superimposed on a multi-channel video signal inputted thereto and is converted into a frequency-modulated signal in a frequency modulator, and is transmitted through an optical fiber to an optical receiver in a state converted into an optical signal in a semiconductor laser device. In the optical receiver, the optical signal is again converted into an electric frequency-modulated signal in a light-receiving device and, after amplified in an amplifier, is demodulated in a frequency demodulator, thereby regenerating the multi-channel video signal before the input to the frequency modulator. In this configuration, the pilot signal is frequency-modulated to modulate the frequency of a distortion occurring at frequencies corresponding to the sum of or difference between the frequencies of the pilot signal and the multi-channel video signal, thus making fringe patterns on a TV monitor disappear.

Multi-channel video optical transmission system, optical transmitter and optical receiver

An HDTV signal transmission system for sending a 10-bit-parallel YPbPr-format HDTV signal converted to ten C4 containers, and further to the SDH (a new synchronous digital network) STM-16 frame for transmission based on CCITT recommendations. The system includes a transmitter and receiver. The transmitter has time dividers for time-based dividing the HDTV signal into eight separated video signals, a C4 container device for multiplexing the eight separated video signals to ten C4 containers, and a STM-16 framing device for reformatting the ten C4 containers to the STM-16 frame. The receiver has an STM-16 deframing device for separating the ten C4 containers from the STM-16 frame, a C4 de-container device for demultiplexing the ten C4 containers to eight separated video signals, and time-division multiplexers for time-division multiplexing the separated video signals to the 10-bit-parallel YPbPr-format HDTV signal.

HDTV signal transmssion apparatus

In a transmitting apparatus, information signal frame position information is supplied from a transmission line frame control unit in a frame constructing unit to an information signal frame control unit provided within a frame constructing unit. In a reception apparatus, information signal frame position information is supplied from transmission line frame control unit provided within a frame analyzing unit to an information signal frame synchronization detection protecting unit provided within a frame analyzing unit. n information signal frames having a length which results from dividing the data area of the transmission line frame by n are located at an arbitrary position within the data area of the transmission line frame and a stuff control is effected on every information signal frame. Also, a value of n which yields a stuff ratio in which a residual jitter can be prevented from being increased is selected by transmitting a single information signal by using n information signal frames.

Method of transmitting a digital signal, digital signal transmission and

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Yokohama, Japan

Seiho Kitaji