Transmission Of Digital Video Signals Research Articles

A statistical feedforward/fedback buffer control for the transmission of digital video signals compressed by DCT-based intrafield coding

A new buffer-control policy for intrafield coding of video signals is presented. This method employs two statistical bit rate predictors-feedback and feedforward. It uses a feedback predictor in stationary portions of an image sequence and a feedforward predictor at scene changes. It is shown that this buffer-control policy is reasonably simple to implement and can effectively control output bit rate even at scene changes.

Transmission for digital video signals coded by CCITT H.261 on a private broadband LAN using co-axial cable

The development of a new multi-media network system for transmitting multi-channel video, audio, digital control signals and other signals on a co-axial cable gives new possibilities for the transmission of digital video signals coded by CCITT H.261. All these signals can be transmitted at the same time using frequency division multiplexing. The paper describes the development of a QPSK (quadrature phase shift keying) transmitter and receiver, and RF (radio frequency) modems which use this system. It is especially concerned with the new QPSK transmitter's and receiver's capability to transmit digital video signals coded by CCITT H.261 either individually or combined with the other signals above. Digital video signals are modulated by QPSK. The QPSK transmitter has a maximum digital data transmission rate of 1O Mbps and transmits digital video signals at the standard rate of 1.5 Mbps. Furthermore it describes new bi-directional multi-channel RF modems for general purposes. Digital control signals are modulated by frequency shift keying. The modem has a maximum digital data transmission rate of 128 kbps.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

特集 ディジタル伝送 シリアルディジタルビデオインタフェース用チップセットの開発

We developed a chip set consisting of two analog ICs and two digital LSIs for serial transmission of digital video signals. It includes analog FIR filters as a part of an automatic cable equalizer that allows digital video signals to be transmitted through a coaxial cable. This chip set can transmit and receive composite NTSC/PAL, component 525/625, and wide component 525/625 digital video signals. It also includes multiplexing/demultiplexing functions for 24-bit audio and Error Detection and Handling (EDH) packets. With this chip set total digital broadcasting systems can easily be constructed.

Novel satellite digital video TDMA system for business video communications

The authors propose a satellite video signal transmission system that uses a time division multiple access (TDMA) scheme for digital video signal transmission and a code division multiple access (CDMA) scheme for voice signal transmission from a video signal reception-only earth station (backward voice signal transmission). The adoption of a TDMA scheme makes it possible to transmit video signals from various places and to communicate in multipoint-to-(multi)point mode. For backward voice channel transmission from video signal reception-only earth stations, a superposed CDMA voice signal transmission over TDMA video signals by using the same transponder is proposed. The employment of high coding gain forward error correction and development of a cochannel interference cancellation technique have made it possible for the proposed system to transmit a practical number of voice channels. The performance of the proposed system has been experimentally evaluated and the results show the proposed scheme can transmit about 20 CDMA voice channels simultaneously. >

A 20-channel optical communication system using subcarrier multiplexing for the transmission of digital video signals

Microwave subcarriers have been used to demonstrate an optical communication system suitable for the distribution of digital video channels. The design, performance, and optical link requirements are discussed for a 2-Gb/s subcarrier-multiplexed (SCM) system with 20 microwave subcarriers modulated at 100 Mb/s and using a frequency-shift-keyed format. The system uses the 2-6-GHz bandwidth and represents the first example of an SCM system using more than one octave of bandwidth. The bit error rate was measured for all 20 channels; results for five typical channels are shown and discussed. The performance results show that a digital SCM approach is attractive in an optical link for a multichannel wide bandwidth video distribution system made from standard microwave components. >

Serial Interface within the Digital Studio

As digital equipment is used increasingly in the video studio, the need for an effective means of interconnecting digital devices becomes more apparent. This article discusses the desired characteristics of such an interface, including selection of the coding to be used. A serializer and deserializer designed for an experimental digital studio developed by Thomson-CSF are described. Serial digital video signal transmission is shown to be reliably achievable over a single coaxial cable.