620 Mbit/s high‐speed switching equipment design

Abstract

IntroductionThis paper considers the design method to realize the high-speed switching equipment at the level of 600 Mbit/s. which can switch the PCM-coded NTSC and HDTV signals. In the switching of the high-speed signals at the level of 600 Mbit/s. the equipment must be designed at the level close to the performance limit of the devices and implementation, which are generally available at the present stage.A method is provided which can estimate the upper limit of the switching equipment performance at the stage of design by relating the performance of the devices. More precisely, the single-stage spacedivision switch is analyzed, and it is shown that the 620-Mbit/s switching equipment can be realized by applying ECL with the transmission delay of some 0.4 ns and providing the retiming for each board. The feasibility is demonstrated by an experimental setup and the usefulness of the proposed method is indicated. By the proposed method, it is also possible to estimate the number of parallel bits, when the parallel switching is planned using low-speed components. The maximum operating speed is discussed also for the switching using retiming methods.The communication service using the moving picture is expected according to the introduction of the optical fiber to the subscriber system and the economical implementation by LSI. The fiber-to-the-home system, which can integrate from the low-speed N-ISDN to the B-ISDN, as well as the communication and the broadcast, has been studied and developed because of its possibility to provide new services in the subscriber system. As to the moving picture that can be handled by this system, NTSC system (4-MHz bandwidth) is standardized at present, but it is desirable that high-definition TV (HDTV) that has superior features such as high-quality and a large-size screen should also be offered.We proposed a high-speed broadband circuit switching system in which digitized video signals such as NTSC and HDTV can be switched [l]. The system can integrate the communication service such as end-to-end communication, e.g., video conferencing and the video retrieval service and the distribution service such as CATV. The digital information to be switched in such a system has the rate of approximately 45 Mbit/s and approximately 140 Mbit/s for NTSC and approximately 140 Mbitls and approximately 600 Mbit/s for the distribution quality of HDTV [2]. There are some examples of realization of the switching equipment for the digital information exceeding 1 1SSN87564621/92/OOO6-OOO1$7.50/0 1992 Scripta Technica, Inc.