HIGH-SPEED SIGNAL TRANSMISSION CHARACTERISTICS FOR IMPROVED COAXIAL PRINTED BOARD CONNECTOR IN A RACK SYSTEM

摘要

In rack systems, the transmission speed is limited by crosstalk and switching noise arising in the signal path, so these noises must be reduced. These noises are large at the connector because of impedance mismatch between the printed board and the connector. We thus developed a coaxial board connector which is 50-ohm matched and is interchangeable with conventional multipin connectors.rnWe evaluated the signal transmission capability using an experimental rack and this connector. This rack system has 20 independently driven channels. It consists of a driver printed board, connector, backplane, and a receiver printed board. The signal is transmitted directly from the driver board to the receiver board, (one-to-one signal connection) under the single-ended condition. The drivers are 210-270 pS edge rate ECL devices. The rack structure allowed the backplane line length to be changed from 30 cm to 60 cm by changing the slot position of the driver and receiver boards.rnThis paper compares the measured error-free signal transmission speeds on a 60 cm backplane line for the conventional multi-pin connector and the improved interchangeable coaxial connector. A 500MHz signal transmission capability is demonstrated.