Minoru Sano

Development of a Railway Signaling Device Based On Mixed Digital and Analog Signals Using Digital Signal Processors

In Japan, automatictrain control(ATC) systems, onetype of railway signaling system, transmit train control informationby using analog signals based on amplitude modulation (AM) in the audio frequency band. To realize highly functional train controlby increasing the data transmission speed, there havebeen many studies on digital ATC that transmits train control information by using digital signals based on phase shift keying (PSK), and these systems are employed in some railway lines. In practice, however, it is difficult to install digital ATC because it is impossible to ensure another transmission band for digital ATC signals due to the existing track circuit configuration and interoperability conditions, and there are many railway lines in which analog ATC is still employed. To overcome this restriction, we proposed a novel railway signaling system using mixed digital and analog signals. We employed quadrature PSK (QPSK) for digital signals and developed a transmission device using digital signal processors. We evaluated the transmission characteristics by conducting a basic experiment.