Minseok Kim, Minkyu Kim, Sanghyeok Lee and Jongwoo Lee
International Journal of Railway, vol. 4, no. 1, pp.12-18, 2011

Abstract : The ATS system is used to provide wayside signaling. Currently, the oscillation frequency is set at 78[kHz] in the normal state. As the on-board receiver crosses over the wayside transmitter, the oscillation frequency is changed by capacitors of the wayside transmitter in a manner dependent on the train speed. As the oscillation frequency is changed, the waveform is modified in the wayside transmitter as well as in the on-board receiver. When there are other signal systems such as a ATO system present near the wayside transmitter, frequency interference occurs. This phenomenon arises since other sig¬nals or communication frequency get to be included in the waveform. Trains often stop due to these other frequencies included in the waveform. In this paper, a model of interaction between the wayside transmitter and on-board receiver is suggested and frequency response in the wayside transmitter and on-board receiver in the presence of the other signals is estimated by the coupling coefficient. Also, the coupling coefficients are estimated, and the optimal value is proposed.

Keyword : ATS system, Coupling coefficient, Frequency response, Frequency interference