| Title |
The Influence of Energy Density upon Detection Time of Information Signal in AF Track Circuit |
| Authors |
김민석(Kim, Min-Seok) ; 황인광(Hwang, In-Kwang) ; 이종우(Lee, Jong-Woo) |
| DOI |
https://doi.org/10.5370/KIEE.2011.60.6.1146 |
| Keywords |
AF track circuit ; Energy density ; Detection time ; Train control ; Information signal |
| Abstract |
There are two methods for train control in information transmission by using track circuit system and installing wayside transmitter. Information signal is transmitted to the on-board antenna by using rails. Continuous information about train intervals, speed and route is received by on-board antenna in AF track circuit system. The information signal is included with carrier wave and received by magnetic coupling in the on-board antenna. Therefore, it is important to define standard current level in the AF track circuit system. When current flowed to rails is low, magnetic sensors are not operated by decreasing magnetic field intensity. Hence, SNR is decreased because electric field intensity is decreased. When the SNR is decreased, there is the serious influence of noise upon demodulation. So, the frequency of information signal is not extracted in frequency response. Thus, it is possible to happen to train accident and delay as the information signal is not analyzed in the on-board antenna. In this paper, standard energy density is calculated by using Parseval's theory in UM71c track circuit. Hence, detection time of information signal is presented. |