多信息移频轨道电路信号调制频率选择的探讨

SELECTION OF MODULATION FREQUENCIES OF 18-CODEFSK TRACK CIRCUIT FOR BEIJING-KOWLOON RAILWAY

京九线要采用１８信息的移频轨道电路，调制频率由原有移频的４个增至１８个，因此合理选择调制频率对系统的性能具有重要意义。本文认为选择调制频率要从我国移频轨道电路的具体情况出发，满足新制式兼容旧制式的要求，考虑所选的频率有利于发码设备的实现，有利于接收设备的接收译码，有利于信号的抗干扰。根据这样的原则，所选择的调制频率最低为７Ｈｚ，最高仍为２６Ｈｚ，以０．５Ｈｚ为基本间隔，选出了１８个频率和一个备用频率。

This paper presents the selection of modulation frequencies for the 18--code FSKtrack circuit which will be used in the Beijing-Kowloon Railway.The new FSK track circuitneeds 18 codes,i.e. 18 modulation frequencies. These frequencies have been selected in considering the compatiblity of the new FSK track circuit with the old 4-code FSK track circuit,and in considering that if the frequencies are suitable for code generator and if the frequenciescan be reliably distinguished by receiving equipments.