A Novel Digital Coded Track Signal-ITRS Based on TVM430

With the developing of the high-speed railways, the requirement for railway signalling turns more and more strict. Came from France, the TVM430 signal has more information up to 27 bits digital word, with each bit corresponding to one of the 27 frequencies modulated onto the carrier frequency in the track circuits. The presence of a particular frequency indicates a "1" bit and lack of corresponds to a "0". But the slow demodulation is the biggest flaw for TVM430. To solve the above problems, we design a new digital coded track signal - Improved TVM430 Railway Signalling (ITRS). ITRS reduces the number of TVM430\´s modulation frequency while provides the same information capacity as TVM430. We also search for cycle generating polynomial, add parity checking to the important code - speed identification code. New frequency, amplitude and phase are defined for frequency modulated signals. ITRS performs better in information capacity, reliability and demodulation speed.