Multi-Valued Automatic Cab Signalling System Based on the CDMA Technology

Purpose. The work is aimed at the development of principles for construction multi-valued automatic cab signalling system (ACS) using wide-band pseudorandom signals. Methodology. An analysis existing ACS systems and modern telecommunication technologies has been performed to achieve stated purpose. CDMA-ACS proposed. mentioned utilizes pseudo-noise signals transmit commands. System parameters: frequency band – 155...395 Hz, codes 16-bit Walsh codes, spectrum spreading factor 16, source signal bandwidth 15 carrier modulation DBPSK (differential binary phase-shift keying), information rate bit/sec, code combination length 4 bits, maximum amount commands 256, duration single command transmission 0.27 sec. Functional diagrams generator receiver have designed. It suggested apply correlation method receive Findings. To investigate proposed simulation modelling accomplished in MATLAB two stages: first stage, was investigated as disturbance-free; second stage under influence powerful narrow-band disturbances (traction current harmonics). found that shows high immunity harmonic disturbances. most significant harmonics traction related are 250 Hz 300 since they closest 275 Hz. determined errors decoding occur if signal-to-noise ratio becomes lower than -8 dB. reduce application additional band-reject filters Originality. For time, authors this carried out research on with use pseudo-random codes. Practical value. Implementation solutions being allows improving informativeness interference system, reducing from railway track cab.