Measurements of the electrical impedance of railway track have been made and the corresponding distributed transmission line components evaluated for wet and dry environmental conditions. Audio frequency (blockjointless) track circuits using various terminations are reviewed and their applicability in terms of safety, shunting sensitivity and resolution is assessed. Amplitude and frequency shift keying techniques for modulating the track circuit carrier frequency are evaluated and some practical examples are given of data transmission using various coding and modulation schemes. The effectiveness of AF track circuits for transmitting safety signalling information to moving trains is dependent upon the quality of rail as a transmission medium. The modulated signal bandwidth is limited if traditional analogue techniques are used, but by adopting signal coding and demodulation methods it appears possible to increase considerably the quantity of information transmitted and yet retain signal security.
Train position detection and track-train data transmission using audio frequency track circuits
Zuglageerkennung und Gleis-Zug-Datenuebertragung mit Hilfe von Tonfrequenzkriesen
Journal of Electrical and Electronics Engineering, Australia ; 5 , 4 ; 267-277
1985
11 Seiten, 13 Quellen
Aufsatz (Zeitschrift)
Englisch
NTRS | 1975
|SAE Technical Papers | 1975
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