| 摘要 |
<p>1,221,894. Determining train position. ATELIERS DE CONSTRUCTIONS ELECTRIQUES DE CHARLEROI. 18 July, 1969 [30 Aug., 1968], No. 36258/69. Heading B7N. In an arrangement for determining the position of a train in a track zone by counting phase reversals at marking points defined by crossovers or the like in an A.C. energized cable extending along the track, a logic circuit arrangement is provided for subtracting marking points passed in the opposite to normal direction of travel through the zone and for determining on entry to the zone this normal direction of travel. The train is provided with three pick-up coils X, Y, Z, aligned in the direction of train travel and pairs of these are connected via respective filters F 1 , F 2 , F 3 to phase detectors DP 1 , DP 2 , DP 3 which supply "1" signals on lines a, b, c when a 180 degree phase difference occurs between the signals picked up by coils x + y, y + z, x + z, respectively. The phase detectors supply logic unit LDM which provides forward or backward counting pulses on lines c and d respectively in dependance on whether the signal on line a occurs before or after that on line b during the presence of a signal on line c. If coil X leads during normal direction of movement through the zone then at the first zone cross-over a a pulse is supplied to logic circuit LDC from level detector DN 2 connected to coil X before it receives a pulse from level detector DN 1 connected to coil Z. If coil Z leads then an opposite pulse sequence is obtained. Logic circuit LDC acts on inverter I to allow direct connection of lines a and b to logic circuit LDM when coil X leads but inverted connection if coil Z leads.</p> |
