| 摘要 |
<p>1461612 Rail vehicle control system MESSERSCHMITT-BÍLKOW-BLOHM GmbH 22 Feb 1974 [7 March 1973] 8245/74 Addition to 1406674 Heading B7N In the rail vehicle control system of the parent Specification 1,406,674, in which unrequired forward transmission along a trackside transmission line of a high frequency signal from a transmitter 5 at the rear of a vehicle to a receiver 6 at its front is reduced by the provision of an auxiliary transmitter 17 on the vehicle which couples to the line an equal and opposite cancelling signal which takes account of the attenuation and phase change in the length of line between transmitters 5 and 17, an improvement comprising the provision of a circuit 49 on the vehicle which couples an impedance into the line between the transmitter 5 and the auxiliary transmitter 17 to provide a signal reflection point which reduces the forward transmission and hence reduces the required amplitude of the cancelling signal. The cancelling signal thus has less effect on the amplitude of the required signal transmitted rearwardly by the transmitter 5.</p> |
