| 摘要 |
1. System for indicating a modification of a trajectory, in particular of a vehicle (VV), with respect to a circulation path, which comprises two transmitter-detector units of electromagnetic waves that are fixed on the vehicle, so as to be distant from each other and upon an axis which is transversal with respect to the axis of the path defining the trajectory, said path being materialized by a coating in contrast with the lateral parts bordering the latter, one at least of said parts being possibly a band that reflects the aforesaid electromagnetic waves and the two detectors (2D, 2G) of the units being coupled to comparison means (7) having a zero output signal when the vehicle runs correctly between the lateral bordering parts of the path, characterized by the fact that the system comprises a generator (10) coupled to the transmitters (1D, 1G) of the units and conceived in such manner that the electromagnetic waves be transmitted and detected in the form of successive impulses of alternative signals, these impulses having a determined frequency, amplitude and duration ; that the two detectors (2D, 2G) are coupled with the comparison means (7) through the intermediary of two rectifiers (5D, 5G) respectively, while one of them lets the negative alternations of the signal pass through and the other one, its positive alternations, each detector (5D or 5G) being mounted in series with a trigger (6D or 6C) which is adapted to transmit a signal to the comparison means but after a certain number of received impulses ; and that luminous (21) and sonorous (22) warning means are adjoined to said comparison means (7), said warning means being made operating when the vehicle (VV) diverging from its trajectory one of said detectors (2D, 2G) intercepts the or one lateral band that borders the path.
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