摘要 |
This invention relates to cab signalling systems that receive various permissible maximum speed signals and decode the maximum speed signal to inform the engineman of a train of the current maximum safe speed that a train may travel. The apparatus of this invention accomplishes the foregoing by utilizing a single digital filter and a microprocessor to decode the various transmitted maximum speed signals and to verify that the decoded maximum speed signal represents one of the permissible maximum safe speeds.
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