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US 7,017,864 B2Granted
Railway track circuits
AssigneeWestinghouse Brake and Signal Holdings Limited
InventorLawrence Lawson McAllister
Life of this patent
Estimating the term…
Abstract
Railway track circuit apparatus for train detection comprises a track circuit transmitter and a receiver, wherein the transmitter generates a QPSK modulated signal that is transmitted into a track circuit and which is detected by the receiver.
Claims8
A railway track circuit apparatus comprising a track circuit transmitter and a track circuit receiver,
- wherein the transmitter generates a QPSK modulated signal, which is transmitted into the track circuit, said signal carrying a digital message, and a unique track circuit identifier code, and
- wherein the QPSK modulated signal is detected by the receiver, the receiver only indicating that the track circuit is clear having received a QPSK modulated signal of amplitude greater than a threshold and carrying the correct track circuit identifier code.
Dependencies are inferred from the claim text.