Electrical transmission or interconnection systems – Nonlinear reactor systems – Parametrons
Patent
1988-07-07
1990-03-20
Heyman, John S.
Electrical transmission or interconnection systems
Nonlinear reactor systems
Parametrons
307358, 250221, 250341, 340552, 367 93, G08B 1300, H03K 522, H03K 5153
Patent
active
049104640
ABSTRACT:
A movable door incorporates a proximity detection system for sensing obstructions in the path of the door. The system comprises an array of transmitter/receiver pairs (21, 22 and 23), each pair comprising a transmitter (1) for transmitting an energy pulse, a receiver (2) located adjacent the transmitter and directed to receive any reflected transmitter pulses, and a shielding (3) for shielding the receiver (2) from receiving energy pulses directly from the transmitter (1). At least two transmitter/receiver pairs (21, 23) are mounted on a leading edge or face of the door (12) to transmit energy pulses in a direction which is not at right angles to the leading surface or edge of the door, to monitor for obstructions in the path of the door (12). Another two transmitter/receiver pairs (26 and 28) are mounted on the leading edge or surface of the door (12) to transmit energy pulses at right angles to the surface or edge of the door (12). Different transmitter/receiver pairs may transmit on different frequencies, and means for suppressing unwanted reflected signals is provided. Means for transmitting data signals on a two-conductor power supply cable for the system is disclosed.
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J. Millman--"Microelectronics", McGraw-Hill--1979--pp. 570-572.
Bradbeer Peter F.
Trett John
Duong Tai V.
Formula Systems Limited
Heyman John S.
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