EP 0206664 A2 19861230 - Guard system.
Title (en)
Guard system.
Title (de)
Schutzsystem.
Title (fr)
Système de protection.
Publication
Application
Priority
GB 8514862 A 19850612
Abstract (en)
Guard system for protecting some space against undetected intrusion uses a plurality of wave beam paths (from transmitter T1 -Tn to receivers R1 -Rn) selectively energised in cycles (multiplexer Tx-Mx) so that each beam (transmitters T1 -Tn) is energised for part only of each cycle. Pressure or absence of beam energy indicative of intrusion is monitored (receivers R1 -Rn and multiplexer Rx-Mx). Signal level discrimination (46) of received signals operates both logic circuitry (flipflop 55) to give effectively continuous output (56, 58) except for beam interruption (52) even through a quiescent state of each cycle, and fault indication logic circuitry (100 via 70, 72) that is shown duplicated.
IPC 1-7
IPC 8 full level
G08B 13/183 (2006.01)
CPC (source: EP)
G08B 13/183 (2013.01)
Designated contracting state (EPC)
AT BE CH DE FR IT LI LU NL SE
DOCDB simple family (publication)
EP 0206664 A2 19861230; EP 0206664 A3 19890301; GB 2177503 A 19870121; GB 8614303 D0 19860716
DOCDB simple family (application)
EP 86304518 A 19860612; GB 8614303 A 19860612