Patent GB-1352185-A (GB)
Title: Remote control receiver
IPC: H02J13/00
Filed: 1971-04-19
Abstract: 1352185 Signalling over power lines, gating circuits ZELLWEGER Ltd 19 April 1971 [26 March 1970] 23070/71 Headings H4R and H3T [Also in Division G4] A ripple control receiver adapted to receive signals from a power supply line includes a stepping switch adapted to interrogate in turn code elements of a key member while corresponding elements of an incoming signal are received and a bi-stable circuit element set at the start of the signal to a first state maintained by a supply and arranged to be short circuited and thus reset upon the detection of an inconsistency between the code and the incoming signal. As described the signal is transmitted by switching between two high frequency modulation currents. Several different receivers are described. Each includes a removable code key (23, Fig. 4, not shown) which connects each of a plurality of first terminals to one or other of two second terminals and according to the particular connections on the inserted key determines the code to which the receiver will respond. Each receiver is arranged to respond to its code performing an external switching operation and subsequently to respond to the inverse of its code to revert the external apparatus to its original condition. In the embodiment shown the key is represented at 23. In operation a signal incoming to a detector 24 closes a contact 25 which starts a synchronous motor 26 maintained over its contact 29. A contact 30 momentarily closes to switch an S.C.R. 50 to conduction. The detector 24 responds to the individual "mark" and "space" elements of the code controlling a changeover switch 36 in accordance therewith and a stepping switch 40 steps its wiper 41 across terminals 43 to 46. For each step the switch 36 connects positive potential 37 to one or other of a pair of terminals 38 and 39 (maintaining via diodes 53 and 54 the power supply path for the S.C.R.) and to one or other of two conductors 69 and 70 of the key. Simultaneously the stepping switch 40 connects for each step a terminal 42 to one or other of the two conductors 69 and 70 via a lead 43 to 46 and a conductive element 65 to 68 of the key. If the code on the key corresponds exactly with the signal received the source 37 and the terminal 42 are at all times connected to different conductors 69 and 70 and the S.C.R. is not reset. Any difference detected causes a short between the source 37 and the terminal 42 thus shorting and turning off the S.C.R. Near the end of the cycle a contact 33 closes and if S.C.R. 50 is still set a relay 59 responds performing the required external switching operation and operating changeover switches 77 and 79 to render the receiver responsive to the inverse code. In a modification (Fig. 5, not shown) the changeover switch is eliminated and two separate S.C.R.'s test for the setting and resetting signal. These S.C.R.'s control a common relay via different windings. In a further modification (Fig. 7, not shown) the sections 22 and 23 are duplicated for different code patterns and are controlled by a common unit 21. Isolating diodes are included in the leads from the unit 22 to terminals 42 to 46. The changeover switch 36 may be in the form of an electronic circuit (Fig. 6). Incoming alternating current at 103 is rectified at 104 and charges a capacitor 105. When the charge rises above a potential set by a Zener diode 106 a resistor 107 conducts, switching a transistor 102 to conduction. This transistor connects a common terminal (previously connected via a transistor 101 to a terminal 38) to a terminal 39 and switches off the transistor 101 by shorting its potential divider supply 112 and 113.