GB2251970A

GB2251970A - Remotely controlled information transmission system

Info

Publication number: GB2251970A
Application number: GB9101111A
Authority: GB
Inventors: John Morrison
Original assignee: GEC Marconi Ltd; Marconi Co Ltd
Current assignee: BAE Systems Electronics Ltd
Priority date: 1991-01-18
Filing date: 1991-01-18
Publication date: 1992-07-22
Also published as: GB9101111D0

Abstract

In a remotely controlled information transmission system at least one information generating apparatus (e.g. video cassette recorder 10) and at least one information utilising apparatus (e.g. television set) are connected together by a coaxial cable 18 extending between remote locations. Information in the form of radio frequency signals and command signals is carried by the coaxial cable throughout the transmission system. Alternatively, the command signals may be carried by the mains wiring. <IMAGE>

Description

REMOTELY CONTROLLED INFORMATION TRANSMISSION SYSTEM This invention relates to remotely controlled information transmission systems wherein information such as television signals is required to be transmitted between a plurality of locations. Particularly, the invention is concerned with the transmission of such information by coaxial cable comprising an inner conductor and outer screening. Such cable is the conventional transmission cable for minimum attenuation and interference to radio frequency signals. In, for example, a domestic situation, there may be a video cassette recorder (VCR) having an antenna by which broadcast television signals may be received.The VCR provides a coaxial cable output and a coaxial cable therefrom may supply a plurality of television sets with radio frequency signals, as broadcast, or as generated by playing a recorded cassette within the VCR.

It is now common for the VCR and the television sets to be provided with infra-red or other sensing means enabling the particular apparatus to be remotely controlled.

Unfortunately, the remotely controlled apparatus can only be so controlled within the range of sensitivity of the sensing means. For infrared sensing means, it is generally required that a line of sight must exist between a remote control and the sensing means. If a television set is being viewed in one room it is not possible, normally to control a connected VCR in another room using a conventional infrared remote controller.

Solutions to this problem have been suggested. For example, UK Specification No. 2140182 describes an arrangement wherein operation of a remote control in one room is caused to be repeated within the range of sensitivity of the VCR's remotely controlled sensor.

It is an object of the present invention to provide a simple transmission system including "remote" control, using the existing conventional cable connection.

According to the present invention, there is provided an information transmission system for use with cable means including a coaxial cable having an inner conductor and outer screening and arranged for transmission of information in the form of radio frequency signals along the inner conductor from a base location to at least one remote location, an information generating apparatus connectable to the cable means at the base location, the information generating apparatus serving to generate the information to be transmitted, at least one information utilising apparatus connectable to the cable means at the or one of the remote locations, at least one transducer, responsive to a remote control device, located at the or a respective remote location, the or each transducer serving to impress command signals on the cable means, the information generating apparatus having decoding means responsive directly to the command signals for changing the information generated by the information generating apparatus.

It will be appreciated that the inner conductor or the outer sheathing of the coaxial cable of the cable means may be used to carry the command signals. Alternatively, where the apparatus is mains powered, the cable means then includes the mains wiring and such mains wiring may be used to carry the command signals.

As can readily be appreciated apparatus other than information generating or utilising apparatus may be connected to the cable means. Each such apparatus is then provided with decoding means for decoding the command signals and actuating means for effecting some function in dependence upon the command signals, if appropriate to that apparatus.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which:- Fig. 1 is a simplified diagrammatic view of an information transmission system in accordance with the present invention; Fig. 2 is a diagrammatic representation of a command signal initiator forming part of the system shown in Fig 1; Fig. 3 is a diagrammatic representation of a command signal receiver forming part of the system shown in Fig 1; Fig. 4 is a diagrammatic fragmentary representation of an alternative way in which command signals may be carried by a coaxial cable of a transmission system according to the present invention; Fig. 5 is a diagrammatic representation, similar to Fig. 2 of part of further information transmission system in accordance with the present invention.

Fig. 6 is a diagrammatic representation, similar to Fig. 3 of another part of the further system serving as a command signal receiver; and Fig. 7 is a diagrammatic representation of yet another system for information transference.

Referring firstly to Figs 1 to 3, there is shown an information transmission system in accordance with the present invention. The system there shown comprises a video cassette recorder (VCR) 10 having an antenna 12 arranged to receive broadcast radio frequency signals. In conventional manner, the incoming rf signals are down-converted, tuned and selected and fed via a selector 14 to either a recording section 15 of the VCR or to an rf modulator 16. The VCR thus constitutes an information generator. A coaxial cable 18 comprising an inner conductor 20 and outer sheathing or screening 22 is arranged to convey the information so generated to a first television set TV1 located adjacent the VCR. A remote control unit 24 incorporates a keypad, encoder and infrared emitter.The unit 24 may be manually operated to transmit coded infrared signals to either TV1 or the VCR 10 to actuate the same. At least the VCR includes an infrared sensing photodiode 26, an amplifier 28 and a decoder 30. The decoder 30 is arranged to operate the selector 14 to perform functions, such as channel changing, of the VCR in known manner.

The transmission system of the present invention includes at least a further information utilising apparatus, in the form of a second television set TV2 in an adjacent area, for example, another room in the house. The second television TV2 is supplied with information by the coaxial cable 18 and has, as shown, its own remote control unit 32.

The inner conductor 20 of the cable 18 is able to carry rf signals corresponding to all selectable channels including any information presently being played back by the VCR.

Operation of the remote control unit 32 causes appropriately coded infrared control signals to be emitted thereby.

Television set TV2 includes infrared receiving means similar to that provided in the VCR and consequently any rf signal on the cable 18 may be selected by a viewer in the same room by using the remote control 32. The occasion arises when a viewer watching television set TV2 may wish to control the VCR. In accordance with the present invention, such control is effected using the remote control 32.

To this end, the infrared sensing means of the television set TV2 is arranged to impress the command signals generated by the control unit 32 onto the inner conductor 20 of the cable 18. In the television set TV2, a photodiode 34, appropriately biased, receives infrared signals from the control unit 32, amplifies them in amplifier 36 and impresses them on the conductor 20.

In order to prevent such command signals from being received by the rf section of the television set TV2, a blocking capacitor 38 is provided inside the set TV2. A similar blocking capacitor is provided in the rf input of the television set TV1, in the rf output of the VCR 10, and in the rf input of any other information utilising apparatus (not shown) connected to a coaxial cable extension 40 of the transmission system of the present invention.

The transmission system of the present invention thus permits the use of any remote control unit 52, in any location wherein an apparatus 54 including the conventional infrared sensing means 50 is included, to actuate directly the apparatus whereat the remote control unit is directed or to impress upon the coaxial cable, command signals for any apparatus of the transmission system including a decoder and selector means.

As described above, the information generating apparatus, the VCR 10 includes an infrared sensor 26. The sensor 26 is itself preferably capable of impressing command signals upon the transmission coaxial cable but, additionally, command signals on the coaxial cable 18 can operate the decoder 30 and selector 14 of the VCR 10.

The transmission system described in relation to Figs 1 to 3 utilises the inner conductor 20 of the cable 18 for carrying both the r. f. information and the command signals.

This necessitates the use of the blocking capacitors 38 in each apparatus which generates or utilises the r.f.

information. It will be appreciated that r.f. apparatus sometimes incorporate such blocking capacitors and so no additional capacitors may be needed. The provision of the capacitor 38 (or existing capacitors) enables a DC bias to be applied to the inner conductor 20 to provide a voltage source for the diodes 26, 34 etc. However, the use of such blocking capacitors can be eliminated if the outer sheathing 22 of the cable 18 is used to carry the command signals.

Fig. 4 shows a fragment of one embodiment of a transmission system in accordance with the present invention wherein outer sheathing 22 of a coaxial cable 18 is used to carry command signals, r.f. information signals being carried, as before, by the inner conductor 20.

As shown in Fig. 4, the outer sheathing or screening 22 of the coaxial cable 18 is connected to earth, adjacent the VCR 10, through switch means 40. The sheathing or screening 22 may be connected to earth, adjacent other apparatus through signal sensing switch means 42 or through capacitative or resistive connectors or may be unconnected thereat. Any command from a remote control unit 24, 32 etc converted to a command signal by the respective one of the infrared sensors 26, 34 etc is impressed directly ontd the outer sheathing 22, is sensed by the switch means 40 which interrupts the earth connection of the sheathing 22 and directs the command signal to the amplifier 28, decoder 30 and selector 14 of the VCR 10.If the inner conductor 20 of the cable 18 is required for a return path of the command signals, the switch means 40 may simultaneously connect the inner conductor 22 to provide an earth return path for the duration of the command signal. A similar switch means may be provided adjacent any apparatus on the transmission system or the switch means 42 may be used if the apparatus includes a decoder and subsequent actuating means such as the selector 14.

Referring now to Figs 5 and 6, a further embodiment an information transmission system in accordance with the present invention is shown. As with the embodiment of Figs 1 to 3, an information generating apparatus such as a VCR 10 is connected by cable means including a coaxial cable 18 to a plurality of information utilising apparatus at least one of which e.g. television TV2 is located remote from the VCR 10. In a domestic situation, all such apparatus are usually mains driven and hence the cable means includes also the mains wiring. For example, a mains source 70 may supply a ring main 56 including a plurality of socket outlets 58.

Each mains driven apparatus is connected to an adjacent socket outlet of the ring main by a cable 64. In accordance with this embodiment of the present invention, the ring main 56 and the cables 66 are used to carry command signals whilst information in the form of r.f. signals is carried by the coaxial cable 18 as before.

As shown in Fig 5, r.f. information is brought into the television set TV2 via the inner conductor of the coaxial cable 18 and is supplied to the tuner/demodulator etc 14 of the television set. AC mains power is brought into the television set TV2 via a cable 64 from a socket outlet 58 on a ring main 56 of the domestic mains supply 70.

The cable 64 provides power for operation of the television set. As before television TV2 incorporates an infrared sensor unit 50 responsive to infrared emitted by a remote controller (such as the controller 24 or 32). The infrared is detected by a diode 34 and amplified by an amplifier 36.

The coded information is fed to a decoder 30 for selecting functions in a selector 30 for the operation of the television TV2. The output of the amplifier 36 is tapped through a bidirectional isolating means 72, for example, an opto-coupler and buffer amplifier and is then fed to the cable 64 to impress command signals onto the ring main 56.

The use of the isolating means 72 enables command signals both to be impressed upon and to be received from the ring main 56.

As shown in Fig. 6, the VCR 10 is likewise connected to the ring main 56 via a socket outlet 58 and cable 64 at some other location remote from the television set TV2. The VCR 10 includes its conventional elements (as described in relation to Figs 1 to 3) and also an isolating means 72 similar to that described in relation to Fig. 5. Thus the cable 64, besides supplying the power requirements of the VCR 10, also enables command signals thereon to be utilised, as above described to select some change of function of the VCR 10. Thus, use of a remote control 32 in conjunction with the television set TV2 enables a change of, for example, channel to be effected at the remote information generating apparatus, the VCR 10.

The embodiment shown in Fig. 7 of the drawings extends the invention as expressed in the embodiment of Figs. 5 and 6. Each socket outlet 58 supplied from a power source 70, e.g. a ring main 56 of a domestic single phase AC supply, has an infrared detector 60, similar to the detectors 26 and 34 above described, and an infrared emitter 62, similar to the infrared emitters of the remote control units 24 and 32. The detectors 60 and the emitters 6i are coupled to the AC mains supply through isolating mean embodied in the socket outlets 58 and similar to the isolators 72 described above.

A plurality of apparatus, such as a VCR 10, television sets TV1 and TV2 and other apparatus 54 are connected to the ring main 56 via respective cables 64. Some or all such apparatus have an infrared sensing means 50 of the kind described above. Operation of any remote control similar to the remote controller 24 or 32 will be detected by an adjacent detector 60 which will cause command signals to be impressed upon the ring main 56 and repeated by each of the emitters 62. An infrared sensor 50 of an apparatus will detect the emitted command signals and, if appropriate to such apparatus i.e. if coded to address such apparatus will cause the apparatus to respond to the command signals.

In such an embodiment, some outlets 58 may be provided with only a detector 60 or an emitter 62 or with neither, as required. Where no emitter 62 is provided, the information generating or utilising apparatus may be provided with means as illustrated in Fig. 5 or Fig. 6 for responding to command signals impressed on the mains wiring 56 of the cable means.

The invention is not confined to the precise details of the foregoing examples and variations may be made thereto. For example, there may be a plurality of television sets in a plurality of locations connected to the transmission system. Some or all of such television sets may include infrared sensors responsive to remote control units to generate command signals for impressing on the inner or, outer of the coaxial cable or upon the associated mains wiring in the manners described above.

An r.f. booster amplifier or amplifiers may be provided in the transmission system if more than two information utilising apparatus are connected to the cable 18. Each information utilising apparatus is then connected to the coaxial cable through a T- or a Y- splitter.

Apparatus such as central heating control means, burglar alarms, exterior or interior lighting, cookers etc as represented by the apparatus 54 of Fig. 1 or Fig. 7 can be connected to the cable means of the transmission system for remote control thereof.

The infrared sensors and associated amplifiers may be provided as units, externally of apparatus connected to the cable means of the transmission system. Similarly, in addition, command signals may be generated by control units directly connected to the cable means of the transmission system.

The invention has been described in relation to the use of a VCR as the information provider. It will be appreciated that, alternatively or additionally, a cable receiver a satellite dish receiver or a CD player may constitute an information generater for the transmission system.

Diagrammatic representation has been made of the remote control units, the infrared sensors, amplifiers, decoders etc but such items are well known in the art and require no further explanation. Similarly, biasing of the infrared diodes and power supplies therefor have not been shown as such are well known in the art.

Other variations are possible within the scope of the present invention as defined in the appended claims.

Claims

1. An information transmission system for use with cable means including a coaxial cable having an inner conductor and outer screening and arranged for transmission of information in the form of radio frequency signals along the inner conductor from a base location to at least one remote location, an information generating apparatus connectable to the cable means at the base location, the information generating apparatus serving to generate the information to be transmitted, at least one information utilising apparatus connectable to the cable means at the or one of the remote locations, at least one transducer, responsive to a remote control device, located at the or a respective remote location, the or each transducer serving to impress command signals on the cable means, the information generating apparatus having decoding means responsive directly to the command signals for changing the information generated by the information generating apparatus.

2. A system as claimed in claim 1 wherein the command signals are impressed upon the inner conductor of the coaxial cable, the outer screening being connected to earth, filter means being provided at each apparatus, the filter means of the information generating apparatus serving to direct the command signals to the decoding means.

3. A system as claimed in claim 1 wherein the outer screening of the coaxial cable is normally connected to earth, there being switch means responsive to the generation of command signals for disconnecting the outer screening from earth, for simultaneously impressing the command signals on the outer screening and for directing the command signals to the decoding means.

4. A system as claimed in claim 1 wherein the cable means includes at least one further conductor whereupon the command signals may be impressed.

5. A system as claimed in claim 4 wherein the at least one further conductor is constituted by mains wiring to which the information generating apparatus and the at least one information utilising apparatus are connectable.

6. A system as claimed in claim 5 further including isolating means enabling command signals to be impressed on the mains wiring and command signals on the mains wiring to be filtered therefrom.

7. A system as claimed in claim 5 or any claim appendant thereto wherein the mains wiring has a plurality of outlets, one or more of said outlets having an infrared detector means responsive to the operation of a remote controller to impress command signals on said distributed mains power supply.

8. A system as claimed in claim 5 or any claim appendant thereto wherein the mains wiring has a plurality of outlets, one or more of said outlets having infrared emitter means responsive to command signals on said wiring to emit the same as an infrared signal.

9. A system as claimed in any preceding claim including at least one non-information utilising apparatus connected to the cable means, the non-information utilising apparatus having means including decoding means for decoding command signals on the cable means and for responding thereto.

10. An information transmission system substantially as hereinbefore described with reference to and as illustrated in Figs 1 and 2 or Figs 1 and 2 and modified by Fig 3 of the accompanying drawings.