Antenna system for receiving broadcast or communication signals from satellite

Abstract: A satellite broadcast receiving system is disclosed, in which when each receiver transmits control pulse to a change-over divider via a signal cable, the change-over divider selects a desired broadcast signal in response to the control pulse, which is led to its output terminal, then transmitted to each receiver via the signal cable.

Description: The present invention relates to a satellite broadcast receiving system and a change-over divider for use in this system. In the near future, satellite broadcast may include Communication Satellite (CS) broadcast using a communication satellite in addition to Broadcast Satellite (BS) broadcast which is actually in execution. Further, CS broadcast may be performed by a plurality of communication satellites. Due to the fact that the height and position of the broadcast satellites and communication satellites are different from each other, a receiver cannot catch all radio waves transmitted therefrom by a single satellite antenna, and thus it should be provided with a plurality of satellite antennas. Additionally, due to overlap of a transmission frequency band of a signal cable for each broadcast, a single signal cable is not sufficient to transmit signals at the same time. Accordingly, when dividing broadcast signals among a plurality of receivers by using a plurality of common satellite antennas, signal cables corresponding to the number of signals are needed to connect a change-over divider to each receiver, resulting in extremely complicated connection. Further, some people cannot dispose a plurality of signal cables according to their domestic conditions. It is, therefore, an object of the present invention to provide a satellite broadcast receiving system and a change-over divider for use in this system which contribute to a simplification of the architecture and a reduction in manufacturing cost. Document JP-A-3/58521 describes a single receiver than can switch between signals received from a plurality of antennas. Document WO 91/00646 describes, as prior art, a system having a plurality of antennas which provide signals to a matrix switcher which in turn outputs signals selected from its input signals to a plurality of demodulators. According to one aspect of the present invention, there is provided a system for receiving broadcast and communication signals, comprising: a plurality of antennas disposed to receive the broadcast and communication signals and a plurality of receivers for receiving the signals commonly from the antennas; a plurality of converters disposed to correspond to said plurality of antennas, for converting received frequencies into predetermined frequencies; and a change-over divider connected to said plurality of antennas and having a plurality of output terminals, said change-over divider separately outputting predetermined ones of the broadcast and communication signals to said plurality of output terminals, respectively; each of said receivers being connected to one of said output terminals of said change-over divider, characterised in that each receiver is adapted to provide a control pulse to said change-over divider for selecting one of said plurality of antennas, respectively; and in that said plurality of receivers are adapted to provide DC power voltage to said plurality of converters, respectively, through said change-over divider. According to another aspect of the present invention, there is provided a change-over divider according to claim 4. The invention will be further described by way of example only, with reference to the accompanying drawings, in which:- Fig. 1 is a circuit block diagram showing a change-over divider (first preferred embodiment); Fig. 2 is a view similar to Fig. 1, showing a satellite broadcast receiving system (first preferred embodiment); and Fig. 3 is a view similar to Fig. 2, showing a broadcast receiving system (second preferred embodiment). Referring to the drawings, wherein like reference numerals designate corresponding parts throughout the views, referring first to Figs. 1 and 2, a first preferred embodiment of the present invention will be described. Fig. 2 shows a circuit block diagram of a satellite broadcast receiving system. Three antennas are disposed as a satellite antenna: BS antenna 1, CS 1 antenna 2, and CS 2 antenna 3. The BS antenna 1 serves to collect BS broadcast wave, and the CS 1 antenna 2 serves to collect CS 1 broadcast wave, and the CS 2 antenna 3 serves to collect CS 2 broadcast wave. BS broadcast wave as collected by the BS antenna 1 is a circularly polarized wave, and it is received in a BS converter 4. A single BS broadcast signal is converted in the BS converter 4 to have a predetermined frequency, then led to a first input terminal t 1 of a change-over divider 6 via a signal cable 5. CS 1 broadcast wave as collected by the CS 1 antenna 2 is two linearly polarized waves which meet at right angles, and it is received in a CS 1 converter 7. A horizontally polarized broadcast signal and a vertically polarized broadcast signal are converted in the CS 1 converter 7 to have a predetermined frequency, respectively, then led to second and third input ternimals t 2 , t 3 of the change-over divider 6 via two signal cables 8, 9, respectively. CS 2 broadcast wave as collected by the CS 2 antenna 3 is two linearly polarized waves like CS 1 broadcast wave, and it is received in a CS 2 converter 10. A holo-zontally polarized broadcast signal and a vertically polarized broadcast signal are converted in the CS 2 converter 10 to have a predetermined frequency, respectively, then led to fourth and fifth input temimals t 4 , t 5 of the change-over divider 6 via two signal cables 11, 12, respectively. The change-over divider 6 has four output terminals t 6 -t 9 , and separately selects a desired one of the five input broadcast signals to output it thereto. A detailed architecture thereof is shown in Fig. 1. The output terminals t 6 -t 9 are connected to signal cables 13-16 at one ends thereof, respectively. The signal cables 13-16 have the other ends connected to BS/CS receivers 17-20, respectively. The BS/CS receivers 17-20 are constructed to output converter power supply (DC power voltage) via the signal cables 13-16 when turned on by a power switch. Additionally, the BS/CS receivers 17-20 have a broadcast selecting switch, respectively, which permits selection of five kinds of broadcast such as BS broadcast, CS 1 horizontally polarized wave broadcast, etc. Information selected by the broadcast selecting switch is converted into control pulse in a pulse code circuit, which is outputted in overlapping with converter power supply via each of the signal cables 13-16. Fig. 1 shows a circuit block diagram of the change-over divider 6. The change-over divider 6 is provided with first to fourth change-over switches SW 1 -SW 4 corresponding to the number of the output terminals t 6 -t 9 , each receiving all the five input broadcast signals. The change-over switches SW 1 -SW 4 select one of the five broadcast signals in response to changeover control signal, respectively. This broadcast signal as selected is provided to the output terminals t 6 -t 9 via a diode D 1 and a control pulse trap circuit 21. The output terminals t 6 -t 9 are connected via a coil L and a diode D 2 to a regulator 22, respectively, which provides constant voltage to a control pulse detection circuit 23 and a microcomputer 24. Additionally, the output terminals t 6 -t 9 are connected via the coil L to the control pulse detection circuit 23, respectively, which detects control pulse as transmitted to output it to the microcomputer 24. The microcomputer 24 decodes control pulse, and outputs change-over control signals to the first to fourth change-over switches SW 1 -SW 4 corresponding to the output terminals t 6 -t 9 to which selected information is inputted in accordance with this selected information as decoded. Next, the operation of this embodiment will be described. One of the four BS/CS receivers 17-20, for example, the BS/CS receiver 17, is turned on by the power switch, and selects BS broadcast by the broadcast selecting switch. Then, converter power supply is outputted via the signal cable 13 while control pulse is outputted in overlapping with this. Since control pulse is a digital signal, it is hardly affected by voltage fluctuation, resulting in sure transmission. The regulator 22 receives converter power supply, and provides power supply to the control pulse detection circuit 23 and the microcomputer 24. The microcomputer 24 receives control pulse from the control pulse detection circuit 23, and it decodes this control pulse and outputs change-over control signal to the first change-over switch SW 1 . The first change-over switch SW 1 selects a BS broadcast terminal. Converter power supply is provided from the first change-over switch SW 1 to the BS converter 4 via the signal cable 5. By this, the BS converter 4 is driven to output BS broadcast signal. This BS broadcast signal as outputted is led to the change-overdivider 6 via the signal cable 5 so as to reach the first output terminal t 6 via the first change-over switch SW 1 . Then, it is outputted to the BS/CS receiver 17 via the signal cable 13. In this situation, when the other BS/CS receivers 18-20 are also turned on and select a desired broadcast signal, respectively, the second to fourth change-over switches SW 2 -SW 4 select a desired broadcast signal terminal, respectively. Converter power supply is provided to the CS 1 converter 7 and CS 2 converter 10 as selected, which are thus driven to output desired broadcast signals to the BS/CS receivers 18-20. Accordingly, disposing a single signal cable 13-16 to connect each of the BS/CS receivers 17-20 to the change-over divider 6 is sufficient to separately receive a desired broadcast. Referring to Fig. 3, a second preferred embodiment of the present invention will be described. The second preferred embodiment is constructed to be a system capable of receiving Ultra High Frequency (UHF) broadcast and Very High Frequency (VHF) in addition to satellite broadcast. Fig. 3 shows a circuit block diagram of a broadcast receiving system. Outputs of a UHF antenna 25 and a VHF antenna 26 are inputted to a UHF/VHF mixer 27 in which a UHF broadcast signal and a VHF broadcast signal are mixed together. Output of the UHF/VHF mixer 27 is led to a sixth input terminal t 10 of a U.V mixer=change-over divider 29 via a signal cable 28. The U.V mixer=change-over divider 29 has first to fifth input terminals t 1 -t 5 to which the same broadcast signals as the first preferred embodiment are inputted, and to which the change-over divider 6 having the same architecture as the first preferred embodiment is connected. Outputs of the change-over divider 6 are inputted to the BS.CS/U.V mixers 30-33, respectively, to which the sixth input terminal t 10 connected, and in which satellite wave and ground wave are mixed together. Outputs of the mixers 30-33 are led to the first to fourth output terminals t 6 -t 9 , respectively. The output terminals t 6 -t 9 are connected to the signal cables 13-16 at one ends thereof, respectively. The signal cables 13-16 have the other ends connected to BS.CS/U.V separators 34-37, respectivety. The separators 34-37 serve to separate satellite wave and ground wave, and output satellite wave to the BS/CS receivers 17-20 and ground wave to televisions (TVs) 38-41, respectively. In this second preferred embodiment, the BS/CS receivers 17-20 can separately receive not only satellite broadcasts, but TVs 38-41, and UHF and VHF broadcasts. In the above embodiments, the number of the output terminals t 6 -t 9 is four, but it is not limited thereto and may be another.

Claims: A system for receiving broadcast and communication signals, comprising: a plurality of antennas (1-3) disposed to receive the broadcast and communication signals and a plurality of receivers (17-20,38-41) for receiving the signals commonly from the antennas (1-3,25,26); a plurality of converters (4,7,10) disposed to correspond to said plurality of antennas (1-3), for converting received frequencies into predetermined frequencies; and a change-over divider (6) connected to said plurality of antennas (1-3,25,26) and having a plurality of output terminals (t 6 -t 9 ), said change-over divider (6) separately outputting predetermined ones of the broadcast and communication signals to said plurality of output terminals (t 6 -t 9 ), respectively; each of said receivers (17-20,38-41) being connected to one of said output terminals (t 6 -t 9 ) of said change-over divider (6); characterised in that each receiver (17-20,38-41) is adapted to provide a control pulse to said change-over divider (6) for selecting one of said plurality of antennas (1-3,25,26), respectively; and in that said plurality of receivers (17-20,38-41) are adapted to provide DC power voltage to said plurality of converters (4,7,10), respectively, through said change-over divider (6). A system as claimed in claim 1, wherein said plurality of antennas (1-3) are of a type capable of receiving waves from satellites. A system as claimed in claim 1 or 2 further comprising: another antenna (25,26) without converter disposed to receive another signal; and another receiver connected to said changeover divider (6), said another receiver providing no control pulse and no DC power voltage. A change-over divider for selecting signals, comprising: a plurality of input terminals (t 1 -t 5 ); a plurality of switches (SW 1 -SW 4 ) each connected to said plurality of input terminals (t 1 -t 5 ) ; and a plurality of output terminals (t 6 -t 9 ) connected to outputs of said plurality of switches (SW 1 -SW 4 ); characterised by further comprising a control pulse detection circuit (23) connected to each of said plurality of output terminals (t 6 -t 9 ) for detecting a control pulse thereat; separator circuit means (21) for separating said control pulse from DC power voltage; and a microcomputer (24) connected to each of said plurality of switches (SW 1 -SW 4 ) and said control pulse detection circuit (23) for decoding a detected control pulse and outputting a change-over control signal to one of said plurality of switches (SW 1 -SW 4 ) in response to said control pulse as decoded, whereby said one of said plurality of switches (SW 1 -SW 4 ) selects a predetermined one of the signals in response to said change-over control signal of said microcomputer (24).

Inventors: FUKUZAWA KEIJI, KAJIWARA TADASHI, NAKAGAWA YUTAKA, YUZAWA KEIJI, FUKUZAWA, KEIJI, KAJIWARA, TADASHI, NAKAGAWA, YUTAKA, YUZAWA, KEIJI
Applicants: SONY CORP, SONY CORPORATION
Application year: 1992
Main classification: H04H1
IPC codes: H04H20, H04B1, H04N5, H04B7, H04N7, H04H40