JP2008153870A - Antenna improper connection preventing device and rf signal generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the improper connection of an antenna, that is, RF radio wave discharge consequently. <P>SOLUTION: The improper connection preventing device 16 is disposed between an IP/RF conversion circuit 12 for converting IP signals to RF signals and an RF output terminal 14. The improper connection preventing device 16 includes a switch 18 functioning as an interruption device for interrupting the output RF signals of the IP/RF conversion circuit 12 in the case of the improper connection. A circulator 20 is disposed between the switch 18 and the RF output terminal 14, and the circulator 20 transfers the RF signals from the RF output terminal 14 to an RF signal level detector 22. The RF signal level detector 22 detects the level of the VHF or UHF band of input RF signals and opens the switch 18 when the detected level is a prescribed threshold or higher. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antenna misconnection prevention device and an RF signal generation device, and more specifically, an antenna misconnection prevention device and an RF signal generation for preventing an erroneous connection to an antenna wire that radiates radio waves into space. Relates to the device.

  Currently, studies are being made on broadcast wave retransmission technology (hereinafter, IP retransmission) using an IP network for the purpose of spreading terrestrial digital broadcasting. In the future, televisions or set-top boxes (STBs) that support IP retransmission will be developed, and the number of users may increase.

  On the other hand, televisions that are compatible with terrestrial digital broadcasting are already prevalent, but it is assumed that these replacement demands will occur before or after the terrestrial analog wave is stopped. In addition, considering the support status including peripheral devices such as video recording devices, even if IP-compatible TVs become widespread in the future, it is highly likely that video devices with RF format input terminals will continue to be used. It is done.

  As one method to spread terrestrial digital broadcast retransmission technology by IP retransmission early and widely, broadcast signals that reach the doorway of the house or apartment as IP signals are converted again into analog or digital broadcast signals in RF format in the house Then, a method of distributing to each room via existing in-house coaxial wiring and reproducing the broadcast signal on an existing TV installed in each room or a TV with built-in digital terrestrial tuner is being studied.

  FIG. 2 shows a schematic block diagram of a home IP broadcast signal receiving system. The access line termination device 210 is a device that terminates a signal from the access line 212 and outputs an IP signal 214 in each residence of each individual house or apartment. Here, it is assumed that the access line 212 is a broadband line that can use a high-speed Internet connection service represented by FTTH (Fiber To The Home). IP signal 214 includes a broadcast wave signal converted into an IP format.

  The IP / RF signal conversion device 216 extracts a broadcast signal included in the IP signal 214 and outputs the broadcast signal as an RF signal 218 in a terrestrial digital broadcast format. The RF signal 218 is input to a distributor 222 previously separated from the VHF / UHF antenna 220 via a coaxial cable, and an existing TV image is received via the existing coaxial cable 224, distributor 226, and coaxial cables 228 to 232. Supplied to the devices 234, 236, the recording device 238, and the like. Coaxial cables 228 to 232 are connected to the coaxial outlet in each room.

  In the future, when a broadcast signal, for example, a terrestrial digital broadcast signal is transmitted using an IP network, an IP / RF signal converter 216 is provided in each dwelling unit. Normally, the output RF signal of the IP / RF signal converter 216 is connected to the distributor separated from the VHF / UHF antenna. However, the user or the contractor mistakenly connects the VHF / UHF antenna from the distributor. If you forget to remove the signal, an RF signal will be radiated from the antenna.

  FIG. 3 shows an example of miswiring where both the VHF / UHF antenna 220 and the IP / RF signal converter 216 are connected to the distributor 222. In this example, the RF signal 218 output from the IP / RF signal converter 216 is supplied not only to the TV receivers 234 and 236 but also to the VHF / UHF antenna 220 as indicated by the broken line, Electromagnetic radiation is emitted from the VHF / UHF antenna 220. The VHF / UHF antenna 220 includes an antenna in which a VHF antenna and a UHF antenna are coupled in parallel, includes only a UHF antenna, or includes only a VHF antenna.

  FIG. 4 shows another example of miswiring. In this example, the VHF / UHF antenna 220 is originally miswired on the output side of the distributor 122, and the IP / RF signal converter 216 is connected to the distributor 222 while keeping the connection of the VHF / UHF antenna 220 as it is. Is connected to the input side. Even when the VHF / UHF antenna 220 is connected to the output side of the distributor 222, the broadcast signal received by the VHF / UHF antenna 220 is transmitted to the TV receivers 234 and 236 connected to the same distributor 222 due to the signal wraparound. As a result, the TV receivers 234 and 236 are in a state in which a television broadcast can be viewed. Therefore, such miswiring may be overlooked.

  In this state, since the input side of the distributor 222 is vacant, the contractor does not notice the incorrect wiring of the VHF / UHF antenna 220 and outputs the output of the IP / RF signal converter 216 to the input side of the distributor 222. It can happen to be connected. In the connection state shown in FIG. 4, the output RF signal of the IP / RF signal conversion device 216 is distributed to the VHF / UHF antenna 220, so that it is electromagnetically radiated from the VHF / UHF antenna 220.

  There are some conventional video decks equipped with an RF output terminal, but these are those that tap the input signal of the RF input terminal and output it, and do not spontaneously output the RF signal. So far, such problems have not been revealed.

  It is an object of the present invention to provide an antenna misconnection prevention device that can prevent broadcast signals from being emitted due to such incorrect wiring.

  An antenna misconnection prevention device according to the present invention includes a blocking device that passes / blocks an RF signal, an RF signal level detection device that detects an RF signal level of an input signal, and controls the blocking device according to a detection result, and the blocking A circulator for transferring the output signal of the device to the RF output terminal and transferring the signal from the RF signal output terminal to the RF signal level detection device, and the RF signal level detection device receives the signal from the circulator. When the RF signal of a predetermined level or more is included, the blocking device is controlled to be in a passing state

  An RF signal generation device according to the present invention includes the above-described antenna erroneous connection prevention device and an RF signal supply device that supplies the RF signal to the antenna erroneous connection prevention device.

  According to the present invention, for example, an erroneous connection of an antenna to an RF signal supply device installed in a home, for example, an IP / RF conversion device can be detected in advance, and radio waves can be prevented from being radiated to the outside.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic block diagram of an embodiment of the present invention. For explanation, FIG. 1 shows an erroneous connection state.

  The IP / RF signal conversion device 10 is provided between an IP / RF conversion circuit 12 that converts an IP signal into an RF signal, and between the IP / RF conversion circuit 12 and the RF output terminal 14 and prevents erroneous connection. Device 16. The IP / RF conversion circuit 12 corresponds to a conventional IP / RF signal conversion device 216.

  In the case of an incorrect connection, the erroneous connection prevention device 16 has a switch 18 that functions as a cutoff device that cuts off the output RF signal of the IP / RF conversion circuit 12, a circulator 20, and the level of the VHF or UHF band of the input RF signal. An RF signal level detection device 22 that detects and opens the switch 18 when the detection level is equal to or higher than a predetermined threshold value.

  A VHF / UHF antenna 32 is connected to the RF output terminal 14 via an RF coaxial transmission line 30 including distributors 222 and 226 and coaxial cables 124, 228, 230, and 232. With correct wiring, instead of the VHF / UHF antenna 32, a TV receiver or a video recording device is connected.

  The output of the IP / RF conversion circuit 12 is connected to the port A of the circulator 20 via the switch 18. The port B of the circulator 20 is connected to the RF output terminal 14, and the port C is connected to the input of the RF signal level detector 22. The circulator 20 is a circuit element that outputs an input signal of the port A from the port B and outputs an input signal of the port B from the port C.

  In the erroneous connection state shown in FIG. 1, the RF signal received from the outside by the VHF / UHF antenna 32 is input to the port B of the circulator 20 via the RF coaxial transmission line 30 and the RF output terminal 14. Since the circulator 20 outputs the input signal of the port B from the port C, the RF signal received from the outside by the VHF / UHF antenna 32 is eventually input to the RF signal level detection device 22. The RF signal level detection device 22 detects the level of the RF signal component in the signal input from the port C of the circulator 20, and opens the switch 18 when the detected level is equal to or higher than the threshold value. The switch 18 is closed.

  By setting the threshold of the RF signal level detection device 22 to a value that can determine whether or not the VHF / UHF antenna 32 is connected to the RF output terminal 14, the RF signal level detection device 22 14 can determine whether or not the VHF / UHF antenna 32 is erroneously connected.

  In this embodiment, when the VHF / UHF antenna 32 is receiving a broadcast wave, the switch 18 is opened and the output RF signal of the IP / RF conversion circuit 12 does not reach the port A of the circulator 20. Therefore, the output RF signal of the IP / RF conversion circuit 12 is not supplied to the erroneously connected VHF / UHF antenna 32 and is not emitted to the outside as radio waves.

  On the other hand, when the VHF / UHF antenna 32 is not connected to the RF output terminal 14, the switch 18 is closed and the output RF signal of the IP / RF conversion circuit 12 is input to the port A of the circulator 20. The circulator 20 outputs an RF signal input to the port A from the port B to the RF output terminal 14. As a result, the output RF signal of the IP / RF conversion circuit 12 is transmitted to a TV receiver or a video device (not shown) connected to the RF coaxial transmission line 30.

  Obviously, the erroneous connection prevention device 16 may be configured as a single device separate from the IP / RF conversion device 12. In this case, the erroneous connection prevention device 16 is connected between the RF output terminal of the existing IP / RF conversion device 116 and the RF transmission coaxial cable.

  In the above embodiment, the broadcast signal sent in the IP format is reconverted to the RF signal format using the IP / RF signal conversion device 12 installed in the doorway of the house or apartment, Although the case where distribution to a room is assumed has been described, it is obvious that the present invention can be applied to other systems in which an RF signal is generated in a home and the signal is transferred using coaxial wiring.

  Although the invention has been described with reference to specific illustrative embodiments, various modifications and alterations may be made to the above-described embodiments without departing from the scope of the invention as defined in the claims. This is obvious to an engineer in the field to which the present invention belongs, and such changes and modifications are also included in the technical scope of the present invention.

It is a schematic block diagram of Example 1 of the present invention. It is a schematic block diagram of a prior art example. It is a schematic diagram explaining the transmission form of RF signal in a divider | distributor. It is a schematic diagram explaining another transmission form of RF signal in a divider | distributor.

Explanation of symbols

10: IP / RF signal conversion device 12: IP / RF conversion circuit 14: RF output terminals 16, 16a: incorrect connection prevention device 18: switch 20: circulator 22: RF signal level detection device 30: RF coaxial transmission line 32: VHF / UHF antenna 40: test signal generator 42: mixer 210: access line terminator 212: access line 214: IP signal 216: IP / RF signal converter 218: RF signal 220: VHF / UHF antenna 222: distributor 224 : Coaxial cable 226: Distributor 228, 230, 232: Coaxial cable 234, 236: TV receiver 238: Recording device

Claims (3)

A blocking device (18) for passing / blocking the RF signal;
An RF signal level detection device (22) for detecting the RF signal level of the input signal and controlling the blocking device (18) according to the detection result;
A circulator (20) for transferring the output signal of the blocking device (18) to the RF output terminal (14) and transferring the signal from the RF signal output terminal (14) to the RF signal level detection device (22).
And
The RF signal level detecting device (22) controls the blocking device to a passing state when the signal from the circulator (20) includes an RF signal of a predetermined level or higher, and prevents erroneous antenna connection, apparatus. An antenna misconnection prevention device according to claim 1;
RF signal supply device (12) for supplying the RF signal to the antenna misconnection prevention device
An RF signal generator characterized by comprising:   The RF signal generation device according to claim 2, wherein the RF signal supply device (12) is an IP / RF conversion device that converts a broadcast signal carried by an IP signal into the RF signal.

Images