JP4908060B2 - Optical wall terminal - Google Patents

Description

  The present invention relates to an optical wall surface terminal provided on a wall surface or the like that converts an optical signal transmitted by an optical fiber into an electric signal and outputs the electric signal.

  In recent years, with the spread of high-speed and high-bandwidth communication services, communication services for connecting homes and transmitting stations with optical cables have been implemented. In this communication service, an optical receiver converts an optical signal supplied from an optical fiber into an electrical signal using an optical-electrical signal, distributes the converted electrical signal, and outputs it from a wall terminal provided on the wall surface. is doing. The television receiver and the recorder are connected to the wall surface terminal by a coaxial cable so as to receive an electric signal.

FIG. 6 is a block diagram showing a configuration example of a conventional receiving system 100 using such an optical fiber.
In the conventional receiving system 100 shown in FIG. 6, a television signal received by the receiving antenna 110 is supplied to the head end 111. The receiving antenna 110 is an antenna for BS digital broadcasting, CS digital broadcasting, terrestrial digital broadcasting, terrestrial analog broadcasting, and the like. The head end 111 receives BS digital broadcasting, CS digital broadcasting, terrestrial digital broadcasting, terrestrial analog broadcasting, etc. Channels such as independent broadcasting are channel-multiplexed and supplied to the optical transmitter 112. The optical transmitter 112 converts the multiplexed signal that has been channel-multiplexed into an optical signal and sends it to an optical fiber. The optical signal is propagated through the optical fiber via the optical coupler group 113, and one of the optical fibers through which the distributed optical signal propagates is introduced into the home. In the home, an optical receiver 114 is provided, and the optical receiver 114 converts the optical signal into an original channel-multiplexed electrical signal.

The electrical signal output from the optical receiver 114 is distributed into a plurality by the distributor 115, and each of the distributed electrical signals is output from the wall surface terminals 120a, 120b,... 120n provided on the wall surface in the house. The The wall surface terminals 120a to 120n are provided with a coaxial terminal, and by connecting a coaxial cable having one end connected to the television receivers 121a, 121b,. Electric signals are supplied to ˜121n so that a television signal of a desired channel can be viewed.
However, the amount of signal attenuation from the optical receiver 114 to the wall surface terminals 120a to 120n is large, and there is a problem in that good viewing may not be performed on the television receivers 121a to 121n. For example, if the distribution number of the distributor 115 is four distributions, the UHF broadcast signal is attenuated by about 11 dB, the BS satellite broadcast signal is attenuated by about 13 dB, and the CS satellite broadcast signal is caused by the propagation loss due to the coaxial cable and the distribution loss of the distributor 115. Is attenuated by about 16.5 dB and is output from the wall surface terminals 120a to 120n. Thus, it has been proposed that an optical fiber is wired in place of a coaxial cable in a house, but there is a problem that there is no wall surface terminal that can use the optical fiber.

  Then, this invention aims at providing the optical wall surface terminal which can utilize an optical fiber.

  In order to achieve the above object, an optical wall terminal of the present invention is supplied with an optical signal transmitted by an optical fiber, converts the optical signal into an electrical signal, and outputs the electrical circuit unit. The main feature is that it includes an output terminal that outputs an electrical signal to be output.

  According to the present invention, an electronic circuit unit that is supplied with an optical signal transmitted through an optical fiber, converts the optical signal into an electrical signal, and outputs the electrical signal, and an output terminal that outputs an electrical signal output from the electronic circuit unit Therefore, it is possible to provide an optical wall surface terminal that converts an optical signal propagated through the optical fiber by introducing an optical fiber into an electrical signal and outputs the electrical signal. When this optical wall terminal is provided in the house, the optical fiber is wired in the house instead of the coaxial cable, and the optical fiber is hardly affected by noise so that the SN ratio can be improved. Become. In addition, since the electric signal output from the electronic circuit unit is not distributed, the output power of the output electric signal can be reduced, so that the power consumption of the electronic circuit unit can be reduced.

FIG. 1 is a block diagram showing a configuration of a receiving system 1 using an optical wall terminal according to the present invention.
In the receiving system 1 using the optical wall surface terminal according to the present invention shown in FIG. 1, a television signal received by the receiving antenna 10 is supplied to the head end 11. The receiving antenna 10 is an antenna for BS digital broadcasting, CS digital broadcasting, terrestrial digital broadcasting, terrestrial analog broadcasting, etc., and the head end 11 receives BS digital broadcasting, CS digital broadcasting, terrestrial digital broadcasting, terrestrial analog broadcasting, etc. Channels such as independent broadcasting are channel-multiplexed and supplied to the optical transmitter 12. The optical transmitter 12 converts the multiplexed signal that has been channel-multiplexed into an optical signal and sends it to an optical fiber on the network. The optical signal is propagated through the optical fiber through the optical coupler group 13 constituting the network, and one of the optical fibers through which the distributed optical signal propagates is introduced into the home. In the house, an optical distributor 20 is provided, and each of the optical signals distributed by the optical distributor 20 is guided to optical wall terminals 21a, 21b,.

Each of the optical wall terminals 21a, 21b,... 21n includes an RF unit that converts an optical signal into an electrical signal, as will be described later. The wall surface terminals 21a, 21b,... 21n are converted into the original channel multiplexed electrical signals. Electric signals output from the optical wall surface terminals 21a, 21b,... 21n are output from coaxial terminals provided on the optical wall surface terminals 21a, 21b,. When a coaxial cable having one end connected to the television receivers 22a, 22b,... 22n is connected to the coaxial terminal, an electric signal is supplied to each television receiver 22a, 22b,. You can watch TV signals of channels.
Thus, when providing the optical wall surface terminal in the house, the optical fiber is wired in the house instead of the coaxial cable. Then, since the optical fiber is hardly affected by noise, the SN ratio can be improved, and the television receivers 22a to 22n can view a television signal that is not affected by noise. In addition, since the propagation loss of the optical signal through the optical fiber is extremely small, the optical signal receives only the distribution loss from the optical distributor 20. For example, if the number of distribution of the optical distributor 20 is four, an optical signal in which channels such as BS digital broadcasting, CS digital broadcasting, terrestrial digital broadcasting, analog terrestrial broadcasting and independent broadcasting are channel-multiplexed receives only about 8 dB of distribution loss. Therefore, these channels can be satisfactorily viewed on the television receivers 22a to 22n.

Next, FIG. 2 and FIG. 3 show a configuration example of the optical wall surface terminals 21a, 21b,... 2 is a perspective view showing a front configuration of the optical wall terminal 21, and FIG. 3 is a perspective view showing a rear configuration of the optical wall terminal 21. As shown in FIG.
As shown in these drawings, the optical wall surface terminal 21 is provided with a metal or synthetic resin casing 32. The casing 32 is embedded in the wall leaving the front panel, and the front panel is substantially the same as the wall surface. It is attached to be on the same plane. The front panel of the casing 32 is supplied with a coaxial plug 33 that outputs an electrical signal obtained by converting an optical signal, a pilot lamp 34 that is lit when operating power is supplied to the optical wall surface terminal 21, and operating power. A DC power jack 35 is provided. An RF unit 38 including an optical adapter 37 is built in the housing 32, and an optical connector 36 provided at the tip of the optical fiber 31 is attached to the optical adapter 37. As a result, the optical signal propagated through the optical fiber 31 is input to the RF unit 38. In the RF unit 38, the input optical signal is converted into an electrical signal and output from the coaxial plug 33. The operating power of the RF unit 38 can be supplied from the DC power jack 35, and the DC power supplied from the coaxial plug 33 can be used as the operating power.

Next, a circuit block diagram showing an example of the circuit configuration of the RF unit 38 is shown in FIG.
In the RF unit 38 shown in FIG. 4, an optical input signal input from the optical adapter 37 is converted into an electrical signal by a photodiode (PD) 41. The electrical signal converted by the PD 41 is preamplified at a first amplification unit 42 with a predetermined amplification degree and supplied to an AGC (Automatic Gain Control) 43. The AGC 43 is a circuit that variably controls the gain so that the output electric signal level is constant even when the level of the optical input signal changes. The electric signal controlled to have a constant level by the AGC 43 is amplified to a required level by the second amplifying unit 44 and is output from the coaxial plug 33 as an RF output. In this case, the control unit 46 controls the AGC 43 in accordance with the level of the electrical signal converted by the PD 41 (the level of the optical input signal), so that even if the level of the optical input signal changes, the control unit 46 outputs from the coaxial plug 33. The level of the RF signal to be controlled is controlled to be constant. The RF output is supplied to television receivers 22a to 22n and a recorder connected to the coaxial plug 33 via a coaxial cable, so that a program on a desired channel can be sampled and recorded.

  By the way, the television receivers 22a to 22n and the recorder are provided with an input terminal for inputting an RF signal through a coaxial cable. A DC power source supplied from this input terminal to an antenna for receiving satellite broadcasts is provided. There are models that can output. In this way, when the DC power can be output from the television receivers 22a to 22n or the input terminal of the recorder, the RF unit 38 uses the DC power supplied from the coaxial connector 33 via the power line. The second amplifier 44, the controller 46, the first amplifier 42 and the PD 41 are supplied. When the DC power is not supplied from the coaxial connector 33, the DC power supply 35 is supplied with DC power from outside, so that the supplied DC power is supplied to the second amplifying unit 44 and the control unit via the power line. 46, the first amplifier 42 and the PD 41 are supplied. By the way, since the electrical signal output from the optical wall surface terminal 21 is not distributed, the output power of the output electrical signal can be reduced. For this reason, since the power consumption of the 2nd amplification part 44 can be reduced, the power consumption of RF unit 38 can be reduced now. For example, the power consumption of the RF unit 38 can be about 1.5 W (about 0.1 A at 15 VDC). The power consumption of the optical receiver 114 in the conventional receiving system 100 shown in FIG. 6 is about 5 W (about 0.3 A at 15 VDC).

Next, FIG. 5 shows a circuit block diagram showing another example of the circuit configuration of the RF unit.
The RF unit 38 ′ shown in FIG. 5 is different from the RF unit 38 shown in FIG. 4 only in the configuration in which an attenuator (ATT) 47 is provided instead of the AGC 43. In the RF unit 38 ′, the optical input signal input from the optical adapter 37 is converted into an electric signal by the photodiode (PD) 41. The electrical signal converted by the PD 41 is preamplified at a predetermined amplification degree in the first amplifying unit 42 and supplied to the ATT 47. The ATT 47 is an attenuator for attenuating the electric signal. The level of the electric signal output from the first amplifying unit 42 is attenuated so that the output electric signal level becomes a predetermined level. The electric signal whose level is controlled by the ATT 47 is amplified to a level required by the second amplifying unit 44 and is output from the coaxial plug 33 as an RF output. The RF output is supplied to television receivers 22a to 22n and a recorder connected to the coaxial plug 33 via a coaxial cable, so that a program on a desired channel can be sampled and recorded.

  Here, when the DC power can be output from the input terminals of the television receivers 22a to 22n or the recorder, the RF unit 38 ′ uses the DC power supplied from the coaxial plug 33 via the power line. The second amplifying unit 44, the first amplifying unit 42, and the PD 41 are supplied. When the DC power is not supplied from the coaxial connector 33, the DC power jack 35 is supplied with DC power from outside, so that the supplied DC power is supplied to the second amplifying unit 44, the first through the power line. The signal is supplied to the amplifying unit 42 and the PD 41. Note that since the power consumption of the second amplifying unit 44 can be reduced as described above, the power consumption of the RF unit 38 'can be reduced. Moreover, the attenuation amount of the signal to the wall surface terminal can be reduced.

  In the optical wall surface terminal described above, the optical fiber introduced into the optical wall surface terminal generally has an extra length portion due to the convenience of wiring. Therefore, an extra length accommodating portion for accommodating the extra length portion of the optical fiber may be provided in the casing of the optical wall surface terminal or around the casing.

It is a block diagram which shows the structure of the receiving system using the optical wall surface terminal concerning this invention. It is a perspective view which shows the structure of the front of the optical wall surface terminal concerning this invention. It is a perspective view which shows the structure of the back surface of the optical wall surface terminal concerning this invention. It is a circuit block diagram which shows an example of the circuit structure of RF unit in the optical wall surface terminal concerning this invention. It is a circuit block diagram which shows the other example of the circuit structure of RF unit in the optical wall surface terminal concerning this invention. It is a block diagram which shows the structural example of the conventional receiving system using an optical fiber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reception system, 10 Reception antenna, 11 Head end, 12 Optical transmitter, 13 Optical coupler group, 20 Optical distributor, 21 Optical wall terminal, 21a-21n Optical wall terminal, 22a-22n Television receiver, 31 Optical fiber, 32 housing, 33 coaxial plug, 34 pilot lamp, 35 DC power jack, 36 optical connector, 37 optical adapter, 38 RF unit, 42 first amplification unit, 44 second amplification unit, 46 control unit, 100 receiving system, 110 receiving antenna, 111 head end, 112 optical transmitter, 113 optical coupler group, 114 optical receiver, 115 distributor, 120a-120n wall terminal, 121a-121n television receiver

Claims (3)

An electronic circuit unit that is supplied with an optical signal transmitted by an optical fiber, converts the optical signal into an electrical signal, and outputs the electrical signal;
An output terminal for outputting the electrical signal output from the electronic circuit unit;
For receiving satellite broadcasts from a receiving means such as a television receiver or a recorder connected to the output terminal via a cable and receiving the electric signal output from the output terminal to the electronic circuit unit via the output terminal . An optical wall surface terminal provided on a wall surface or the like, characterized in that a direct-current power supplied to the antenna is supplied . 2. The light provided on a wall surface or the like according to claim 1, wherein the electronic circuit unit has an optical adapter, and an optical connector provided at a tip of the optical fiber is attached to the optical adapter. Wall terminal. 3. An optical wall surface terminal provided on a wall surface or the like according to claim 1, further comprising a surplus length storage portion for storing a surplus length portion of the optical fiber.

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