JP2008236360A - Power line communication device - Google Patents

Abstract

A power line communication device capable of ensuring better communication quality is provided.
A power line communication device (PLC modem 1) capable of transmitting and receiving a power line communication signal using a power line as a signal transmission path is provided with a coaxial line connector 11 for connecting a coaxial line, and the power line and the coaxial line are simultaneously connected to the same system. An input / output circuit 9 is provided for outputting power line communication signals and inputting power line communication signals from each system.
[Selection] Figure 1

Description

  The present invention relates to a power line communication device (PLC modem) in power line communication (PLC) using a power line as a signal transmission path.

  Power line communication is a communication method in which a data communication signal is superimposed on a commercial AC voltage (current) using a power line as a signal transmission line, and has an advantage that there is no need to newly perform communication wiring (for example, non-patent) Reference 1). In recent years, attention has been focused on power line communication using indoor wiring as a communication method for constructing a LAN (local area network) in a home or office.

Interface, pp. 70-81, “Current Status of Power Line Communication (PLC)”, Kiyoshi Eto, CQ Publishing, September 2000

However, power lines for indoor wiring generally have many branches, and therefore, signals for power line communication are attenuated, and good communication quality (communication speed) may not be ensured.
In view of the conventional problems as described above, an object of the present invention is to provide a power line communication apparatus that can ensure better communication quality.

  The present invention is a power line communication device capable of transmitting and receiving power line communication signals using a power line as a signal transmission path, comprising a connector for connecting a communication line, and simultaneously supplying the same power line to the two systems of the power line and the communication line. It has a function of outputting a communication signal and inputting a power line communication signal from each system.

  In the power line communication device configured as described above, for example, the same connection is established by connecting the existing communication line terminal indoors provided for receiving TV broadcasts and the connector of one power line communication device with a communication line. It is possible to perform power line communication with another power line communication device that has been made via a communication line. Since the communication line is less attenuated than the power line and is less susceptible to noise, better communication quality can be ensured. On the other hand, when there is no communication line terminal nearby or when connection to the communication line terminal is difficult, communication can be performed using the power line. Further, the power line communication device itself does not need to recognize the signal transmission path, and therefore, it is not necessary to use different transmission / reception controls corresponding to the signal transmission path.

In the power line communication apparatus, the communication line may be a coaxial line, and a filter that restricts the passage of harmonics included in the signal of the power line communication may be interposed in the power line of the system of the coaxial line.
In this case, it is possible to prevent the harmonics included in the power line communication signal from affecting the reception of the television broadcast through the coaxial line.

In the power line communication device, the communication line is a coaxial line, and a filter that restricts the passage of harmonics included in the signal of the power line communication is detachable between the connector and the coaxial line connected thereto. It may be worn.
In this case, the filter can be omitted when it is not necessary.

In the power line communication device, a switching device that selects only one of the power line, only the communication line, and any one of the power line and the communication line may be provided as a system for inputting and outputting power line communication signals.
In this case, even with one power line communication device, the system for inputting and outputting the signal can be properly used according to the environment of the installation site.

  Since the power line communication apparatus of the present invention can be used for both of the two signal transmission paths (power line / communication line), the communication line is connected when the communication line can be connected. As a result of this simple action, better communication quality can be ensured.

  Hereinafter, a power line communication apparatus (hereinafter referred to as a PLC modem) according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, “power line communication” is basically data communication using a power line as a signal transmission path, but in addition to the power line, a communication line (for example, a coaxial line) wired in a house, a building, or the like. , Telephone lines, and other signal lines) are also used as signal transmission paths in a broad sense.

  FIG. 1 is a block diagram schematically showing the internal circuit configuration of a PLC modem. The PLC modem 1 includes a power supply unit 2 that supplies power to an internal circuit, a PLC digital processing unit 3 that performs digital processing of power line communication signals, a PLC analog processing unit 4 that performs analog processing of power line communication signals, and an Ethernet ( A PHY (Physical) unit 5 as a physical layer having a registered trademark interface function, a switching device 6 having a transmission path switching function, and the passage of a frequency signal higher than the signal frequency of power line communication are regulated in both directions. Ethernet connected to the LAN cable 13 and the low-pass filter 7 for filtering, the filter device 8 for allowing commercial AC power to pass between the ports 8a and 8b, and for allowing the power line communication signals to pass bidirectionally between the ports 8a and 8c. Trademark) data communication port 10, coaxial cable connector 11 to which coaxial cable 14 can be connected, and power cord 15 And a power connector 12, units are connected as shown.

  FIG. 2 is a perspective view showing an example of the appearance of the PLC modem 1. The data communication port 10, the coaxial line connector 11, and the power connector 12 are provided side by side on the back surface of the PLC modem 1.

  Returning to FIG. 1, the LAN cable 13 is connected to a personal computer 16. Note that other devices having information communication functions (for example, game machines and information home appliances) can be connected. The coaxial line 14 is connected to a coaxial line terminal (television terminal) TV provided on a wall surface or the like for receiving a television broadcast when the PLC modem 1 is located near the installation place. The power cord 15 is connected to the outlet C.

  The switching device 6, the low pass filter 7 and the filter device 8 constitute an input / output circuit 9. That is, the switching device 6 can select an input / output path as viewed from the PLC analog processing unit 4 by, for example, a manual switching operation. (1) Only the power line, (2) Only the coaxial line, (3) The power line and Any one of the coaxial lines can be selected. When (1) is selected, signal transmission between the switching device 6 and the low-pass filter 7 is blocked. When (2) is selected, signal transmission between the switching device 6 and the filter device 8 is interrupted. When (3) is selected, the switching device 6 performs signal transmission with both the low-pass filter 7 and the filter device 8, and the PLC analog processing unit 4 uses two systems of power lines and coaxial lines as input / output paths. It becomes a state to do. Thereby, the function of simultaneously outputting the same power line communication signal to the two systems of the power line and the coaxial line and inputting the power line communication signal from each system is achieved. Normally, (3) is selected, and power line communication signals are input to and output from the two systems of the power line and the coaxial line.

  FIG. 3 is a graph showing the frequency characteristics of the low-pass filter 7. The horizontal axis represents frequency and the vertical axis represents the input / output ratio. The low-pass filter 7 allows the signal to pass through almost 46 MHz without being attenuated. However, when the frequency exceeds about 46 MHz, the attenuation suddenly increases, and exhibits a very large attenuation characteristic for frequencies above about 60 MHz. . A signal with a frequency of 2 to 30 MHz is used for power line communication, while a signal with a frequency of 90 MHz or more is used for television broadcasting. Accordingly, the passage of television broadcast signals is restricted by the low-pass filter 7. Thereby, it is possible to prevent a television broadcast signal from being input to the PLC analog processing unit 4. Moreover, although the use frequency of power line communication is up to 30 MHz as above-mentioned, the harmonic of the frequency (frequency range of a television broadcast) exceeding this occurs. However, the passage of harmonics of power line communication exceeding about 46 MHz is restricted by the low-pass filter 7. Therefore, it is possible to prevent the harmonics from affecting the reception of the television broadcast.

  The low-pass filter 7 is inserted to avoid interference with other communication services on the coaxial line. If the influence of interference can be avoided at a frequency higher or lower than 46 MHz, a frequency range to be cut is selected. It may be changed.

  FIG. 4 is an example of an indoor wiring diagram regarding power line communication using the PLC modem 1. Here, indoor wiring in an apartment house such as an apartment will be described. The figure is a view of four rooms 21 to 24 on the first to fourth floors in a four-story apartment house. Among the wirings in the figure, the thick line is a power line, and the thin solid line is a coaxial line (coaxial cable). In the figure, output signals from, for example, the UHF antenna 31 and the BS / CS antenna 32 installed on the roof are mixed by a booster 33 and amplified. The amplified signal is equally distributed by the distributor 34 and provided to the rooms 21 to 24. The figure shows the indoor wiring of the room 21 on the first floor as an example. Also, the PLC modems 1M, 1S1, 1S2, 1S3, and 1S4 in the figure are the above-described PLC modem 1 set as a master unit (Master) or a slave unit (Slave). The setting as the parent device or the child device can be performed from the personal computer 16 (FIG. 1) connected to the PLC modem 1M, 1S1, 1S2, 1S3, 1S4.

  The signal from the distributor 34 is amplified by the booster 35 of each house, and the output signal is sent to the mixer 36. The mixer 36 mixes and outputs this signal and the power line communication signal output from the PLC modem 1M (master unit). This output signal is, for example, divided into four by a distributor and supplied to the coaxial line terminals TV1 to TV4 in each room. The PLC modem 1M is connected to an external network 41 such as the Internet via the media converter 40. In addition, when a PLC modem as a master unit that supervises the entire apartment house is provided in a common part such as an electric room, for example, the media converter 40 is installed in the electric room. Provided.

  In addition, when the booster 35 and the mixer 36 do not have a function of amplifying or passing the frequency band of the PLC signal, this portion may be short-circuited by another line to bypass the booster 35 and the mixer 36. A separate line for bypass may include a filter to prevent passage of other communication services (CATV signal, etc.) amplified by the booster 35 and the mixer 36.

PLC modems 1S1 and 1S2 as slave units are connected to the coaxial line terminals TV1 and TV2, respectively. Televisions 38 and 39 are connected to the coaxial line terminals TV3 and TV4, respectively.
On the other hand, the commercial AC voltage is wired from the distribution board 42 for indoor wiring to the outlets C1 to C5 in each room, and the aforementioned PLC modems 1S1, 1S2, and 1M are connected to the outlets C1, C2, and C5, respectively. Has been. Further, the other PLC modems 1S3 and 1S4 as slave units are connected to outlets C3 and C4, respectively. These PLC modems 1S3 and 1S4 are not connected to the coaxial line terminals because, for example, there are no coaxial line terminals nearby or they are already in use for television broadcast reception even if they are nearby.

  In the indoor wiring as described above, the PLC modems 1M, 1S1, and 1S2 are connected to both the power line and the coaxial line. In these PLC modems, both the power line and the coaxial line are selected as input / output paths by the operation of the switching device 6 described above. Therefore, the PLC modem 1M is connected to the PLC modems 1S1 and 1S2 via the mixer 36 and the distributor 37 via the coaxial line, and can perform “power line communication” via the coaxial line. The original power line communication via the power line is possible, but the signal level via the coaxial line is relatively less attenuated and less susceptible to noise, resulting in the use of the signal via the coaxial line. Is done.

  As described above, the coaxial line has less signal attenuation than the power line and is less susceptible to noise. Therefore, the communication speed is faster than that of the power line, and long-distance communication is possible. For example, communication is possible up to a distance of about 300 m, which is about three times the communicable distance by Ethernet (registered trademark).

On the other hand, in the PLC modems 1S3 and 1S4, the switching device 6 selects only the power line as the input / output path. Accordingly, these PLC modems can perform power line communication with the master PLC modem 1M via the power line. Further, the communication between the slave units can be performed by power line communication using a common power line.
In this way, the input / output circuit 9 (selection is made by the switching device 6) capable of two-way input / output and selective input / output enables the transmission of the signal even for a single PLC modem as a product. The system can be properly used according to the environment of the installation site.

  As described above, by connecting a coaxial line terminal to an existing coaxial line terminal provided for receiving television broadcasts (but may be newly provided) and the coaxial line connector 11 of one PLC modem. It is possible to ensure good communication quality by performing power line communication with other PLC modems connected in the same way via a coaxial line that is less attenuated than the power line and is less susceptible to noise. it can. On the other hand, when there is no coaxial line terminal nearby or when it is difficult to connect to the coaxial line terminal, communication can be performed using the power line. The signal of the PLC modem connected to the coaxial line is injected into two systems and can be extracted from each system, so the PLC modem itself does not need to recognize the signal transmission path, and corresponds to the signal transmission path. Therefore, there is no need to use different transmission / reception controls. Therefore, if not only the power line but also the coaxial line is used by using the PLC modem, better communication quality can be ensured.

  Although the low-pass filter 7 in FIG. 1 of the above embodiment is provided in the PLC modem 1, it is also possible to provide the low-pass filter 7 outside (externally attached) instead. FIG. 5 is a diagram showing such a configuration. In the figure, no low-pass filter is provided in the PLC modem 1. Instead, a filter unit 7U having a built-in low-pass filter 7 and having male and female coaxial line connectors 7a and 7b is attached to the coaxial line connector 11, and the coaxial line (not shown) is further connected to the connector 7b. .) Can be connected to achieve the same filter function as the built-in filter. According to such a configuration, there is an advantage that the low-pass filter 7 can be omitted when it is not necessary (for example, when a television is not installed).

  In addition, although the said embodiment demonstrated the wiring in the house in a collective housing, it is not restricted to this, The place where the coaxial line for television broadcast reception, such as establishments, such as a detached house and an office and a factory, is provided Similarly, a PLC modem capable of inputting / outputting two systems as described above can be connected to ensure better communication quality.

  Moreover, it is also possible to use a telephone line wired indoors instead of the coaxial line. Telephone lines are inferior to coaxial lines in terms of communication speed, but are superior to power lines. When the telephone line is used, the PLC modem is provided with a telephone line connector (modular jack) instead of the coaxial line connector 11 (FIG. 1). FIG. 6 is an example of an indoor wiring diagram related to power line communication using a power line and a telephone line as a signal transmission path. The same parts as those in FIG.

  In FIG. 6, the telephone line 43 is branched and wired indoors, and the telephone line terminals (modular jacks) TEL1, TEL2, TEL3 are provided in a plurality of rooms so that the place of the telephone can be arbitrarily selected. TEL4 is provided. PLC modems 1S1, 1S2, and 1M are connected to telephone line terminals TEL1, TEL2, and TEL4, respectively, and a telephone 44 is connected to telephone line terminal TEL3. In such a configuration, similar to the configuration of FIG. 4, PLC modems (1S1, 1S2, 1M) connected to each other via a telephone line can transmit and receive using the telephone line as a signal transmission path. Moreover, transmission / reception is possible between these and the other PLC modems 1S3 and 1S4 using the power line as a signal transmission path.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined not by the above-mentioned meaning but by the scope of claims for patent, and is intended to include all modifications within the scope and meaning equivalent to the scope of claims for patent.

It is a block diagram which shows the outline of the internal circuit structure of the power line communication apparatus (PLC modem) by one Embodiment of this invention. It is a perspective view which shows an example of the external appearance of a PLC modem. It is a graph which shows the frequency characteristic of a low-pass filter. It is an example of the indoor wiring diagram regarding the power line communication using a PLC modem. It is a perspective view which shows the structure which attached the low pass filter externally. It is another example of the indoor wiring diagram regarding power line communication using a PLC modem.

Explanation of symbols

1 PLC modem (power line communication equipment)
6 switching device 7 low-pass filter 9 input / output circuit 11 coaxial line connector 14 coaxial line (communication line)
15 Power cord (part of power line)
43 Telephone line (communication line)

Claims (4)

A power line communication device capable of transmitting and receiving power line communication signals using a power line as a signal transmission path,
A connector for connecting a communication line is provided, and the power line communication signal is simultaneously output to the two systems of the power line and the communication line, and the power line communication signal is input from each system. A power line communication device.   The power line communication apparatus according to claim 1, wherein the communication line is a coaxial line, and a filter that restricts the passage of harmonics included in a signal of the power line communication is interposed in an electric path of a system of the coaxial line.   2. The communication line is a coaxial line, and a filter for restricting passage of harmonics included in a signal of power line communication is detachably mounted between the connector and a coaxial line connected to the connector. The power line communication device described.   2. The power line communication according to claim 1, wherein a switching device for selecting only one of the power line, only the communication line, and any one of the power line and the communication line is provided as a system for inputting and outputting power line communication signals. apparatus.

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