JP2012227820A - Communication apparatus and splitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication apparatus and a splitter for transmitting and receiving communication signals conforming to a plurality types of communication methods to and from other apparatuses via a common communication line, capable of avoiding impact of communication signals conforming to the other communication methods to achieve enhanced communication.SOLUTION: A communication apparatus 101 includes: a first filter part 12, disposed between a first communication processing part 102 for transmitting and receiving a first communication signal and a communication line LN, for attenuating at least a part of a frequency component outside the range of a frequency band for a first communication signal; and a second filter part 11, disposed between a second communication processing part 52 for transmitting and receiving a second communication signal and the communication line LN, for attenuating at least a part of a frequency component outside the range of a frequency band for a second communication signal. The communication band of the first communication signal and the second communication signal are not overlapped each other. The first filter part 12 includes a filter circuit 41 for removing common code noise containing frequency components in the frequency band of the second communication signal.

Description

  The present invention relates to a communication device and a splitter, and more particularly, to a communication device and a splitter for transmitting and receiving communication signals according to a plurality of types of communication methods with other devices via a common communication line.

XDSL (x Digital Subscriber) for high-speed data communication using existing telephone lines
Examples of the Line (digital subscriber line) method include ADSL (Asymmetric DSL) and VDSL (Very high-bit-rate DSL).

  ITU-T Recommendations from the Telecommunications Standards Department (ITU-T) of the International Telecommunications Union. 993.2 (see “Very high speed digital subscriber line transceivers 2 (VDSL2)”, ITU-T recommendation G.993.2 (Non-Patent Document 1)) defines various functions in the VDSL system.

  In the VDSL system, communication is performed using a telephone line. Therefore, a VDSL signal, which is a communication signal conforming to the VDSL system, is superimposed on the same telephone line as an ISDN signal, which is a communication signal conforming to the ISDN (Integrated Services Digital Network) system. There is a case.

  For this reason, for example, in a VDSL apparatus for transmitting and receiving a VDSL signal, a splitter for separating the VDSL signal and the ISDN signal is required.

"Very high speed digital subscriber line transceivers 2 (VDSL2)", ITU-T recommendation G.993.2 (Non-patent document 1)

  In the VDSL apparatus provided with such a splitter, when the ISDN communication is performed while the VDSL communication is performed, an error occurs in the VDSL line, and the VDSL communication may be disconnected. I discovered that.

  A technology for preventing the occurrence of such an error by improving the performance of a splitter in a communication device for transmitting / receiving communication signals according to a plurality of types of communication methods to other devices via a common communication line, such as a VDSL device. Is desired.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide another communication method in a configuration in which communication signals according to a plurality of types of communication methods are transmitted to and received from other devices via a common communication line. It is an object of the present invention to provide a communication device and a splitter that can prevent the influence of a communication signal that complies with the above and can perform communication well.

  In order to solve the above-described problem, a communication apparatus according to an aspect of the present invention is a communication apparatus for transmitting and receiving communication signals according to a plurality of types of communication schemes with other apparatuses via a common communication line, Provided between the communication line and the first communication processing unit for transmitting and receiving the first communication signal to and from other devices via the communication line, and outside the frequency band of the first communication signal A first communication unit for attenuating at least a part of the frequency component and a second communication signal between other devices via the communication line according to a communication method different from that of the first communication processing unit. A second filter unit for attenuating at least a part of a frequency component outside the frequency band of the second communication signal, provided between the second communication processing unit for transmitting and receiving the signal and the communication line; Comprising the first communication signal Several frequency bands and the frequency band of the second communication signal do not overlap each other, and the first filter unit removes common mode noise including frequency components in the frequency band of the second communication signal. including.

  With such a configuration, the common mode component existing in the frequency band of the second communication signal can be sufficiently removed. Thereby, in the communication device, when communication by transmission / reception of the second communication signal is performed, an error occurs in the line of the second communication signal by performing communication by transmission / reception of the first communication signal, It is possible to prevent disconnection of communication due to transmission / reception of the second communication signal. Therefore, in a configuration in which communication signals according to a plurality of types of communication methods are transmitted to and received from other devices via a common communication line, the influence of communication signals according to other communication methods can be prevented and communication can be performed satisfactorily.

  Preferably, the filter circuit includes a common mode choke coil and a passive element for forming a secondary or higher order filter together with the common mode choke coil.

  Thus, by configuring a second-order or higher-order filter for the common mode component, the filter characteristics can be made steep, so that the noise removal capability can be improved and common mode noise can be sufficiently removed.

  More preferably, the first filter unit includes a first signal path and a second signal path for transmitting the first communication signal as a balanced signal, and the common mode choke coil includes the first signal path. The filter circuit is connected in series between the first signal path and the second signal path, and each connection node is supplied with a fixed voltage. Two power storage elements connected to the node are included.

  With such a configuration, a secondary filter for the common mode component can be configured with a simple circuit while preventing the influence on the normal mode component, and common mode noise can be sufficiently removed.

  More preferably, the passive element is provided between the common mode choke coil and the first communication processing unit.

  Thus, the noise reduction effect can be enhanced by providing the passive element at a position close to the first communication processing unit that is a common mode noise source. Further, it is possible to prevent deterioration of splitter characteristics such as LCL (unbalance attenuation).

  Preferably, the first communication processing unit transmits and receives the first communication signal in accordance with an ISDN (Integrated Services Digital Network) system, and the second communication processing unit includes a VDSL (Very high-bit- The second communication signal is transmitted and received according to the rate Digital Subscriber Line) method.

  Thus, by applying to a communication apparatus that processes two communication signals superimposed on the same telephone line, the effect of the present invention can be obtained more remarkably.

  In order to solve the above-described problems, a splitter according to an aspect of the present invention is a splitter used in a communication device for transmitting and receiving communication signals according to a plurality of types of communication methods with other devices via a common communication line. A frequency of the first communication signal provided between the communication line and the first communication processing unit for transmitting and receiving the first communication signal to and from another device via the communication line. A first filter unit for attenuating at least a part of the frequency component outside the band and a second communication between the first communication processing unit and another device via the communication line according to a communication method different from the first communication processing unit. A second communication processing unit for transmitting and receiving a communication signal of the second communication signal and a second communication unit for attenuating at least a part of the frequency component outside the frequency band of the second communication signal. With a filter section The frequency band of the first communication signal and the frequency band of the second communication signal do not overlap each other, and the first filter unit includes common mode noise including frequency components in the frequency band of the second communication signal. Including a filter circuit for removing.

  With such a configuration, the common mode component existing in the frequency band of the second communication signal can be sufficiently removed. Thereby, in the communication device, when communication by transmission / reception of the second communication signal is performed, an error occurs in the line of the second communication signal by performing communication by transmission / reception of the first communication signal, It is possible to prevent disconnection of communication due to transmission / reception of the second communication signal. Therefore, in a configuration in which communication signals according to a plurality of types of communication methods are transmitted to and received from other devices via a common communication line, the influence of communication signals according to other communication methods can be prevented and communication can be performed satisfactorily.

  According to the present invention, in a configuration in which communication signals according to a plurality of types of communication methods are transmitted to and received from other devices via a common communication line, it is possible to prevent the influence of communication signals according to other communication methods and to perform communication satisfactorily. it can.

It is a figure which shows the structure of the communication apparatus which concerns on embodiment of this invention. It is a circuit diagram which shows the structure of the splitter in the communication apparatus which concerns on embodiment of this invention. (A)-(c) is a figure for demonstrating the objective which provides a resonance circuit in a filter part. It is a figure which shows roughly the frequency relationship of an ISDN signal, a VDSL signal, and noise. It is a figure which shows roughly an example of the filter characteristic of the filter circuit for common modes in the low-pass filter part of the splitter which concerns on embodiment of this invention. It is a figure for demonstrating the filter characteristic of the filter circuit 41 for common modes with respect to a normal mode component. It is a figure for demonstrating the filter characteristic of the filter circuit 41 for common modes with respect to a common mode component.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a diagram showing a configuration of a communication apparatus according to an embodiment of the present invention.

  Referring to FIG. 1, a VDSL device (communication device) 101 includes a splitter 51 and a communication processing unit (second communication processing unit) 52. The splitter 51 includes a high pass filter (HPF) unit 11 and a low pass filter (LPF) unit 12. The communication processing unit 52 includes a transmission unit 31 and a reception unit 32. The transmission unit 31 includes a D / A converter 21, an IFFT processing unit 22, and a modulation unit 23. The reception unit 32 includes an A / D converter 24, an FFT processing unit 25, and a demodulation unit 26.

  The VDSL device 101 transmits / receives communication signals according to a plurality of types of communication methods to / from other devices via a common communication line such as a telephone line LN. More specifically, the VDSL device 101 is a collective device in the VDSL system, and is connected to one or more home-side devices in the VDSL system via the telephone line LN, and transmits / receives a VDSL signal to / from the home-side device. To do.

  The ISDN device (first communication processing unit) 102 is a station-side device in the ISDN system, and transmits and receives ISDN signals to / from one or a plurality of home-side devices in the ISDN system via the VDSL device 101 and the telephone line LN. .

  In the communication processing unit 52, the transmission unit 31 converts the downlink data to be transmitted to the home device via the telephone line LN into a VDSL signal and outputs it to the splitter 51.

  The receiving unit 32 converts the VDSL signal received from the splitter 51 from the home device into uplink data and outputs it.

  In the splitter 51, the high-pass filter unit (second filter unit) 11 is provided between the communication processing unit 52 and the telephone line LN, and attenuates at least a part of the frequency component outside the frequency band of the VDSL signal. Specifically, the high-pass filter unit 11 attenuates a component equal to or lower than a predetermined frequency among the frequency components of the signal received from the communication processing unit 52, and outputs the attenuated component to the telephone line LN. Further, the high pass filter unit 11 attenuates a component equal to or lower than a predetermined frequency among the frequency components of the signal received from the telephone line LN, and outputs the attenuated component to the communication processing unit 52.

  The low-pass filter unit (first filter unit) 12 is provided between the ISDN device 102 and the telephone line LN, and attenuates at least a part of frequency components outside the frequency band of the ISDN signal. Specifically, the low-pass filter unit 12 attenuates a component having a frequency equal to or higher than a predetermined frequency among the frequency components of the signal received from the ISDN device 102 and outputs the attenuated component to the telephone line LN. The low-pass filter unit 12 attenuates a component having a frequency equal to or higher than a predetermined frequency among the frequency components of the signal received from the telephone line LN, and outputs the attenuated component to the communication processing unit 52.

  In the transmission unit 31, the modulation unit 23 performs orthogonal modulation on the downlink data, for example, and outputs the result to the IFFT processing unit 22.

  The IFFT processing unit 22 performs inverse fast Fourier transform (IFFT) on the data received from the modulation unit 23 and outputs the result to the D / A converter 21.

  The D / A converter 21 converts the data received from the IFFT processing unit 22 into an analog signal and outputs the analog signal to the splitter 51 as a VDSL signal.

  In the receiving unit 32, the A / D converter 24 converts the VDSL signal received from the splitter 51 into a digital signal and outputs the digital signal to the FFT processing unit 25.

  The FFT processing unit 25 performs fast Fourier transform (FFT) on the digital signal received from the A / D converter 24 and outputs the fast Fourier transform to the demodulation unit 26.

  The demodulator 26 orthogonally demodulates the data received from the FFT processor 25, for example, and outputs it as uplink data.

  FIG. 2 is a circuit diagram showing a configuration of the splitter in the communication apparatus according to the embodiment of the present invention.

  Referring to FIG. 2, splitter 51 includes a high-pass filter unit 11, a low-pass filter unit 12, surge absorbers SA1 and SA2, and fuses F1 and F2. The low-pass filter unit 12 includes a common mode filter circuit 41 and a normal mode filter circuit 42. The high pass filter unit 11 includes a common mode filter circuit 43 and a normal mode filter circuit 44.

  In the low-pass filter unit 12, the common mode filter circuit 41 includes a common mode choke coil CMC1 and capacitors C12 and C13. Common mode choke coil CMC1 includes coils L21 and L22 having a common core. Normal mode filter circuit 42 includes inductors L1, L2, L3, L11, L12, and L13, and capacitors C1, C2, C3, C14, and C15.

  In the low-pass filter unit 12, the inductors L1 and L11 have, for example, a common core. Inductors L2 and L12 have, for example, a common core. Inductors L3 and L13 have, for example, a common core.

  In the high pass filter unit 11, the common mode filter circuit 43 includes a common mode choke coil CMC2. Common mode choke coil CMC2 includes coils L23 and L24 having a common core. Normal mode filter circuit 44 includes inductors L4 and L5 and capacitors C4, C5, C6, C7, C8, C9, C10, and C11.

  The surge absorber SA1 is connected to the telephone line LN. The surge absorber SA2 is connected to the ISDN device 102 installed in the station building via, for example, a telephone line.

  The low-pass filter unit 12 includes a balance signal line SL1 and a balance signal line SL2 for transmitting the ISDN signal as a balanced signal.

  The high pass filter unit 11 includes a balance signal line SL11 and a balance signal line SL12 for transmitting the VDSL signal as a balanced signal.

  In normal mode filter circuit 42, inductor L1 has a first end connected to the first end of surge absorber SA1 and a second end connected to the first end of capacitor C1. Inductor L2 has a first end connected to the second end of inductor L1 and the first end of capacitor C14, and a second end connected to the second end of capacitor C14 and the first end of capacitor C2. Inductor L3 has a first end connected to the second end of inductor L2, and a second end connected to the first end of capacitor C3. Inductor L11 has a first end connected to the second end of surge absorber SA1, and a second end connected to the second end of capacitor C1. Inductor L12 has a first end connected to the second end of inductor L11 and the first end of capacitor C15, and a second end connected to the second end of capacitor C15 and the second end of capacitor C2. Inductor L13 has a first end connected to the second end of inductor L12, and a second end connected to the second end of capacitor C3.

  In the common mode filter circuit 41, the coil L21 of the common mode choke coil CMC1 is provided on the balance signal line SL1, and is connected to the first end connected to the first end of the capacitor C3 and the first end of the fuse F1. And a second end. The second end of the fuse F1 and the first end of the surge absorber SA2 are connected. Coil L22 of common mode choke coil CMC1 is provided on balance signal line SL2, and has a first end connected to the second end of capacitor C3 and a second end connected to the first end of fuse F2. . The second end of the fuse F2 and the second end of the surge absorber SA2 are connected. Capacitor C12 has a first end connected to the second end of coil L21 of common mode choke coil CMC1, and a second end connected to the first end of capacitor C13. Capacitor C13 has a first end connected to the second end of capacitor C12 and a second end connected to the second end of coil L22 of common mode choke coil CMC1. A connection node between the second end of capacitor C12 and the first end of capacitor C13 is connected to a ground node to which a fixed voltage, for example, a ground voltage is supplied.

  In normal mode filter circuit 44, capacitor C4 has a first end connected to the first end of surge absorber SA1 and a second end connected to the first end of inductor L4. Capacitor C6 has a first end connected to the second end of capacitor C4, and a second end connected to the first end of inductor L5. Capacitor C8 has a first end connected to the second end of capacitor C6, and a second end. The second end of the inductor L4 and the first end of the capacitor C10 are connected. The second end of the inductor L5 and the first end of the capacitor C11 are connected. Capacitor C5 has a first end connected to the second end of surge absorber SA1, and a second end connected to the second end of capacitor C10. Capacitor C7 has a first end connected to the second end of capacitor C5 and a second end connected to the second end of capacitor C11. Capacitor C9 has a first end connected to the second end of capacitor C7, and a second end.

  In the common mode filter circuit 43, the coil L23 of the common mode choke coil CMC2 is provided on the balance signal line SL11, connected to the first end connected to the second end of the capacitor C8, and to the communication processing unit 52. And a second end. The coil L24 of the common mode choke coil CMC2 is provided on the balance signal line SL12, and has a first end connected to the second end of the capacitor C9 and a second end connected to the communication processing unit 52.

  The common mode filter circuit 41 removes common mode noise generated between the ISDN device 102 and the telephone line LN.

  The normal mode filter circuit 42 removes normal mode noise generated between the ISDN device 102 and the telephone line LN. More specifically, inductors L1, L2, L3, L11, L12, and L13 and capacitors C1, C2, and C3 constitute a plurality of LC filters that function as low-pass filters. The inductor L2 and the capacitor C14 constitute a parallel resonant circuit. The inductor L12 and the capacitor C15 constitute a parallel resonance circuit.

  The common mode filter circuit 43 removes common mode noise generated between the communication processing unit 52 and the telephone line LN.

  The normal mode filter circuit 44 removes normal mode noise generated between the communication processing unit 52 and the telephone line LN. More specifically, inductors L4 and L5 and capacitors C4, C5, C6, C7, C8, and C9 constitute a plurality of LC filters that function as high-pass filters. The inductor L4 and the capacitor C10 constitute a series resonance circuit. The inductor L5 and the capacitor C11 form a series resonance circuit.

  By configuring the resonance circuit in the low-pass filter unit 12 and the high-pass filter unit 11 as described above, the filter characteristics can be made steep.

  FIGS. 3A to 3C are diagrams for explaining the purpose of providing a resonance circuit in the filter unit.

  FIG. 3A shows the characteristics of a low-pass filter as an example. In order to make this characteristic steep, a method of increasing the order of the filter as shown in FIG. However, such a method increases the number of parts of the filter.

  Therefore, in the splitter according to the embodiment of the present invention, by providing a resonance circuit, a resonance point is created in the filter characteristics as shown in FIG.

  With such a configuration, the number of parts of the filter can be reduced as compared with a configuration in which the order of the filter is increased.

  FIG. 4 is a diagram schematically showing the frequency relationship between the ISDN signal, the VDSL signal, and noise.

  Referring to FIG. 4, the frequency band of the ISDN signal and the frequency band of the VDSL signal do not overlap each other, and the frequency band of the ISDN signal is lower than the frequency band of the VDSL signal.

  More specifically, the frequency band of the ISDN signal is 0 Hz to 320 kHz, and normal mode noise that is a side lobe of the ISDN signal is generated at 320 kHz or more. Part of this normal mode noise is also present in the frequency band of the VDSL signal. The frequency band of the VDSL signal is 640 kHz or more.

  The inventors of the present application have discovered that in the conventional VDSL apparatus, if ISDN communication is performed while VDSL communication is performed, an error occurs in the VDSL line and the VDSL communication may be disconnected. Further, the conventional VDSL apparatus has found that such an error occurs because the common mode noise of the ISDN signal is not sufficiently removed instead of the normal mode noise of the ISDN signal.

  That is, since an error has occurred in the VDSL line, at least a part of the common mode component exists in the frequency band of the VDSL signal. In the conventional VDSL apparatus, the common mode component exists in the frequency band of the VDSL signal. It was thought that the removal of was insufficient.

  Therefore, the inventors of the present application have taken measures to newly provide capacitors C12 and C13 in addition to the common mode choke coil CMC1 in the common mode filter circuit 41 of the splitter 51.

  That is, the common mode filter circuit 41 removes common mode noise including frequency components in the frequency band of the VDSL signal.

  More specifically, as shown in FIG. 2, in the common mode filter circuit 41, the common mode choke coil CMC1 is provided on the balance signal line SL1 and the balance signal line SL2. The capacitors C12 and C13 are connected in series between the balance signal line SL1 and the balance signal line SL2, and their connection nodes are connected to a node to which a fixed voltage, for example, a ground voltage is supplied.

  FIG. 5 is a diagram schematically showing an example of the filter characteristics of the common mode filter circuit in the low-pass filter section of the splitter according to the embodiment of the present invention.

  Referring to FIG. 5, when it is assumed that capacitors C12 and C13 are not provided in common mode filter circuit 41, the characteristics of common mode filter circuit 41 are relatively gentle (characteristic A). That is, when only the common mode choke coil CMC1 is provided in the common mode filter circuit 41, the common mode filter circuit 41 forms a primary filter for the common mode component.

  For this reason, among the frequency components of common mode noise generated between the ISDN device 102 and the telephone line LN, the frequency components in the frequency band of the VDSL signal cannot be sufficiently attenuated.

  On the other hand, in the splitter according to the embodiment of the present invention, the common mode filter circuit 41 further includes capacitors C12 and C13, so that the common mode filter circuit 41 forms a secondary filter for the common mode component. can do. As a result, the filter characteristics can be made steep (characteristic B), so that the noise removal capability of the common mode filter circuit 41 can be improved and common mode noise can be sufficiently removed.

  FIG. 6 is a diagram for explaining the filter characteristics of the common mode filter circuit 41 with respect to the normal mode component.

  Referring to FIG. 6, in the normal mode, if the potential of balance signal line SL1 is + V, the potential of balance signal line SL2 is -V, and the potentials of the midpoint, that is, the connection nodes of capacitors C12 and C13 are Zero.

  The state where the potential at the midpoint is zero 0 is the same as the normal mode component whether or not the midpoint is grounded. For this reason, the circuit including the capacitor C12 and the capacitor C13 has a combined capacitance of the capacitor C12 and the capacitor C13 with respect to the normal mode component.

  Here, the capacitance of the capacitor C12 and the capacitor C13 is set to a value that is, for example, an order of magnitude smaller than the capacitance of the capacitor C3 in the normal mode filter circuit. For this reason, in the filter characteristic for the normal mode component, the capacitor C3 is dominant, and the capacitor C12 and the capacitor C13 have little influence on the filter characteristic for the normal mode component.

  That is, for the normal mode component, it can be considered that there is no circuit including the capacitor C12 and the capacitor C13. That is, even if the capacitors C12 and C13 are provided, there is no influence on the pass characteristic of the ISDN signal.

  FIG. 7 is a diagram for explaining the filter characteristics of the common mode filter circuit 41 with respect to the common mode component.

  Referring to FIG. 7, in the common mode, if the potential of balance signal line SL1 is + V, the potential of balance signal line SL2 is + V.

  When the midpoint, that is, the connection node of the capacitor C12 and the capacitor C13 is not grounded, the potential at the midpoint is + V. For this reason, since there is no potential difference between the balance signal lines SL1 and SL2, the common mode component cannot be attenuated.

  On the other hand, in the splitter according to the embodiment of the present invention, the connection node of capacitor C12 and capacitor C13 is grounded. Thereby, a potential difference is generated between the balance signal lines SL1 and SL2, and the common mode noise can be removed according to the filter characteristics of the common mode filter circuit including the common mode choke coil CMC1 and the capacitors C12 and C13.

  In the common mode filter circuit 41, a third or higher order filter may be configured.

  Further, the capacitor C12 and the capacitor C13 may be provided in other parts of the low-pass filter unit 12.

  Furthermore, the capacitor C12 and the capacitor C13 may be provided before the branch portion of the low-pass filter unit 12 and the high-pass filter unit 11, that is, before or after the surge absorber SA1.

  However, by providing the capacitors C12 and C13 between the common mode choke coil CMC1 and the ISDN device 102, the following effects can be obtained.

  That is, the noise reduction effect can be enhanced by providing it at a position close to the ISDN device 102 which is a common mode noise source.

  Further, LCL (unbalance attenuation) is defined as one of the splitter characteristics. This LCL deteriorates when there is a variation in the capacitance of the capacitor C12 and the capacitance of the capacitor C13. The LCL is measured from the telephone line LN side. Since the common mode choke coil CMC1 has a very large impedance with respect to the common mode component, the capacitors C12 and C13 are provided on the ISDN device 102 side, that is, on the opposite side of the telephone line LN with respect to the common mode choke coil CMC1. According to the configuration, the influence of variations in the capacitors C12 and C13 can be ignored, and deterioration of the splitter characteristics can be prevented.

  Further, the common mode filter circuit 41 is not limited to a capacitor, and may be any configuration including a passive element for forming a secondary or higher order filter together with the common mode choke coil CMC1.

  By the way, in a VDSL device provided with a splitter, if ISDN communication is performed while VDSL communication is being performed, an error may occur in the VDSL line, and the VDSL communication may be disconnected. For this reason, a technique for preventing the occurrence of such an error by improving the performance of the splitter is desired.

  Therefore, in the communication apparatus according to the embodiment of the present invention, the low-pass filter unit 12 is provided between the ISDN apparatus 102 and the telephone line LN for transmitting and receiving ISDN signals to and from other apparatuses via the telephone line LN. And attenuating at least part of the frequency component outside the frequency band of the ISDN signal. The high-pass filter unit 11 is provided between the communication processing unit 52 and the telephone line LN for transmitting / receiving a VDSL signal to / from another apparatus via the telephone line LN according to a communication method different from that of the ISDN apparatus 102. , At least part of the frequency component outside the frequency band of the VDSL signal is attenuated. The frequency band of the ISDN signal and the frequency band of the VDSL signal do not overlap each other. In the low-pass filter unit 12, the common mode filter circuit 41 removes common mode noise including frequency components in the frequency band of the VDSL signal.

  With such a configuration, common mode components existing in the frequency band of the VDSL signal can be sufficiently removed. As a result, it is possible to prevent the VDSL communication from being disconnected due to the occurrence of an error in the VDSL line due to the ISDN communication being performed when the VDSL communication is being performed in the VDSL device.

  Therefore, in the communication device according to the embodiment of the present invention, in a configuration in which communication signals according to a plurality of types of communication methods are transmitted to and received from other devices via a common communication line, the influence of communication signals according to other communication methods is prevented. Communication can be performed satisfactorily.

  In the communication device according to the embodiment of the present invention, the common mode filter circuit 41 includes a common mode choke coil CMC1 and a passive element for forming a secondary or higher order filter together with the common mode choke coil CMC1. .

  Thus, by configuring a second-order or higher-order filter for the common mode component, the filter characteristics can be made steep, so that the noise removal capability can be improved and common mode noise can be sufficiently removed.

  In the communication device according to the embodiment of the present invention, the common mode choke coil CMC1 is provided in the balance signal line SL1 and the balance signal line SL2. The capacitors C12 and C13 are connected in series between the balance signal line SL1 and the balance signal line SL2, and their connection nodes are connected to nodes to which a fixed voltage is supplied.

  With such a configuration, a secondary filter for the common mode component can be configured with a simple circuit while preventing the influence on the normal mode component, and common mode noise can be sufficiently removed.

  Further, in the communication device according to the embodiment of the present invention, capacitors C12 and C13 are provided between common mode choke coil CMC1 and ISDN device 102.

  Thus, the noise reduction effect can be enhanced by providing the capacitors C12 and C13 at positions close to the ISDN device 102 that is a common mode noise source. Further, it is possible to prevent deterioration of splitter characteristics such as LCL.

  In the communication system according to the embodiment of the present invention, ISDN device 102 transmits and receives ISDN signals according to the ISDN method. The communication processing unit 52 transmits and receives VDSL signals according to the VDSL system.

  Thus, by applying to a communication apparatus that processes two communication signals superimposed on the same telephone line, the effect of the present invention can be obtained more remarkably.

  Although the communication apparatus according to the embodiment of the present invention is a VDSL apparatus, the present invention is not limited to this. It may be configured to perform communication processing according to a communication method different from at least one of ISDN and VDSL, or may be configured to perform communication processing according to another communication method in addition to ISDN and VDSL.

  In the communication apparatus according to the embodiment of the present invention, the second-order or higher-order filter is configured in the common mode filter circuit 41 of the low-pass filter unit 12, but the present invention is not limited to this. When common mode noise generated between the communication processing unit 52 and the telephone line LN becomes a problem, the common mode filter circuit 43 of the high pass filter unit 11 may constitute a second or higher order filter.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

11 High-pass filter section (second filter section)
12 Low-pass filter section (first filter section)
21 D / A converter 22 IFFT processing unit 23 Modulation unit 24 A / D converter 25 FFT processing unit 26 Demodulation unit 31 Transmission unit 32 Reception unit 41 Common mode filter circuit 42 Normal mode filter circuit 43 Common mode filter circuit 44 Normal Mode filter circuit 51 Splitter 52 Communication processing unit (second communication processing unit)
101 VDSL equipment (communication equipment)
102 ISDN device (first communication processing unit)
F1, F2 fuse C12, C13 capacitor C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15 capacitor CMC1, CMC2 common mode choke coils L21, L22, L23 , L24 Coil L1, L2, L3, L4, L5, L11, L12, L13 Inductor LN Telephone line SA1, SA2 Surge absorber SL1, SL2 Balance signal line

Claims (6)

A communication device for transmitting and receiving communication signals according to a plurality of types of communication methods with other devices via a common communication line,
Provided between the communication line and a first communication processing unit for transmitting / receiving a first communication signal to / from another device via the communication line, and out of the frequency band of the first communication signal A first filter unit for attenuating at least a part of the frequency components of
According to a communication method different from that of the first communication processing unit, between the second communication processing unit and the communication line for transmitting / receiving a second communication signal to / from another device via the communication line. And a second filter unit for attenuating at least a part of the frequency component outside the frequency band of the second communication signal,
The frequency band of the first communication signal and the frequency band of the second communication signal do not overlap each other,
The first filter unit includes a filter circuit for removing common mode noise including a frequency component in a frequency band of the second communication signal. The filter circuit is
A common mode choke coil;
The communication device according to claim 1, further comprising a passive element for forming a secondary or higher order filter together with the common mode choke coil. The first filter unit includes:
Including a first signal path and a second signal path for transmitting the first communication signal as a balanced signal;
The common mode choke coil is provided in the first signal path and the second signal path,
The filter circuit is
The communication according to claim 2, wherein the first signal path and the second signal path are connected in series, and each connection node includes two power storage elements connected to a node supplied with a fixed voltage. apparatus.   The communication device according to claim 2, wherein the passive element is provided between the common mode choke coil and the first communication processing unit. The first communication processing unit performs transmission and reception of the first communication signal according to an ISDN (Integrated Services Digital Network) system,
5. The second communication processing unit according to claim 1, wherein the second communication processing unit transmits and receives the second communication signal in accordance with a VDSL (Very High-bit-rate Digital Subscriber Line) method. 6. Communication equipment. A splitter used in a communication device for transmitting and receiving communication signals according to a plurality of types of communication methods with other devices via a common communication line,
Provided between the communication line and a first communication processing unit for transmitting / receiving a first communication signal to / from another device via the communication line, and out of the frequency band of the first communication signal A first filter unit for attenuating at least a part of the frequency components of
According to a communication method different from that of the first communication processing unit, between the second communication processing unit and the communication line for transmitting / receiving a second communication signal to / from another device via the communication line. And a second filter unit for attenuating at least a part of the frequency component outside the frequency band of the second communication signal,
The frequency band of the first communication signal and the frequency band of the second communication signal do not overlap each other,
The first filter unit is a splitter including a filter circuit for removing common mode noise including a frequency component in a frequency band of the second communication signal.

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