JP2009088958A - Equalization system in modem and modem - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform accurate equalization even when using electric wiring wherein transmission line characteristics are dynamically varied at the same time for communication. <P>SOLUTION: In the equalization system in the modem used for the communication of using the electric wiring at the same time and superimposing communication signals on the electric wiring 101, a transmission line change point detection circuit 6 for detecting the change point of the state of a transmission line from the communication signals which passed through the transmission line of the communication signals and a power supply cycle detection circuit 7 for detecting a power supply cycle are provided, and the equalization is performed in synchronism with the cycle variation of the transmission line by the output of the transmission line change point detection circuit 6 and the output of the power supply cycle detection circuit 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an equalization method and a modem device in a modem device in a communication method in which electrical wiring such as a power line and general wiring is used for communication.

  As a typical example of a communication method that uses electrical wiring for communication, in a power line carrier communication device, conventionally, transmission characteristics of a communication signal (hereinafter simply referred to as “signal”) vary depending on a power cycle. An equalization device is provided to detect a power cycle and switch a constant equalization pattern. (For example, see Patent Document 1)

JP-A-2-172332 (FIGS. 1 to 3 and explanation thereof)

  It is well known that the transmission characteristics vary depending on the power cycle. If an equalizing device that detects the power cycle and switches a certain equalization pattern as shown in Patent Document 1 is used, the variation of the transmission characteristics depending on the power cycle. Can cope with it.

  However, in communication systems that use electrical wiring such as power lines and general wiring for communication, signal transmission path characteristics (signal attenuation, noise, communication line impedance, etc.) (hereinafter simply referred to as “transmission path characteristics”) ) Has severe frequency characteristics depending on conditions such as line type, line length, branching, etc. of electrical wiring used for communication, and further, power supply circuits such as power devices connected to the same wiring used for communication and the same wiring It has been found that the characteristics of the transmission path dynamically change due to the influence of the type of other equipment connected to the PC and its load state.

  In this way, the transmission line characteristics are severe in frequency characteristics depending on conditions such as the line type, line length, branching, etc. of electric wiring used in communication, and further, such as power equipment connected to the same wiring used in communication When the transmission line characteristics change dynamically due to the influence of the type of power supply circuit and other equipment connected to the same wiring and its load condition, the fluctuation period is detected only for the power supply period and a constant equalization pattern is set. The conventional equalizer that performs the switching operation cannot cope with the dynamic fluctuation, that is, the signal amplitude and phase of the input signal to the demodulator such as a demodulator are matched with the transmission signal from the communication signal transmission source. It has been found that there is a problem that cannot be equalized (hereinafter simply referred to as “equalization”).

  The present invention has been made in view of the above-described circumstances, and an object thereof is to enable accurate equalization even when electrical wiring whose transmission path characteristics are dynamically changed is used for communication. Is.

  An equalization method in a modem device according to the present invention is an equalization method in a modem device used for communication in which an electrical wiring is used together and a communication signal is superimposed on the electrical wiring. A transmission line change point detection circuit for detecting a change point of the state of the transmission line from the transmitted communication signal, and a power supply cycle detection circuit for detecting a power supply cycle, and an output of the transmission line change point detection circuit and the power supply cycle detection circuit Is equalized in synchronism with the period fluctuation of the state of the transmission line.

The modem device according to the present invention is a modem device used for communication in which an electrical wiring is used in combination to superimpose a communication signal on the electrical wiring and performs equalization between a transmission signal and a reception signal. A transmission path change point detection circuit that detects a change point of the state of the transmission path from a received signal that has passed through the transmission path of the signal, and a power supply cycle detection circuit that detects a power supply cycle; Equalization is performed in synchronism with the period fluctuation of the state of the transmission path by the output and the output of the power cycle detection circuit.

  The present invention relates to an equalization method in a modem device used for communication in which an electrical wiring is used in combination and a communication signal is superimposed on the electrical wiring, and from the communication signal that has passed through the transmission path of the communication signal, A transmission line change point detection circuit for detecting a state change point and a power supply cycle detection circuit for detecting a power supply period are provided, and an output of the transmission line is determined by an output of the transmission line change point detection circuit and an output of the power supply period detection circuit. Since equalization is performed in synchronization with the periodic fluctuation of the state, there is an effect that accurate equalization can be performed even when electrical wiring whose transmission path characteristics are dynamically changed is used in communication.

  The present invention relates to a modem device that is used for communication in which electrical wiring is used in combination to superimpose a communication signal on the electrical wiring and performs equalization between a transmission signal and a reception signal, wherein the transmission signal is a transmission path of the communication signal. A transmission line change point detection circuit that detects a change point of the state of the transmission line from a received signal that has passed through the power supply, and a power supply cycle detection circuit that detects a power supply period, the output of the transmission line change point detection circuit and the power supply Since equalization is performed in synchronization with the period fluctuation of the state of the transmission line based on the output of the period detection circuit, accurate equalization can be performed even when electrical wiring whose transmission line characteristics change dynamically is used in communication. effective.

Embodiment 1 FIG.
A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram illustrating an example of the internal configuration of a modem device including a device that executes a periodic variation synchronization adaptive equalization method and the relationship between peripheral devices and devices of the modem device, and FIG. 2 is an example of periodic variation synchronization adaptation in FIG. FIG. 3 is a block diagram illustrating an example of the internal configuration of the equalization circuit 5 and the relationship between the period variation synchronization adaptive equalization circuit 5 and its peripheral circuits. FIG. 3 is a diagram of the zero cross detection circuit in the power supply period detection circuit 7 in FIGS. 4 is a connection diagram illustrating an example, FIG. 4 is a diagram illustrating an example of the relationship between the power supply waveform of the AC power source and the output waveform of the photocoupler in FIG. 3, and FIG. 5 is a signal transmitted from the communication signal transmission source (the signal in FIG. 1). FIG. 6 is a diagram illustrating an example of a signal frame configuration including a reference signal, FIG. 6 is a diagram illustrating a communication system model, and FIG. 7 is a diagram illustrating a transmission path change in FIGS. FIG. 8 is a diagram illustrating an example of a concept of detecting an error value from a transmission path estimation value and a reference point by the point detection circuit 6, FIG. 8 is a diagram illustrating an example of a function of the equalization timing generation circuit 54 in FIG. 2 is a diagram showing an example of the internal configuration of the equalization coefficient learning circuit 53 in FIGS. 2 and 8, FIG. 10 is a block diagram showing an example of the internal configuration of the equalization coefficient generation circuit 52 in FIGS. 2 and 8, and FIG. FIG. 12 is a diagram showing a transmission line characteristic A, which is an example of a fluctuation in path characteristics, and FIG.

  First, a first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, and 4. FIG.

  Referring to FIG. 1 illustrating an example of the internal configuration of a modem device including a device that executes a period variation synchronous adaptive equalization method and the peripheral device / equipment of the modem device. The modem device 1 used for the communication method used together is connected to the electrical wiring 101 by a known signal coupling device 12 as shown in the figure. As is well known, a signal transmitted from a communication signal source (not shown) using, for example, a megahertz (MHz) level carrier using the electrical wiring 101 as a transmission medium is taken out by the signal coupling device 12 and inputted to the receiving side of the modem device 1. Received data that is the output of the modem device 1 is sent to a terminal device or the like (not shown).

  Here, the power line means all so-called power lines such as outdoors, indoors, high voltage, low voltage, etc., and general wiring means coaxial cable such as LAN cable, twisted pair line such as telephone line, roadside This means not only the built-in communication line, etc., but also all the wiring that enables communication in the vehicle and other modems.

  The modem device 1 has a well-known analog signal interface unit 2 of a receiving unit, a well-known A / D (Analog / Digital) conversion unit 3, a time axis on the receiving side to which a receiving signal from the electrical wiring 101 is inputted. A well-known FFT (First Fourier Transform) unit 4 for converting a signal to a frequency axis, a newly installed periodic fluctuation synchronization adaptive equalization function circuit 5, a newly installed transmission line change point detecting circuit 6, a well-known power cycle detecting circuit 7, and a well-known The decoding unit 8 is provided.

  The modem device 1 includes a known transmission data encoding unit 11 and a known IFFT (Inverse First Fourier Transform) unit 10 for converting a frequency axis signal to a time axis on the signal transmission side to the electrical wiring 101. A well-known D / A (Digital / Analog) conversion unit 9 and a well-known analog interface unit 8 are provided.

  Next, in FIG. 2 illustrating an example of the internal configuration of the periodic variation synchronization adaptive equalization circuit 5 in FIG. 1 and the relationship between the periodic variation synchronization adaptive equalization circuit 5 and its peripheral circuits, the periodic variation synchronization adaptive equalization circuit 5 is illustrated. As shown in the figure, an equalization coefficient multiplication circuit unit 51 for multiplying an input signal by an equalization coefficient in an equalizer, an equalization coefficient learning circuit 53 by calculating an equalization coefficient by an LMS (Least Mean Square) algorithm or the like. The equalization coefficient generation circuit 52 that selects and sets the equalization coefficient learned in step 5 in the equalization coefficient multiplication circuit unit 51, the equalization coefficient learning circuit 53 that learns the equalization coefficient in the fluctuation period of the transmission path, and the equalization coefficient A timing generation function unit 54 is provided.

  In FIG. 3 illustrating an example of the zero cross detection circuit in the power cycle detection circuit 7 in FIGS. 1 and 2, the power supply waveform of the AC 50/60 Hz power supply is as illustrated in FIG. The photocoupler detects the vicinity of the zero crossing at the changing point where the voltage becomes a predetermined threshold, and the output waveform of the photocoupler is as illustrated in FIG. From the output of the photocoupler, the timing from the zero cross point can be arbitrarily generated by the zero cross detection circuit and the timing count circuit illustrated in FIG.

  Next, referring to FIG. 2 to FIG. 9, the periodic fluctuation synchronization adaptive equalization circuit 5, the transmission line change point detection circuit 6, and the power supply cycle detection, which are the internal functional blocks of the modem device, which are the main features of the first embodiment. The function, internal configuration, and operation of the circuit 7 will be described.

  The cycle variation synchronization adaptive equalization circuit 5 having the cycle variation synchronization adaptive equalization function, the transmission path change point detection circuit 6 having the transmission path change point detection function, and the power cycle detection circuit 7 having the power cycle detection function are implemented in this embodiment. In the accurate adaptive equalization function that is the object of the first embodiment, the fluctuation period of the transmission line is automatically detected, the equalization coefficient of the received signal is learned at the timing, and the equalization coefficient is matched to the fluctuation of the transmission line Realize the function to switch between.

Here, a supplementary explanation will be given of a general equalization function.
For example, a communication system model is defined below with reference to FIG.

  The transmission signal s (t) is subjected to waveform distortion by the transmission path, added with noise, and received as a signal y (t). This received signal is input to the equalizer as m received sequences. The equalizer compensates for waveform distortion by estimating the transmission signal s (t-d) using this data series. Note that d in the transmission signal s (t−d) is a delay in the equalizer.

  Taking a linear equalizer as an example, the coefficient of the filter generated on the electrical wiring is learned according to the state of the transmission line. When a known signal sequence is transmitted during learning and the received signal can be used as training data, the coefficient is adjusted using an adaptive algorithm such as LMS (Least Mean Square) algorithm or RMS (Recursive Least Square).

タップ係数ベクトルは次の（２）式で表される。

フィルタ合成ベクトルは次の（３）式で表される。ただし、ベクトルに付した上付きのＨは、複素共役転置ベクトルを意味する。

所望信号d(i)との誤差信号c(i)は、以下の（４）式で表される。

The input signal vector is expressed by the following equation (1). However, the superscript T added to the vector means a transposed vector.

The tap coefficient vector is expressed by the following equation (2).

The filter synthesis vector is expressed by the following equation (3). However, the superscript H attached to the vector means a complex conjugate transposed vector.

The error signal c (i) from the desired signal d (i) is expressed by the following equation (4).

具体的には、以下の（６）式にしたがって、タップ係数を更新する。 In order to reduce the channel estimation error including the quantization error calculated by the equalization algorithm, the tap coefficient error is corrected so as to minimize the least square error LMS between the equalizer output and the reference signal. The square error LMS is expressed by the following equation (5).

Specifically, the tap coefficient is updated according to the following equation (6).

ただし、（６）式におけるμは、ステップサイズである。
タップ係数更新には、入力系列が既知である必要があるが、この既知の入力系列は、通常トレーニングフレームのプリアンブルを使用する。なお、タップとは、特許文献１にも示されているように等化器あるいは等化装置における周知のタップである。

However, μ in the equation (6) is a step size.
In order to update the tap coefficient, the input sequence needs to be known. This known input sequence usually uses the preamble of the training frame. Note that the tap is a well-known tap in an equalizer or an equalization apparatus as disclosed in Patent Document 1.

Hereinafter, the description returns to the contents of the first embodiment.
The equalizer of the first embodiment has a transversal filter configuration as an example.

  In FIG. 2 illustrating an example of the internal configuration of the periodic variation synchronization adaptive equalization circuit 5 in FIG. 1 and an example of the relationship between the periodic variation synchronization adaptive equalization circuit 5 and its peripheral circuits, the periodic variation synchronization adaptive equalization circuit 5 includes: An equalization coefficient multiplication circuit unit 51, an equalization coefficient generation circuit 52, an equalization coefficient learning circuit 53, and an equalization coefficient timing generation function unit 54 are provided.

  The equalization coefficient multiplication circuit unit 51 multiplies the input signal by the equalization coefficient in the equalizer. The equalization coefficient generation circuit 52 calculates an equalization coefficient by an LMS (Least Mean Square) algorithm or the like, and further selects the equalization coefficient learned by the equalization coefficient learning circuit 53 to the equalization coefficient multiplication circuit unit 51. To set. The equalization coefficient learning circuit 53 learns the equalization coefficient in the fluctuation cycle of the transmission path. The equalization coefficient timing generation function unit 54 uses the transmission line change point detection timing based on the output of the transmission line change point detection circuit 6 and the power supply period detection timing based on the output of the power supply period detection circuit 6, to change the true transmission line fluctuation period. And the equalization coefficient is optimally switched in synchronization with the period fluctuation of the transmission path state.

  When switching equalization coefficients in synchronization with periodic fluctuations in the state of the transmission line, detection of periodic fluctuations in the state of the transmission line becomes an issue in communication systems that use electrical wiring such as power lines and general wiring for communication. . Transmission in which amplitude and phase fluctuations occur at certain periodic intervals due to the influence of the type of power supply circuit such as power equipment connected to the same wiring used for communication and other equipment connected to the same wiring, and its load state Road conditions are considered. Such periodic fluctuations in transmission path characteristics do not necessarily occur in the power supply period. Therefore, with regard to such periodic fluctuations in transmission line characteristics, the fluctuation period is accurate in the conventional equalization coefficient switching method that assumes transmission line fluctuations linked to the power supply period as proposed in Patent Document 1. Detection is difficult.

  Therefore, as described above, the amplitude of the power supply circuit such as the power equipment connected to the same wiring used for communication and the other equipment connected to the same wiring, the influence of the load state, and the like on a certain periodic basis. For periodic fluctuations in transmission path characteristics such as phase fluctuations, detection of the transmission path fluctuation period requires an optimum method or mechanism with further improved detection accuracy. In the first embodiment, more accurate cycle detection is performed by further calculating two detection signals of the transmission path change point detection circuit 6 and the power supply cycle detection circuit 7.

  Here, the operation of the transmission line change point detection circuit 6 which is an internal functional block in FIG. 2 will be described with reference to FIGS.

  FIG. 5 is a diagram illustrating an example of the configuration of a signal frame of a signal transmitted from a communication signal transmission source (a signal input to the signal combining device 12 in FIG. 1) including a reference signal. As described above, a preamble serving as a reference signal is added to the head of the frame. The transmission line change point detection circuit 6 uses the FFT result of this reference signal (FFT result by the FFT unit 4 in FIG. 1) to measure how much the received signal actually received through the transmission line has changed, If the fluctuation amount exceeds a certain threshold, it is determined that fluctuation has occurred and is detected. As can be seen from the image of the variation amount illustrated in FIG. 7 on the amplitude / phase coordinates, the transmission path change point detection circuit 6 can detect the transmission path estimated value (reception point) and the error value from the reference point. . In other words, the transmission path change point detection circuit 6 measures how much the received signal actually received through the transmission path has fluctuated, and if the fluctuation amount exceeds a certain threshold, it is determined that fluctuation has occurred and the fluctuation amount Is detected.

  Here, in FIG. 3 illustrating an example of the circuit configuration of the power cycle detection circuit 7, the power waveform of the AC 50/60 Hz power source is as shown in FIG. 4, but the photocoupler in FIG. The vicinity of the zero cross is detected at the change point serving as the threshold. The output waveform of the photocoupler is as illustrated in FIG. The output signal of the photocoupler can arbitrarily generate timing from the zero cross point by the zero cross detection circuit and the timing count circuit shown in FIG.

  The transmission line change point detection timing by the transmission line change point detection circuit 6 described above with reference to FIG. 5 and the output of the power cycle detection circuit 7 described with reference to FIGS. FIG. 8 illustrates an equalization coefficient timing generation function for detecting the fluctuation period and optimally switching the equalization coefficient.

  In FIG. 8 for explaining an example of the function of the equalization timing generation circuit 54 in FIG. 2, the equalization coefficient timing generation function 54 includes a timing selection circuit 542 and a period determination circuit 541, and the following (1) ( It has the main function of 2). (1) A change point of transmission path fluctuation is detected, and a learning timing for storing an equalization coefficient according to the transmission path fluctuation is notified to the equalization coefficient learning circuit 53. (2) The change point of the transmission path fluctuation is detected, and the equalization coefficient stored in the equalization coefficient learning circuit 53 is notified to the equalization coefficient multiplication circuit 51 of the equalizer.

  The timing selection circuit 542 monitors the output of the transmission line change point detection circuit 6 and the output of the power supply cycle detection circuit 7. (1) When the power supply circuit cycle matches the detection timing of the transmission line change point And (2) a case where a transmission point change point detection circuit alone detects a change point other than the power cycle, and the cycle determination circuit 541 determines whether or not the same cycle occurs for a longer fixed period. By counting a certain number of times, it is determined whether or not the periodic fluctuation is certain.

  The period signal detected and detected by the period determination circuit 541 as described above is notified to the equalization coefficient learning circuit 53, the equalization coefficient generation circuit 52, and the equalization coefficient multiplication circuit 51, as shown in FIG. .

  The equalization coefficient learning circuit 53 will be described with reference to FIG. 9 showing an example of the internal configuration of the equalization coefficient learning circuit 53 in FIGS.

  The equalization coefficient learning circuit 53 has a memory structure, and the equalization coefficient calculated by the equalization coefficient generation circuit 52 in FIG. 2 at the timing of the periodic signal determined and detected by the period determination circuit 541 is shown in FIG. As illustrated, it is stored in accordance with the pattern of the cycle timing.

In the example of FIG. 9, an equalization coefficient (weights to be multiplied (W ₀ , W ₁ ,... W _m ,... W _M in FIG. 2)) corresponding to the period timing pattern A is stored in the memory unit A. stored in the memory unit B, the equalization coefficient corresponding to the pattern B different period timing and pattern a (weight to be multiplied _(W 0 in FIG. _{2, W 1, ··· W m} , ··· W M) ) Is remembered.

  Next, the equalization coefficient generation circuit 52 will be described with reference to FIG. 10 showing an example of the internal configuration of the equalization coefficient generation circuit 52 in FIGS.

The equalization coefficient generation circuit 52 includes an equalization coefficient calculation circuit 522 based on an LMS algorithm or the like and a selector 521, and the equalization coefficient (multiplication) calculated by the equalization coefficient calculation circuit 522 according to the timing of the equalization timing generation circuit 54 And the equalization coefficient stored in the equalization coefficient learning circuit 53, and the equalization coefficient (weight (W ₀ , W ₁ ,... In FIG. 2) of the equalization coefficient multiplication circuit 51 in the adaptive equalizer. W _m ,... W _M )) are set.
In the equalization coefficient calculation circuit 522, an RLS (Recursive Least Square) algorithm having convergence characteristics superior to the LMS algorithm can also be used for the least square error calculation.

  When the fluctuation period of the above-described period fluctuation is detected, it is necessary to switch the equalizer equalization coefficient (weight) at the head of the period. After the fluctuation period is detected, the end of the previous period is If the equalization coefficient (weight) of the equalizer is switched at the time of detection, adaptation is possible from the next cycle.

  In the conventional apparatus, as described above, the fluctuation of the transmission line linked to the power cycle is assumed, the fluctuation cycle is detected only by the power cycle, and the constant equalization pattern is switched. Frequency characteristics are severe depending on conditions such as type, line length, branching, etc.Furthermore, the type of power supply circuit such as power equipment connected to the same wiring used for communication, the type of other equipment connected to the same wiring, and the load state thereof (1) It is not possible to equalize periodic fluctuations other than the power cycle, under the transmission line conditions where the transmission line characteristics dynamically change due to the influence of (2) Adaptive equalization to the transmission line characteristics and periodic fluctuations Since it does not have an equalization function, sufficient characteristics cannot be improved.

  For example, in a power line, it is assumed that various home appliances and power devices are connected on the same line. However, for example, amplitude and phase fluctuations as shown in FIGS. In the receiving circuit of the modem device, there is a possibility that a reception error occurs due to the deviation of the amplitude / phase point, and it is preferable to take a supplementary means associated with this phenomenon. Furthermore, in the case of using other general communication lines, etc. (including not only communication but also a common line with a modem. For example, wiring in a factory, wiring in a train, etc.) However, it is impossible to assume what kind of communication disturbance will be connected to the same line, and it is better to take supplementary means to compensate for errors by switching not only in the power supply cycle but also in periodic cycles, etc. preferable.

  In the first embodiment, as can be seen from the above-described configuration, function, and operation, (1) not only the transmission line fluctuation is estimated, but also the fluctuation level and the repetition period are estimated from the transmission line estimation result. It is possible to detect unknown periodic fluctuations and switch between (2) an adaptive equalization method that constantly learns equalization coefficients and an equalization coefficient of a fluctuation period that has been learned in advance by calling it at the period fluctuation timing. Thus, it is possible to perform equalization quickly and accurately, and to perform the complement.

  In the first embodiment, as can be seen from the configuration, function, and operation described above, communication data is superimposed on electrical wiring such as power lines and general wiring, and the data is assigned to a single carrier or a plurality of carriers on the frequency axis. In the modem system that communicates with each other, the period fluctuation synchronous adaptive equalization function that performs adaptive equalization in synchronization with the period fluctuation of the transmission path state, the state of the amplitude and phase at the reception point when the transmission side communication signal passes on the transmission path The modem device includes a transmission line change point detection circuit that estimates a transmission line from the reference signal and detects a change in the transmission line state based on a deviation value from a reference signal, and a power supply period detection circuit that detects a power supply period.

  In other words, the first embodiment uses the transmission signal in a modem device that is used for communication in which an electrical wiring is used in combination and a communication signal is superimposed on the electrical wiring to equalize a transmission signal and a reception signal. Includes a transmission line change point detection circuit that detects a change point of the state of the transmission line from a received signal that has passed through the transmission line of the communication signal, and a power supply cycle detection circuit that detects a power supply period, and the transmission line change inspection The modem device performs equalization in synchronization with a period fluctuation of the state of the transmission path by an output of the output circuit and an output of the power cycle detection circuit.

  In other words, the first embodiment is a modem device that detects the change point of the state of the transmission path based on the state of the amplitude and phase of the received signal.

  In other words, the first embodiment is a modem device that detects a change point of the state of the transmission path based on an error from the reference signal of the amplitude / phase of the received signal.

From the viewpoint of the first embodiment, in the equalization method in the modem device used for communication in which the electrical signal is used together and the communication signal is superimposed on the electrical wire, the communication signal passes through the transmission path of the communication signal. A transmission line change point detection circuit for detecting a change point of the state of the transmission line from the transmitted communication signal, and a power supply cycle detection circuit for detecting a power supply cycle, and an output of the transmission line change point detection circuit and the power supply cycle detection circuit Is an equalization method in a modem device that performs equalization in synchronization with the period fluctuation of the state of the transmission path.

Embodiment 2. FIG.
The second embodiment of the present invention will be described below with reference to FIGS. FIG. 13 is a block diagram illustrating another example of the internal configuration of a modem device including a device that executes the periodic variation synchronization adaptive equalization method, and FIG. 14 illustrates the internal configuration and period of the periodic variation synchronization adaptive equalization circuit 5 in FIG. FIG. 15 is a block diagram illustrating another example of the relationship between the fluctuation synchronization adaptive equalization circuit 5 and its peripheral circuits. FIG. 15 illustrates an example of detection condition setting by the detection condition setting function unit 20 in FIGS. It is explanatory drawing for.

  In the second embodiment, a detection condition setting function unit 20 is added to FIG. 1 in the first embodiment. Therefore, in the following description of the second embodiment, the points different from FIG. 1 will be mainly described, and descriptions of the same points as in FIG. 1 will be omitted.

  In FIG. 13, the detection condition setting function unit 20 has a function that allows the transmission line change point detection circuit 6 to set a detection threshold and a detection time width (Window) from the outside when detecting a transmission line change point. It is possible to perform accurate detection that is more adapted to the transmission path condition by setting cases such as when it is difficult to determine the threshold due to noise or when it is necessary to detect the period of time at long timing It is what.

  Next, the operation of the second embodiment will be described with reference to FIG. 13, FIG. 14, and FIG.

  In FIG. 13 and FIG. 14, the detection condition setting function unit 20 makes it possible to set conditions for the transmission line change point detection circuit 6 via, for example, an internal register that can be accessed by a CPU or the like. When the transmission line change point detection circuit 6 detects the transmission line change point, it is difficult to judge the threshold due to noise or the like by providing a function that can set the detection threshold and the detection time width (window) from the outside. By setting the case or the case where the period detection of the time at the long timing is necessary, it is possible to perform the accurate detection more adapted to the transmission path state.

  FIG. 15 is a time chart showing an example of detection condition setting by the detection condition setting function 20, and in FIG. 15E, the detection level, short-term detection width, and periodicity for detecting the transmission line change point detection circuit 6 are detected. It shows how the detection width can be set.

  As can be seen from the above description, the second embodiment includes a period variation synchronous adaptive equalization function that performs adaptive equalization in synchronization with a period variation, a transmission line change point detection circuit, and a power supply period detection circuit. The modem device is provided with a function capable of externally setting a detection threshold level and a detection time width (window) when detecting a transmission line change point.

  In other words, the second embodiment is a modem device provided with a function of setting a threshold level for detection of a transmission line change point and a detection time width.

Embodiment 3 FIG.
The third embodiment of the present invention will be described below with reference to FIGS. FIG. 16 is a diagram illustrating another example of the configuration of a signal frame of a signal transmitted from a communication signal transmission source (a signal input to the signal combining device 12 in FIG. 1) including a reference signal, and FIG. It is a block diagram which illustrates another example of the internal structure of the modem apparatus containing the apparatus which performs a synchronous adaptive equalization system, and the relationship with the peripheral device and function part of a modem apparatus.

  FIG. 16 shows an example of a frame configuration in which a postamble including a reference signal is added to the end of the frame signal in FIG. 5 in the first embodiment.

  FIG. 17 includes a transmission frame postamble addition function unit 312 for transmission side data to the electrical wiring 101 and a reception frame postamble analysis function unit 311 on the reception side in FIG. This is an example in which a function for receiving a fluctuation period timing signal from the period fluctuation synchronization adaptive equalization function 5 is added as a postamble generation timing.

  Therefore, in the following description of the third embodiment, the points different from FIGS. 1 and 5 will be mainly described, and the description of the same points as those in FIGS. 1 and 5 will be omitted.

  Next, operations and functions of the third embodiment will be described with reference to FIGS. 1, 2, 5, 16, and 17.

  As shown in FIG. 17, in FIG. 1, a transmission frame postamble addition function unit 312 is additionally provided for the transmission side data, and a reception frame postamble analysis function unit 311 is additionally provided on the reception side. By adding a function for receiving a fluctuation period timing signal from the period fluctuation synchronization adaptive equalization function (circuit) 5, the transmission frame postamble addition function unit 312 adds the transmission frame to the transmission frame and the preamble of FIG. Add a postamble containing a reference signal to

  On the received frame side, the fluctuation variation is further detected from the reference signal of the postamble, and the fluctuation cycle detection accuracy is further improved by detecting the fluctuation cycle in parallel independently between the preamble and the postamble. It is possible to improve.

  Although the postamble is described as being provided at the end of the frame, it may be in the middle of the frame.

  In the first embodiment, with respect to the reference signal in FIG. 2, a reference signal serving as a reference signal as a preamble is provided at the head of the frame as shown in FIG. 5, but in the third embodiment, in FIG. As shown, a postamble is further provided in the middle or end of the frame on the frame, and the reference signal is increased, so that the number of fluctuations detected on the transmission path can be increased and the accuracy can be improved. For example, it is effective in a transmission line having a low S / N (Signal to Noise Ratio) ratio.

  In the third embodiment, as can be seen from the above description, a frame other than the frame head is used for the preamble at the head of the frame serving as a reference signal in the communication frame used in the transmission path estimation circuit of the transmission path change point detection circuit. This is a modem device that reduces a transmission path change point detection error by providing a postamble including a reference signal in the middle of the frame or at the end of the frame.

  In other words, Embodiment 3 is a modem device in which a preamble and a postamble each having a reference signal are provided in a signal frame of a transmission signal.

Embodiment 4 FIG.
A fourth embodiment of the present invention will be described below with reference to FIGS. FIG. 18 is an explanatory diagram for explaining an example of the relationship between signal frames and occurrence of reception errors due to transmission path fluctuations, and FIG. 19 is a diagram showing an example of data redundancy in a frame in anticipation of reception errors with respect to transmission frames; FIG. 20 is a block diagram illustrating still another example of the internal configuration of a modem device including a device that executes the period variation synchronous adaptive equalization method and the relationship between peripheral devices and function units of the modem device.

  In the first embodiment described above, the configuration of the communication frame in the transmission signal and the reception signal illustrated in FIG. 1 is as shown in FIG. 5. However, if a fluctuation period on the transmission path is detected, an error (communication NG) is previously detected on the frame. In the fourth embodiment, as shown in FIGS. 18 and 19, in the transmission signal, the portion on the frame is made redundant (invalidated) or the received frame is analyzed. By making the part of the frame redundant (invalidated), there is no need to perform retransmission or invalid frame processing in communication error processing. By receiving only normal frames, synchronous control and reception of modem devices It is possible to avoid the state of control communication abnormality.

  20 adds a transmission frame reconstruction unit 302 for the transmission side data to FIG. 1 and adds a reception frame redundancy unit analysis unit 301 to the reception side, As a timing for judging reception of a frame, a function for receiving a fluctuation cycle timing signal from the period fluctuation synchronization adaptive equalization function 5 is added.

  Next, the operation of the fourth embodiment will be described with reference to FIG. 1, FIG. 5, FIG. 18, FIG.

  In the first embodiment, the configuration of the communication frame in the transmission signal and the reception signal illustrated in FIG. 1 is as shown in FIG.

  On the other hand, FIG. 18 in the fourth embodiment exemplifies a location where an error (communication NG) occurs on the frame when a fluctuation period on the transmission path is detected. In this way, when an error occurs in the received frame, for example, if it is a header part, synchronization loss due to synchronization abnormality or reception abnormality of all the frames occurs, and if it is a data part, for example, a retransmission operation occurs, If the communication band is compressed and buffer overflow and retransmission are not completed in one time, various abnormal states such as reception NG due to the number of times exceeding may occur.

  FIG. 19 illustrates measures for avoiding various abnormal state states such as the above-mentioned reception NG. When a periodic motion can be detected, the timing at which an error occurs on a frame can be predicted in advance. Therefore, a redundant bit is added at the time of constructing frame data such that no meaningful data is transmitted to the location where the error occurs in the transmission frame, that is, it is configured with redundant bits. The function is added to the function of the first embodiment.

  20 adds a transmission frame reconstruction unit 302 for transmission side data to FIG. 1 and adds a reception frame redundancy unit analysis unit 301 to the reception side in order to realize the function described with reference to FIG. A function for receiving a fluctuation period timing signal from the period fluctuation synchronization adaptive equalization function 5 is added as a timing for generating a reconstructed frame provided with bits and a timing for judging reception of the frame.

  As can be seen from the above description, in the fourth embodiment, when the period variation can be detected, the portion in which the reception characteristics deteriorate due to the period variation on the communication frame is set as redundant data other than the communication data. This is a modem device having a function of reconstructing a transmission frame.

  In other words, the fourth embodiment has a function of reconstructing a transmission frame so that a portion where reception characteristics on a communication frame deteriorate due to a period variation of the state of the transmission path is made redundant data other than data. This is a provided modem device.

Embodiment 5 FIG.
The fifth embodiment of the present invention will be described below with reference to FIGS. FIG. 21 is a diagram exemplifying a case where the signal frame period and the transmission path fluctuation period coincide with each other and a reception error occurs periodically. FIG. 22 changes the frame length so that the signal frame period does not coincide with the transmission path fluctuation period. FIG. 23 is a diagram illustrating an example of avoidance. FIG. 23 shows a case in which the frame length is changed when the signal frame period and the transmission line fluctuation period coincide with each other, and the reception error is periodically generated so as not to coincide with the signal frame period and the transmission line fluctuation period. FIG. 6 is a diagram illustrating a means for avoiding the problem, and illustrates still another example of the internal configuration of the modem device including the device that executes the period variation synchronous adaptive equalization method and the relationship between the peripheral device and the function unit of the modem device. It is a block diagram.

  In the first embodiment, the configuration of the communication frame in the transmission signal and the reception signal illustrated in FIG. 1 is as shown in FIG.

  On the other hand, as illustrated in FIGS. 21 and 22 in the fifth embodiment, when a fluctuation period on the transmission path is detected and coincides with the frame period, a communication error occurs at the same location on the frame every frame. there's a possibility that.

  Thus, if an error occurs in the received frame every time, for example, if it is a header part, the state of out-of-synchronization due to synchronization abnormality occurs and the state where it does not return continues or if it is a data part, for example, a retransmission operation occurs every time. However, even if the communication band is compressed and the buffer overflow and retransmission are not completed in one time, there is a possibility that various abnormal states such as a reception NG due to the excessive number of times may occur.

  Therefore, in FIG. 23 in the fifth embodiment, a transmission frame length reconstruction unit 304 for transmission side data is added to FIG. 1 in the first embodiment, and a reception frame length analysis unit 303 is provided on the reception side. In addition, as a reconstructed frame generation timing provided with redundant bits and a timing for judging reception of the frame, a function of receiving a variation cycle timing signal from the cycle variation synchronization adaptive equalization function 5 has been added, When the fluctuation period is detected by this configuration and this function, the frame length is changed so as not to coincide with the fluctuation period, thereby avoiding the occurrence of occurrence at the same position of the frame every time.

  Thus, if an error occurs in the received frame every time, for example, if it is a header part, the state of out-of-synchronization due to synchronization abnormality occurs and the state where it does not return continues or if it is a data part, for example, a retransmission operation occurs every time. However, there is a possibility that various abnormal conditions such as reception NG due to excessive number of times may occur even if buffer overflow and retransmission are not completed in one time, but if the fluctuation period is detected, By changing the frame length so as not to coincide with the fluctuation period by the function of the fifth aspect, it is possible to avoid the occurrence of the frame at the same position every time.

  As can be seen from the above description, in the fifth embodiment, when period fluctuations can be detected, in order to avoid the occurrence of error at a specific period on a communication frame, the frame configuration is re-changed by changing the communication frame length. This is a modem device having a function to be constructed.

  In other words, the fifth embodiment is a modem device provided with a function of reconfiguring the frame configuration by changing the signal frame length of the transmission signal and avoiding an error from occurring at a specific period on the signal frame. is there.

  1 to 23, the same reference numerals denote the same or corresponding parts in each figure.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of this invention, and is a block diagram which illustrates an example of the internal structure of a modem apparatus containing the apparatus which performs a period fluctuation synchronous adaptive equalization system, and the relationship with the peripheral apparatus and apparatus of a modem apparatus. . 1 is a diagram illustrating a first embodiment of the present invention, and is a block diagram illustrating an example of an internal configuration of a periodic variation synchronization adaptive equalization circuit 5 in FIG. 1 and an example of a relationship between the periodic variation synchronization adaptive equalization circuit 5 and its peripheral circuits. is there. FIG. 5 is a diagram illustrating the first embodiment of the present invention, and is a connection diagram illustrating an example of a zero-cross detection circuit in the power cycle detection circuit 7 in FIGS. 1 and 2. FIG. 5 is a diagram illustrating the first embodiment of the present invention, and is a diagram illustrating an example of a relationship between a power supply waveform of an AC power supply and an output waveform of a photocoupler in FIG. 3. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of this invention, and illustrates an example of the structure of the signal frame of the signal (signal input into the signal coupling device 12 of FIG. 1) transmitted from a communication signal transmission source including a reference signal. FIG. It is a figure which shows Embodiment 1 of this invention, and is a figure which shows a communication system model. It is a figure which shows Embodiment 1 of this invention, and is a figure which shows an example of the idea which detects the error value from the transmission line estimated value and reference point by the transmission line change point detection circuit 6 in FIG.1 and FIG.2. FIG. 2 is a diagram illustrating the first embodiment of the present invention, and is a diagram illustrating an example of the function of an equalization timing generation circuit 54 in FIG. 2. FIG. 9 is a diagram illustrating the first embodiment of the present invention, and is a diagram illustrating an example of an internal configuration of an equalization coefficient learning circuit 53 in FIGS. 2 and 8. FIG. 9 is a diagram illustrating the first embodiment of the present invention, and is a block diagram illustrating an example of an internal configuration of an equalization coefficient generation circuit 52 in FIGS. 2 and 8. It is a figure which shows Embodiment 1 of this invention, and is a figure which shows the transmission line characteristic A which is an example of the fluctuation | variation of a transmission line characteristic. It is a figure which shows Embodiment 1 of this invention, and is a figure which shows the transmission line characteristic B which is another example of the fluctuation | variation of a transmission line characteristic. It is a figure which shows Embodiment 2 of this invention, and is a block diagram which illustrates another example of the internal structure of the modem apparatus containing the apparatus which performs a period fluctuation synchronous adaptive equalization system. FIG. 14 is a diagram illustrating the second embodiment of the present invention, and is a block illustrating another example of the internal configuration of the periodic fluctuation synchronization adaptive equalization circuit 5 and the relationship between the periodic fluctuation synchronization adaptive equalization circuit 5 and its peripheral circuits in FIG. FIG. It is a figure which shows Embodiment 2 of this invention, and is explanatory drawing for demonstrating an example about the setting of the detection condition by the detection condition setting function part 20 in FIG. 13 and FIG. FIG. 9 is a diagram illustrating a third embodiment of the present invention, including another example of a signal frame configuration of a signal transmitted from a communication signal transmission source (a signal input to the signal combining device 12 in FIG. 1) including a reference signal. It is a figure illustrated. The figure which shows Embodiment 3 of this invention, and is a block which illustrates another example of the internal structure of the modem apparatus containing the apparatus which performs a period fluctuation synchronous adaptive equalization system, and the relationship with the peripheral device and a function part of a modem apparatus FIG. It is a figure which shows Embodiment 4 of this invention, and is explanatory drawing explaining an example of the relationship between a signal frame and generation | occurrence | production of the reception error by a transmission line fluctuation | variation. It is a figure which shows Embodiment 4 of this invention, and is a figure which shows an example of the redundancy of the data in the frame which anticipated the reception error with respect to a transmission frame. FIG. 10 is a diagram illustrating a fourth embodiment of the present invention, and illustrates still another example of the internal configuration of a modem device including a device that executes a period variation synchronous adaptive equalization method and the relationship between peripheral devices and function units of the modem device. It is a block diagram. It is a figure which shows Embodiment 5 of this invention, and is a figure which illustrates the example which a signal frame period and a transmission-line fluctuation | variation period correspond, and a receiving error generate | occur | produces periodically. It is a figure which shows Embodiment 5 of this invention, and is a figure which illustrates an example which changes a frame length and it avoids so that it may not correspond with a signal frame period and a transmission-line fluctuation period. FIG. 5 is a diagram showing Embodiment 5 of the present invention, in which the frame length is changed when the signal frame period and the transmission path fluctuation period coincide with each other, and the reception error is periodically changed so as not to coincide with the signal frame period and the transmission path fluctuation period. FIG. 5 is a diagram illustrating a means for avoiding occurrence, and illustrates still another example of the internal configuration of a modem device including a device that executes a period variation synchronous adaptive equalization method and the relationship between peripheral devices and function units of the modem device FIG.

Explanation of symbols

1 modem device,
2 Analog signal interface,
3 A / D (Analog / Digital) converter,
4 FFT (First Fourier Transform) part,
5 Period variation synchronous adaptive equalization function circuit,
51 equalization coefficient multiplication circuit section,
52 Equalization coefficient generation circuit,
521 selector,
522 equalization coefficient calculation circuit,
53 Equalization coefficient learning circuit,
54 Equalization coefficient timing generation function part,
541 period determination circuit,
542 timing selection circuit,
6 Transmission line change point detection circuit,
7 Power cycle detection circuit,
8 Decryption unit,
9 D / A (Digital / Analog) converter,
10 IFFT (Inverse First Fourier Transform) part,
11 Encoding part,
12 signal coupling device,
20 Detection condition setting function section,
101 electrical wiring,
301 Receive frame redundant part analysis part,
302 transmission frame reconstruction unit,
303 Received frame length analysis section,
304 Transmission frame length reconstruction unit,
311 Received frame postamble analysis function part,
312 Transmission frame postamble addition function part.

Claims (8)

  In an equalization method for a modem device used for communication in which an electrical wiring is used together and a communication signal is superimposed on the electrical wiring, the change point of the state of the transmission path from the communication signal passing through the transmission path of the communication signal A transmission line change point detection circuit for detecting a power supply period and a power supply period detection circuit for detecting a power supply period, and the fluctuation of the state of the transmission line according to the output of the transmission line change point detection circuit and the output of the power supply period detection circuit An equalization method in a modem device characterized by performing equalization in synchronization with   In a modem device that is used for communication in which an electrical wiring is used and a communication signal is superimposed on the electrical wiring and equalizes a transmission signal and a reception signal, the transmission signal has passed through the transmission path of the communication signal A transmission line change point detection circuit for detecting a change point of the state of the transmission line from a received signal, and a power supply cycle detection circuit for detecting a power supply period are provided, and the output of the transmission line change point detection circuit and the power supply cycle detection circuit A modem device characterized in that equalization is performed in synchronism with period fluctuations of the state of the transmission path by output.   3. The modem device according to claim 2, wherein a change point of the state of the transmission path is detected based on the amplitude / phase state of the received signal.   3. The modem device according to claim 2, wherein a change point of the state of the transmission path is detected based on an error from the amplitude / phase reference signal of the received signal.   5. The modem device according to claim 2, further comprising a function of setting a threshold level and a detection time width for detecting the transmission line change point.   5. The modem apparatus according to claim 4, wherein a preamble and a postamble each having a reference signal are provided in a signal frame of the transmission signal.   7. The modem device according to claim 2, wherein a transmission data is transmitted so that a portion where reception characteristics on a communication frame deteriorate due to a period variation of a state of the transmission path is redundant data other than data. A modem device provided with a function of reconstructing a frame.   8. The modem device according to claim 2, wherein a signal frame length of the transmission signal is changed to reconstruct the frame configuration to prevent an error from occurring at a specific period on the signal frame. A modem device provided with a function for

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