JP2015037337A - On-vehicle apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle apparatus capable of eliminating a noise mixed into an amplitude-demodulated wave signal (an input signal) related to train-control.SOLUTION: A signal discrimination part 30 constituting an on-vehicle apparatus 3 generates an output signal S2 corresponding to an input signal S1, where: the input signal S1 is an amplitude-modulated signal supplied from a ground apparatus 2; and the output signal S2 is produced by extracting a signal component from the input signal S1 at a given temporal width and converting the signal component into a frequency zone, comparing a spectrum obtained by the conversion with spectra (Fm1, Fm2, through FmN) of pre-stored plural modulation wave frequencies to derive correlation coefficients (r1, r2, through rN), and selecting a modulation wave frequency with which the derived correlation coefficient is the highest.

Description

  The present invention relates to an on-vehicle device, and more specifically, on-vehicle that removes noise mixed in an amplitude-modulated wave signal (input signal) related to train control when used in a train control device in combination with a ground device. Relates to the device.

  As a device for removing noise mixed in an input signal, devices having various structures have been proposed and put into practical use. For example, the noise removal device described in Patent Document 1 is intended to suppress noise by extracting noise from the input signal by smoothing the spectrum and subtracting the noise from the input signal on the frequency axis. is there. Specifically, the noise removal apparatus of Patent Document 1 includes a frequency analyzer that calculates frequency spectrum information of an input signal, a noise power spectrum estimator that estimates a noise power spectrum of a noise component included in the input signal, and an input A subtractor that subtracts a noise power spectrum from a power spectrum; and a frequency synthesizer that restores a time signal from the phase spectrum of the input signal and the power spectrum obtained by the subtractor, and the noise power spectrum estimator comprises: For each frequency, a small level power spectrum within a certain period is extracted as the noise power spectrum.

  The noise removal apparatus described in Patent Document 2 is a signal receiver arranged at two points in different spaces with a certain reception interval, and a mutual correlation coefficient that measures a cross-correlation coefficient of the noise with the reception interval as a parameter. Correlation coefficient measurement means, correlation length calculation means for obtaining a correlation length related to the noise space from the cross correlation coefficient, and using the correlation length, the reception interval according to the analysis frequency band and the attenuation rate of the noise level is determined. A reception interval setting / control means for setting and controlling the reception interval; and a cross spectrum calculation means for calculating a cross spectrum between the reception signals of the two signal receivers.

  The sound collecting device described in Patent Document 3, a main microphone that detects a target sound, a reference microphone that detects noise, and a silent section based on a time average value of output power of the main microphone and the reference microphone A silent section determination unit, a correlation determination unit that determines a correlation based on a correlation coefficient between the output of the main microphone and the output of the reference microphone, and the output of the main microphone using an adaptive filter An adaptive noise removal unit that subtracts the output of the reference microphone to remove the noise component, indicates that the determination result of the silence interval determination unit is a silence interval, and the determination result of the correlation determination unit is correlated Only when it is shown that there is a relationship, the adaptive filter coefficient of the adaptive noise removing unit is updated.

  By the way, in train control, various noises are mixed in an input signal received on the vehicle upper side. This noise must be removed as much as possible. This is because in the field of train control, the signal characteristics of the input signal directly affect appropriate train control and safety management of train operation.

  In particular, it is known that noise (VVVF noise) received from an inverter device performing variable voltage variable frequency is mixed in an input signal related to this type of train control. This VVVF noise cannot be sufficiently removed by a bandpass filter or the like that attenuates noise in a predetermined frequency band because the frequency at which the noise is generated varies depending on the train speed. Further, even if the techniques described in Patent Documents 1 to 3 already described are used, the VVVF noise having the above-described characteristics cannot be sufficiently removed.

  Therefore, in the conventional train control device, in order to reduce the influence of the VVVF noise included in the input signal described above, it is possible to increase the transmission output from the ground side and increase the S / N ratio (signal-noise ratio). Has been done. However, in order to increase the transmission output, it is necessary to increase the current. As a result, new problems such as an increase in power consumption and an increase in capacity of the train control device occur.

JP-A-11-102197 JP-A-5-252064 JP-A-5-119794

  The subject of this invention is providing the on-vehicle apparatus which can remove the noise mixed in the amplitude modulation wave signal (input signal) which concerns on train control.

  Another object of the present invention is to provide an on-vehicle device that can reduce power consumption required for signal transmission.

  Still another object of the present invention is to provide an on-board device that can increase the track circuit length and reduce the number of devices.

  In order to solve the above-described problem, the on-board device according to the present invention includes a signal determination unit. The signal discriminating unit generates an output signal corresponding to the input signal. Here, the input signal is an amplitude-modulated wave signal supplied from the ground device. On the other hand, the output signal is obtained by extracting a signal component from the input signal with a predetermined time width and converting it to the frequency domain, and comparing the spectrum obtained by the conversion with the spectrum of a plurality of modulation wave frequencies stored in advance. Each correlation coefficient is derived, and the correlation coefficient obtained by deriving is the highest modulation wave frequency.

  As described above, the signal discriminating unit constituting the on-board device according to the present invention generates an output signal corresponding to the input signal, and is a signal with a predetermined time width from the input signal supplied from the ground device. The component is extracted and converted to the frequency domain, and the correlation coefficient is derived by comparing the input signal spectrum obtained by the conversion with the spectrum of multiple modulation wave frequencies stored in advance. The modulation wave frequency having the highest correlation coefficient is set as the output signal. According to this configuration, when an on-board device is combined with a ground device and used in a train control device, even if, for example, VVVF noise is mixed in the input signal, the input signal is not affected by the modulation wave. It is possible to accurately determine and output the frequency. Accordingly, it is possible to remove noise mixed in the amplitude-modulated wave signal (input signal) related to train control and to perform appropriate train control based on the output signal without the influence of noise.

  Since the noise suppression unit constituting the on-vehicle device according to the present invention can determine the modulation wave frequency of the input signal based on the correlation coefficient, the signal output on the ground side is suppressed and the signal is reduced with the same track circuit length. Power consumption required for transmission can be reduced. Further, with the same transmission output, the track circuit length can be increased, and the number of equipment on the ground side can be reduced (efficiency of the ground side equipment).

As described above, according to the present invention, the following effects can be obtained.
(1) It is possible to provide an on-board device that can remove noise mixed in an amplitude-modulated wave signal (input signal) related to train control.
(2) An on-vehicle device that can reduce power consumption required for signal transmission can be provided.
(3) It is possible to provide an on-board device that can increase the track circuit length and reduce the number of devices.

  Other objects, configurations and advantages of the present invention will be described in more detail with reference to the accompanying drawings. The accompanying drawings are merely examples.

It is a block diagram of a train control device using an on-board device concerning an embodiment of the present invention. It is a flowchart of the signal discrimination | determination process which concerns on embodiment of this invention. It is a wave form diagram of signal discrimination processing concerning an embodiment of the present invention. It is a figure which shows typically the signal discrimination | determination process which concerns on embodiment of this invention.

  1 to 4, the same reference numerals indicate the same or corresponding parts. The present invention relates to an on-vehicle device, specifically, even when noise is included in an amplitude-modulated wave signal (input signal) related to train control when used in a train control device in combination with a ground device, The present invention relates to an on-board device capable of determining a modulation wave frequency and outputting the determined modulation wave frequency. The train control device 1 in FIG. 1 includes a ground device 2 and an on-board device 3. The on-board device 3 is mounted on a train 5 that travels on the rail 4 in the direction of the arrow F1.

  The ground device 2 generates a train control signal current (ATC signal S1) including speed limit information such as an allowable operation speed of the train 5 according to the interval between the train 5 and the preceding train and the condition of the route. The ATC signal S1 is a sine wave subjected to amplitude modulation (amplitude modulated wave). The ATC signal S1 is supplied to the on-board device 3 through the rail 4 and each track circuit (not shown).

  The train 5 includes an on-vehicle device 3, an on-vehicle antenna 51, an inverter device 52, and a brake device 55. The on-board antenna 51 receives the ATC signal S1 supplied to the rail 4, and sends the received ATC signal S1 to the on-board device 3.

  The inverter device 52 performs variable voltage variable frequency control. The inverter device 52 converts the direct current W1 taken from the overhead line 6 through the pantograph 7 into the alternating current W2 and supplies the alternating current W2. The alternating current W2 supplied to the motor 53 becomes a return current W3 after passing through the motor 53, flows to the rail 4 through the wheels 54, and returns to a substation (not shown).

  The on-board device 3 includes a signal processing unit 31. The signal processing unit 31 checks the supplied ATC signal (S1) and a speed signal supplied from a speed detector (not shown). In the case of exceeding, a brake signal is generated and brake control is given to the brake device 55.

  Here, the train control apparatus 1 of FIG. 1 has one of the features in that it includes a signal determination unit 30 in addition to the basic configuration of the conventional train control apparatus described above. That is, in this type of train control, various noises are mixed in the ATC signal S1 received on the upper side of the vehicle. This noise must be removed as much as possible. This is because, in the field of train control, the signal characteristic (S / N ratio) of the ATC signal S1 directly affects appropriate train control and safety management of train operation.

  In particular, it is known that this type of ATC signal S1 is directly mixed with noise (VVVF noise) caused by the return current W3 in the on-board antenna 51. The VVVF noise cannot be sufficiently removed only by signal processing that attenuates noise in a predetermined frequency band such as a bandpass filter because the frequency at which the noise is generated varies depending on the traveling speed of the train 5. Moreover, since the ATC signal S1 has a small level fluctuation, when the VVVF noise having a large level fluctuation is mixed with the ATC signal S1, the transmission output from the ground side is increased to reduce the influence. As a result, new problems such as an increase in power consumption and an increase in the capacity of the train control device will arise.

  In order to solve the problem peculiar to the railway signal described above, the on-board device 3 of FIG. In short, the signal discriminating unit 30 removes noise from the ATC signal S1, and generates and outputs an ATC signal S2 corresponding to the input ATC signal S1. The ATC signal S1 is an amplitude-modulated wave signal supplied from the ground device. The ATC signal S2 is obtained by extracting a signal component from the ATC signal S1 with a predetermined time width and converting the signal component into a frequency domain, and comparing the spectrum obtained by the conversion with spectra of a plurality of modulation wave frequencies stored in advance. Each of the correlation coefficients is derived, and the modulation wave frequency signal having the highest correlation coefficient is obtained.

  The ATC signal S2 is supplied to the signal processing unit 31. The signal processing unit 31 checks the ATC signal S2 from the signal determination unit 30 and the speed signal supplied from the speed detector (not shown), generates a brake signal, for example, when the speed is exceeded, and sends it to the brake device 55. Give brake control.

  The specific signal discrimination processing in the signal discrimination unit 30 described above will be further described in detail with reference to FIGS. As shown in FIG. 2, the signal discrimination processing of the signal discrimination unit 30 includes a signal reception step, a frequency band extraction step, a frame extraction step (see FIG. 3a), a Fourier transform step (see FIG. 3b), and a phase relationship. A number derivation step (see FIG. 3c), a modulation wave frequency discrimination step (see FIG. 4), and a signal output step.

  First, in the signal receiving step, the ATC signal S <b> 1 supplied from the ground device 2 to each track circuit and the rail 4 is received through the on-board antenna 51.

  Next, in the frequency band extraction step, a BPF (Band-pass filter) process is performed on the ATC signal S1 received by the on-board antenna 51 to extract a frequency band including a signal component.

  Next, in the frame extraction step, a signal is extracted at a predetermined length from the signal component obtained by the frequency band extraction step and the waveform of the time axis, and a frame is obtained by extracting the signal at regular intervals. The BPF-processed signal component is divided into lengths including at least one wavelength of the modulated wave in the frame extraction step. As shown in FIG. 3A, one frame includes one or more wavelengths of the modulated wave as a unit, and is preferably set based on one period of the modulated wave.

  Next, as shown in FIG. 3B, the signal component for one frame extracted in the frame extraction step of FIG. 3A is converted from the time domain to the frequency domain by the Fourier transform step. The frequency spectrum (input signal spectrum) is stored in a storage area (not shown).

  The correlation coefficient derivation step in FIG. 3C is a process for removing noise on the stored frequency spectrum. First, in the signal discriminating unit 30, the spectrum of the modulation wave frequency of the ATC signal S1 related to train control is stored in advance in the storage area (not shown) as an internal spectrum. This internal spectrum is a spectrum that serves as a criterion for determining a correlation coefficient, and is composed of internal spectra Fm1, Fm2,... FmN (N is an integer of 3 or more) according to train control information. Specifically, in the ATC signal S1, for example, a modulation frequency spectrum used as a code such as a train speed and a track ID is determined in advance, and the internal spectra Fm1, Fm2,... FmN (N is an integer of 3 or more) Corresponds to the code.

  The correlation coefficient derivation step in FIG. 3C compares the input signal spectrum obtained in the frame extraction step with the internal spectra (Fm1, Fm2,... FmN) of a plurality of modulation wave frequencies stored in advance. The correlation coefficients (r1, r2,... RN) are derived.

  Next, in the modulation wave frequency discrimination step, the one having the highest correlation coefficient (r) is discriminated from each of the correlation coefficients (r1 to r3) derived in the correlation coefficient deriving step in FIG. . In the modulation wave frequency discrimination step of FIG. 4, since the correlation coefficient (r2) between the input signal spectrum and the internal spectrum Fm2 is the highest, the signal discrimination unit 30 determines that the modulation wave frequency of the input signal S1 is based on the internal spectrum Fm2. For example, the modulation wave frequency based on the determined internal spectrum Fm2 is output to the signal processing unit 31 as the ATC signal S2. The signal processing unit 31 performs train control based on the ATC signal S2. Since the ATC signal S2 output according to FIG. 4 has a modulation wave frequency based on the internal spectrum Fm2 stored in advance, it does not include VVVF noise or the like.

  As described with reference to FIGS. 1 to 4, the signal determination unit 30 constituting the on-board device according to the present invention generates an output signal (S2) corresponding to the input signal (S1). The ATC signal S1 supplied from the ground device 2 is extracted as one frame from the ATC signal S1 and subjected to Fourier transform, and a spectrum of the ATC signal S1 and a plurality of modulation wave frequencies stored in advance (Fm1, Fm2). ... (FmN) and correlation coefficients (r1, r2,... RN) are derived, respectively, and the modulation wave frequency (Fm2) having the highest correlation coefficient is determined as the output signal (S2).

  According to the above-described configuration, for example, even if VVVF noise whose generated frequency varies according to the traveling speed of the train 5 is mixed in the ATC signal S1, it can be removed and the S / N ratio can be improved. . Therefore, it is possible to provide the on-board device 3 that can improve the signal characteristics and noise resistance of the ATC signal S1, and the train control device 1 using the same.

  In other words, the signal discriminating unit 30 can remove noise mixed in the ATC signal S1 and improve the S / N ratio. And power consumption required for signal transmission can be reduced. Further, with the same transmission output, the track circuit length can be increased, and the number of equipment on the ground side can be reduced (efficiency of the ground side equipment).

  The train control device 1 shown in FIGS. 1 to 4 performs noise removal processing with the characteristics of the ATC signal S1 in the railway in mind. That is, in a railway, noise having a large fluctuation generated in a wide band such as VVVF noise is generated with respect to the ATC signal S1 having a small fluctuation. Therefore, it is necessary to perform a noise removal process using the feature. Moreover, the ATC signal S1 related to train control is characterized in that a modulation frequency spectrum used as a code such as a train speed and a track ID is determined in advance. In this regard, the train control device 1 of FIGS. 1 to 4 performs the correlation coefficient derivation step and the modulation wave frequency determination step in consideration of the characteristics of the ATC signal S1 described above, thereby performing a known internal spectrum (Fm1). , Fm2... FmN), the correlation coefficient (r) is derived, so that the modulation wave frequency of the ATC signal S1 can be accurately determined and output efficiently without being affected by noise. Therefore, the on-board device 3 that can improve the noise resistance and the train control device 1 using the same can be provided.

  Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is. For example, in the correlation coefficient derivation step of FIG. 3C, the correlation coefficient (r) is obtained by calculating the spectrum related to the input signal (S1) and all frequencies of the spectra (Fm1, Fm2,... FmN) stored in advance. In contrast, it can be derived. The correlation coefficient (r) can also be derived by comparing the spectrum related to the input signal (S1) with the frequency band including the signal components of the spectra (Fm1, Fm2,... FmN) stored in advance.

DESCRIPTION OF SYMBOLS 1 Train control apparatus 2 Ground apparatus 3 On-board apparatus Fm1, Fm2 ... FmN Internal spectrum r1, r2 ... rN Correlation coefficient 30 Signal discrimination | determination part S1 Input signal S2 Output signal

Claims (3)

An on-vehicle device including a signal discrimination unit,
The signal discriminating unit generates an output signal corresponding to the input signal,
The input signal is an amplitude-modulated wave signal supplied from a ground device,
The output signal is obtained by extracting a signal component from the input signal with a predetermined time width and converting it into a frequency domain, and comparing the spectrum obtained by the conversion with a spectrum of a plurality of modulation wave frequencies stored in advance. The correlation coefficient is derived respectively, and the correlation coefficient obtained by the derivation is the highest modulation wave frequency.
On-vehicle equipment. The on-vehicle device according to claim 1,
The predetermined time width is a frame including a range including one wavelength or more of the modulated wave,
On-vehicle equipment. A train control device including an on-vehicle device and a ground device,
The on-board device is the one described in claim 1 or 2,
The ground device supplies the input signal to the on-vehicle device.
Train control device.

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