JPH05254437A - Communication device for train control - Google Patents

Abstract

PURPOSE:To improve a noise-proof characteristic and a mutual interference characteristic with an adjoining track circuit in a communication method for train detection, train control in which a track circuit is used. CONSTITUTION:This communication device for train control is composed of a signal spreading means 2 that spreads and processes a signal with a specified PN code, a transmitting means 3 that transmits the spread signal to the side (S) of the starting end of a rail (T) that forms a track circuit, a receiving means 5 of spread signal from the side (R) of the terminal end or from the rail (T), a means 7 that demodulates and processes the spread signal received with the same frequency as a transmit signal and extracts a specified PN code, a noise eliminating means 8 that analyzes the extracted signal with FFT frequency to eliminate noise, and a detecting means 10 that detects the coincidence state of the signal from which noise is eliminated and the specified PN code, and detects the existence of a train on the rail from its presence, or detects a train control signal from the side of the ground on the side of the train that travels on that rail.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a train control communication device, and more particularly to the use of a track circuit and spread spectrum communication (SS communication) and FFT (Fast Four).
ier Transform) Applying frequency analysis,
The present invention relates to a device capable of detecting a train or transmitting train control information from the ground to a train (train).

[0002]

2. Description of the Related Art Conventionally, for example, in train position detection using a track circuit, a rail in a block section formed by dividing a rail (track) into predetermined lengths is used as a part of the track circuit, and the block section is formed. Connect a transmitter that sends out a signal of a predetermined frequency to the start side of the train (the side where the train advances) and a receiver that receives the signal at the end of the closed section (the side where the train enters). It is configured.

In the above structure, when a train exists in the closed section and the rail is short-circuited by the train axle (wheel), the output level of the receiver decreases, while the train does not exist in the closed section. At this time, the output of the receiver is maintained at a predetermined height. Therefore, if the track relay is turned ON / OFF by the output of the receiver, the presence / absence of a train in the closed section can be detected in the ON / OFF state.

Further, in train control communication in which a rail is a part of a transmission path, a train control signal supplied from the starting end of the rail is received by a receiver via an antenna provided in the train,
It is used for train control.

The blocking section is electrically insulated from an alternating current signal by an impedance bond or the like with the adjacent blocking section, so as not to interfere with the signals used in the adjacent blocking sections. It is devised. Further, in the case of being electrically non-insulated with respect to the AC signal, the frequencies of the signals used in the adjacent blocking sections are made different from each other to prevent interference.

[0006]

However, in train detection and train control communication using the conventional track circuits described above, the rails forming a part of the track circuits are in an environment susceptible to noise, and thus S / N. There is a drawback that the ratio tends to be low and the circuit configuration becomes complicated because the carrier frequency is changed to eliminate mutual interference with adjacent tracks or a resonance circuit is provided at the track boundary.

The present invention has been made to solve the above-mentioned drawbacks, and an object thereof is to provide a train control communication device having excellent noise resistance.

[0008]

In order to achieve the above-mentioned object, a train position detecting device according to the present invention comprises a signal spreading means for spreading a predetermined transmission signal with a predetermined PN code, and the signal spreading means. Sending means for sending the spread spread signal to the starting end side of the rail forming the track circuit, receiving means for receiving the spread signal from the terminal end side of the rail or from the rail, and the receiving means Extraction means for demodulating the spread signal using a signal having the same frequency as the predetermined transmission signal to extract the predetermined PN code, and FFT frequency analysis of the extracted signal extracted by the extraction means to remove noise. A noise removing unit for removing the signal, the signal removed by the noise removing unit and the matching state of the predetermined PN code are detected, and the existence of the train on the rail is detected from the presence or absence of the matching state, It is characterized by having a detecting means for detecting a train control signal from the ground side by train traveling on the rail.

[0009]

In the above construction, the spreading signal spread by the signal spreading means is supplied to the starting end side of the rail forming the track circuit by the sending means. Then, the received signal received from the terminal end of the rail, or the received signal received on the train running on the rail is demodulated using the signal having the same frequency as the transmitted signal and used by the signal spreading means. The code is extracted. The noise of the extracted signal is removed by the FFT frequency analysis by the noise removing means. Then, when the PN code extracted by the detecting means and the PN code used by the signal spreading means match, the presence of a train is detected, or a train control signal corresponding to the detected signal is obtained on the vehicle. When a train is present on the rail at the time of train detection, the receiving level of the receiving means is low, and therefore the PN code is not extracted by the extracting means. For this reason, the detection means detects the presence of a train on the condition that there is no PN code matching state.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram when a train control communication device according to an embodiment is applied to a train detection device, and a track (corresponding to a rail of the present invention, hereinafter also referred to as a rail) T Are divided into block sections at predetermined intervals (only three block sections are shown around the block section T for simplification of the drawing in FIG. 1) T, T ′, T ″. Each block section T, T ', T "may be a section using a well-known impedance bond, or may be a non-insulating section in which a capacitor or the like is interposed between rails.

Since the apparatus of this embodiment is installed in each block section, the train position detecting apparatus corresponding to the block section T will be described below. Although not limited to the present invention, the start side S and the end side R of the closed section T are the equipment room b.
And a transmitter / receiver section a and b are installed in the equipment room b so that the position in the block section T of the train can be detected.

First, as the transmitting section a, the signal generator 1,
A spreading circuit 2 and a transmitter 3 are provided. Signal generator 1 is conventional AM by unmodulated or a predetermined transmission signal modulation circuit, (corresponding to the transmission signal of the present invention) modulation carrier wave to the FM or the like (f _c) to output to spreading circuit 2 Is configured.

The spreading circuit 2 uses a predetermined PN code (PN ₁ )
The carrier wave (f _c ) is spread using the PN code from the PN code generator 4 for generating and then output to the next transmitter 3. The transmitter 3 is formed of a well-known amplifier and is configured to supply the output to the starting side a of the rail T.

Next, a receiver 5, a bandpass filter circuit 6, a demodulation circuit 7, a noise canceller circuit 8, a lowpass filter 9 and a correlation matched filter circuit 10 are provided as the receiving section b. The receiver 5 is formed of a well-known widening circuit, and is configured to output its output signal to the bandpass filter circuit 6. Demodulating circuit 7, the signal generator 1 is configured to divide process using a carrier (f _c) which is sent to the spreading circuit 2.

FIG. 2 shows a concrete example of the noise canceller circuit 8, which is A / D for A / D converting the output of the demodulation circuit 7.
A D conversion circuit 8 ', a sampling circuit 11 for sampling the output by alternately dividing the output into two, a pair of noise removal circuits 12a and 12b for removing noise by FFT frequency analysis, and a noise It is composed of a synthesizing circuit 13 which synthesizes the outputs of the removing circuits 12a and 12b into a temporally continuous signal.

The sampling circuit 11 has a pair of ANs each of which inputs the output of the A / D conversion circuit 7 to one input terminal.
D circuit 11a, 11b, AND circuit 11
The timing signal generating circuit 1 is provided at the other input terminals of a and 11b.
The signals are alternately input from 1c. That is, the timing signal generation circuit 11c generates a pulse signal having a time length A that is sufficiently longer than the transmission data bit length, and outputs the generated signal to one AND circuit 11a.
And the other is input via the inverting circuit 11d.

Since the noise removing circuits 12a and 12b have the same configuration, the noise removing circuit 12a corresponding to the AND circuit 11a will be described as an example.
In 2a, the output of the AND circuit 11a is divided into two systems, and in one system, an FFT circuit 20, a noise detection circuit 21, a noise waveform creation circuit 22, and an inverting circuit 23 are provided in series. In addition, a memory 24 and an A / D conversion circuit 25 are provided in series in the other system. The outputs of these two systems are added by the adder circuit 2.
6 is input.

The synthesizing circuit 13 includes the noise removing circuits 12
It has a pair of AND circuits 13a and 13b for respectively inputting the outputs of a and 12b to one input terminal, and the timing signal from the timing generating circuit 11c is applied to the other input terminal of these AND circuits 13a and 13b. ，
11b is configured to be input while maintaining the opposite relationship. The output of both AND circuits 13a and 13b is O.
It is input to the R circuit 13c, and its OR circuit 13c
The output of is input to the low-pass filter 9.

The operation of the noise canceller circuit 8 having the above configuration will be described. A PN code (PN code) from the demodulation circuit 7 is described.
Signals containing ₁ ) (Noisy signals as shown)
Is the noise removing circuit 1 by the sampling circuit 11.
2a and 12b are temporally divided into two and input. That is, the signal is 1 of the timing pulse generation circuit 11c.
It is divided into ½ pulses (A and bar A) and input to the respective noise removal circuits 12a and 12b. Since the noise removing circuits 12a and 12b have the same configuration and the same processing operation, the noise removing circuit 12a will be mainly described below.

The signal sampled by the siling circuit 11 is input to the FFT circuit 20 and the memory 2
Input to 4. The FFT circuit 20 analyzes the frequency within a predetermined required band according to a well-known FFT frequency analysis method. That is, for the frequency within the predetermined required band, level and phase data are obtained for each frequency component. Then, the levels of all the obtained bands are added, and the added value is divided by the total number of components to obtain the average level value. Since the spectrum of the received signal wave is stored in advance in the internal memory (not shown) of the FFT circuit 20, a spectrum having a magnitude corresponding to the above average level value is generated as a comparison signal.

Next, in the noise detection circuit 21, a level difference of a predetermined value or more, for example, 6 dB, is generated between the comparison signal spectrum and each component value of the FFT analysis value of the input signal.
If there is the above difference, it is determined to be noise. Then, the noise waveform generation circuit 22 performs a Fourier inverse transform on the component value of the frequency determined as noise to generate a noise wave. After that, an inverted signal of noise is obtained via the inverting circuit 23. The obtained inversion signal of noise is input to the addition circuit 26. On the other hand, the signal temporarily stored in the memory 24 is input to the addition circuit 26 via the D / A conversion circuit 25, and is added to the above-mentioned noise inversion signal.

Each noise removal circuit 12 from which noise has been removed
The sampling signals from a and 12b are the AND circuits 1
3a and 13b, respectively, and output to the OR circuit 13c at the sampling timing. Therefore, as shown in the drawing, the PN code (PN ₁ ) containing no noise is output from the OR circuit 13c and input to the matched filter circuit 10 via the next low-pass filter 9. The noise canceller circuit 8 can be composed of an LSI.

The matched filter 10 is formed of a well-known correlation matched filter circuit, and has the PN code generator 4 described above.
Enter a PN code (PN ₁₎ from, detects a match condition between the PN code (PN ₁₎ from the low-pass filter circuit 9 is configured so as to drive the track relay TR in the presence of the matching condition ..

Since the signal generator 1, the spreading circuit 2, the PN code generator 4 and the mud filter 10 are installed in the same equipment room b and connected by wire, the synchronization process can be performed very easily. You can Therefore, it is not necessary to provide any complicated synchronizing circuit or the like unlike ordinary spread spectrum communication in which the transmitting and receiving facilities are isolated.

The device of the present embodiment having the above-mentioned configuration has a block section T.
Of course, it can be applied even when is electrically insulated from an AC signal by an impedance bond or the like. However, in the case of non-insulated without such insulation equipment phase adjacent block section T ', in order to prevent interference with T ", the frequency of the carrier wave (f _c), the type of the PN code,
Any one of the phases of the PN code, or two of these phases, or even all of them are adjacent to each other in a closed interval T ′, T ″.
Different from the one used in.

Next, the train detection operation of the apparatus of this embodiment will be described. First, a case where the train a does not exist in the closed section T will be described. The carrier wave (f _c ) sent from the signal generator 1 is spread by the spreading circuit 2 using the PN code (PN ₁ ) to become a spread signal, and is supplied to the starting end side S of the rail T via the transmitter 3. To be done.

On the terminal side R of the rail T, there is a spread signal with attenuation due to the length of the rail T. Then, the spread signal, after being Zohaba processed at the receiver 5 takes the PN code (PN ₁₎ and demodulation using a carrier (f _c) in the demodulation circuit 7, the above-mentioned noise canceller circuit 8
, The original pure PN code (PN ₁ ) is extracted.

After that, the matched filter 10 enhances the track relay TR when the PN code (PN ₁ ) is present in the input signal. At this time, for example, even if noise caused by the harmonics of the commercial power source or noise sent from a train traveling on another track adjacent to the track T is present in the block section T, the noise canceller circuit 8 completely eliminates the noise. Since trains are removed, train position detection with extremely high noise resistance can be achieved.

On the other hand, when the train a is present in the closed section T, the rail T is short-circuited by the axle of the train a, so that the level of the spread signal on the terminal side R is small and the output level of the receiver 5 is also small. Therefore, the matched filter 10 cannot maintain the lift of the track relay TR and falls. By the fall of the track relay TR, it can be known that the train a was in the closed section T.

In addition, in the above-mentioned embodiment, the example applied to the train detection is shown, but to apply to the train control information communication,
The signal generator 1 and the PN code generator 4 on the ground side and the receiving section B are mounted on the train a, and an antenna is provided on the train a to receive the spread signal from the rail T for performing the operation.

[0031]

The train position detecting device according to the present invention comprises a signal spreading means for spreading a predetermined transmission signal with a predetermined PN code, and a rail for forming a track circuit on the spread signal spread by the signal spreading means. Of the spread signal received by the receiving means and the receiving means for receiving the spread signal from the end side of the rail or from the rail, and the same frequency as the predetermined transmission signal. The extraction means for demodulating the predetermined PN code by using this signal, the noise removal means for removing noise by FFT frequency analysis of the extracted signal extracted by the extraction means, and the noise removal means Detects the coincidence state of the removed signal and the predetermined PN code, detects the presence of the train on the rail from the presence or absence of the coincidence state, or the train running on the rail from the ground side Because comprising a detection means for detecting a train control signal may be a noise resistance superior train control communication system. In particular, the matching state of the PN code, that is,
If the code length is increased, the correlation can be more distinguished from noise and a large noise resistance can be obtained. In addition, since the noise removing means is used, the train control communication device having higher noise resistance can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram when an apparatus according to an embodiment of the present invention is applied to train detection.

FIG. 2 is a schematic configuration diagram of a noise canceller circuit.

[Explanation of symbols]

 1 signal generator 2 spreading circuit (spreading means) 3 transmitter (sending means) 4 PN code generator 5 receiver 7 demodulation circuit (extracting means) 8 noise canceller circuit (noise removing means) 10 correlation matched filter (detecting means)

Claims (1)

[Claims] 1. A signal spreading means for spreading a predetermined transmission signal by a predetermined PN code, and a sending means for sending the spread signal spread by the signal spreading means to a starting end side of a rail forming a track circuit. From the terminal side of the rail or from the rail, receiving means for receiving the spread signal, and demodulating the spread signal received by the receiving means using a signal having the same frequency as the predetermined transmission signal, Extraction means for extracting a predetermined PN code, noise removal means for removing noise by FFT frequency analysis of the extracted signal extracted by the extraction means, signal removed by the noise removal means, and the predetermined PN
A detection means for detecting the coincidence state of the signs, detecting the presence of the train on the rail based on the presence or absence of the coincidence state, or detecting the train control signal from the ground side in the train traveling on the rail. A train control communication device.