JP2775112B2 - Open circuit type train detection method and circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open-circuit-type train detection method for receiving a signal transmitted from a transmitting side by short-circuiting the train axle at a receiving side, and a circuit therefor.

2. Description of the Related Art As shown in FIG. 3 (a), a conventional open-circuit-type train detection method uses a transmission unit (SE ') to transmit a transmission signal to an oscillator (1).
9 ′) and an amplifier (20 ′) to form a rail (R ₁ ′,
R ₂ ′), and the transmission signal is short-circuited between the rails (R ₁ ′, R ₂ ′) on the axle of the train to make the receiving unit (RE ′)
, The received signal (a ₁ ′) is amplified by an amplifier (7 ′) and rectified by a rectifier (11 ′) to make it operable to make the relay (1)
8 ') have to actuate the, in this case, the transmitting unit (SE') and the rail (R ₁ ') and the receiver (RE') and the rail (R ₂ 'a connection point between) (1'), (2 ′) Are provided at a certain distance l ′ along the rails (R ₁ ′, R ₂ ′), and the level of the received signal (a ₁ ′) depends on the axle of the train as shown in FIG. In this method, a hump characteristic based on the increase and decrease of the short-circuit effect is minimized, and a train is detected only when the level of the received signal (a ₁ ′) is equal to or more than a certain value (D ′).

SUMMARY OF THE INVENTION In this method, a short circuit between rails due to tampering,
A similar level change was also detected due to a pseudo short circuit due to leakage fluctuations such as rain, malfunction due to noise, and the like, and there was a risk of being mistaken as a train. SUMMARY OF THE INVENTION It is an object of the present invention to improve the conventional open-circuit-type train detection method and eliminate the above-mentioned problems.

Means for Solving the Problems In order to achieve the above object, an open-circuit-type train detection method according to the present invention comprises a transmitting unit (SE), a rail (R ₁ ) and a receiving unit (RE) as shown in FIG. a rail (R ₂₎ and connection points (1,
2) is provided within the range (l) where the distance along the rail is shortened and the hump characteristic appears in the time change of the level of the received signal. Note that the hump characteristic described here means that a peak or a valley due to an increase or decrease in the level based on the magnitude of the short-circuit effect between the rails due to the axle of the train changes with time in the level of the received signal. This phenomenon is used for consent. Then, when the level of the received signal obtained by short-circuiting between the rails (R ₁ , R ₂ ) near the connection point by the axle of the traveling train is equal to or more than a certain value, the state is set to “1”, Is the peak of the level of the received signal obtained by sequentially short-circuiting near the connection point (1, 2), or the valley of the level of the received signal obtained when the midpoint of the axle of the train sequentially passes near the connection point. Is counted as a predetermined number, the other state "1" is set as a logical product input, and the output "1" activates the relay. The counting is performed by setting a predetermined level as a reference value between peaks and valleys of sequentially appearing levels, and inputting the reference value and the level of the received signal to a comparison circuit so that the level of the received signal is larger than the reference value. This is done by outputting the case or the case of being small as state "1" and counting this. Here, the reference value is provided by dividing the received signal by a resistor, lowering its level by a fixed ratio, and holding and outputting the highest value.

Operation In the open-circuit-type train detection method configured as described above, the connection points between the rail (R ₁ ) and the transmission unit and between the rail (R ₂ ) and the reception unit are as shown in FIG. 1 (1, 2). Since the distances along the rails are shortened and provided within a range (l) in which the hump characteristic appears in the time change of the level of the received signal, the change in the level (effective value) of the received signal is limited to one train. 2 (a), the peak of the level of the received signal obtained by the train axle short-circuiting the connection points (1, 2) at the same time and the middle point of the train axle are the connection points. , The valley of the level of the received signal obtained when the signal sequentially passes through is more noticeable than the received signal according to the conventional method. Therefore, it is possible to count the number of peaks or valleys of the received signal that appear sequentially as the train progresses by a predetermined number, thereby confirming that the train is a train. Here, the counting is performed by setting a predetermined level between the peak and the valley of the level as a reference value, and comparing the reference value with the reception level to determine whether the reception level is higher or lower than the reference value. This is done by outputting as 1 "and counting this. Furthermore, the reference value is divided by a resistor, one of the levels is reduced by a certain ratio, and the highest value is used as the reference value. Therefore, the reference value is not affected by the fluctuation of the entire reception level due to the external environment. In addition, the state where the reception level is equal to or higher than a certain value is set to the state "1", the train is checked, and the trigger of the whole counting circuit is used, so that the fail-safe function is further enhanced.

EXAMPLES Hereinafter, the present invention will be specifically described based on examples shown in the drawings.

FIG. 1 is a block diagram showing an embodiment of an open-circuit-type train detection circuit when the number of vehicles is one. The configuration and functions of the circuit will be described with reference to FIG.

In the figure, (1,2) is the rail (R ₁ , R ₂ ) and the transmitter (SE)
And a connection point with the receiving unit (RE) are provided within a range (l) of a distance along the rail where a hump characteristic appears in the time change of the level of the received signal. It is on a straight line substantially perpendicular to (R ₁ , R ₂ ). Therefore, the short-circuit effect due to the axle appears most strongly. (3) is a trigger generation circuit which is set to "1" when the level of the received signal (a ₁ ) exceeds a predetermined level (D).
The trigger pulse (g) is output. In the trigger generating circuit (3), (9) is a Schmitt circuit which operates when the input level exceeds a predetermined level. The output is amplified by an amplifier (10) and rectified by a rectifier (11) to generate a "1" trigger pulse (1). g) will be output. (4) is a counting circuit that counts the number of peaks of the level appearing in the level of the received signal (a ₁ ), and outputs “1” when the number of peaks of a predetermined number is counted. In the counting circuit (4), (12) is a resistor which divides the received signal (a ₂ ) amplified by the amplifier (7) and rectified by the rectifier (8) and lowers its level by a predetermined ratio; Is a peak hold circuit which receives the signal (a ₂ ) whose predetermined level has been lowered, holds the maximum value of the signal, and outputs the signal. And its maximum output (E)
Is input to the comparison circuit (14) together with the signal (a ₂ ) as a reference value. Here, as for the reference level (E), it is required that there is a reference level between the level (B) and the level (C) in the level of the received signal (a ₁ ) shown in FIG. This condition is achieved by providing the resistor (12) at a predetermined value. (14) is a comparison circuit for inputting the signal (a ₂ ) and the reference level (E), and outputs “0” when a ₂ > E and outputs “1” when a ₂ <E. (15) is a counter which is inverted when the output of the comparison circuit (14) is input twice, and (17) is an inverted output (d) of the counter (15) and an output (C) of the comparison circuit (14). an aND circuit which receives the, the output (e) has counted by "1" received signal when it becomes (a ₁₎ to appear level number a predetermined number of peaks "2" in this embodiment It will show that. The output "1" of the trigger generation circuit (3) is input as a trigger to the peak hold circuit (13), the comparison circuit (14), and the binary counter (15). (5) is the level of the output (g) of the trigger generation circuit (3) indicating that the level of the received signal (a ₁ ) is equal to or higher than the predetermined level (D) and the level appearing sequentially in the level of the received signal (a ₁ ). This is an AND circuit that receives as input the output (e) of the counting circuit (4) indicating that the number of peaks has been counted by a predetermined number.

FIG. 2 is an output waveform diagram of each block in the block diagram of the open circuit type train detection circuit.

FIG. 2 (a) is a graph showing the temporal change of the level (effective value) of the received signal (a ₁ ) obtained through the bandpass filter (6) of the receiving unit. Indicates the level when the short circuit is caused near the connection point (1, 2), and the short circuit effect is maximum and becomes the maximum value in the graph. (B)
Indicates the level when the connection point (1, 2) is located substantially in the middle of the two axles at the front of the vehicle, and the level is reduced by α due to the maximum value (A). (C) shows the level when the connection point (1, 2) is located almost in the middle between the vehicle at the front of the vehicle and the axle at the rear, shows the minimum value of the graph with the short-circuit effect being minimal while passing through the train, and shows the maximum value ( The level is lower by β than in A). (D) shows a level indicating that the train is traveling toward the connection point and the short-circuit effect due to the axle has sufficiently appeared, and above this level the trigger generation circuit (3) operates and the receiving unit (RE) Triggered and activated.

FIG. 2 (b) is a waveform diagram of the output (b) of the peak hold circuit (13). When the level of the received signal (a ₁ ) reaches the trigger level (D ₁ ), the output starts and the maximum output ( E)
Indicates that this state continues until the level of the received signal (a ₁ ) drops and reaches the trigger level (D) again. The graph represented by the dotted line shows the level of the signal (a ₂ ) input to the comparison circuit (14) together with the output (b).

FIG. 2 (c) is a waveform diagram of the output (C) of the comparison circuit (14), and the levels of the input signals (a ₂ ) and (b) when a ₂ > E from FIG. 2 (b). The output (C) becomes "0", indicating that the output (C) becomes "1" when a ₂ <E.

FIG. 2 (d) is a waveform diagram of the output (d) of the binary counter (15). When the output (C) of the comparison circuit (14) has "1" twice, the output (d) is inverted. Indicates "0".

FIG. 2 (e) is a waveform diagram of the output (e) of the AND circuit (17), showing the output (C) of the comparison circuit (14) and the binary counter (1).
When the inverted output (d) of (5) is input and the outputs (C) and (d) are "1", the output (e) indicates "1".

FIG. 2 (f) shows the output state of the relay (18) operated by the output of the AND circuit (5).

The operation of the open-circuit-type train detection circuit will be described with reference to FIG. 1 and FIG.

When the train advances toward the connection point (1, 2) and the level of the received signal (a ₁ ) increases and reaches a certain level (D), the trigger generation circuit (3) outputs “1” and holds the peak. begins to start circuit (13), its output is increased at a constant amount ratio by level lower than the level of the signal (a ₂₎ with an increase of the received signal (a _1), the front axle connection points of the vehicle (1, When the level of the received signal (a ₁ ) reaches the maximum value (A) after reaching 2), the highest level (E) lower than the highest level of the signal (a ₂ ) by a fixed ratio is held and output. The reference level of the comparison circuit (14) is reached, and this state continues while the train is in progress.

Thereafter, as the front axle of the vehicle moves away from the connection point (1, 2), the level of the received signal (a ₁ ) decreases, and the level of the other signal (a ₂ ) input to the comparison circuit (14) accordingly increases. When the level also decreases and falls below the fixed output (E) of the peak hold circuit (13), "1" is output from the comparison circuit (14), and this state indicates that the intermediate point between the front axle and the rear axle of the axle is set. Upon reaching the connection point (1, 2), the level of the received signal (a ₁ ) becomes the minimum value (C). Further, as the train advances, the rear axle of the vehicle approaches the connection point (1, 2), and the received signal (a a ₁₎ level starts to increase again, until the level of the signal (a ₂₎ have the same value as the constant output (E) of the peak hold circuit (13).
Thereafter, the level of the received signal (a ₁ ) continues to increase and reaches the maximum value (A) again when the rear axle of the train reaches the connection point (1, 2), and thereafter, the rear axle becomes the connection point (1, 2). ), The level decreases again, and when the level of the signal (a ₂ ) becomes equal to the constant output (E) of the peak hold circuit (13), “1” is output again from the comparison circuit (14). . This state continues until the level of the received signal (a ₁ ) drops again and reaches the trigger level (D).

Therefore, when the first "1" is output from the comparison circuit (14) as the train advances, the binary counter (15) outputs "1".
Is output, and this output is the second "1" of the comparison circuit (14).
Is inverted when the output of is input. And comparison circuit (14)
When the output of “1” of the second time of “1” and the inverted output “1” of the output of “0” of the binary counter (15) are input to the AND circuit (17), this A
"1" is output from the ND circuit (17), which means that the number of peaks of the reception signal (a ₁ ) by the front axle and the rear axle of the vehicle is twice per vehicle. This AND
The output "1" of the circuit (17) is input to the AND circuit (5) together with the output "1" of the trigger generation circuit (3), and the output activates the relay (18). Therefore, this AND circuit (5)
Accordingly, a higher operation of the fail-safe function can be performed.

Effect of the Invention As described above, the present invention provides a connection point between a rail and a transmission unit and a connection point between a rail and a reception unit within a range of a distance along a rail where a hump characteristic appears in a time change of a level of a reception signal. By increasing the short-circuit effect and using the change in the level of the received signal obtained by short-circuiting the signal sent from the transmitting side by the axle of the train, the level of the received signal is more than a certain value, and the axle of the train is The train is obtained by counting a predetermined number of peaks of the level of the received signal obtained by short-circuiting near the connection point or the number of valleys of the level obtained when the midpoint of the axle of the train passes near the connection point. , It is possible to detect a train in distinction from a short circuit between rails due to mischief, a pseudo short circuit due to leakage fluctuations such as rain, noise, and the like. Also, when counting the number of peaks or valleys of the level of the received signal, a reference level is provided between the peak and valley, and the reference level is divided by the received signal and lowered by a certain percentage level, and the maximum value thereof is reduced. Is set as the reference level, and the fail-safe function can be further enhanced without being affected by fluctuations in the level of the entire received signal due to an unusual external environment such as rain.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of an open-circuit type train detection circuit according to the present invention, and FIG. 2 is an operation explanatory diagram of each block diagram of the embodiment shown in FIG. A) is a diagram showing a temporal change of the level (effective value) of the received signal (a ₁ ) obtained through the bandpass filter (6) of the receiving unit, and (B) is obtained through the rectifier (8). Received signal (a ₂ )
(C) is the output waveform of the comparison circuit (14), (d) is the output waveform of the counter (15), and (e) is the AND circuit (17). (F) is an output waveform diagram of the relay (18). FIG. 3 is an explanatory view of a conventional open circuit type train detection method. (A) is a block diagram of a conventional open circuit type train detection circuit, and (b) is a band film (6 ′) in a receiving section of the circuit. FIG. 7 is a diagram illustrating a temporal change in a level (effective value) of a reception signal (a ₁ ′) obtained through the antenna. (SE, SE '): transmission unit, (RE, RE'): _{receiver, (R 1, R 2,} R 1 ', R 2'): _{rails, (a 1, a 2,} a 1 '): (B): peak hold circuit (13) output signal, (c): comparison circuit (14) output signal, (d): counter (15) output signal, (e): AND circuit (17) output signal (F): relay (18) output level, (1,1 '): connection point between rail and transmission section, (2,2'): connection point between rail and reception section, (3): trigger generation Circuit, (4): counting circuit, (5, 17): AND circuit, (6, 6 '): band-pass filter, (7, 10, 20, 7', 20 '): amplifier, (8, 11, 11) '): Rectifier, (9): Schmitt circuit, (12): resistor, (13): peak hold circuit, (14): comparison circuit, (15): counter, (16): negation circuit, (18, 18) '): Relay, (19, 19'): Oscillator.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-229668 (JP, A) JP-A-56-60378 (JP, A) JP-A-60-76468 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) B61L 1/00-23/34

Claims (2)

(57) [Claims] 1. A distance along a rail at which a hump characteristic appears in a time change of a level of a reception signal obtained by short-circuiting a connection point between a rail and a transmission section and a connection point between a rail and a reception section with a train axle. Each state is provided within the range, and the level (effective value) of the received signal obtained by short-circuiting the axle of the train traveling between the rails near the connection point is equal to or more than a certain value, and the state is “1”. The number of peaks of the level of the received signal obtained by the axle sequentially short-circuiting near the connection point or the number of valleys of the level of the received signal obtained by the intermediate point of the train axle sequentially passing near the connection point The other state "1" is counted as a predetermined number.
An open-circuit-type train detection method, characterized in that the two states “1” are ANDed and the output “1” detects a train. 2. A connection point (1, 2) between a rail (R ₁ ) and a transmission unit (SE) and a connection point (1, 2) between a rail (R ₂ ) and a reception unit (RE) can be obtained by short-circuiting the rails with a train axle. Each is provided within a distance along the rail where the hump characteristic appears in the time change of the level of the received signal, and is sent by short-circuiting the rails near the connection point (1, 2) by the axle of the traveling train. A trigger generation circuit (3) that operates when the level of the received signal is higher than a certain value in a receiving unit (RE) that receives an incoming signal; and that the train axle short-circuits sequentially near the connection point (1, 2). Counting circuit for counting a predetermined number of valleys of the level obtained when the peak of the level of the received signal obtained by the above or the midpoint of the axle of the train sequentially passes near the connection point (1, 2) And (4) dividing the received signal into the counting circuit (4). A dividing resistor (12) for lowering the bell by a predetermined ratio; a peak hold circuit (13) for holding and outputting the maximum value of the level of the received signal reduced by a predetermined ratio by the dividing resistor (12); A comparison circuit (14) having a reception signal as one input and the output of the peak hold circuit (13) as a reference level and the other input, and a counter (15) for counting the output of the comparison circuit (14)
An AND circuit (17) that receives an output of the comparison circuit and an inverted output of the counter as inputs, the peak hold circuit (13), a comparison circuit (14), and a counter (15). ), And the output of the trigger generation circuit (3) and the counting circuit (4).
And an AND circuit (5) that receives the output of the open circuit as an input.