JPH09221030A - On-vehicle device and vehicle control equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a on-vehicle device and a vehicle control equipment capable of making adjustment of joining degree of on-vehicle pieces facile. SOLUTION: Amplification circuits 11 to 14 compose a multistage amplification circuit by cascade connection. An on-vehicle piece 2, which includes a pair of coils 21, 22 joining each other, has one of the coils 21 connected to the output side of the last stage of an amplification circuit 14, while the other coil 2 is connected to the input side of the first stage of an amplification circuit 11 and compose a return circuit for the multistage amplification circuit. The multistage amplification circuit 11 to 14 and the on-vehicle piece 2 compose an oscillation circuit oscillating at a set oscillation frequency fo. A monitor circuit 3 is connected to the output side of the amplification circuit 12 positioning more to this side than the last amplification circuit 14 and outputs a monitor signal S1 corresponding to the output of the amplification circuit 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle device and a vehicle control device.

[0002]

2. Description of the Related Art In a conventional vehicle control device, for example, an automatic train stop device (hereinafter referred to as "ATS device"), the oscillation frequency is constantly changed to the resonance frequency of the ground train when the train car is connected to the ground train. By taking advantage of the change-of-turn phenomenon, the control information from the ground side is received on the upper side of the vehicle and the vehicle is controlled according to the control information. Such an ATS device is an electrical introduction / signal series No.7 / ATS / AT for railway engineers.
C ”(published by Japan Railway Electrical Engineering Association), pages 6 to 19.

The on-vehicle device includes an amplifying circuit and an on-board member which constitutes a feedback circuit thereof, and the amplifying circuit and the on-board member constitute an oscillating circuit. The oscillating circuit normally oscillates at a fixed oscillation frequency, but when the car top is coupled to the ground element, the oscillation frequency constantly oscillates (changes frequency) at the resonance frequency of the ground element. On the basis of this changing effect, speed control and the like are performed on the upper side of the vehicle.

The vehicle upper member is composed of a pair of coils electromagnetically coupled to each other, and is arranged under the floor of the vehicle body. The pair of coils needs to be adjusted to have a certain degree of coupling so that the oscillation state is maintained and the frequency variation phenomenon occurs. The coupling degree of the pair of coils is adjusted by adjusting the induced voltage of the secondary coil to fall within a certain width. When adjusting the degree of coupling of the upper body, remove the connector that is connected to the upper body from the upper body connection box, connect the connector to the connection degree tester, and observe the measurement results of the connection degree tester. , The electromagnetic coupling of the pair of coils is adjusted by changing the position of the adjusting bar.

However, the vehicle upper junction box is usually provided on the lower side of the vehicle body. Therefore, in order to connect the car top to the coupling tester, it is necessary to go under the vehicle and disconnect the connector connected to the car top from the car top connection box. For this reason, the work place is restricted, and the workability is significantly deteriorated. Moreover, if there is a metal object or the like at the place where the car top is installed, the degree of coupling may be adjusted incorrectly.

Further, since the degree of coupling of the upper body is not always monitored, it is difficult to detect the fluctuation of the degree of coupling and it is difficult to judge the maintenance time. Therefore, maintenance work is required frequently. Frequent insertion / removal of the connector may result in poor contact and lower reliability.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an on-vehicle device and a vehicle control device that can easily adjust the degree of coupling of the vehicle upper member.

Another object of the present invention is to provide an on-vehicle device and a vehicle control device which can know the maintenance time of the on-vehicle child.

[0009]

In order to solve the above-mentioned problems, an on-vehicle device according to the present invention includes a plurality of amplifier circuits, an on-board child, and a monitor circuit. The plurality of amplifier circuits are connected in cascade to form a multistage amplifier circuit. The car top includes a pair of coils coupled to each other. One coil is connected to the output side of the final stage amplifier circuit among the plurality of amplifier circuits. The other coil is connected to the input side of the first-stage amplifier circuit. This constitutes a feedback circuit for the multistage amplifier circuit.

The multistage amplifier circuit and the car top always constitute an oscillation circuit which oscillates at a predetermined constant oscillation frequency. The monitor circuit has an input side connected to the output side of an amplifier circuit located in front of the final stage amplifier circuit, and outputs a monitor signal according to the input signal.

As described above, the car top includes a pair of coils coupled to each other, one coil is connected to the output side of the final stage amplifier circuit, and the other coil is connected to the first stage input side. A feedback circuit of the multistage amplifier circuit is configured. The multi-stage amplifier circuit and the train top constitute an oscillation circuit that oscillates at a predetermined oscillation frequency. According to this configuration, an output voltage that linearly changes according to the coupling degree of the pair of coils can be obtained from the amplifier circuit located before the final-stage amplifier circuit during constant oscillation.

The monitor circuit is connected to the output side of the amplifier circuit located before the final stage amplifier circuit and outputs a monitor signal according to the input signal. Since the monitor signal changes linearly according to the coupling degree of the pair of coils, the coupling degree of the pair of coils can be adjusted while monitoring the monitor signal. For this reason, unlike the prior art, the work of removing the connector from the vehicle upper junction box and connecting it to the coupling degree tester is unnecessary, and the coupling degree of the vehicle upper portion can be easily adjusted. Moreover, there is no restriction on the work place, and the wrong degree of coupling is not adjusted.

Since the monitor signal changes linearly according to the coupling degree of the pair of coils, it is possible to know the maintenance time of the vehicle upper member when the monitor signal changes by a predetermined value.

The vehicle control device according to the present invention includes an on-vehicle device and a ground device. The on-vehicle device includes the above-described on-vehicle device according to the present invention. The ground device includes a ground element that is coupled to the onboard device of the onboard device. According to this configuration, the degree of coupling of the upper body can be easily adjusted, and
You can know the maintenance time of the car child.

Other features of the present invention and effects thereof will be described in more detail with reference to the accompanying drawings.

[0016]

FIG. 1 is a block diagram showing the configuration of an on-board device according to the present invention. The on-vehicle device according to the present invention is
It includes a plurality of amplifier circuits 11 to 14, a car top 2, and a monitor circuit 3.

The amplifier circuits 11 to 14 are connected in cascade to form a multistage amplifier circuit. The amplifier circuits 11 to 14 can be configured using, for example, operational amplifiers (op amps).

The train car 2 includes a pair of coils 21 and 22 which are coupled to each other with a pitch interval L1. One coil 21 is connected to the output side of the final stage amplifier circuit 14 and the other coil 22 is connected. It is connected to the input side of the first-stage amplifier circuit 11 and constitutes a feedback circuit for the multi-stage amplifier circuit.

The amplifier circuits 11 to 14 and the car top 2 constitute an oscillating circuit which oscillates at a predetermined constant oscillation frequency fo. The constant oscillation frequency fo constitutes the constant oscillation frequency,
For example, it is set to 103 KHz corresponding to the "G presentation" information. The multi-stage amplifier circuit keeps the oscillation signal S2 of the continuous oscillation frequency fo
Is output.

The monitor circuit 3 is connected to the amplifier circuit located before the amplifier circuit 14 at the final stage, that is, the output side of the amplifier circuit 12 in the example shown in FIG. 1, and receives the input signal supplied from the amplifier circuit 12. The corresponding monitor signal S1 is output.

As described above, the car top 2 includes the pair of coils 21 and 22 which are coupled to each other, and the one coil 21
Is connected to the output side of the final stage amplifier circuit 14, and the other coil 22 is connected to the input side of the first stage amplifier circuit to form a feedback circuit for the amplifier circuits 11-14. Amplifier circuit 1
1 to 14 and the on-board child 2 constitute an oscillation circuit which normally oscillates at a predetermined oscillation frequency fo. According to this configuration, the amplifier circuits 11 to 14 at each stage, for example, the amplifier circuit 1
It is possible to obtain an output voltage Vo that linearly changes according to the coupling degree M of the pair of coils 21 and 22 from the second output terminal. This point will be described more specifically with reference to FIG.

FIG. 2 is a diagram showing the relationship between the coupling degree of the vehicle top and the output voltage of the amplifier circuit. In the figure, the horizontal axis represents the degree of coupling between the pair of coils 21 and 22 that form the vehicle upper body 2. The degree of coupling M is indicated by the voltage received by the coil 22. The vertical axis represents the output voltage Vo of the amplifier circuit 11. As shown, the output voltage Vo of the amplifier circuit 12 changes in proportion to the coupling degree M of the train core 2.

The monitor circuit 3 is connected to the output side of an amplifier circuit, for example, the amplifier circuit 12 located before the final stage amplifier circuit 14, and outputs a monitor signal S1 corresponding to the input signal Vo. Here, since the voltage Vo that is the source of the monitor signal S1 changes linearly according to the coupling degree M of the pair of coils 21 and 22, as shown in FIG.
The monitor signal S1 also changes linearly according to the coupling degree M of the pair of coils 21 and 22. Therefore, the degree of coupling between the pair of coils 21 and 22 can be adjusted while monitoring the monitor signal S1. For this reason, unlike the prior art, the work of removing the connector from the vehicle upper junction box and connecting it to the coupling degree tester is not necessary, and the degree of coupling of the vehicle top 2 can be easily adjusted. Moreover, there is no restriction on the work place, and the wrong degree of coupling is not adjusted.

As described with reference to FIG. 2, the monitor signal S1 changes linearly according to the coupling degree M of the pair of coils 21 and 22, so that when the monitor signal S1 changes by a predetermined value. You can know the maintenance time of the car child 2. For example, when the coupling degree M of the vehicle top 2 is adjusted to 85 mV in a normal state, the maintenance time of the vehicle top 2 can be known when the coupling degree M changes by ± 5 mV.

The monitor circuit 3 shown in FIG. 1 is composed of a linear amplifier. According to this configuration, the monitor circuit 3 can output the monitor signal S1 having high linearity without affecting the oscillation circuits formed by the amplifier circuits 11 to 14 and the car top 2.

The on-vehicle device shown in FIG. 1 includes a filter circuit 4. The filter circuit 4 is provided on the input side of the first-stage amplifier circuit 11 and always passes a frequency signal in the frequency band of the oscillation frequency fo. The filter circuit 4 can be configured by a bandpass filter, a comb filter, or the like. According to this configuration, the stable oscillation signal S2 having the oscillation frequency fo can be obtained, and the monitor signal S1 having high reliability can be obtained.

The on-vehicle device shown in FIG. 1 further includes at least two transformers 51 and 52. The transformer 51 is provided between the output side of the amplifier circuit 14 at the final stage and the one coil 21 of the train core 2. The transformer 52 is provided between the other coil 22 of the vehicle top 2 and the filter circuit 4. According to this configuration, the amplifier circuits 11 to 14 and the train car 2
It is possible to insulate between and, and a stable oscillation signal S2 can be obtained.

When the amplifier circuits 11 to 14 are composed of operational amplifiers (op amps), the input impedance and the output impedance of the amplifier circuits in each stage can be increased, and therefore, they are located in the middle stage. Amplifier circuit 1
It is possible to obtain a stable output voltage Vo from 2.

The amplifier circuit, for example, the amplifier circuit 13, located at the subsequent stage of the amplifier circuit 12 for extracting the output voltage Vo has a voltage limiting function. According to this configuration, the oscillation signal S2 of a constant level is obtained, and the distance L2 between the car core 2 and the ground core 8 is increased.
It is possible to obtain an output voltage Vo that changes linearly with respect to the output voltage Vo.

FIG. 3 is a block diagram showing the configuration of a vehicle control device including another embodiment of the on-vehicle device according to the present invention and a ground element 8 which constitutes a ground device. The on-board device A has a control circuit 9 in addition to the configuration shown in FIG. Ground child 8
Are provided at specific points on the ground side for point detection and transmission of control information. The control circuit 9 uses the monitor signal S1
Is input and has at least two reference levels Vk1 and Vk2, and the level of the monitor signal S1 is the first reference level Vk1.
And the second reference level Vk2, the abnormality detection signal S3 is output.

According to this structure, when the adjusted coupling degree M changes by a certain amount due to the deterioration of the vehicle upper member 2, the abnormality detection signal S3 can be output.
It is possible to know the maintenance time of the vehicle upper shell 2 and take measures before the system down of the vehicle control device occurs due to the deterioration. Further, since the coupling degree M of the ground element is constantly monitored while the vehicle is traveling, the reliability of the control information transmitted from the ground side to the vehicle upper side is improved.

The car body 2 shown in FIG. 3 includes a pair of coils 2.
1, 22 are provided so as to face the ground side, and are electromagnetically coupled to the tuning coil 81 of the ground element 8 provided on the ground side.

The control circuit 9 detects the ground element 8 when the level of the monitor signal S1 exceeds a third reference level Vk3 higher than the first reference level Vk1 and the second reference level Vk2, and A point control signal S4 corresponding to the position of the child 8 is output. The point control signal S4 can be used as a control signal for limiting the speed of the pendulum train to a speed suitable for traveling on a curve and controlling the vehicle body to a posture suitable for traveling on a curve, for example.

When the car core 2 is electromagnetically coupled to the tuning coil 81 of the ground element 8, the pair of coils 21 and 22 are directly coupled to each other, and the tuning coil 81 of the ground element 8 is added.
Also, the monitor signal S1 changes in accordance with the degree of coupling between the onboard child 2 and the ground child 8. Generally, when the car top 2 is coupled to the ground conductor 8, the level of the monitor signal S1 is higher than the first reference level Vk1 and the second reference level Vk2 for monitoring the change in the coupling degree of the car top 2. Will also be higher. Therefore, the level of the monitor signal S1 is the first reference level Vk1 and the second reference level Vk1.
The ground element 8 can be detected when the third reference level Vk3, which is higher than the reference level Vk2, is exceeded. As a result, it becomes possible to detect a point even if the oscillation circuit by the amplifier circuits 11 to 14 and the car top 2 does not cause a frequency change phenomenon, detect the traveling point without reducing the amount of control information, and perform precise detection at the traveling point. It is possible to perform various vehicle controls. Moreover, in this case, the point detection can be reliably performed without being affected by the rails, sleepers, or the like. This point will be described in more detail with reference to FIG.

FIG. 4 is a diagram showing changes in the output voltage Vo of the amplifier circuit 12 when the type of the object to be detected is changed. In the figure, the horizontal axis is the distance L2 between the upper body 2 and the object to be detected.
(See FIG. 3). The vertical axis represents the output voltage Vo of the amplifier circuit 12. Characteristic Qo shows the output characteristic with respect to the constant oscillation frequency, characteristic Q1 shows the output characteristic when it is combined with the grounding element of resonance frequency 103KHz, and characteristic Q2 shows the output characteristic when it is combined with the iron plate imitating rails or sleepers. Shows.
The ground element includes a tuning coil and a capacitor, and the resonance frequency of both is set to 103 KHz. Distance L1
Is set to 160 mm to 260 mm according to the normal use condition.

As shown in FIG. 4, the constant oscillation output characteristic Qo
Shows a characteristic that the output voltage Vo becomes almost constant regardless of the change in the distance L2, and moreover, the output voltage V is higher than the output characteristic Q2 when the iron plate is coupled and the output characteristic Q1 when the ground element is coupled.
o becomes low. A first reference level Vk1 and a second reference level Vk2 for monitoring the pair of coils 21, 22.
Is set on both sides of the constant oscillation output characteristic Qo within a range of a level lower than the output voltage Vo obtained by the output characteristic Q2 when the iron plate is coupled and the output characteristic Q1 when the ground element is coupled.

On the other hand, in the case of a ground element having a resonance frequency of 103 KHz, as shown by the output characteristic Q1 when the ground element is coupled,
In the case of an iron plate imitating a rail, sleeper, or the like, a higher output voltage Vo can be obtained than the output characteristic Q2 when the iron plates are combined. Therefore,
By setting the judgment level Vk3 between the output characteristic Q2 when the iron plate is coupled and the output characteristic Q1 when the ground element is coupled,
It is possible to reliably detect the ground child without being affected by rails, sleepers, or the like.

Next, a more limited mode of the embodiment shown in FIG. 3 will be described. First, the pair of coils 21 and 22 are loosely coupled. According to this configuration, the loose coupling between the pair of coils 21-22 can be influenced by the coupling of the ground element 8. A pair of coils 2
As is clear from the comparison between the output characteristic Qo and the output characteristic Q1 shown in FIG. 4, the coupling between the first and the second coil 22 and the ground element 8 is a tighter coupling than the coupling between the pair of coils 21 and 22. Therefore, the coupling degree of the entire upper body including the ground element 8 and the pair of coils 21 and 22 is governed by the coupling between the pair of coils 21 and 22 and the ground element 8, and the entire upper body of the vehicle The degree of coupling is substantially higher. As a result, a large change in the output voltage Vo can be obtained. Therefore, the ground child 8
Can be reliably detected, and a highly reliable point detection signal S1 can be obtained.

The ground element 8 is composed of a plurality of capacitors 821-82n.
And a switching circuit 83. The switching circuit 83 uses the control signal S
One of the capacitors 821 to 82n and the tuning coil 81 are connected in correspondence with 5, and the resonance frequency f corresponding to the combination is connected.
Set 1 to fn. The amplifier circuits 11 to 14 and the train car 2
When the car core 2 is coupled to the ground element 8 provided on the ground side, the oscillation frequency fo is the resonance frequency f1 to
A variable-frequency oscillator circuit that changes the frequency to fn is configured. The output of the amplifier circuit 14 at the final stage is led to the output terminal. The output of the amplifier circuit 14 at the final stage is subjected to frequency discrimination by a filter (not shown) connected to the subsequent stage, and converted into control information corresponding to each frequency. As a result, similarly to the conventional ATS device, control information corresponding to the control signal S5 can be transmitted from the ground side to the vehicle upper side.

An amplifier circuit located at the subsequent stage of the amplifier circuit 12,
For example, the amplifier circuit 14 has a voltage addition function, the superimposition signal S6 corresponding to the vehicle control information is input, and the oscillation signal S2 corresponding to the oscillation frequencies fo and f1 to fn and the superposition signal S6 are added and output. . The superposition signal S6 is always given as a frequency signal having a frequency different from the oscillation frequencies fo and f1 to fn. As a result, in addition to the conventional control information for ATS control, vehicle control information that enables more advanced vehicle control can be transmitted.

FIG. 5 is a circuit diagram showing a concrete example of the on-vehicle device. In the figure, the same reference numerals as those in FIGS. 1 and 3 denote the same components. In FIG. 5, the monitor circuit 3 shown in FIGS. 1 and 3 is omitted.

The amplifier circuit 11 comprises resistors R1 to R5, capacitors C1 to C3 and an operational amplifier IC1 and constitutes an inverting amplifier circuit.

The amplifier circuit 12 comprises resistors R6 to R10, capacitors C4 to C6 and an operational amplifier IC2,
It constitutes an inverting amplifier circuit. The output terminal of the operational amplifier IC2 is connected to the terminal 67 and outputs the output voltage Vo.

The amplifier circuit 13 comprises resistors R11 to R17, capacitors C7 to C9 and an operational amplifier IC3,
It constitutes an inverting amplifier circuit. The amplifier circuit 13 is configured to limit the voltage when the voltage of the oscillation signal S2 becomes equal to or higher than the power supply voltage Vd1 as a result of the amplification.

The amplifier circuit 14 comprises resistors R18 to R25, capacitors C10 to C12 and an operational amplifier IC4, and constitutes an inverting amplifier circuit.

The constants of the resistors R1 to R25 and the capacitors C1 to C12 are combined with the filter 4 to constantly oscillate the frequency fo.
Is set to oscillate.

The power amplifier circuit PA amplifies the power of the oscillation signal S2 supplied from the amplifier circuit 14, and the transformer 5
The power-amplified oscillation signal S2 is supplied to the primary winding 511 of FIG. The power amplifier circuit PA includes resistors R26 to R38, capacitors C13 to C18, transistors T1 to T5, and a diode D1.
It is comprised including. The power-amplified oscillation signal S2 is
It is guided to the terminals 61 and 62 via the secondary winding 512 of the transformer 51. The secondary winding 512 of the transformer 51 has a resistor R51
Is connected. The terminals 61 and 62 are terminals to which the one coil 21 (see FIGS. 1 and 3) of the vehicle top 2 is connected.

The terminals 64 and 65 are terminals to which the other coil 22 (see FIGS. 1 and 3) of the vehicle top 2 is connected. The terminals 64 and 65 are connected to the primary winding 521 of the transformer 52. The secondary winding 522 of the transformer 52 is connected to the input side of the bandpass filter 4 via a resistor R40. In the bandpass filter 4, the center selection frequency is always set in correspondence with the oscillation frequency fo. A resistor R41 is connected to the output side of the bandpass filter 4, and the terminal voltage of the resistor R41 constitutes the input voltage of the amplifier circuit 11.

The terminal 63 is a secondary winding 512 of the transformer 51.
Connected to the midpoint. The terminals 63 and 69 are connected to the 0V line. The terminal 68 is connected to the terminal 61.
The terminals 68 and 69 are terminals for monitoring the presence or absence of the oscillation signal S2.

The tertiary winding 513 of the transformer 51 has a resistor R61.
And a series circuit of resistors R62 and R63. Both ends of the resistor R63 are connected to the input side of the bandpass filter 42. The center selection frequency of the bandpass filter 42 is always set in correspondence with the oscillation frequency fo and the resonance frequencies f1 to fn. The output side of the bandpass filter 42 is connected to the terminals 71 and 72. As a result, the on-board child 2 is coupled to the ground element 8 and the oscillation frequency fo is constantly maintained at the ground element 8.
When the frequency is changed to the resonance frequency f1 of 1, the output of the bandpass filter 42 is lost and the same ATS control information as in the conventional case can be obtained.

ATS control information includes a plurality of resonance frequencies f1 ...
When given by fn, the center selection frequency of the bandpass filter 4 and the bandpass filter 43 is set to the resonance frequency f.
It may be set to 1 to fn. As a result, the conventional ATS
Similar to the device, when the frequency of the oscillation signal S2 is changed to the resonance frequencies f1 to fn of the ground element 8, the frequencies f1 to fn
ATS control information according to fn can be obtained.

The terminal 66 is the primary winding 521 of the transformer 52.
Connected to the midpoint. The middle point of the primary winding 521 is connected to the 0V line. One end of the secondary winding 522 of the transformer 52 is connected to the 0V line.

The superimposed signal S6 is input to the terminals 73 and 74. The terminals 73 and 74 are connected to both ends of the resistor R71. The terminal 73 is connected to the negative input terminal of the operational amplifier IC4 via the capacitors C71, R72 and R73. The superimposed signal S6 is voltage-amplified by the amplifier circuit 14, power-amplified by the power amplifier circuit PA, and supplied to the primary winding 511 of the transformer 51. The input side of the bandpass filter 43 has a resistor R
Connected to both ends of 63. The center selection frequency of the bandpass filter 43 is set corresponding to the frequencies of the superposition signal S6 and the frequency change signals (resonance frequencies) f1 to fn. The output side of the bandpass filter 43 is connected to the terminals 75 and 76. Thereby, vehicle control information can be obtained from the terminals 75 and 76.

[0054]

As described above, according to the present invention, the following effects can be obtained. (A) It is possible to provide an on-vehicle device and a vehicle control device that can easily adjust the coupling degree of the vehicle upper member. (B) It is possible to provide an on-board device and a vehicle control device that can know the maintenance time of the on-board child. (C) It is possible to provide a vehicle control device that enables precise vehicle control at each traveling point.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an on-board device according to the present invention.

FIG. 2 is a diagram showing a relationship between a coupling degree of a vehicle top and an output voltage of a middle stage amplifier circuit.

FIG. 3 is a block diagram showing a configuration of a vehicle control device according to the present invention.

FIG. 4 is a diagram showing an output voltage of a middle-stage amplifier circuit in the case where an on-board member is coupled with a ground member.

FIG. 5 is a circuit diagram showing a specific example of an on-vehicle device.

[Explanation of symbols]

 11-14 Amplification circuit 2 Car coil 21, 22 Coil 3 Monitor circuit 8 Ground coil 9 Control circuit fo Oscillation frequency Vo Amplification circuit output S1 Monitor signal S2 Oscillation signal S3 Abnormality detection signal S4 Point control signal Vk1 First judgment level Vk2 Second judgment level Vk3 Third judgment level

Claims (12)

[Claims] 1. An on-vehicle device including a plurality of amplifier circuits, a car top, and a monitor circuit, wherein the plurality of amplifier circuits are connected in cascade to form a multistage amplifier circuit. The upper member includes a pair of coils coupled to each other, one coil is connected to the output side of the final stage amplifier circuit among the plurality of amplifier circuits, and the other coil is connected to the input side of the first stage amplifier circuit. The multistage amplifier circuit and the car top normally constitute an oscillation circuit that oscillates at a predetermined oscillation frequency, and the monitor circuit is a feedback circuit for the multistage amplifier circuit. An on-vehicle device, the input side of which is connected to the output side of an amplifier circuit located in front of the final stage amplifier circuit and which outputs a monitor signal according to the input signal. 2. The on-vehicle device according to claim 1, wherein the monitor circuit includes a linear amplifier. 3. The on-vehicle device according to claim 1, further comprising a filter circuit, wherein the filter circuit is provided on an input side of the first-stage amplifier circuit and has a frequency band of the oscillation frequency. An on-board device that passes frequency signals. 4. The on-vehicle device according to claim 3, further comprising at least two transformers, wherein one of the transformers includes an output side of the final stage amplification circuit and An on-vehicle device that is provided between the coil and one of the coils, and the other of the transformers is provided between the other coil of the on-board child and the filter circuit. 5. The on-vehicle device according to claim 1, wherein each of the amplifying circuits includes an operational amplifier. 6. The on-vehicle device according to claim 5, wherein the amplifier circuit located at a stage subsequent to the amplifier circuit to which the input side of the monitor circuit is connected has a voltage limiting function. . 7. The on-vehicle device according to claim 1, further comprising a control circuit, wherein the control circuit receives the monitor signal and has at least two reference levels. The level of the monitor signal is the first reference level and the second
An on-board device that outputs an abnormality detection signal when it deviates from the reference level of. 8. The vehicle control device according to claim 7, wherein the control circuit has a third reference level in which the level of the monitor signal is higher than the first reference level and the second reference level. An on-board device that detects the ground element and outputs a point control signal according to the position of the ground element when the vehicle crosses over. 9. A vehicle control device including an on-vehicle device and a ground device, wherein the on-vehicle device comprises the on-vehicle device according to claim 1. The ground control device is a vehicle control device having a ground control element coupled to the vehicle control element of the vehicle control device. 10. The vehicle control device according to claim 9, wherein the ground element has a tuning coil that is electromagnetically coupled to the vehicle upper element. 11. The vehicle control device according to claim 10, wherein the ground element includes a plurality of capacitors and a switching circuit, and the switching circuit corresponds to one of the capacitors in response to a control signal. The tuning coil is connected to set a resonance frequency according to the combination, and the on-vehicle device has the oscillation frequency of the resonance of the ground element when the on-board element is coupled to the ground element. A vehicle control device that changes frequency. 12. The vehicle control device according to claim 9, wherein the amplifier circuit located at a stage subsequent to the amplifier circuit to which the input side of the monitor circuit is connected has a voltage adding function, and A vehicle control device that receives a superposition signal corresponding to control information, adds an oscillation signal corresponding to an oscillation frequency and the superposition signal, and outputs the sum.