JPH0279704A - Ground-to-car transmitter - Google Patents

Abstract

PURPOSE:To enable information transmission at low speed and high speed by one car device by usually connecting a modulation and demodulation means for transmission at high speed and a car transmission-reception means by a changeover means but changing over the changeover means during the reception of a low-speed transmission signal from the group side to connect the car transmission-reception means to the modulation and demodulation means side for transmission at low speed. CONSTITUTION:A changeover switch 5 is connected to a contact (a) on the high-speed modem 3 side usually a transmission signal having high carrier frequency from a ground piece 11 is received by a car piece 2 during the running of a train, and input to the high-speed modem 3 through a relay transformer 8b and an amplifier 7b, and a signal processing section 6 emits control outputs to each car equipment on the basis of the information. When the train enters into a station and the car piece 2 receives a low-speed signal, the time after the start of an input is measured, and the changeover switch 5 is changed over and connected to a contact (b) on the low-speed modem 4 side when a fixed time or more passes.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a ground-to-vehicle transmission device for transmitting and receiving information between the ground and a vehicle.

<Prior art> For example, in railway transportation, when information is transmitted between the ground and the train, there are two types of transmission: one is to transmit information over an extremely short section, and the other is to transmit information over a certain length of section. There is.

The former is applied to sending and receiving point information, etc., and a beacon is installed at a predetermined point on the track, and information is transmitted while the onboard of a running train passes the beacon, and the information is transmitted between the ground and onboard. In order to ensure reliable information transmission with an extremely short connection time, it is necessary to increase the transmission speed so that information can be transmitted more than a specified number of times even when a train passes at maximum speed. Therefore, it is necessary to increase the carrier frequency in accordance with the transmission speed.

On the other hand, the latter is applied to the sending and receiving of departure permission signals to build a function to prevent false departures, and the sending and receiving of train number signals to reconfirm the train number set on the train before departure on the ground side before departure, and the train number is growing. In order to ensure a certain length of information transmission section, considering that the stopping position of the train is not necessarily a fixed position depending on the accuracy of the train and train stopping accuracy, a loop coil of a predetermined length is installed on the track instead of the ground coil as an antenna on the ground side. In this case, since the train speed is stopped or low, the connection time between the ground and the onboard can be long, and the transmission speed can be low. Since the inductance is large, a low carrier frequency is more advantageous for information transmission (the lower the input impedance, which is the product of the carrier frequency and the inductance), the better.

Therefore, in order to transmit various information between the ground and the vehicle, it is better to use different carrier frequencies depending on the transmission form.

<Problem to be solved by the invention> For this reason, conventionally, a single train has been equipped with an on-board device for high-speed transmission used for sending and receiving point information, etc., and an on-board device for low-speed transmission used for sending and receiving departure permission signals, etc. Was. Therefore, there are problems such as the number of parts in the ground-to-vehicle transmission device being large and the cost being high.

The present invention has been made in view of the above circumstances, and provides a low-cost ground-to-vehicle transmission device with a small number of parts by enabling low-speed and high-speed information transmission with a single on-board device. The purpose is to

Means for Solving the Problems> Therefore, as shown in FIG.
a receiving means, a high-speed transmission modulation/demodulation means for modulating/demodulating the high-speed transmission signal transmitted/received by the on-vehicle transmission/reception means, and a low-speed transmission signal transmitted/received by the on-vehicle transmission/reception means. modulation·
Modulation/demodulation means for low-speed transmission performs demodulation, and controls the output to each on-board device based on the received signal demodulated by each of the modulation/demodulation means, and also controls each modulation based on the signal from each on-board device.・Control means for controlling the output to the demodulation means, low-speed transmission signal detection means for detecting reception of low-speed transmission signals from the ground side, and modulation/demodulation of the on-board transmission/reception means for high-speed transmission during normal times. An on-vehicle device is provided, which is connected to the on-vehicle device and has a switching means that switches and connects the on-vehicle transmitting/receiving means to the low-speed transmission modulating/demodulating means when reception of a low-speed transmission signal is detected.

Function> In the above configuration, normally the high-speed transmission modulation/demodulation means and the on-board transmission/reception means are connected by the switching means,
While the low-speed transmission signal detection means detects reception of the low-speed transmission signal from the ground side, the switching means is switched and the on-board transmission/reception means is connected to the low-speed transmission modulation/demodulation means side. Therefore, low-speed and high-speed information transmission is possible with one on-board device, and since the high-speed transmission mode is set when low-speed transmission signals are not manually transmitted, high-speed transmission signals can be reliably received.

<Example> Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIG. 2 showing an embodiment of the present invention, reference numeral 1 denotes an on-board device of this embodiment that is mounted on a train.

Such an on-board device 1 includes an on-board element 2 as an on-board transmitting/receiving means for transmitting and receiving signals with a loop coil 13 on the ground element side and an on-board element 11, which will be described later, and a high-speed transmission signal received by the on-board element 2. The high-speed modem 3 serves as a high-speed transmission modulation/demodulation means that demodulates the on-board high-speed transmission information from the signal processing section 6 (described later), and also demodulates the low-speed transmission signal received by the on-board child 2 and processes the signal. A low-speed modem 4 as a low-speed transmission modulation/demodulation means for modulating the on-board low-speed transmission information from the section 6, and each modem 3 interposed in the transmission path from the high-speed modem 3 and the low-speed modem 4 to the onboard element 2. . At the same time, both modems 3.
The signal processing section 6 controls the output to the low-speed modem 4, and controls the changeover switch 5 to be switched to the low-speed modem 4 side when a low-speed carrier detection signal from the low-speed modem 4 is input manually. Here, the signal processing section 6 corresponds to a control means and a low-speed transmission signal detection means. In addition, 7a to 7d are amplifiers,
8a and 8b are relay transformers.

On the other hand, on the ground equipment side, as in the past, the ground element 11 is placed at an appropriate location in the train running section, and the ground element 11 is connected to the high-speed modem 1.
In addition, a loop coil 13 is installed in a station or the like and connected to a low-speed modem 14. Note that 15a to 15d are amplifiers, and 16a to 16d are relay transformers.

Next, the operation will be explained.

Normally, the selector switch 5 is connected to contact a (high-speed transmission mode) on the high-speed modem 3 side, as shown in the second diagram. In this state, when the onboard element 2 passes over the beacon 11 while the train is running, the onboard element 2 receives a transmission signal with a high carrier frequency from the beacon 11, and the relay transformer 8b and amplifier 7
input to the high-speed modem 3 via b. The input transmission signals are demodulated here and output as ground information signals R and D to the signal processing section 6, and high-speed carrier detection signals C and D are input from the high-speed modem 3 to the signal processing section 6. When ground information signals R and D are input, the signal processing section 6 issues control outputs for each on-board device based on the information.

On the other hand, since the high-speed carrier detection signals C and D are manually generated, the on-board information is input to the high-speed modem 3 as high-speed on-board information signals T and D via the signal processing section 6, where they are modulated. Amplifier 7a, changeover switch 5 and relay transformer 8
The signal is sent to the onboard element 2 via the onboard element 2, and is transmitted at high speed from the onboard element 2 to the ground element 11.

Next, when the train enters the station, for example, the onboard coil 2 receives the low-speed transmission signal from the loop coil 13 and the relay transformer 8 receives the low-speed transmission signal from the loop coil 13.
b. The signal is input to the low-speed modem 4 via the amplifier 7d, where it is demodulated and input to the signal processing unit 6 as low-speed transmission ground information signals R and D, which generate control outputs for each on-board device. Then, from the low-speed modem 4 to the signal processing section 6, the low-speed carrier detection signal C! is sent together with the ground information signal RED. D inputs. In this case, the signal processing unit 6, as shown in the third diagram,
It is determined whether or not this low-speed carrier detection signal CzD is input (31) in the figure, and when it is input, the time from the start of input is measured (82) in the figure, and if it continues for a predetermined time or longer,
A switching command signal is output to the changeover switch 5, and the changeover switch 5
is switched and connected to contact b (low-speed transmission mode) on the low-speed modem 4 side (33 in the figure).

As a result, the low-speed modem 4 is connected to the onboard element 2, the on-board information signal T2D from the signal processing section 6 is modulated by the low-speed modem 4, the amplifier 7c, the changeover switch 5, the relay transformer 8a
The signal is transmitted to the onboard child 2 through the loop coil 13, and is transmitted at low speed to the loop coil 13.

Incidentally, when the connection between the onboard child 2 and the loop coil 13 is released and the low-speed carrier signal from the ground side disappears, the low-speed carrier detection signal CJ disappears, and as a result, the changeover switch 5 returns to the contact a side. The switch returns to high-speed transmission mode (34 in the figure).

According to this configuration, the on-vehicle element and signal processing section, which were conventionally provided separately for low-speed transmission and high-speed transmission, can be shared, and the number of parts can be reduced, making it possible to significantly reduce costs. In addition, when there is no input of low-speed transmission information, selector switch 5 is always
is connected to the high-speed modem 3 side and is already in high-speed transmission mode when it passes over the ground transducer 11, so information can be reliably transmitted and received even during high-speed transmission where the transmission area is short.

<Effects of the Invention> As described above, according to the present invention, one on-board device is configured to be able to perform two types of information transmission, high speed and low speed. Compared to a system equipped with two on-board devices, there are fewer parts and costs can be reduced. Furthermore, since the high-speed transmission mode Y is always set except when a low-speed transmission signal is being input, no information is lost during high-speed transmission in which the transmission section is extremely short.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining the present invention in detail, FIG. 2 is a block diagram showing one embodiment of the present invention, and FIG. 3 is a control flowchart of a changeover switch in the same embodiment. ■...Onboard device 2...Onboard device 3.12...
・High-speed modem 4, 14...Low-speed modem 5...
・Selector switch 6...Signal processing section 11...
Ground coil 13...Loop coil

Claims (1)

[Claims] An on-board transmitting/receiving means for transmitting signals to the ground side and receiving signals from the ground side, and a high-speed transmission modulator for modulating and demodulating high-speed transmission signals transmitted/received by the on-board transmitting/receiving means. demodulation means, low-speed transmission modulation/demodulation means for modulating/demodulating low-speed transmission signals transmitted/received by the on-board transmission/reception means; A control means that controls the output to the on-board equipment and also controls the output to each modulation/demodulation means based on signals from each on-board equipment, and a low-speed controller that detects reception of a low-speed transmission signal from the ground side. The transmission signal detection means and the on-vehicle transmission/reception means are normally connected to the high-speed transmission modulation/demodulation means, and when reception of a low-speed transmission signal is detected, the on-board transmission/reception means is connected to the low-speed transmission modulation/demodulation means. What is claimed is: 1. A ground-to-vehicle transmission device comprising an on-vehicle device equipped with switching means for switching connection to the side.