JPS598093B2 - mobile communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mobile communication device that transmits information to a moving object moving on a running road, and has a function of controlling the connection/disconnection of information output depending on the moving direction of the moving object. It is.

Generally, radio waves are used as a medium for mobile communication, but in order to provide information to moving objects over a fixed section of a road, many methods have been put into practical use, such as installing lines along the road and using induced magnetic fields or leakage electric fields.

However, if there are moving objects in both directions within the communicable range, and the information is intended only for objects heading in one direction, the transmitting side sends a signal that can be identified by direction along with the information. A method is used to determine this on the receiving side. That is, by operating a switch on the receiving side, the selection of signals indicating the direction is changed, and information corresponding to the current direction is output. The most commonly used method for transmitting information that can distinguish between directions is to use separate frequencies for upstream and downstream radio waves, and when upstream and downstream information is provided in different sections, the same frequency can be used. A method is also used in which the code or signal to be modulated as a carrier wave is different for uplink and downlink. However, this method requires manpower to operate the switch, and when the moving object is a car traveling on a general road where it is not clear whether it is going up or down, it is assumed that the passenger will be able to determine the direction. It could not be expected that the switch would be completely implemented. This invention was made in order to eliminate the above-mentioned drawbacks, and even if the occupant of the moving object does not recognize his/her own direction, the information transmission side automatically selectively sends information to the target moving object traveling in the direction designated by the information transmitting side. The present invention provides a mobile communication device that transmits. Embodiments of the present invention will be described below with reference to the drawings.

According to the present invention, a moving object that enters from an unspecified direction among moving objects traveling within the communication range of a ground transmitting device can receive a control signal that closes the reception output circuit at a point immediately before the moving object enters the communication area. As an embodiment of the present invention, a mobile communication system for a car running on a general road and using a cable as a radiator (an antenna) is shown in FIG. 1 and will be described. In Figure 1, the main transmitter is on the roadside of road 1! Device 2
is installed, and transmits information to cars traveling on the road via a cable-shaped antenna 3. This information is
The purpose is to provide signals only to cars traveling from right to left in the figure, and a weak output trigger transmitter 4 with the same frequency as the main transmitter 2 is installed near the left of the antenna 3. Control radio waves modulated with signals or codes are emitted continuously or intermittently. The trigger transmitter 4 may be located on the same side of the road as the main transmitter 2 or on the opposite side of the road, but since it acts as a trigger for cars traveling in the opposite direction, it is better to install it on the opposite side of the road.
A car 5 traveling in a designated direction, that is, from right to left in FIG.
The receiving device first determines that it has received the radio wave from the main transmitting device, performs normal reception output operation and outputs information, but the receiving device of the car 6 traveling in the opposite direction first receives the trigger. It receives radio waves from the transmitter 4 and is controlled to close audio output. When the vehicle 5 leaves the communication range of the main transmitter, it also closes when receiving radio waves from the trigger transmitter 4 and returns to its original state. The outline of an example of the transmitter system is shown in the second section.
It is shown and explained in the figure.

The output of the main transmitter 11 is fed to the main antenna 13, and the output of the trigger transmitter 12 is radiated from the trigger antenna 14.
The main transmitter 11 has a pilot signal oscillator 15 in addition to a modulation circuit 17 for audio, which is the information to be transmitted, and the output thereof is simultaneously modulated, and the trigger transmitter 12 is modulated by the output of a trigger signal oscillator 16. and the frequencies of both oscillators are specific but different. An example of a receiving device on the mobile body side is schematically shown in FIG. 3 and will be described.

In FIG. 3, an input signal input from a reception input terminal 21 passes through a reception section 22, a demodulation section 23, and is sent to a reception output section 25 as an audio signal, which is information, but a gate 24 is inserted in the middle. There is. On the other hand, the demodulated signal is sent to a pilot signal detector 26 modulated in parallel with the voice and a trigger signal detector 27.
to obtain respective control output signals. 28 is a gate control device, 29 is a sequence determining circuit, and 30 is a timer, which performs the following control operations.

(1) When a pilot signal is first output from the standby state (no signal is detected and the audio gate is closed), open the gate and allow the audio signal to pass through according to the normal wireless receiver operating procedure. .

This operation is similar to a general-purpose tone squelch.
After the pilot signal output disappears, the device returns to the standby state when a certain period of time determined by the timer has elapsed or when a trigger signal output is detected during this period. (2) Control to open the gate is not performed within a certain period of time set by the timer from when the trigger signal is first detected in the standby state.

Even if a pilot signal is output during this period, the gate cannot be opened during the period in which that signal continues. After the pilot signal output disappears, the device returns to the original standby state after a certain period of time determined by the timer has elapsed. (3) During reception, even if the signal output is interrupted due to interference or noise, the timer maintains the current state for a certain period of time.

In the above description, it is preferable that the timer maintains the current state for a certain period of time, starts when the detector output is cut off, and that the holding time can be adjusted.

It is also obvious that the timer can be replaced directly with something that can detect a fixed distance traveled after startup. By keeping the trigger transmitter output to the minimum necessary, the distance from the main device communication range is reduced, reducing the influence of interference.
Malfunctions can be reduced.

In practice, the radio waves from the trigger transmitter may be received by cars in opposite lanes, so if systems in both directions are installed close together, one trigger will also trigger the other. It may work as
It is necessary to arrange the device in such a way as to avoid such malfunctions as much as possible.

Although the embodiments of this invention have been explained using wireless communication using radio waves emitted from a cable as a medium, it is possible that the invention can be widely applied to the same purpose in transmission using other media used in a similar manner. Of course.

In addition, the target area is not limited to general roads, but can also be used for railways, waterways, specific passageways, etc. Transmission information is not limited to audio, but also applies to visual output. It is clear that the pilot signal is not limited to a tone signal that is modulated in parallel with the voice, but can also be a digital code system or a control signal that is inserted at a specific position, such as before or after a message. Although it has a wide range of uses, there is a recent trend in which information systems for moving objects on general roads are being put into practical use, and when there are moving objects in multiple directions, information is transmitted only to objects in a specific direction. This is a relatively easy method that can be used, and being able to eliminate unnecessary information is extremely effective in increasing the recipient's sense of trust. As explained above, according to the mobile communication device of the present invention, information can be automatically selectively transmitted to a mobile object moving in a specific direction.

[Brief explanation of the drawing]

FIG. 1 is a system block diagram showing the entire mobile communication device according to an embodiment of the present invention, FIG. 2 is a block diagram of the transmitting device shown in FIG. 1, and FIG. 3 is a system block diagram showing the mobile communication device shown in FIG. 1. FIG. 2 is a block diagram of a receiving device installed in In the figure, 1 is a road, 2 is a transmitter, 3 is an antenna, 4 is a trigger transmitter, 5 and 6 are moving vehicles, 15 is a pilot tone generator, 16 is a trigger tone generator, 1
7 is a modulation circuit that modulates information; 23 is a demodulation unit that demodulates a received signal; 24 is a gate; 25 is a reception output unit;
7 is a tone detector, 28 is a gate control device, 29 is an order determining circuit, and 30 is a timer.

Claims (1)

[Claims] 1. An antenna installed along the path of a mobile object to define a communication range, a transmitting device for transmitting modulated information signals and pilot signals to this antenna, and a transmitting device installed in the path at one end of the antenna for transmitting a trigger signal. a trigger transmitter to transmit;
Receives signals from the transmitting device and trigger transmitter provided in the mobile body, and when a pilot signal is first received from the transmitting device in a standby state, passing the output of the information signal from the transmitting device; When the trigger signal from the trigger transmitter is first received in a standby state, the receiving device blocks the output of the information signal from the transmitting device, and returns to the standby state after the mobile object passes through the communication range. A mobile communication device comprising: