JPS61256832A - On-vehicle communication equipment - Google Patents

Abstract

PURPOSE:To facilitate the mounting of an on-vehicle communication equipment onto a vehicle and removal of it from the vehicle by simplifying the constitution of the antenna in the on-vehicle communication equipment. CONSTITUTION:A transmission and reception end being a series resonance circuit as an output terminal is connected to a power line 5, and the 1st inductor (coil) L2 acting like an antenna element and a start switch SW are inserted between the 1st connecting point A and a transmission/reception section 6. The 2nd inductor L3 is connected to the side of a plug 4 of the power line 5 and the distance between the 2nd connecting point B and the 1st connecting point A is set to satisfy the formula of distance (l)=K.(lambda/4).n, where K is a wavelength shortening factor, lambda is a wavelength for communication frequency and (n) is an odd number (1, 3, 5 ...). Then the power line 5 is used in common also as a line antenna to attain efficient communication.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to an in-vehicle communication device that is mounted on a vehicle such as a car running on a test course and that communicates with a management center etc. in order to confirm the driving status of the vehicle. Regarding.

(Summary of the Invention) The present invention is an in-vehicle communication device that simplifies the configuration of the antenna so that it can be easily mounted on and removed from the vehicle.

(Prior art and its problems) This type of device is designed to transmit a unique code signal in each vehicle, for example, to identify the driver. Therefore, when the driver gets on and off the vehicle, it is necessary to attach the communication device when getting on the vehicle and remove it when getting off the vehicle.

Therefore, conventional vehicle-mounted communication devices have been constructed as shown in FIGS. 4 and 5. FIG. 4 is a schematic vertical sectional view showing the state in which the device is mounted on an automobile, and FIG. 5 is a block diagram.

In these figures, 01 is an antenna, 02 is a transmitting/receiving section constituting a communication circuit, 03 is a feed line connecting the antenna O1 and the transmitting/receiving section 02, and 04 is the transmitting/receiving section 0 on one end side.
2, and these antennas Of.

The transmitting/receiving section 02, the power supply line 03, and the power line 04 constitute an on-vehicle communication device. When this communication device is installed in an automobile, the antenna 01 is placed on the bonnet 05 at the front of the automobile, and the transmitter/receiver section 02 is installed inside the vehicle.
The antenna O1 and the transmitting/receiving unit 02 are connected via the power supply line 03 that is passed from outside the vehicle to the inside of the vehicle, and
The other end of the power line 04 connected to the transmitting/receiving section 02 is connected to the battery 06 via an outlet 07 for a cigarette lighter. Conversely, when removing the communication device from the vehicle, the antenna O11, the transmitter/receiver section 02, the power supply line 03, and the power line 04 are disconnected from each other.

However, in the case of the conventional example having such a configuration, each time the driver gets on and off, the antenna Of, the transmitting/receiving section 02, the power supply line 03, and the power line 04 must be attached and detached, and the communication device It took a lot of effort to install and use it, and it had the disadvantage that it was not easy to use. Moreover, especially in a car that runs on a test course, it is not preferable to expose the antenna 01 to the outside, and it is desired that the antenna 01 be housed inside the car as much as possible.

(Object of the Invention) The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a communication device that is easy to install and remove and is easy to use.

(Structure and Effects of the Invention) In order to achieve such an object, the present invention includes a plug connected to a battery mounted on a vehicle, and a communication circuit that transmits a frequency signal of a specific frequency. In a power line from the plug to the communication circuit, connect the output end of the frequency signal, connect a first inductor element from the connection point to the communication circuit side, and connect the first inductor element from the connection point to the plug side. , relational expression % expression %) However, K: wavelength shortening rate, λ: wavelength of communication frequency, n:
A second inductor element is connected at a distance that satisfies L3.5, . . . (odd number), and the power supply line is also used as a linear antenna.

According to this configuration, the communication device can be mounted and installed in the vehicle by carrying the main body that constitutes the communication circuit into the vehicle and connecting the plug connected to it to a cigarette lighter outlet, etc. Conversely, the communication device can be removed by disconnecting the plug and carrying the main body out of the vehicle.

Therefore, it is possible to extremely easily attach and remove the communication device when mounting it, and it is possible to provide a communication device that is easy to use.

Moreover, since the entire antenna can be stored inside the vehicle without exposing the antenna to the outside of the vehicle, it can be effectively used in a vehicle used for driving on a test course.

Furthermore, since the battery is the power source, communication is carried out using weak radio waves, but since the length of the linear antenna is set to a predetermined multiple of the wavelength of the communication frequency, the communication energy can be increased and the communication is performed using weak radio waves. However, we were able to communicate well.

(Description of Examples) Hereinafter, the present invention will be described in detail based on examples shown in the drawings. FIG. 1 is a circuit diagram of a vehicle-mounted communication device according to an embodiment of the present invention, and FIG. 2 is a configuration diagram.

In these figures, ■ is a communication circuit, 1a is a casing containing the communication circuit 1, 2 is a battery mounted on the car, 3 is an outlet for a cigarette lighter connected to the battery 2, and 4 is a casing with a built-in communication circuit 1. , a plug for connecting to the outlet 3, and 5 a power line for supplying power from the battery 2 to the communication circuit 1.

The communication circuit I is provided with a transmitting/receiving section 6 and a series resonant circuit consisting of a coil and a semi-fixed capacitor C, and the transmitting/receiving section 6 and the series resonant circuit are electromagnetically coupled (M). .

The series resonant circuit is set to obtain a predetermined communication frequency ω based on the following relational expression %.

A transmitter/receiver end of the series resonant circuit serving as an output end is connected to the power supply line 5, and its first connection point A and the transmitter/receiver section 6
and a first inductor element (coil) L for functioning as an antenna element.

and a start switch SW are interposed.

A second inductor element L is provided on the plug 4 side of the power line 5.
3 is connected, and the distance between the second connection point B and the first connection point A is expressed by the relational expression (%), where K: wavelength shortening rate, λ: wavelength of communication frequency, n:
1, 3.5, . . . (odd number), and is configured to double as a linear antenna so that the power line 5 can communicate efficiently. Here, the wavelength shortening rate is, for example, about 0.9 in the case of copper wire.
5, etc., and is determined by the material of the power supply line 5. The first and second inductor elements L2.
Each of L3 has a high impedance at the communication frequency ω (each of ωLt and ωL3 is much higher in number than Ω).

For example, the communication frequency may have a wavelength of 1.
A length of about 5 to 2.0 m is used, and the length of the power line 5 is about 1.0 to 1.5 m.

The second inductor element L3 is installed inside the plug 4.

A mounting bracket 8 for clamping the sun visor 7 is attached to the upper surface of the casing 1a.

Although not shown, the transmitter/receiver section 6 is equipped with an oscillator, an amplifier, a comparator, and the like.

Next, the operation of this embodiment will be explained.

As shown in FIG. 3, the communication device is carried into the vehicle, and the casing 1a is held between the sun visors 7. The middle part of the cord 5a of the power line 5 is hooked on a rearview mirror 9 to guide it downward while ensuring a driving field of view. The plug 4 at the lower end is connected to the outlet 3, and in this state, the start switch SW is closed to supply power to the transmitting/receiving section 6.

A frequency signal from an external transmitting/receiving means is input to the transmitting/receiving section 6 via the series resonant circuit and the electromagnetic coupling M, and when the frequency signal is of a specific frequency (carrier), in response thereto, Then, a unique frequency signal set by the semi-fixed capacitor C of the series resonant circuit is transmitted from the transmitting/receiving section 6 to the external transmitting/receiving means via the electromagnetic coupling M1 series resonant circuit and the linear antenna component of the power supply line 5. .

In the above embodiment, the communication circuit 1 receives the carrier to avoid interference with frequency signals between the external transmitting/receiving means and other communication devices. It may be something that constitutes.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of an in-vehicle communication device according to an embodiment of the present invention, Fig. 2 is a configuration diagram, Fig. 3 is an external view showing how it is mounted on an automobile, and Fig. 4 is a conventional example of an automobile. FIG. 5 is a block diagram of the schematic vertical cross-sectional view showing the mounted state of the device. DESCRIPTION OF SYMBOLS 1...Communication circuit, 2...Battery, 4...Plug, 5...Power line, A...Connection point, L...
A first inductor element, L,... a second inductor element.

Claims (1)

[Claims] (1) It has a plug that connects to a battery mounted on a vehicle, and a communication circuit that transmits a frequency signal of a specific frequency, and an output end of the frequency signal in a power line from the plug to the communication circuit. a first inductor element is connected to the communication circuit side from the connection point, and
From the connection point to the plug side, the relational expression 1=K・(λ/4)・n where K: wavelength shortening rate, λ: wavelength of the communication frequency, n:
1, 3, 5, . . . (an odd number) A communication device for a vehicle, characterized in that second inductor elements are connected at intervals satisfying the following formula, and the power supply line is also used as a linear antenna.