JPH0797877B2 - Communication device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device used for a remote control device of an automobile, etc., and particularly, when a normal signal is received, the power is turned on.
And the power is forced to OF when an abnormal signal is received.
Regarding the communication device that becomes F.

[Background of the Invention]

Recently, a remote control device for an automobile as shown in FIG. 1 has been developed. With this device, the transmitter 21
When the switch 21a is pressed, the signal is received by the antenna provided on the vehicle body 22 of the automobile, and the receiver 23 and the controller in the vehicle body are activated. Then, under the control of the controller 24, the door lock is released and the interior light is turned on.

[Problems to be solved by the invention]

In this type of device, a signal as shown in FIG. 4 (a) is obtained by reception from the transmitter 21. This signal is composed of a header pulse Dh and data pulses Da, Db ... In this type of remote control device, the car battery is used as the power source for driving the receiver 23 and the controller 24, so it is not possible to keep the power source ON at all times, and when the header pulse Da is detected. Only
The power is turned on for a certain period of time.

However, considering the actual usage environment, Fig. 4 (e)
As shown in, there may be a carrier having the same frequency as the header pulse Dh of the signal from the transmitter. When such a carrier wave is input from the antenna, the receiver 23 operates in the same manner as the header pulse and the power is turned on. If this carrier wave is received for a long time, the power will be kept on all the time, which will increase the battery consumption of the car.

The present invention solves the above-mentioned conventional problems. When a carrier wave other than the signal from the transmitter is received, the power supply
After it is turned on, the receiver judges whether it is a normal header pulse, and when it is found that it is an abnormal signal,
It is intended to provide a communication device which can be turned off immediately.

[Specific means for solving problems]

A communication device according to the present invention comprises a transmitter for transmitting a header pulse and a data pulse following the header pulse for a certain period of time, and a receiver for receiving a transmission signal. When it is detected that a signal has been received, the power control circuit for normal operation that turns on the power for a fixed time, and the signal received after the power is once turned on by the power control circuit for normal operation And a power supply control circuit at the time of abnormality for turning off the power supply for a fixed time when the power supply continues for a time longer than the header pulse.

In the present invention, when a normal header pulse is received from the signal from the transmitter, the power supply control circuit at normal time is activated to turn on the power of the receiver, and the length of the received signal is a normal header pulse. If it is longer than the above, the power supply control circuit at the time of abnormality operates and the power is immediately turned off.
It is what

Example of Invention

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a device layout diagram of a remote control device for an automobile, FIG. 2 is a block diagram showing a power supply control circuit in a receiver 23, and FIG.
FIG. 4 is a specific circuit diagram of the power supply control circuit, and FIG. 4 is a time chart showing signals processed by the circuit of FIG.

As shown in FIG. 2, the receiver 23 is provided with an RF tuner 31, a normal signal discrimination circuit 32, a power supply control circuit 33 in a normal state, and a power supply control circuit 34 in an abnormal state. When the RF tuner 31 receives a normal signal, the power is turned on for a certain period of time to operate the controller 24, and based on a command from the controller 24, the door lock is released and the interior light is turned on. When an abnormal signal is received, the power supply control circuit 34 at the time of abnormal operation is activated, and the circuits of the receiver 23 and the controller 24 are forcibly turned off.

Next, an example of a specific circuit will be described with reference to FIG. In this figure, the normal signal determination circuit and the power supply control circuit in the normal state are arranged below the one-dot chain line, and the power supply control circuit in the abnormal state is arranged above the one-dot chain line.

A reception input from an antenna 1 of the vehicle body is tuned and selected by a reception circuit 2 including an RF tuner, and waveform-shaped by a pulse shaping circuit 3. The output from the pulse shaping circuit 3 is sent to the controller 24 and also input to the AND circuit 4. The code is a timerable circuit. Taimaburu circuit 7 in FIG. 4 (b) time at time interval t ₂ as shown in
An intermittent pulse P that continues for t ₃ is output. The interval t ₂ between the intermittent pulses P is the header pulse sent from the transmitter 21.
It is set shorter than the duration t _{1 of} Dh. The intermittent pulse P output from the timerable circuit 7 is input to the AND circuit 4. The output from the AND circuit 4 is input to the multivibrator 9. With this multivibrator 9, AN
When a signal is input from the D circuit 4, a continuous pulse of time t ₄ is output as shown in FIG. 4 (c). The output time t ₄ of this continuous pulse is set to a length sufficient for sending the data pulses Da, Db ... To the controller 24, as shown in FIG. The output from the multivibrator 9 and the output from the timerable circuit 7 are both input to an OR circuit 8, and the OR circuit 8 controls the power supply circuit 6. The power supply circuit 6 is for sending or cutting off the power supply from the battery of the automobile to the receiver 23 and the controller 24.

Further, a counter 11 is provided in the power supply control circuit at the time of abnormality arranged above the one-dot chain line. This counter
11 is started by the output from the AND circuit 4, and counts the intermittent pulse from the timerable circuit 7. Counter 11
From this, as shown in FIG. 4 (d), one pulse is emitted every time a plurality of intermittent pulses P are counted. The pulse interval t ₅ is set longer than the time t ₁ of the header pulse Dh. In the abnormal power supply control circuit, the output from the counter 11 and the output from the pulse shaping circuit 3 are input to the AND circuit 12. Then, the output from the AND circuit 12 causes the timer 13 to operate for a certain time, and the power supply circuit 6 forcibly turns off the power for the time set by the timer 13.

Next, the operation will be described.

The signal emitted from the transmitter 21 is received by the receiving circuit 2 and shaped by the pulse shaping circuit 3. The normal signal to be received is, as shown in FIG. 4 (a), a header pulse Dh at time t ₁ and data pulses Da, Db,
It consists of ... and. On the other hand, the timerable circuit 7 outputs an intermittent pulse P at an interval of time t ₂ as shown in FIG. 4 (b). Since the intermittent pulse P is given to the power supply circuit 6 via the OR circuit 8, the receiving circuit 2 performs the intermittent receiving operation only during the time when the pulse P rises. In this way, the signal received by the intermittent receiving operation is waveform-shaped by the pulse shaping circuit 3
It is given to the D circuit 4. A signal is output from the AND circuit 4 when the signal received by the receiving circuit 3 and the pulse Pa from the timerable circuit 7 are detected, whereby the multivibrator 9 is activated and the continuous pulse at time t ₄ is generated. Is output. Therefore, the signal output from the OR circuit 8 is the fourth signal.
The pulse has the waveform shown in FIG. When this signal is at high level, the power supply circuit 6 is activated, the power is turned on, and the receiver 23 and the controller 24 are activated. That is, when the signal from the transmitter 21 is not received, the power source is intermittently turned on according to the intermittent pulse P,
It is designed to save power consumption. Then, after receiving the header pulse Dh, the power continues to be turned on for time t ₄ . At this time, data pulses Da, Db, ... Are sent to the controller 24, and the controller 24 responds to this data signal.
Is activated and the door lock is released and the interior lights are turned on.

Next, as shown in FIG. 4 (e), when a signal having the same frequency as the transmission from the transmitter 21 and longer than the header pulse Dh is received, the following operation is performed.

When such an abnormal signal is received, a signal is emitted from the AND circuit 4 by the pulse Pa emitted from the timerable circuit 7 immediately after the abnormal signal is received as in the normal signal, and the multivibrator 9 is activated. , The power keeps on. However, when the output from the AND circuit 4 is input to the counter 11, the counter 11 starts and the pulse P emitted from the timerable circuit 7 is counted. The counter 11 outputs one pulse each time a plurality of pulses P are counted. This pulse interval t ₅ is the fourth
As shown in FIG. 7D, the header pulse Dh is longer than the time t ₁ . The output from the counter 11 is input to the AND circuit 12 together with the output from the pulse shaping circuit 3. When the abnormal signal is received and the abnormal signal continues longer than the time t ₁ of the header pulse Dh, the signal continuously output from the pulse shaping circuit 3 and the output from the counter 11 cause the AND circuit 12 to output the signal. The signal shown in FIG. 4 (f) is output. This signal causes the timer 13 to operate for a relatively long time as shown in FIG.
The power supply circuit 6 forcibly turns off the power only while is operating. The counter 11 automatically stops after a certain period of time.

After the time set by the timer 13 has elapsed, the power circuit 6
Returns. At this time, if the abnormal signal is still being received, the above operation is repeated, and the power is turned off again.
Become F. If the abnormal signal is not received when the power is restored, the power supply circuit 6 continues to operate intermittently by the intermittent pulse P from the timerable circuit 7.

The present invention is not only implemented by the circuit shown in FIG. 3, but is, for example, the normal signal discriminating circuit 32 shown in FIG.
At, the length of the signal received by the RF tuner 31 is
Compared with the length of the stored signal, when it is determined that the header pulse Dh is normal by the time, the power supply control circuit 33 at normal time is activated, and the received signal is longer than the time of the header pulse Dh. If it is determined that the power supply is too long, it is possible to operate the power supply control circuit 34 at the time of abnormality to forcibly turn off the power supply.

The present invention is not limited to the communication device in the remote control device of the automobile, and it goes without saying that the present invention can be implemented in various communication devices other than this.

〔The invention's effect〕

As described above, in the present invention, when the signal is received, the power is once turned on, but when the received signal lasts longer than the header pulse, the power is immediately turned off. It is possible to prevent the power from continuing to be turned on unnecessarily at the time of receiving the received signal, and to save power consumption.

In addition, the power-off timing is set based on whether the signal duration is longer than the header pulse duration, so the power can be turned off immediately without the need to judge the identification code by the controller. . Therefore, power off
The timing for switching to can be set quickly, and no extra burden is imposed on the controller or the like.

[Brief description of drawings]

Each of the drawings shows an embodiment of the present invention. FIG. 1 is a device layout view showing a remote control device of an automobile as an example of a device using a communication device according to the present invention, and FIG. 2 is a power supply control. FIG. 3 is a block diagram showing the configuration of the circuit, FIG. 3 is a circuit diagram showing a concrete example of the power supply control circuit, and FIG. 4 is a time chart showing signals in the circuit of FIG. 1 ... Antenna, 6 ... Power supply circuit, 7 ... Timer circuit, 9 ... Multivibrator, 11 ... Counter, 13 ...
… Timer, 21 …… Transmitter, 23 …… Receiver, 24 …… Controller, 32 …… Normal signal discriminating circuit, 33 …… Power control circuit when normal, 34 …… Power control circuit when abnormal

Claims (1)

[Claims] 1. A transmitter for transmitting a header pulse and a data pulse following the header pulse for a certain period of time, and a receiver for receiving a transmission signal, wherein the receiver receives a signal by an intermittent reception operation. When the reception is detected, the power supply is turned on for a certain period of time and the power supply control circuit at normal time turns on the power supply once by the power supply control circuit at normal time, and then the received signal is the header pulse. And a power supply control circuit at the time of abnormality for turning off the power supply for a fixed time when the power supply is continued for a longer time.