JPH0983439A - Communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct data transmission after confirming the presence of a communication opposite party available for data signal transmission reception. SOLUTION: A confirmation signal is subjected to ASK modulation and sent to a communication opposite party for each period t1 for a non-transmission period of a data signal. On the other hand, a confirmation signal is sent for each period t1 similarly from the communication opposite party. Upon the receipt of the confirmation signal sent from the communication opposite party, a latch circuit 28 latches the reception confirming signal and provides an output of a status signal representing a valid state. When the latch circuit 28 does not receive a succeeding confirming signal within a period t2, the circuit 28 is reset by expiration of time of a timer circuit 20 and the status signal is invalid. Then the presence of communication opposite party is confirmed with each other during non-data transmission period and only when the presence is clear, the data signal is sent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device for wirelessly transmitting and receiving information, and more particularly to the structure of a communication device using infrared rays.

[0002]

2. Description of the Related Art Infrared communication is widely used in remote control devices for various equipment. Communication using infrared rays is low in power consumption of the device and simple in configuration of the transmission / reception device, and is therefore excellent in cost. Therefore, it has been proposed to provide such an infrared communication function in a portable information device or the like.

Generally, in infrared communication, communication is performed by a so-called aiming method as shown in FIG. This aiming method is a method in which the emission direction of infrared rays from the transmission unit is narrowed down to one point and the data signal is sent to the reception unit of the communication partner existing in a position visible from the transmission unit. The communication is possible without considering the reflection signal reflected by the wall or the like.

[0004]

However, in the aiming method as described above, since the radiation direction of infrared rays is limited to one point, if the communication partner does not exist at the position assumed, data is transmitted. However, the other party cannot receive this. Further, after transmitting the data signal, it is unknown whether or not the communication partner receives the data signal until the acknowledge signal is returned from the communication partner. Therefore, in the above-mentioned conventional infrared communication, data transmission is performed regardless of the other party who can receive the transmitted data signal.

In order to reliably transmit the data to the communication partner, for example, as shown in FIG. 6, the so-called multipath system is adopted, in which the transmission output is spread and the data signal reaches the receiving unit of the communication partner. Can be considered. In the multi-path method, not only the data signal directly transmitted from the transmitter to the receiver, but also the data signal once reflected by a reflector such as a wall can be used if the signal reaches the receiver. It is possible to improve the probability that the signal reaches the receiving unit compared to the shooting method.

However, even with this multipath system, it is still impossible to determine whether or not the communication partner exists before the data signal is transmitted, even if the data signal is transmitted or received. In addition, a large transmission output is required to diffuse the transmission output, and the low power consumption of the communication device, which is an advantage of infrared communication, is lost. Further, since the infrared rays also have an influence on the usage environment of the device, the transmission output cannot be made too large. Furthermore, since a function of compensating for the arrival time difference between the data signal directly reaching the receiving unit and the data signal once reflected is also required, there is a problem that the configuration of the communication device becomes complicated.

In order to solve the above-mentioned problems, it is an object of the present invention to provide a communication device for transmitting data after confirming that there is a communication partner which can surely transmit / receive a data signal.

[0008]

In order to achieve the above object, the communication device of the present invention communicates the confirmation signal with a confirmation signal generator which generates a confirmation signal during a non-data transmission period. It is configured to have a transmitting unit that transmits to a partner and a receiving unit that receives a confirmation signal from the communication partner. As a result, it is possible to confirm whether or not the other communication partner exists during the non-data transmission period based on the received confirmation signal from the communication partner.

Further, as a concrete configuration example, in addition to the above configuration, the other party confirmation that receives the confirmation signal from the other party and generates the other party confirmation signal permitting the transmission and reception of the data signal in response to the confirmation signal It has a signal generator, and stops the generation of the partner confirmation signal when the confirmation signal from the communication partner is not received for a predetermined period or longer. Therefore, the existence of the communication partner can be confirmed in advance, and the data signal can be transmitted only when the existence of the communication partner is clear, which eliminates the need for meaningless communication.

Further, in this communication apparatus, if each of the signals is transmitted and received by using infrared rays, communication by a communication apparatus having a simple apparatus configuration and low power consumption becomes possible.

Further, the confirmation signal and the data signal are amplitude-modulated with carrier frequencies different from each other and transmitted, so that the two signals are extracted from the received signal without mutual interference of the signals. It is easy to do.

[0012]

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

The communication device according to this embodiment has a configuration as shown in FIG.

The OSC 10 has a frequency FOSC1 (for example, 50
A carrier signal for a data signal of 0 kHz (hereinafter referred to as a data carrier signal) is generated, and is generated by the first ASK (Am
Plitude Shift Keying) Supply to the modulator 12. 1A
The SK modulator 12 is connected to the data signal line 11,
When the data signal is supplied, the data signal is amplitude-modulated (hereinafter referred to as ASK) based on the data carrier signal from the OSC 10.
Called modulation. The first ASK modulator 12 includes a combiner 1
A light emitting diode 16 is connected via 4, and a signal is transmitted from this light emitting diode 16 as infrared rays.

A timer circuit 20 is further connected to the data signal line 11. The timer circuit 20 has a t1 timer and a t2 timer, and measures the periods t1 and t2, respectively. A confirmation signal generator 22 is provided on the output side of the timer circuit 20, and generates a confirmation signal for notifying the communication partner of his / her existence every period t1 based on the measurement of the period t1 of the timer circuit 20. To do.

The OSC 26 has a frequency FOSC2 (eg 76
A carrier signal (hereinafter referred to as a confirmation carrier signal) of a confirmation signal of (kHz) is generated, and this confirmation carrier signal is supplied to the second ASK modulator 24. Second ASK modulator 2
4 is provided between the confirmation signal generator 22 and the combiner 14, and ASK-modulates the confirmation signal from the confirmation signal generator 22 based on the confirmation carrier signal from the OSC 26.

On the other hand, when the photodiode 30 receives an infrared signal from a communication partner, it converts the infrared signal into an electric signal. Then, the converted signal is passed through the preamplifier 32 to the bandpass filters (BPF1) 34 and (BPF1).
2) 36. The BPF1 is a filter for extracting a signal in the frequency band FOSC1 of the confirmation carrier signal from the received signal. The BPF1 is connected with the timer circuit 20 and the latch circuit 28, respectively, and the signal extracted by the BPF1, that is, from the communication partner. Confirmation signal of timer circuit 2
0 and the latch circuit 28.

When the BPF 1 outputs a confirmation signal for the communication partner, the latch circuit 28 latches the signal and outputs a partner confirmation signal (status signal of H level). Also,
The timer circuit 20 is connected to the latch circuit 28,
The latch circuit 28 is supplied with the time-up information of the period t2 by the t2 timer of the timer circuit 20.

When the data signal from the communication partner is received, the BPF 2 extracts the signal in the frequency band FOSC2 of the data carrier signal from the received signal, and the data signal thus extracted is output to the data demodulation unit 38. Demodulated here.

(Operation of Device) When the transmission data signal is no longer supplied from the information equipment to the data signal line 11 of the communication device of FIG. 1, the data signal is H level as shown in FIG. 2 (a).
Level. The timer circuit 20 detects the rise of the data signal from the L level to the H level and starts the measurement of the period t1. If the H level of the data signal continues for the period t1 or more, that is, if the data signal is not transmitted for the period t1 or more, the confirmation signal generating unit 22 responds to the pulse shape as shown in FIG. The confirmation signal of is generated every period t1. The second ASK modulator 24
When the confirmation signal is supplied from the confirmation signal generator 22,
This confirmation signal is ASK at the frequency of the confirmation carrier signal.
Modulate. The modulated confirmation signal is transmitted from the light emitting diode 16 to the communication partner via the adder 14 as an infrared signal.

On the other hand, the communication partner also has the same configuration as that shown in FIG. 1 and, as described above, transmits a confirmation signal every t1 during the period in which it does not transmit the data signal. Then, the confirmation signal from the communication partner is sent to the photodiode 3
When 0 is received, the reception confirmation signal is supplied to the BPF 1 via the preamplifier 32 and extracted there. The latch circuit 28 latches the confirmation signal output from the BPF 1, and as shown in FIG. 2C, the latch circuit 28 outputs the confirmation signal.
Outputs an H-level status signal from the.

When the confirmation signal is output from the BPF 1, the t2 timer of the timer circuit 20 is cleared, and the measurement of the period t2 is started from that point. If the next confirmation signal from the other party is not received within the period t2, the t2 timer times out and the latch circuit 28 is reset.
As a result, the status signal becomes L level, which means that there is no communication partner. On the other hand, if the next confirmation signal is transmitted from the other party within the period t2, the t2 timer of the timer circuit 20 is cleared again, the latch circuit 28 is not reset, and the status signal is maintained at the H level. The status signal is set to be valid during the H level period, and therefore, there is a communication partner that can reliably communicate during this valid period.

Next, when the data signal from the other party is received, the received data signal is supplied from the photodiode 30 via the preamplifier 32 and the BPF 2 to the data demodulation section 38 for demodulation, and the demodulated data signal is output from this. . When the demodulated data signal is output, the t1 timer and the t2 timer of the timer circuit 20 are cleared accordingly. Therefore, during the reception period of the data signal, the two timers are continuously cleared, and the confirmation signal is not generated during this period, while the latch circuit 28 is not reset, so the status signal is maintained at the H level. .

When the data signal is transmitted by itself, the data signal becomes L level. When the data signal becomes L level, the t1 timer and the t2 timer of the timer circuit 20 are cleared accordingly. Therefore, during the data transmission period as well as during the reception period, the confirmation signal is not generated and the status signal is maintained at the H level.

As described above, while the status signal is at the H level, the communication partner surely exists. Therefore, if the data signal is transmitted and received only during this period, the communication with the partner can be surely performed. Therefore, it is possible to prevent meaningless communication even if there is no other party who can receive the transmission data signal.

Further, in this embodiment, as shown in FIG. 3, the frequency of the confirmation carrier signal (for example, 76 kHz).
Is the frequency of the data carrier signal (eg 500 kHz)
Is set to a different frequency. The two frequencies are set to different values so that the data signal is not adversely affected by the confirmation signal. Further, even if the output power of the confirmation signal is slightly small, the reception accuracy does not change so much, so the output power of the confirmation signal is set smaller than the output power of the data signal. Therefore, even if the confirmation signal is output every t1 when the communication device does not communicate the data signal, it is possible to reduce the power consumption. Further, if the confirmation signal having a small output can be correctly received, the data signal having a larger output can be received more reliably, so that the reception of the data can be predicted and the reliability of the data can be secured.

(Application Example) Next, an example in which the communication device of the above embodiment is applied to a notebook type information device or the like will be described with reference to FIG.

In the information device 50, a UART (Universal Asynch) that is usually used for its communication interface is used.
By connecting a modem to the ronous receiver transmitter 52, it is possible to communicate with other devices via a telephone line. The UART 52 has a DSR (Data Set Ready) terminal for monitoring the operating state of the modem, monitors the operating state of the modem based on the DSR signal supplied to this terminal, and the DSR signal is valid. During the period, communication is performed via a modem.

Therefore, if the status signal is supplied to the DSR terminal instead of the DSR signal, the information device 50 can be provided with the communication function of the present invention of confirming the existence of the communication partner before transmitting and receiving the data signal. In the above case, if the presence of the communication partner is confirmed and the status signal from the communication device 40 is valid, the information device 50 permits the transmission and reception of the data signal. For data transmission, UAR
A transmission data signal is supplied to the communication device 40 via the transmission data terminal Txd of T and is transmitted as an infrared signal. In the case of data reception, the infrared data signal received during the valid period is demodulated and supplied to the reception data terminal Rxd of the UART.

As described above, the communication device of this embodiment can be used very easily in a general-purpose information device.

Although the communication device has been described as performing infrared communication in the present embodiment, the present invention is not limited to this.
For example, it can be applied to communication using radio waves.

[0032]

As described above, according to the configuration of the present invention, the existence of the communication partner can be confirmed in advance during the non-data transmission period. Therefore, the data signal can be transmitted only when the existence of the communication partner is clear, and it is not necessary to perform meaningless communication.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a communication device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation of the communication device in FIG.

FIG. 3 is a diagram for explaining the difference between the frequency of a confirmation carrier signal and the frequency of a data carrier signal.

FIG. 4 is a diagram showing an example of application of the communication device of the present invention to an information device.

FIG. 5 is a diagram showing a general communication method using infrared rays.

FIG. 6 is a diagram showing a multi-path infrared communication method.

[Explanation of symbols]

10, 26 OSC, 12 First ASK modulator, 14
Synthesizer, 16 light emitting diodes, 20 timer circuits, 2
2 Confirmation Signal Generation Unit 24 Second ASK Modulation Unit, 28
Latch circuit, 30 photodiode, 32 preamplifier, 34, 36 bandpass filter, 38 data demodulation section, 40 communication device.

Claims (4)

[Claims] 1. A confirmation signal generator that generates a confirmation signal during a non-data transmission period, a transmitter that transmits the confirmation signal to a communication partner, and a receiver that receives the confirmation signal from the communication partner. A communication device comprising: a unit, and confirming the presence of a communication partner based on the received confirmation signal. 2. A confirmation signal generator that generates a confirmation signal at predetermined timings during a non-data transmission period, a transmitter that transmits the confirmation signal to a communication partner, and a confirmation transmitted from the communication partner. A reception unit for receiving a confirmation signal, and a confirmation signal generation unit for generating a confirmation signal for permitting transmission and reception of a data signal when receiving a confirmation signal from the communication destination, A communication device, wherein generation of the partner confirmation signal is stopped when the confirmation signal is not received for a predetermined period or longer. 3. The communication device according to claim 1 or 2, wherein the communication device transmits and receives each of the signals by infrared rays. 4. The communication device according to claim 3, wherein the confirmation signal and the data signal are amplitude-modulated and transmitted at carrier frequencies different from each other.