JP2000165325A - Transmission output control system for optical communication unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a transmission output control system for an optical communication unit which executes communication with a required minimum output at all times by remotely controlling the transmission output of a transmitter in response to the reception level of a receiver. SOLUTION: The receiver 200 is provided with means 12-16 that informs a transmitter 100 of the occurrence of a communication error and the transmitter 100 is provided with means 2-4 that decrease the transmission output level of an optical communication signal 18 until a notice of occurrence of the communication error from the receiver 200 is received.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a transmission output control method of an optical communication device used for a port of a computer or the like.

[0002]

2. Description of the Related Art The present invention is a technology applicable to general optical communication devices for transmitting data from a transmitter to a receiver by optical communication. Hereinafter, the conventional technology and the PCM audio transceiver using infrared light will be described. The present invention will be described. FIG. 5 is a block diagram showing an example of a conventional PCM audio transmitter / receiver using infrared rays.
1 shows a CM audio receiver. In the PCM audio transmitter 100b, the light emitting unit 2 is driven by the driver 3 based on the carrier frequency (transmission signal) modulated by the PCM signal, and the infrared communication signal 18 is transmitted.

In the PCM audio receiver 200b, the infrared communication signal 1 transmitted from the transmitter 100b by the light receiving section 9 is transmitted.
8 is converted into an electric signal, and noise is removed and amplified by a receiver 10 having a built-in BPF, AMP, etc.
The PCM signal is taken out by demodulation by the decoder 11 and
It is input to the CM decoder 12. The PCM decoder 12 performs differential conversion, descrambling, deinterleaving, error correction, and the like on the input signal, demodulates the signal into an audio signal, inputs the audio signal to the audio signal processing unit 20, filters the audio signal by the audio signal processing unit 20, / A conversion and amplification are performed and output as audio.

[0004]

In a conventional optical communication apparatus, the output of an optical signal output from a transmitter is always constant, as in the PCM voice transceiver described with reference to FIG. Even if the level of the receivable optical signal fluctuates, this fluctuation must be absorbed in the dynamic range of the receiver. Therefore, when the reception level is low at the time of long-distance communication or the like, a communication error frequently occurs. Further, even when the reception level is high at the time of short-distance communication or the like, the transmitter side causes the light-emitting element to emit light with high output as in the case of long-distance communication, so that unnecessary power is consumed. There is a problem that the life of components such as the light emitting element is shortened.

[0005] Japanese Unexamined Patent Application Publication No. 8-33,054 entitled "Optical Space Transmission Apparatus" and Japanese Unexamined Patent Application Publication No. 9-83443, entitled "Automatic Transmission Output Control Device for Infrared Transmitter / Receiver", provide a bidirectional optical communication device with a reception signal. Although a technique for adjusting the level of a reply signal returned by the receiving side according to the reception level has been disclosed, the transmission level of the received signal itself cannot be minimized, so the above-described problem still remains. Dots remain.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and a remote control of a transmission output of a transmitter in accordance with a reception level at a receiver enables an optical transmission to be constantly adjusted to an optimum reception level. It is an object of the present invention to provide a transmission output control method for a communication device.

[0007]

According to the present invention, there is provided a transmission output control method for an optical communication device, wherein the transmission output control method for an optical communication device connects an optical communication signal between a transmitter and a receiver. Means for notifying the transmitter when a communication error occurs, and transmitting the optical communication signal until receiving a notification that a communication error has occurred from the receiver. Means for reducing the output level.

[0008] Further, when the communication error occurs, the means for notifying the transmitter of the communication error uses an optical control signal between a light emitting unit provided in the receiver and a light emitting unit provided in the transmitter. It is performed by optical communication. Further, the means for reducing the transmission output level of the optical communication signal until receiving a notification that a communication error has occurred from the receiver, the optical communication signal until receiving a notification that a communication error has occurred from the receiver. The transmission output of the optical communication signal is reduced step by step, and when a notification that a communication error has occurred is received, the transmission output of the optical communication signal is returned to a high output side by one or more steps. And The light control signal is a signal output from the receiver only when the communication error occurs. Further, the optical communication is performed using infrared rays. Further, a PCM audio transmitter is used as the transmitter, and a PCM audio receiver is used as the receiver. The means for detecting a communication error is a means for determining a communication error when data cannot be normally synchronized by a PCM decoder built in the PCM audio receiver. Further, the transmitter and the receiver are further provided with means for automatically adjusting the installation angles of the respective light-emitting units and light-receiving units until the reception state becomes the best even with the same transmission output.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a PCM audio transceiver according to an embodiment of the present invention. In FIG. 1, reference numeral 100 denotes a PCM audio transmitter;
2 is a light emitting unit, 3 is a driver, 4 is a CPU, 5 is a decoder, 6 is a receiver, and 7 is a light receiving unit. Reference numeral 200 denotes a PCM audio receiver, 9 denotes a light receiving unit, 10 denotes a receiver, 11 denotes a decoder, 12 denotes a PCM decoder, and 13 denotes a CM audio receiver.
PU, 14 is an encoder, 15 is a driver, 16 is a light emitting unit, 17 is a display unit, 20 is an audio signal processing unit, and 21 is a memory.

In the PCM audio transmitter 100, the light emitting section 2 is driven by the driver 3 based on the carrier frequency (transmission signal) modulated by the PCM signal, and the infrared communication signal 18 is transmitted. , The drive current of the light emitting unit 2 is controlled.

In the PCM audio receiver 200, the light receiving section 9 receives the infrared communication signal 18 transmitted from the transmitter 100 and converts it into an electric signal, and the noise is removed by the receiver 10 having a built-in BPF, AMP and the like. The PCM signal is extracted by the decoder 11 and demodulated by the decoder 11.
Input to the decoder 12. In the PCM decoder 12,
The input signal is subjected to differential conversion, descrambling, deinterleaving, error correction, etc., demodulated into an audio signal, input to the audio signal processing unit 20, and filtered, D / A converted, and amplified by the audio signal processing unit 20. Is performed and output as audio.

In order to control communication rationally in this type of optical communication apparatus, first, communication is performed at a minimum output level (at a required minimum level) within a range where no communication error occurs. Therefore, according to the present invention, an error signal is output to the CPU 13 when the synchronization for demodulating the PCM signal cannot be normally obtained by the PCM decoder 12, and the CPU 13 receiving the error signal outputs the error signal. , Encoder 14, driver 15,
An infrared control signal 19 is transmitted to the PCM audio transmitter 100 via the light emitting unit 16 to notify the transmitter 100 that a communication error has occurred.

Therefore, the CPU 4 of the transmitter 100 transmits the infrared communication signal 18 at the maximum output at the time of the initial setting, gradually lowers the transmission output level, and generates an error in the infrared control signal 19 from the receiver 200. Is notified, the output is slightly increased until an error occurs, and the infrared communication signal 18 is transmitted at the output, thereby performing optical communication at a minimum output level within a range where no communication error occurs. It should be noted that such a control may be configured to be mainly controlled on the transmitter side 100, or may be performed on the receiver side 20.
It is also possible to adopt a configuration in which control is mainly performed at 0.

The flowchart of FIG.
An operation step in the case where the infrared control signal 19 output from the transmitter 100 is a simple control signal for notifying that an error has occurred and the transmitter 100 performs main control will be described. That is, when the transmitter 100 and the receiver 200 are installed and each power is turned on, the CPU 4 of the transmitter 100 first controls the driver 3 to maximize the drive current, The control signal 19 is monitored (step 201). Then, while the infrared control signal 19 is not detected, the drive current is decreased by one step (steps 202 and 203), but when the infrared control signal 19 is detected, the CPU 4 returns to the state before the infrared control signal 19 is detected. The drive current is returned to the level, and the transmission of the infrared communication signal 18 is continued (step 204). Therefore, communication can be performed at the minimum output level within a range where no communication error occurs.

During communication, the transmitter 100 or the receiver 2
00 may move and the communication distance may fluctuate, or the reception level may fluctuate due to changes in the communication environment. Therefore, in the next step 205, the infrared control signal 19 is constantly monitored,
Infrared control signal 19 due to low reception level and communication error
Is detected, the process returns to step 204 to increase the drive current until a communication error does not occur. Conversely, when the reception level at the receiver 200 becomes high, the infrared control signal 19 is not transmitted and cannot be detected in this configuration, and the communication is continued at the high output level. Power is wasted. Therefore, in step 206, when a certain period has elapsed, the process returns to step 202 and checks whether there is no waste in the output level.

The above operation is an operation in the case where control is mainly performed on the transmitter side 100, but a configuration in which control is mainly performed on the receiver side 200 may be adopted. The flowchart in FIG. 3 shows an operation when main control is performed on the receiver side 200. That is, as shown in steps 301 and 302 in FIG. 3, the power of the transmitter 100 and the receiver 200 is first turned on, and the installation is adjusted so that analog audio can be normally received.
At this time, the drive current for driving the light emitting unit 2 of the transmitter 100 is set to the maximum value within a range that does not destroy the light emitting unit 2.

Next, when a reception state is set, step 303 is executed.
Thus, the PCM decoder 12 of the receiver 200
Based on the synchronization signal output indicating the normal reception status output to
Compared with the condition set in the CPU 13, if the synchronization signal cannot be confirmed, the process returns to step 301 and the transmitter 100 and the receiver 200 are reinstalled and adjusted. Monitor error frequency. The error frequency is digitized and displayed on the display unit 1.
7, and an infrared control signal 19 is transmitted from the CPU 13 as a drive current control signal via the encoder 14, the driver 15, and the light emitting unit 16. The drive current control signal reduces the drive current by a fixed amount of attenuation, and the control value is stored in the rewritable memory 21 at any time, and steps 305 and 306 are performed until an error occurs.
Is repeated.

When an error occurs, the operation of reducing the drive current with a fixed attenuation is stopped, the drive current control value before the error is generated is read from the memory 21, and the infrared control signal 19 is retransmitted from the light emitting unit 16. Put out.
If the operation is normal with the minimum drive current, step 3
At 07, peripheral circuits of the light emitting unit 16 of the receiver 200 are stopped,
An error signal monitoring state from the PCM decoder 12 is entered.
Unless an error signal is detected, this stop state is maintained, and the transmitter 100 enters a state of monitoring the infrared control signal 19 from the light emitting unit 16 as in step 308.
Then, when an error signal from the PCM decoder 12 is detected, the operation from step 304 is repeated. As described above, the optimal reception state is held with power saving.

FIG. 4 is a block diagram showing another embodiment of the present invention. 4, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and 22 denotes a CP in the transmitter 100a.
A motor for automatically adjusting the orientation of the light-emitting unit 2 and the light-receiving unit 7 based on the reception state information output from U4;
Reference numeral denotes a motor for automatically adjusting the directions of the light emitting unit 16 and the light receiving unit 9 based on the information on the reception state output from the CPU 13 in the receiver 200a. In this embodiment, the initial installation adjustment is simplified by providing a motor for automatic adjustment, and the transmitter 100a or the receiver 20
Even if 0a moves and the angle between the light emitting unit and the light receiving unit shifts, the angle is automatically adjusted to the optimum angle, so that it is possible to prevent unnecessary increase in transmission output.

In the above-described embodiment, the P
Although the CM audio transceiver has been described as an example, the present invention can be applied to an optical communication device in which a transmitter and a receiver are connected by an optical communication signal in general.
00, a communication error occurs when the PCM decoder 12 cannot properly synchronize data, but a communication error occurs when the reception level falls below a predetermined threshold. Needless to say, detection of a communication error is not limited to the method of the above-described embodiment. In the above-described embodiment, the notification that a communication error has occurred is configured to be notified from the receiver 200 to the transmitter 100 using an infrared control signal. For example, only this notification is performed by radio communication using radio waves. For example, another communication means may be used.

[0021]

As described above, the transmission output control method of the optical communication apparatus according to the present invention has a configuration in which the transmission output of the transmitter is remotely controlled by the optical control signal according to the reception level at the receiver. There is an effect that accurate and stable optical communication can always be performed with power saving, and unnecessary high-output transmission / reception can be eliminated to extend the product life.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of an operation according to the exemplary embodiment.

FIG. 3 is a flowchart showing another example of the operation of the embodiment.

FIG. 4 is a block diagram for explaining another embodiment of the present invention.

FIG. 5 is a block diagram showing an example of a conventional PCM audio transceiver using infrared rays.

[Explanation of symbols]

 2,16 light emitting unit 3,15 driver 4 CPU 5,11 decoder 6,10 receiver 7,9 light receiving unit 12 PCM decoder 13 CPU 14 encoder 17 display unit 20 audio signal processing unit 21 memory 22,23 motor 100 PCM audio transmitter 200 PCM audio receiver

Claims (8)

[Claims] 1. A transmission output control method for an optical communication device for connecting a transmitter and a receiver by an optical communication signal, wherein the transmission output control method is provided in the receiver and notifies the transmitter when a communication error occurs. Means provided in the transmitter, and means for reducing the transmission output level of the optical communication signal until receiving a notification from the receiver that a communication error has occurred from the receiver. The transmission output control method of the device. 2. The transmission output control method for an optical communication device according to claim 1, wherein, when the communication error occurs, a means for notifying the transmitter of the communication error includes: a light emitting unit provided in the receiver; A transmission output control method for an optical communication device, wherein the transmission output control method is performed by optical communication using a light control signal with a light emitting unit provided in a device. 3. The transmission output control method for an optical communication device according to claim 1, wherein the transmission output level of the optical communication signal is reduced until a notification that a communication error has occurred is received from the receiver. The transmission output of the optical communication signal is gradually reduced until a notification that a communication error has occurred is received from the receiver.If a notification that a communication error has occurred is received, the transmission output of the optical communication signal is reduced. Transmission output control method for an optical communication device, wherein the transmission output control method is performed to return to the high output side in one or more stages. 4. The transmission output control method for an optical communication device according to claim 2, wherein the optical control signal is a signal output from the receiver only when the communication error occurs. Transmission output control method for optical communication devices. 5. The transmission output control method for an optical communication device according to claim 1, wherein the optical communication is performed using infrared rays. method. 6. The transmission output control method for an optical communication device according to claim 1, wherein a PCM audio transmitter is used as the transmitter, and a PCM audio receiver is used as the receiver. A transmission output control method for an optical communication device, wherein: 7. The transmission output control method for an optical communication device according to claim 6, wherein said means for detecting a communication error can normally synchronize data with a PCM decoder built in said PCM audio receiver. A transmission output control method for an optical communication device, wherein the transmission output control method is a means for setting a communication error when the communication cannot be performed. 8. The transmission output control method for an optical communication device according to claim 1, wherein the transmitter and the receiver have their respective light-emitting units and light-receiving units until the reception state becomes optimal even with the same transmission output. A transmission output control method for an optical communication device, further comprising means for automatically adjusting an installation angle of the unit.