JPH07273726A - Transmission equipment and reception equipment - Google Patents

Abstract

PURPOSE:To realize communication based on a differential signal by two polarized optical signals. CONSTITUTION:In a transmission unit, the signal modulated by a parallel-serial conversion circuit 71 is supplied to driving elements 72 and 73. The signal supplied to the driving element 73 is modulated into the signal having the same phase as or the opposite phase of the signal supplied to the driving element 72 by a polarity inversion signal. Signals are supplied from driving elements 72 and 73 to LEDs 74 and 75 and are converted into optical signals and are transmitted to a reception unit as two optical signals of rightward or leftward circular polarized light by polarizing plates 76 and 77.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is, for example, an electronic notebook, C
The present invention relates to a transmitter and a receiver suitable for use in the technical field of personal information terminals such as DI.

[0002]

2. Description of the Related Art FIG. 13 shows a configuration example of a commonly used remote commander (remote controller) 1 and a video tape recorder (VTR) 11 controlled by the remote commander.

For example, when the reproduction button 2 of the remote controller 1 is pressed, the infrared LED (light emitting diode) 3 blinks in accordance with the pattern defined as the reproduction code, and the infrared remote controller signal is generated. On the other hand, VTR11
Detects the infrared rays by the photodiode 12, starts reproduction of a built-in video tape (not shown), and outputs the reproduction signal to the television receiver 13,
Display it.

[0004]

However, the conventional remote control system as described above has the following problems.

In order to avoid the influence (disturbance noise) of infrared sources other than the remote controller, such as sunlight, electric lights, and stoves, it is necessary to increase the light emission output of the infrared LED 3.

For the same reason, it is difficult to increase the blinking speed of the infrared LED 3.

Further, since the infrared LED 3 has already been adopted in various devices such as a television and an air conditioner, it is difficult to use it for a new purpose such as transferring image data. On the contrary, when it is used for transferring the image data, the remote control system of the existing device may malfunction.

The present invention has been made in view of such a situation, and uses an LED of relatively small power,
An object of the present invention is to provide a transmission device and a reception device capable of transmitting and receiving signals at high speed without being affected by disturbance and without causing other systems to malfunction.

[0009]

According to a first aspect of the present invention, there is provided a transmitting device which emits two lights with the same spectrum in accordance with a transmission signal (for example, LEDs 74 and 75 in FIG. 3).
And a polarizing means (for example, the polarizing plate 7 in FIG. 3) that polarizes the light from the light emitting means into two lights having different polarization modes.
6, 77) and modulation means (for example, drive elements 72, 73 in FIG. 3) that modulates the two lights emitted from the light emitting means so that the sum of the light emission intensities thereof is always constant. Characterize.

This polarizing means is a polarizing plate (for example, the polarizing plate 76 shown in FIG. 3) which converts two lights into circularly polarized lights which rotate in opposite directions.
77).

The modulating means can perform pulse modulation, AM modulation, FM modulation, QAM modulation, or PSK modulation on two lights.

When the transmission signal is an image signal, the modulating means modulates two lights so that the sum of the light emission intensities becomes constant, and when the transmission signal is a control signal, the two lights are modulated. , Can be modulated so that the sum of the light emission intensities changes.

According to a fifth aspect of the present invention, there is provided a receiving device that separates two lights having different polarization modes from the transmitted light (for example, the polarizing plates 91 and 92 in FIG. 7) and the separating device. Light receiving means (for example, the photodiodes 93 and 94 in FIG. 7) that receives the two separated lights and emits a received signal, and a calculating means that calculates the difference between the two received signals output by the light receiving means (for example, the figure 7 and the demodulation means for demodulating the output of this arithmetic means (for example, the serial-parallel conversion circuit 10 in FIG. 7).
0) and are included.

This calculating means can be composed of a comparator (for example, the comparator 97 in FIG. 7) which compares two received signals.

The calculating means may further include a comparing means (for example, the comparator 95 in FIG. 7) for comparing at least one of the two received signals with a predetermined reference voltage.

The comparing means compares the two received signals with a predetermined reference voltage (for example, comparators 95 and 96 in FIG. 7) and an AND circuit (for example, a logical product of outputs of the two comparators). 7A
ND circuit 98).

[0017]

In the transmitting device having the above structure, the transmission signal is
By the drive elements 72 and 73, signals of opposite phases are generated, and the LED
Two optical signals are emitted by 74 and 75. The two optical signals are converted into right-handed or left-handed circularly polarized light by the two polarizing plates 76 and 77 and transmitted.

In the receiving device having the above configuration, the two optical signals having different polarization modes are different from each other.
It is separated by two polarizing plates 91 and 92, and photoelectrically converted into received signals by photodiodes 93 and 94, respectively. The difference between the two received signals is calculated by the comparator 97 and sent to the serial-parallel conversion circuit 100 to be demodulated into received information.

Therefore, noise due to light in the natural world is suppressed, and high-speed communication with a small amount of electric power becomes possible. In addition, it is possible to suppress malfunction of existing equipment.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a transmitting device and a receiving device of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of an electronic album to which the transmitter and the receiver of the present invention are applied. The player 21 as a transmission device has operation buttons 22 such as a play button 22a, a stop button 22b, and a backward play button 22c.
By operating it, the magneto-optical disk 23 on which the image data is recorded can be accessed, and the recorded data can be reproduced, stopped, or reproduced in the reverse direction. Further, the transmission unit 24 provided in the player 21 converts the reproduction data from the magneto-optical disk 23 into an optical signal (infrared signal) and transmits it.

On the other hand, the VTR 31 as a receiving device has a receiving unit 32, which receives an optical signal from the player 21, demodulates it into a video signal, and outputs it from an output terminal 33. This image signal is input to the television receiver 41 from the input terminal 42 via the cable 51, and is displayed on the television screen.

Next, the operation of the embodiment of the electronic album shown in FIG. 1 will be described. When the reproduction button 22a of the player 21 is pressed, the recording data recorded on the magneto-optical disk 23 is reproduced and transmitted from the transmission unit 24 as an optical signal (infrared signal). The transmitted optical signal is received by the receiving unit 32 of the VTR 31,
It is restored to a video signal and output as a video signal from the output terminal 33. The output video signal is the cable 5
1 is input from the input terminal 42 to the television receiver 41 and is displayed on the television screen.

In the conventional VTR, it is necessary to mount a recording medium (video cassette) on the VTR main body, so the user needs to reciprocate between the seat to be watched and the VTR and operate both the remote controller and the VTR. In contrast to this, in this embodiment, it is possible to perform all operations at hand, including replacement of the disc as the recording medium.

FIG. 2 shows an example of the internal structure of the player 21. The keyboard 61 corresponds to the operation button 22 of the player 21, and the operation button 22a and the switch 62a, the operation button 22b and the switch 62b, and the operation button 22c and the switch 62c, respectively. One ends of the switches 62a to 62c are grounded, and the other ends thereof are grounded to a predetermined voltage source via the resistors 63a to 63c, respectively. When each switch is OFF, a high voltage is applied to the microcomputer 64 via each resistor, and when ON, a low voltage is applied. Microcomputer 64
Is the keyboard 61 at a constant cycle of, for example, about 50 ms.
Is scanned to detect the state of each switch, and each unit is controlled according to the detection result.

Under the control of the microcomputer 64, the disk drive 65 reads digital image data from the magneto-optical disk 23 and transfers it to the transmission unit 24. The transmission unit 24 converts the image data from the disk drive 65 and the control command from the microcomputer 64 into a serial signal typified by an asynchronous signal of an RS-232C interface, and turns on / off the light.
It is designed to be turned off and transmitted.

Next, the operation of the internal configuration example of the player 21 shown in FIG. 2 will be described. For example, player 21
When the operation button 22a of is pressed, the switch 62a is turned on.
The state becomes N. Then, the resistor 63a is grounded via the switch 62a, and a low voltage is applied to the microcomputer 64.
Since the operation buttons 22b and 22c of the player 21 are not pressed, the switches 62b and 62c are in the OFF state, and a high voltage is applied to the microcomputer 64 via the resistors 63b and 63c. The microcomputer 64 scans the keyboard 61 at a constant cycle of 50 ms, detects the voltage applied to the microcomputer 64, and in this case, detects that the switch 62a is ON.

Therefore, the microcomputer 64 uses the magneto-optical disk 2
3 controls the mounted disc drive 65 to read digital image data from the magneto-optical disc 23,
Transfer to the transmission unit 24. The transmission unit 24 sends the image data from the disk drive 65 to RS-232.
The signal is converted into a serial signal typified by a start-stop synchronization signal of the C interface, converted into ON / OFF of light, and transmitted.

On the other hand, when transmitting a predetermined control command, the microcomputer 64 sends the control command to the transmission unit 24.
Supply directly to. The transmission unit 24 converts this control command into an optical signal and outputs it.

FIG. 3 shows a configuration example of the transmission unit 24. The data input from the disk drive 65 is converted into a start-stop synchronous serial signal by the parallel-serial conversion circuit 71, and the drive element 72 and the drive element 73.
Is being supplied to. The drive signal A generated by the drive element 72 including an amplifier is sent to the LED 74,
74 is adapted to blink (ON / OFF) in accordance with the drive signal A and generate an optical signal. The polarizing plate 76 transmits only the right-handed circularly polarized light component of the optical signal and transmits it as the optical signal A.

On the other hand, the polarity inversion signal is input from the microcomputer 64 to the drive element 73 formed of an XOR (exclusive OR) circuit. When the polarity inversion signal is "0", the drive signal A is driven in the same phase. The signal B is output, and when it is "1", the opposite phase drive signal B is output. That is,
The drive element 73 operates so as to have an XOR (exclusive OR) characteristic. The drive signal B is sent to the LED 75, and the LED 75 blinks according to the drive signal B (ON /
It is turned off) and an optical signal is generated. The polarization plate 77 transmits only the left-handed circularly polarized light component of the optical signal and transmits it as the optical signal B.

Next, the operation of the transmission unit 24 shown in FIG. 3 will be described. The data output from the disk drive 65 is input to the parallel-serial conversion circuit 71, converted into a start-stop synchronization type serial signal, and then supplied to the drive element 72 and the drive element 73. The serial signal supplied to the driving element 72 is the driving signal A by the driving element 72.
And sent to the LED 74. The LED 74 blinks (ON / OFF) in accordance with the sent drive signal A and converts the drive signal A into an optical signal. Only the right-handed circularly polarized light component of the optical signal passes through the polarizing plate 76 and is transmitted as the optical signal A.

On the other hand, when transmitting the image data, the microcomputer 64 sets the polarity inversion signal to "1". Therefore, the polarity of the serial signal supplied to the drive element 73 is inverted by the drive element 73, and the drive signal B having the same phase as the drive signal A is generated.
Is sent to the LED 75. The LED 75 blinks (ON / OFF) according to the drive signal B sent, and converts the drive signal B into an optical signal. Of this optical signal, only the left-handed circularly polarized component passes through the polarizing plate 77 and is transmitted as an optical signal B.

FIG. 4 is a diagram showing an example of an optical signal when transmitting image data. FIG. 4A shows the optical signal A, and FIG. 4B shows the optical signal B. As is clear from these figures, the optical signal A is at a high level (when light is present) when it is "1" and at a low level (when there is no light) when it is "0". On the other hand, the optical signal B
Is set to a low level (a state where there is no light) when it is "1", and a high level (a state where there is light) when it is "0". Thus Figure 4c
As shown in, the intensity of the combined light is always constant.

On the other hand, when transmitting the control command (control signal), the polarity inversion signal is set to "0". Therefore, the drive signal B output from the drive element 73 becomes a signal in phase with the drive signal A output from the drive element 72.

FIG. 5 is a diagram showing an example of an optical signal when a control signal is transmitted. FIG. 5A shows the optical signal A, and FIG. 5B shows the optical signal B. As is clear from these figures, the optical signal A and the optical signal B are in-phase signals. Therefore, when the two are combined, the light intensity changes in accordance with the transmission signal, as shown in FIG.

FIG. 6 shows a partial configuration example of the VTR 31 shown in FIG. The receiving unit 32 is the player 21
The optical signal from the memory circuit 81 is received to demodulate and separate the image data and the control command.
And the control command to the control circuit 82. The control circuit 82 controls page switching of the memory circuit 81 and controls the power supply circuit 84 in response to the supplied control command to turn on / off the power supply.
Etc. are controlled. Memory circuit 81
Is controlled by the control circuit 82, outputs image data, and outputs the image data to the D / A conversion circuit 83. D / A conversion circuit 8
3 converts the sent image data into an analog signal and supplies it to the television receiver 41 via the output terminal 33.

Next, the operation of the embodiment shown in FIG. 6 will be described. An optical signal as a transmission signal transmitted from the transmission unit 24 of the player 21 is received by the reception unit 32, demodulated into image data and a control command, and separated. The separated image data is stored in the memory circuit 81.
The control command is supplied to the control circuit 82. In response to the supplied control command, the control circuit 82
Controls the page switching of the memory circuit 81, controls the power supply circuit 84, and controls ON / OFF of the power supply. The memory circuit 81 stores the supplied image data under the control of the control circuit 82 and sends the stored data to the D / A conversion circuit 83 at a predetermined timing. The image data sent to the D / A conversion circuit 83 is converted to an analog signal and then sent to the television receiver 41 via the output terminal 33.

FIG. 7 shows a configuration example of the receiving unit 32. The polarizing plate 91 transmits only the clockwise circularly polarized component of the incident optical signal, and the polarizing plate 92 transmits only the counterclockwise circularly polarized component. That is, of the optical signals transmitted by the player 21, only the optical signal A passes through the polarizing plate 91 and the photodiode 93
Is converted into a received signal A by. Further, only the optical signal B passes through the polarizing plate 92 and is converted into the received signal B by the photodiode 94.

The comparator 95 compares the received signal A with a predetermined reference voltage E which has been set in advance. When the received signal A is higher than the reference voltage E, it outputs "1", or otherwise. By outputting "0", the serial signal A is output. The comparator 96 compares the received signal B with the reference voltage E, outputs "1" when the received signal B is higher than the reference voltage E, and otherwise.
By outputting "0", the serial signal B is output.

The AND circuit 98 includes comparators 95 and 9
The logical product of the serial signals A and B output from 6 is calculated, and the control serial signal is output.
The serial-parallel conversion circuit 99 converts this control serial signal into parallel command data and outputs it as a control command to the control circuit 82.

On the other hand, the comparator 97 compares the received signals A and B output by the photodiodes 93 and 94, and outputs "1" when the signal A is larger than the signal B, and otherwise outputs "0". By doing so, the serial signal C is output. The serial-parallel conversion circuit 100 converts the serial signal C into parallel data and outputs it as image data to the memory circuit 81.

Next, the operation of the receiving unit 32 shown in FIG. 7 will be described. Of the optical signals A and B transmitted by the player 21, only the optical signal A having only the right-handed circularly polarized light component passes through the polarizing plate 91, is converted into the received signal A by the photodiode 93, and is rotated leftward. Only the optical signal B having only the circularly polarized light component of is transmitted through the polarizing plate 92 and converted into the received signal B by the photodiode 94. The received signal A is supplied to the comparator 95 and the comparator 97. The received signal B is also supplied to the comparator 96 and the comparator 97.

The reception signals A and B supplied from the photodiodes 93 and 94 to the comparator 97 are compared by the comparator 97. The comparator 97 outputs the signal A
Is "1" when is larger than signal B, otherwise "1"
0 "is output. As described above with reference to FIGS. 4 and 5, in the case of image data, the optical signals A and B are in opposite phases, and in the case of a control command, the optical signals are in phase. When a control command is received, both inputs of the comparator 97 are at the same level, so that the output is always “0.” On the other hand, when image data is received, “1”.
At this time, the output of the photodiode 93 becomes larger than the output of the photodiode 94, so the output of the comparator 97 becomes "1". Further, when it is "0", the output of the photodiode 93 is smaller than the output of the photodiode 94, so that the output of the comparator 97 is "0". That is, the comparator 97 detects and outputs only the image data.

The photodiodes 93 and 94 are provided with
A disturbance (noise) component is also incident, but since this component is an in-phase component, it is canceled by the comparator 97.

On the other hand, in the comparator 95, the received signal A is compared with the preset reference voltage E.
The comparator 95 outputs "1" when the received signal A is larger than the reference voltage E, and outputs "0" otherwise. On the other hand, in the comparator 96, the reception signal B is compared with the preset reference voltage E. Comparator 9
6 is "when the received signal B is larger than the reference voltage E"
1 ", otherwise" 0 "is output.

The serial signals output from the comparators 95 and 96 are supplied to the AND circuit 98. When the received image data is image data, the reception signals of opposite phases are input to the comparators 95 and 96, so that the output is "0" when one is "1". On the contrary,
When the control command is received, the comparator 9
Since in-phase received signals are input to 5 and 96, the output becomes "1" when one is "1", and the output becomes "0" when one is "0". Therefore, AND
The output of the circuit 98 is "1" or "0". That is, the AND circuit 98 detects and outputs only the control command.

In the above embodiment, the control command is transmitted / received by the in-phase optical signals A and B.
Similar to the image data, it is also possible to transmit and receive as a reverse phase signal.

For example, a VT that is commonly used now
It is assumed that R has a format system as shown in FIG. In this format system, the command "P" meaning PLAY is playback, "R" meaning RECORD is recording, "S" meaning STOP is stop, and "F" meaning FORWARD is fast-forwarding. BA
"B", which means CK, represents rewinding.

In such a state, the electronic album format system as shown in FIG. 9 is configured. In this format system, the command "P" meaning PRINT means print and NEXT means "
N "means the reproduction of the next image, BEFORE"
“B” represents reproduction of the previous image, and “S” meaning SHOT represents shooting.

VTR having the format system shown in FIG.
And an electronic album having the format system shown in FIG. 9 together, for example, if a command “P” is transmitted from the transmitting device in an attempt to reproduce a VTR, the electronic album also receives the command “P”, The printing operation corresponding to the command "P" is completed for the first time. Also, for example, VT
When trying to shoot the image being played on R with an electronic album,
When the command “S” is transmitted from the transmitter, the VTR also receives the command “S” and the stop operation corresponding to the command “S” is performed, so that the VTR stops and the electronic album shooting fails. .

Therefore, in such a case, the electronic album having the format system shown in FIG. 9 is assembled with the transmitting device and the receiving device having the above-mentioned configuration, and the control command is transmitted / received by the optical signal of the opposite phase. Since the light receiving unit of the VTR cannot detect the polarized optical signal, it can only recognize the control command from the transmitting unit of the electronic album as continuous light. On the other hand, the light receiving unit of the electronic album of this embodiment rejects the polarized light of the same intensity, and therefore does not recognize the command issued by the VTR transmitting unit. Therefore, the VTR and the electronic album can be used without malfunctioning each other.

In the above description, the optical signal is pulse-modulated for the sake of simplicity. However, by continuously changing the light intensity, a configuration such as AM modulation, FM modulation, PSK modulation, QAM modulation or the like is possible. It is also possible to build a new format system. In this case, the comparators 95 and 96 and the AND circuit 99 in FIG. 7 can be configured by an addition circuit, and the comparator 97 can be configured by a subtraction circuit.

FIG. 10 is a diagram showing an example of a waveform of an AM-modulated transmission signal. In this case, the information is transmitted by expressing the magnitude of the amplitude of the transmitted signal, and the receiving unit obtains the received information by reading the magnitude of the amplitude.

FIG. 11 is a diagram showing an example of the waveform of the FM-modulated transmission signal. In this case, the information is transmitted represented by the change in frequency of the transmitted signal and the receiving unit is
The reception information is obtained by reading the change in the frequency.

FIG. 12 is a diagram showing an example of a signal point arrangement for QAM modulation. QAM modulation is a method of transmitting information in correspondence with predetermined signal points. The receiving unit will obtain the received information by reading the position of the signal point.

[0057]

As described above, according to the transmitting device and the receiving device of the present invention, since it is possible to perform communication by the differential signal by the polarized optical signal, the following effects can be obtained. (1) The influence of extraneous noise can be reduced, and an LED with a small power can be used. (2) The influence of external noise can be reduced, and the communication speed can be improved by multilevel modulation or the like.

Since the sum of the intensities of the two lights is always constant, the following effects can be obtained. (3) It does not affect the AM and FM of other lights. (4) It does not cause a malfunction with respect to the conventional remote control device. (5) Independent of the command system of the conventional remote control device,
It is possible to create a new command system and expand the application field of optical communication.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of an electronic album to which a transmitter and a receiver of the present invention are applied.

FIG. 2 is a diagram showing an example of an internal configuration of a player 21 in FIG.

3 is a diagram showing a configuration of a transmission unit 24 in FIG.

FIG. 4 is a diagram showing an example of a pulse-modulated transmission signal of start-stop synchronization when transmitting image data.

FIG. 5 is a diagram showing an example of a pulse-modulated transmission signal of start-stop synchronization when transmitting a control signal.

6 is a diagram showing a partial configuration of the VTR shown in FIG.

7 is a diagram showing a configuration of a receiving unit 32 shown in FIGS. 1 and 6. FIG.

FIG. 8 is a diagram showing an example of a format system of a commonly used VTR.

FIG. 9 is a diagram showing an example of a format system of an electronic album.

FIG. 10 is a diagram showing an example of a waveform of an AM-modulated transmission signal.

FIG. 11 is a diagram showing an example of a waveform of an FM-modulated transmission signal.

FIG. 12 is a diagram showing the principle of QAM modulation.

FIG. 13 is a diagram showing a configuration example of a conventional remote commander (remote control) and a video tape recorder controlled by the remote commander.

[Explanation of reference numerals] 72,73 Drive element (modulating means) 74,75 LED (light emitting means) 76,77,91,92 Polarizing plate (polarizing means) 93,94 Photodiode (light receiving means) 95,96,97 Comparator (Calculation means) 99,100 Serial-parallel conversion circuit (demodulation means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical indication H04B 10/152 10/142 10/04 10/06

Claims (8)

[Claims] 1. According to a transmitted signal, 2 with the same spectrum
A light emitting means for emitting two lights, a polarizing means for polarizing the light emitted by the light emitting means into two lights having different polarization modes, and two light emitted by the light emitting means A transmission device comprising: a modulation unit that modulates the sum so that the sum is always constant. 2. The transmission device according to claim 1, wherein the polarization means has a polarizing plate that makes the two lights circularly polarized in opposite directions. 3. The modulation means converts the two lights into pulse modulation, AM modulation, FM modulation, QAM modulation, or PS.
The transmitter according to claim 1 or 2, wherein the transmitter performs K modulation. 4. The transmission signal is an image signal and a control signal, and the modulating means, when the transmission signal is an image signal,
Modulating the two lights so that the sum of their emission intensities is constant, and modulating the two lights so that the sum of their emission intensities changes when the transmission signal is a control signal. The transmitter according to claim 1, 2 or 3, which is characterized in that. 5. Separation means for separating two lights of different polarization modes from the transmitted light, and light receiving means for respectively receiving the two lights separated by the separation means and emitting a reception signal, A receiving device comprising: a calculating means for calculating a difference between two received signals output by the light receiving means; and a demodulating means for demodulating an output of the calculating means. 6. The receiving apparatus according to claim 5, wherein the arithmetic means has a comparator that compares the two received signals. 7. The reception device according to claim 5, wherein the calculation means further comprises a comparison means for comparing at least one of the two reception signals with a predetermined reference voltage. apparatus. 8. The comparison means calculates a logical product of a comparator that compares each of the two received signals with the reference voltage and an output of the two comparators.
The receiving device according to claim 7, further comprising a D circuit.