JPH07231301A - Optical transmitter - Google Patents

Abstract

PURPOSE:To enable stable duplex communication by driving a universal head for changing the directivity of a light transmitting part and a' light receiving part based on signals in a storage part. CONSTITUTION:While moving an optical interface in a direction, before and after moving, the levels of a position adjusting signal transmitted from a light emitting part 1 as an optical signal are compared, and data in a memory 21 are updated so that the angle data of the optical interface to maximize the reception level and the reception level at a light receiving part 2 at that time can be finally stored in the memory 21. When the data in the memory 21 are not updated any more, a CPU 22 finishes the angle adjustment in this direction, fetches the angle data in the memory 21 and controls a universal head driving circuit 25 so that the optical interface can be moved at this angle. Then, while moving the optical interface at a certain fixed angle in the reverse direction this time, the reception level of the position adjusting signal is similarly measured; the angle of the optical interface to maximize the reception level is decided; and the position adjustment of the optical interface is finished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical transmission device which is used indoors to mutually transmit video / audio data and the like.

[0002]

2. Description of the Related Art A conventional optical transmission device is miniaturized and can be freely carried with a digitizer. Therefore, it may be used as a terminal device for conference attendees to operate a video conference system, for example.

[0003]

Since this conventional optical transmission device is excellent in portability, the usage pattern is left to the user. Therefore, depending on the installation angle of the optical transmission device, mutual optical signals may not be received well, and stable bidirectional communication may not be performed.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide an optical transmission device capable of performing stable bidirectional communication.

[0005]

In order to combine the above objects, in an optical transmission apparatus according to the present invention, a modulation circuit that is connected to an input terminal for inputting a transmission signal and modulates the signal, and a pan head. A light emitting unit that is mounted on the light emitting unit and emits an optical signal by connecting to the modulation circuit; a light receiving unit that is mounted on the platform and receives an optical signal; and an amplifying unit that amplifies a received signal from the light receiving unit, In a spatial light transmission device that has a demodulation unit that is connected to the amplification unit and demodulates a signal, and an output terminal that outputs an output signal from the demodulation unit, and that transmits and receives information bidirectionally, the amplification unit amplifies the signal. Bandpass filter that passes only a predetermined frequency band of the generated signal, an amplitude detection circuit that detects the amplitude level of the output signal of the bandpass filter, and the output signal of the amplitude detection circuit is converted to a digital signal. A / D
A conversion circuit, a storage unit that is connected to a signal output unit that outputs the digital signal and stores an amplitude level, and selectively selects an output signal from the signal output unit and an input signal from the input terminal. And a drive unit for driving the camera platform to change the directivity directions of the light emitting unit and the light receiving unit based on the signal from the storage unit. .

[0006]

The optical transmission device having the above-mentioned configuration measures the reception level of the reception signal, stores this level and the position of the platform at this time in the storage unit, and moves in the direction of the light emitting unit and the light receiving unit. The detection level of the optical signal from another device is detected, the current reception level is compared with the reception level stored in the storage unit, and if the value is large, the pan head position and the reception level of the storage unit are rewritten. The platform is moved to move the light emitting unit and the light receiving unit to the positions finally stored in the storage unit.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. FIG. 1 is a side view of a camera platform according to this embodiment.
In the optical interface 3 that integrates the
The openings of the light emitting section 1 and the light receiving section 2 are provided in the same direction. The optical interface 3 is mounted on a platform 6 having a vertical motor 4 and a horizontal motor 5,
With these motors 4 and 5, vertically and horizontally,
The pointing direction can be changed.

FIG. 2 is a block circuit configuration diagram of the present embodiment, in which an input terminal 7 for inputting information is sequentially provided to a gate circuit 8, a modulation circuit 9, and a drive circuit 10 for driving the light emitting section 1 shown in FIG. The signals that are connected and obtained by the light receiving unit 2 shown in FIG. 1 are sequentially connected to the amplifier circuit 11, the band pass filter 12 that extracts only the modulated signal from the received signal, the demodulation circuit 13, the gate circuit 14, and the output terminal 15. Has been done. Further, the other output branched from the amplifier circuit 11 is a band pass filter 16 that passes only a predetermined frequency band for position adjustment, a smoothing circuit 17 that removes noise in the signal, and a signal of the signal. Amplitude detection circuit 18 for detecting the amplitude level, A / D conversion circuit 1 for converting the signal into a digital signal
9. The data processing unit 20 is sequentially connected.

The data processing unit 20 includes a memory 21, an input end of the gate circuit 8, an output end of the demodulation circuit 13 and a CPU.
It is also connected to the input / output terminals of 22. The CPU 22 has
A position adjustment start switch 23, a platform angle detection circuit 24 for detecting the direction of the optical interface 3, a vertical motor 4 of the platform 6, and a platform driving circuit 25 for driving the horizontal motor 5 are connected. Further, the output of the CPU 22 is branched and connected to the gate circuit 8 and the gate circuit 14, respectively, to switch the input direction of the gate circuit 8 and the opening / closing of the output of the gate circuit 14.

At the time of communication, the gate circuit 8 takes in the signal from the input terminal 7, and the gate circuit 14 outputs the signal to the output terminal 15. During transmission, information is input from the input terminal 7, modulated by the modulation circuit 9 via the gate circuit 8, and input to the drive circuit 10. The drive circuit 10 amplifies the modulation signal and then drives the light emitting unit 1 according to this signal,
The oscillation light of the light emitting unit 1 is converted into an optical signal and sent to the space.
Further, at the time of reception, the optical signal is received by the light receiving unit 2, converted into an electric signal, amplified by the amplifier circuit 11, passed through the band pass filter 12, demodulated by the demodulation circuit 13, and demodulated by the gate circuit 14 and then output terminal 15. Taken from.

The position of the platform 6 is adjusted before starting this communication. In the present embodiment, when the position adjustment start switch 23 is input by either one of the devices that perform communication, the counterpart device also adjusts the position in response to the input. For example, two devices A and B having the same configuration
When the position adjustment start switch 23 is input in the device A in the case of performing communication by means of, the CPU 22 outputs a gate switching signal to the gate circuits 8 and 14, and switches the input of the gate circuit 8 to the data processing section 20 side. Gate circuit 14
The output from is muted, and the control signal is output to the data processing unit 20 together with the identification signal IA of the local station. Data processing unit 20
On the basis of this control signal, the position adjustment signal SA of a predetermined frequency is added to the identification signal IA of the own station, and the gate circuit 8
To the modulation circuit 9. The modulation circuit 9 modulates the input signal and then inputs it to the drive circuit 10. The drive circuit 10 amplifies the input signal and drives the light emitting unit 1 according to the input signal to modulate the oscillation light of the light emitting unit into an optical signal.

The transmitted optical signal comprises an identification signal IA of the apparatus A and a position adjustment signal SA. The position adjustment signal SA is the angle data and amplitude detection of the optical interface 3 detected by the platform angle detection circuit 24. It is composed of reception level data of the light receiving section 3 detected by the circuit 18.

In the device B, the identification signal IA and the position adjustment signal SA are received by the light receiving section 2 and amplified by the amplifier circuit 11. Among them, the identification signal IA passes only the band pass filter 12, and the position adjustment signal SA passes only the band pass filter 16. Identification signal IA passed through the band pass filter 12
Is input to the gate circuit 14 and the data processing unit 20 after being demodulated by the demodulation circuit 13. On the other hand, position adjustment signal SA
Is input to the smoothing circuit 17 through the band pass filter 16.

The smoothing circuit 17 removes whiskers and the like from the input signal so that it will not react to the same signal as the position adjustment signal SA even during normal communication. The amplitude detection circuit 18 detects the amplitude from the smoothing circuit 17 and outputs an analog signal having a voltage level corresponding to the magnitude of the amplitude to the A / D conversion circuit 19. The A / D conversion circuit 19 converts the input signal into a digital signal and outputs the digital signal to the data processing unit 20.
The data processing unit 20 processes the input signal to obtain the reception level data, and when it detects that the reception level data exceeds a certain value, C
A detection signal is output to PU22. As a result, the CPU2
2 detects that any device has started position adjustment,
The data processing unit 2 that takes in the signal from the platform angle detection circuit 24
Output to 0.

In the data processing section 20, this input signal is processed into angle data of the optical interface 3 and written in the memory 21 together with the reception level data at this time. Further, the CPU 22 switches the input of the gate circuit 8 to the data processing unit 20 side. In the data processing unit 20, the identification signal IA of the device A is fetched from the demodulation circuit 13, the optical transmission device which has started the position adjustment is collated, and the result is output to the CPU 22. CPU 22 is own device B
The control signal is input to the data processing unit 20 together with the identification signal IB. The data processing unit 20 adds the position adjustment signal SB having a predetermined frequency to the identification signal IB, and transmits it as an optical signal from the light emitting unit 1.

When the optical signal is received by the device A, the position adjustment signal SB is detected by the data processing section 20 via the band pass filter 16 and processed as reception level data. The CPU 22 fetches the identification signal IB from the demodulation circuit 13 to check the device of the transmission partner, and fetches the signal of the platform angle detection circuit 24 to output it to the data processing unit 20. In the data processing unit 20, this input signal is processed as angle data of the optical interface 3 and written in the memory 21 together with the reception level data at this time. Furthermore, C
The PU 22 controls the camera platform drive circuit 25 to drive the camera platform 6 to move the optical interface 3 in the same directivity direction at a certain angle.

A position adjustment signal from the device B is generated for each movement.
The SB reception level is measured, the CPU 22 compares the current reception level data with the reception level data stored in the memory 21, and if the newly received reception level is higher, the camera platform angle detection circuit 24 Of the angle data, and rewrites the data in the memory 21 with the current angle data and the reception level data. If the newly received reception level is smaller, the data in the memory 21 is not rewritten. That is, the optical interface 3
Positioning signal SB before and after moving while moving
The level data of the optical interface 3 that maximizes the reception level and the reception level at that time are stored in the memory 21 by comparing the levels of the above and updating the data of the memory 21. become.

When the data in the memory 21 is no longer updated, the CPU 22 finishes the angle adjustment in this direction, fetches the angle data in the memory 21, and moves the optical platform 3 to this angle to move the platform driving circuit 25. To control.
Then, this time, while moving the optical interface 3 in the opposite direction at a certain angle, the reception level of the position adjustment signal is similarly measured, and the angle of the optical interface 3 at which the reception level becomes maximum is determined. The position adjustment of the optical interface 3 is completed.

In the device A, when the adjustment of the direction of the optical interface 3 is completed, the CPU 22 sends a control signal to the data processing section 20 in order to output a signal to that effect. Upon receiving the control signal, the data processing unit 21 outputs a position adjustment end signal to the modulation circuit 9 via the gate circuit 8. This signal is modulated by the modulation circuit 9 and then the driving circuit l
The signal is amplified by 0 and is emitted from the light emitting unit 1 as an optical signal.

In the device B, when the position adjustment end signal is received by the light receiving section 2, it is input to the CPU 22 via the band pass filter 16 and the data processing section 20. Upon detecting the position adjustment end signal, the CPU 22 starts the position adjustment of the optical interface 3 in the same process as the device A. actually,
Since a series of position adjustment routines are alternately performed a plurality of times by the devices A and B for accuracy, it is possible to adjust the optical interface 3 to the optimum position for two-way communication. When bidirectional communication becomes possible in the devices A and B, the CPU 22 of both devices A and B outputs a gate switching signal to the gate circuits 8 and 14 to switch the input of the gate circuit 8 to the input terminal 7 side, and also to the gate circuit. 14 to output terminal 15
Output and set to communication status.

For example, when the present embodiment is applied to a video conference system or the like, position adjustment is performed after detecting from which direction a signal is sent when the power of the terminal side is turned on. It may be started.

In the above-described embodiment, the position of the optical interface 3 is adjusted so that the reception level of the own device is maximized. On the contrary, the position of the own device is maximized so that the reception level of the other device is maximized. You can also move. In this case,
First, for example, the optical signal is transmitted from the device A. The device B receives the optical signal, measures the reception level, and transmits the value to the device A as reception level data. In the device A, this reception level data is received by the light receiving unit 2,
Demodulation circuit 1 through amplifier circuit 11 and band pass filter 12
3 is demodulated and output to the data processing unit 20 to be stored in the memory 2
1 and is further output to the CPU 22. CPU2
Reference numeral 2 drives the platform driving circuit 25 to change the directivity direction of the optical interface 3 by a certain angle.

Again, the CPU 22 takes in the reception level data from the device B, compares it with the data stored in the memory 21 and judges the increase or decrease of the reception level after the position adjustment, and if it increases, it is the same in the same direction. The optical interface 3 is rotated by an angle, and if decreased, the optical interface 3 is moved in the opposite direction. If the reception level decreases in any of the pointing directions, the increase or decrease in the reception level is monitored while decreasing the movement angle amount. When the amount of movement angle becomes a certain value or less, the position adjustment is finished and the device B
A position adjustment end signal is transmitted to. When the device B receives this signal, the position adjustment is started. in this way,
By performing the position adjustment by the devices A and B, the devices A and B can be opposed to each other in the optimum pointing direction.

[0024]

As described above, in the optical transmission device according to the present invention, in order to adjust the directions of the light emitting portion and the light receiving portion,
By detecting the received signal level of the optical signal of a predetermined frequency and moving the light emitting unit and the light receiving unit so that the received level is maximized, even a small portable device,
Since the light emitting unit and the light receiving unit can be moved to a communicable position by a simple operation, stable communication becomes possible.

[Brief description of drawings]

FIG. 1 is a side view of an optical communication device.

FIG. 2 is a block circuit configuration diagram.

[Explanation of symbols]

 l Light emitting part 2 Light receiving part 3 Optical interface 6 Pan head 8, 14 Gate circuit 12, 16 Band pass filter 13 Demodulation circuit 18 Amplitude detection circuit 20 Data processing part 21 Memory 22 CPU 23 Position adjustment start switch 24 Pan head angle detection circuit 25 Platform drive circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H04B 10/14 10/06 10/04

Claims (4)

[Claims] 1. A modulation circuit connected to an input terminal for inputting a transmission signal to modulate a signal, a light emitting unit mounted on a platform and connected to the modulation circuit to emit an optical signal, and mounted on the platform. A receiver for receiving an optical signal, an amplifier for amplifying a received signal from the receiver, a demodulator for connecting to the amplifier for demodulating a signal, and an output signal from the demodulator And a band pass filter for passing only a predetermined frequency band of the signal amplified by the amplifying unit, in the spatial light transmission device for bidirectionally transmitting and receiving information. The amplitude detection circuit for detecting the amplitude level of the output signal, the A / D conversion circuit for converting the output signal of the amplitude detection circuit into a digital signal, and the signal output section for outputting the digital signal are connected to each other to change the amplitude level. Storage unit to store and output of the signal A switching unit that selectively outputs an output signal from the input unit and an input signal from the input terminal to the modulation circuit, and directing directions of the light emitting unit and the light receiving unit based on the signal of the storage unit. And a drive unit for driving the platform to change the optical transmission device. 2. The optical transmission device according to claim 1, further comprising a position detection circuit that detects the position of the platform. 3. The optical transmission device according to claim 1, further comprising a signal generation circuit that generates an identification signal for identifying the device. 4. The optical transmission device according to claim 1, further comprising a signal generation circuit that generates the amplitude level detected by the amplitude detection circuit as a reception level signal.