JPH07297788A - Optical radio data transmission system and optical radio data transmitter-receiver - Google Patents

Abstract

PURPOSE:To provide an optical radio data transmission system which has simple circuit constitution and is robust against impairment by the illuminating light. CONSTITUTION:The light receiving means of a HUB-side transmitter-receiver 15 is arranged preferably above the transmitter-receiver 15, and the light emitting means is arranged preferably under the transmitter-receiver 15. With respect to the light receiving means, a semicylindrical cylindrical lens 19 is provided on the light reception face of a light receiving substrate 18 long in the horizontal direction. With respect to the light emitting means, three LEDs 20 are arranged in the horizontal direction, and semicylindrical lenses 21 are provided on their light emitting faces. Filters 22 and 23 are provided in front of the cylindrical lens 19, and the light emitting means and the light receiving means are completely isolated from each other by a partition 24 to optically separate these means from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless data transmission system for wirelessly transmitting data between a plurality of transceivers, and more particularly to a portable information processing terminal device such as a personal computer (PC) and a LAN. The present invention relates to an optical wireless data transmission system suitable for optically transmitting data to and from a wired network.

[0002]

2. Description of the Related Art Conventionally, information processing terminal devices such as a plurality of personal computers (hereinafter referred to as personal computers or PCs) are mutually connected to form a LAN (Local Area Network).
When building rk), PCs were connected to each other by wire such as coaxial cable or optical cable. Wired connection is mechanically and securely connected, so it is advantageous in that there are few data errors due to external noise, but the cost of wiring work is high, and there is also the problem that construction is required every time the layout is changed. .

In recent years, laptop computers, book computers, palmtop computers, and further,
There is also an increasing demand for data transmission by connecting portable information processing terminal devices such as electronic notebooks, but since these devices were originally intended for mobile use, they should be connected by wire. It is extremely rare to use it as it is. For this reason, there are many restrictions, such as mechanical damage to the connection part due to the insertion and removal of the connector and troublesome connection work. Therefore, there is a demand for making all or part of the transmission path wireless so as to easily connect the personal computer.

As a means for wireless transmission, there are a method using radio waves as a medium and a method using light as a medium. In the case of performing high-speed data transmission, wireless transmission using light, which is not legally regulated, is advantageous. is there. Moreover, since the Ethernet LAN, which is the most popular wired LAN, has a transmission rate of 10 Mbps, it is desirable that the wireless transmission line has a transmission rate of 10 Mbps. Furthermore, the wireless transmission line can completely replace the wired transmission line. In order to realize the above, it is essential to use a completely bidirectional communication path.

In this optical wireless transmission, it is necessary to prevent the interference by the illumination light. Inverter-type fluorescent lamps used in recent years emit noise up to around 1 MHz, so it is desirable to set the transmission band to several MHz or more. Therefore, when performing data transmission, it is not appropriate to directly transmit the baseband signal with optical intensity modulation, and the FSK, PSK,
A method of performing light intensity modulation with a broadband signal obtained by converting the transmission band into a high frequency band by ASK modulation has been performed.

[0006]

The optical wireless transmission by broadband transmission requires a modulation / demodulation means, so that the circuit scale is large and the cost is high. In addition, since it is necessary to recover the data clock from the data signal in order to perform correct decoding on the receiving side, the HDL
It was necessary to process the data into packets in the form of C (High-level Data Link Control), etc., resulting in a more complicated circuit.

Therefore, an object of the present invention is to provide an optical wireless data transmission system which has a simple circuit configuration and is resistant to interference by illumination light. Furthermore, a portable information processing terminal device such as a book type personal computer is used for a desk. Provide a transceiver suitable for use in the free position above.

[0008]

As means for achieving the above object, in an optical wireless data transmission system for performing bidirectional data communication by an optical signal between a first transceiver and a second transceiver, Optically separating the light emitting means and the light receiving means of the first transceiver from each other and optically separating the light emitting means and the light receiving means of the second transceiver to reproduce a clock signal from the signal itself. An optical wireless data transmission system characterized in that bidirectional data transmission is performed between the first transceiver and the second transceiver by an optical signal intensity-modulated with a bi-phase code signal Is to provide.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical wireless data transmission system of the present invention will be described below with reference to the drawings with reference to some embodiments. In the optical wireless data transmission system of the present invention, the light emitting means and the light receiving means of the first transceiver are optically separated, and the light emitting means and the light receiving means of the second transceiver are optically separated to obtain a signal. Bidirectional data between the first transceiver and the second transceiver by an optical signal obtained by intensity-modulating a baseband signal with a bi-phase code signal capable of reproducing a clock signal from itself. It enables transmission at the same time.

The Ethernet LAN uses Manchester code which is a kind of bi-phase code as a signal form. Also, in data transmission by optical wireless communication, by using this Manchester code, complete clock recovery is possible on the receiving side, and reliable decoding can be performed.

Now, the Manchester code signal will be described with reference to FIGS. 1A to 1C are graphs showing the relationship between a clock signal, an NRZ (Non Return-to Zero) signal, and a Manchester code signal, respectively. FIG. 1A shows the case where the code 0 continues. (B) shows the case where the code 1 continues, and (C) shows the case of an arbitrary code string.

As can be seen from FIGS. 1A and 1B, N
The RZ signal is followed by a signal of the same level when followed by the same sign, from which a clock signal cannot be generated.
Further, when the transmitting side and the receiving side are separate devices, it is difficult to match the clock signals generated by the respective devices, and therefore accurate decoding cannot be performed and a signal reading error may occur. is there. However, since the Manchester code signal is always displaced at the rising edge of the clock, the clock signal can be generated from this displacement point, and accurate synchronization can be achieved even if the transmitting side and the receiving side are separate devices. It can be taken and decrypted. As can be seen from FIG. 6C, the Manchester code signal has the same level only for a period of ½ clock or 1 clock, so that signal disturbance due to noise or the like can be easily detected. it can.

Further, the encoding / decoding of the Manchester code signal can be easily realized by an exclusive-OR (EX-OR) circuit as shown in FIGS. 2 (A) and 2 (B). it can. Here, FIG. 1A is a diagram showing an encoding circuit, and a Manchester code signal is obtained by inputting a clock signal and an NRZ signal to the EX-OR circuit 1. Further, FIG. 3B is a diagram showing a decoding circuit.
In the figure, a clock reproduction circuit 2 is a circuit for generating a clock signal in which the displacement point of the Manchester code signal rises, and the clock signal generated by this clock reproduction circuit 2 and the Manchester code signal are EX-ORed.
By inputting to the circuit 1, the NRZ signal can be decoded.

Here, N when transmitting at 10 Mbps
FIG. 3 shows the relationship between the transmission band and the signal level of the RZ signal and the Manchester code signal. Since the Manchester coded signal has a frequency band twice as large as that of the baseband signal (NRZ signal), its transmission also requires a band twice as large.
However, since the signal level in the low frequency part of the frequency is falling, even if the part with the low signal level is deleted during transmission, it does not cause a significant deterioration in the transmission performance.
Even if the signal in the frequency band up to around 1 MHz is deleted by the filter, the effect on the transmitted signal is small.

Therefore, when the intensity of light is modulated by the Manchester code signal and wireless transmission is performed, even if noise of a frequency of about 1 MHz flows in from an inverter type fluorescent lamp or the like, a signal in a frequency band of about 1 MHz or less. Is eliminated by the high-pass filter, the interference component due to the illumination light can be suppressed to a level at which there is no problem, and good transmission can be performed.

When the Manchester code signal is used as the transmission signal and the light is directly intensity-modulated, the transmitting side simply performs EO conversion (conversion from electric signal to optical signal) of the Manchester code signal flowing through the Ethernet cable. The transmission side terminal can be realized with an extremely simple configuration. Also, on the receiving side, the data can be transmitted on the Ethernet by simply converting the received light into OE (converting the optical signal into an electrical signal) and converting the signal voltage to the TTL level. The terminal can also be configured very simply.

Here, FIG. 4 shows a configuration example of the transmission side terminal and the reception side terminal. The data signal supplied as a Manchester code signal from the Ethernet to the transmission side terminal is supplied to the receiver 4 via the transformer 3, and the control signal is output from this to the LED driver 5. LED driver 5
The data signal is wirelessly transmitted as an optical signal by intensity-modulating the current flowing through the LED (light emitting diode) 6 based on the control signal.

In the receiving side terminal, the optical signal transmitted from the transmitting side terminal is received by the pin photodiode 7 to which a bias voltage is applied, converted into an electric signal, and a DC component is removed by a capacitor, and then an amplifier circuit ( The signal is amplified by the amplifier 8. Then, it is supplied to the TTL level conversion circuit 9,
The voltage that can process the signal with a transistor (for example, H is 2.4V
As described above, L is converted to 0.4 V or less), output to the driver 10, and output to the Ethernet via the transformer 11.

Next, description will be made of a case where two-way optical wireless transmission is simultaneously performed by the transmitters / receivers having the configuration of both the transmitting side terminal and the receiving side terminal having the above-mentioned configuration. When Manchester code signals with completely the same frequency band are simultaneously transmitted from both transceivers, the light emitted from one transceiver enters the light receiving part (pin photodiode 7) of its own and is transmitted from the other transceiver. It may cause noise in the transmitted light. However, this problem can be solved by optically completely separating the transmitting light and the receiving light of the transceiver. With such a configuration, complete bidirectional communication can be performed without causing interference or the like even without performing frequency conversion and using transmission light in different bands, and with a simple configuration. Since it can be realized, the price can be reduced and the size can be reduced. Also,
Optical wireless can completely replace a wired transmission path.

Not only the Manchester code but also the bi-phase code in which a displacement point always exists in one code can perform perfect clock recovery, and the low-frequency spectrum also exhibits a falling characteristic. Even if the noise due to the illumination light is removed by filtering, it does not affect the transmission signal. Therefore, not only the Manchester code but also the bi-phase code can be used as the transmission signal.

As one of the problems in performing wireless transmission,
Since the distance between the two transmitters and receivers is unspecified, the reception level is different each time, and a constant reception level cannot be obtained. When the reception level is low, proper decoding cannot be performed, and when the reception level is too high and saturated, correct data can be received by the modulation means such as FSK. When light is directly intensity-modulated by a bi-phase code signal and sent, saturation causes signal distortion, making correct data reception impossible. Therefore, in order to enable correct data reception regardless of the reception level, it is necessary to control the amplification factor of the amplifier on the reception side to a value that brings the received signal to the TTL level without saturating the received signal.

This control function is performed by AGC (Automati
c Gain Control), which changes the amplification factor of the amplifier according to the received signal level, has been used conventionally, but this AGC changes the amplification factor after the input signal is supplied. The control characteristic has a time constant and cannot cope with a sudden change in the amplitude of the input signal. Then, as shown in FIG. 5 (A), since data is transmitted in the state of packets that are intermittently transmitted on the Ethernet, the data signal a is suddenly started from the state of no signal, and the AGC follows. Therefore, the head portion of the data signal a cannot be received correctly.

Therefore, in the present invention, an optical signal is sent in a state where the insertion signals b and c having substantially the same amplitude as the data signal a are inserted in the non-data section, and the amplification factor of the amplifier by the AGC is adjusted in advance to the data signal level. As a result, the data head part can be received correctly.

In order to use the transmitter / receiver together with a battery-powered portable information processing terminal, it is necessary to reduce the power consumption as much as possible.
As shown in (B), it is desirable to shorten the time of H level and shorten the time during which the LED 6 emits light (ON period) as much as possible. However, if the blinking cycle is made too long, the time constant of AGC will be increased and L
While the ED6 is off, the amplification factor of the amplifier rises,
When the data signal is transmitted, it saturates, making accurate decoding impossible. Further, since the amplifier circuit on the receiver side is composed of an AC amplifier, the transient response due to the differential response becomes large, which causes a problem. Therefore, the blinking cycle in this case must be set according to the transmission rate.

Further, when power consumption is not considered as important, FIG.
As shown in (C), the insertion signal c has a duty of 50%.
Is most preferable, and in this case, the influence of the AGC time constant and the transient response of the amplifier circuit can be minimized.

Next, there will be described a form of a wired Ethernet side transceiver and a form of a personal computer side transceiver when connecting a PCMCIA compatible personal computer having a slot into which a PCMCIA card can be inserted and a wired Ethernet LAN by optical wireless communication. Several examples will be described.

As shown in FIG. 6, consider a case where bidirectional transmission of data to and from the Ethernet 12 is carried out on the desks A to D using the book type personal computers 17a to 17d. On the wired side, the HUB 14 connected to the transceiver 13 on the Ethernet 12 by wire, and the HUB side transceivers (first transceivers) 15a to 1 connected to the HUB 14 by wire, respectively.
5d, and the HUB side transceivers 15a to 15
d is movably installed on each of the desks A to D within a reach of a cable. Then, the data signal supplied from the Ethernet 12 (10 Mbps Manchester code)
Is EO converted by the HUB side transceivers 15a to 15d and transmitted as an optical signal.

On the side of the personal computers 17a to 17d, PC side transceivers (second transceivers) 16a to 16d having a shape capable of partially or completely inserting into the slots are inserted, and data signals from the personal computers 17a to 17d ( 10 Mbps Manchester code) is E-O converted and transmitted as an optical signal.

Further, each of the transceivers 15a to 15d, 16a
When the optical signal is received by ˜16d, it is converted into an electric signal by OE conversion, and the data is supplied to the Ethernet 12 or the personal computers 17a to 17d through the route opposite to the case of the above-mentioned transmission. In this case, the function of the receiving side is
Basically, a TTL level signal is reproduced by only the O-E conversion function and used as a received data signal.

Here, an embodiment of the HUB side transceiver 15 is shown in FIG. 7 and its structure will be described. Note that FIG. 7A is a plan view, FIG. 7B is a sectional view, and FIG. 7C is a front view.

In the figure, the light receiving means of the HUB side transceiver 15 is arranged as much as possible above the HUB side transceiver 15, and the light emitting means is as much as possible of the HUB side transceiver 15.
It is located below. This is to enable good transmission and reception regardless of the height position of the PC-side transceiver 16 inserted into the slot of the personal computer 17, as described later.

The light receiving means has a structure in which a kamaboko type cylindrical lens 19 is provided on the light receiving surface of a light receiving substrate (pin photodiode) 18 that is long in the horizontal direction.
The light emitting means has a configuration in which three LEDs 20 are arranged in the horizontal direction and a kamaboko-shaped cylindrical lens 21 is provided on the light emitting surface side. In addition, the cylindrical lenses 19 and 2
Filters 22 and 23 are respectively provided on the front surface of 1, and a partition plate 24 is provided between the light emitting means and the light receiving means.
The light emitting means and the light receiving means are optically separated by completely separating the light emitting means and the light receiving means.

By optically separating the light emitting means and the light receiving means in this way, the L of the HUB side transceiver 15 itself is
It is possible to prevent the light emitted from the ED 20 from entering the light receiving substrate 18 and becoming noise, and it is possible to perform complete bidirectional communication without causing interference or the like.

A first embodiment of the transceiver 16 on the PC (personal computer) 17 side is shown in FIGS. 8 (A) -8 (C). 1A is a perspective view of the PC 17, FIG. 1B is a plan view of the PC-side transceiver 16, and FIG. 1C is a cross-sectional view of the PC-side transceiver 16.

In the PC-side transceiver 16 of this embodiment, the light emitting means and the light receiving means are PC 17 as shown in FIG.
Of the PCMCIA card of the PC 17 inserted into the slot 25 of the connector 26 while protruding to the outside of the connector 26.
Are electrically connected to the PC 17 to enable transmission / reception of data signals. Then, as shown in FIGS. 3B and 3C, the light emitting means is arranged in the upper side and the light receiving means is arranged in the lower side so as to be in close proximity. Further, the light emitting means is composed of the LED 20 having the cylindrical lens 21 provided on the light emitting surface side thereof, and the light receiving means is composed of the light receiving substrate 18 having the cylindrical lens 19 provided on the light receiving surface thereof. An IR filter 27 is provided on the front surfaces of the cylindrical lenses 19 and 21, and the light emitting means and the light receiving means are completely separated by a partition plate 24 so that the light emitting means and the light receiving means are optically separated. It is separated into

A second embodiment of the transceiver 16 on the PC (personal computer) 17 side is shown in FIGS. 1A is a plan view of the PC-side transceiver 16, FIG. 1B is a side view thereof, and FIG. 1C is a front view thereof.

The PC side transceiver 16 of this embodiment is inserted into the slot 25 including the light emitting means and the light receiving means, and is constructed to have a thickness that can be accommodated in the slot 25. And, as can be seen from the figures (A) to (C),
In order to reduce the overall thickness, the light emitting means and the light receiving means are
It is located on the left and right. This light emitting means has a structure in which two LEDs 20 are arranged in the horizontal direction and a kabushi type cylindrical lens 21 is provided on the light emitting surface side thereof. The light receiving means is a light emitting surface of a light receiving substrate 18 which is long in the horizontal direction. A cylindrical lens 19 of the mold is provided. The light emitting means and the light receiving means are optically separated by a partition plate 24.

When the HUB side transceiver 15 explained in FIG. 7 and the PC side transceiver 16 explained in FIG. 8 and FIG. 9 explained above are used on the desks A to D as shown in FIG. Each height position will be described with reference to FIGS. In the figure, the PC-side transceiver 16
9 uses the second embodiment described in FIG. 9, but the same applies to the case of the PC side transceiver 16 in FIG.

When the PC 17 is used on the desks A to D, the user places the HUB side transceiver 15 at an arbitrary position near the slot 25 of the PC 17 on the desk and uses it. At this time, the height position of the slot 25 of the PC 17 varies depending on the type of the PC 17, but the height of the HUB side transceiver 15 is almost the same as that of the PC 17, and the light receiving means of the HUB side transceiver 15 transmits and receives as much as possible to the HUB side. It is arranged above the device 15 and the light emitting means is provided as much as possible on the HUB side transceiver 15
By placing it below the slot 25 of the PC 17,
Good transmission / reception is possible regardless of the height position.
In addition, in the figure (A), the height position of the slot 25 is HUB.
In the case where the side transceiver 15 is located approximately at the center of the height, FIG. 7B shows the case above, and FIG. 7C shows the case below. Also, the HUB side transceiver 1
The exterior 27 of 5 prevents light from a fluorescent lamp or the like from entering the light-receiving surface of the light-receiving substrate 18, and prevents the PC-side transceiver 16 from coming too close to secure a communication path. , Protrudes in front of the filter 22.

HUB side transceiver 15 and PC side transceiver 1
Both 6 are used on the desk. The relative height position at this time is as shown in FIG. 10, and the relative horizontal positions are not so far apart from each other, but the relative horizontal position is
There are various cases as shown in FIG. 6, and the respective light emitting means and light receiving means are not always placed in the facing directions. Considering these matters and the fact that the illumination such as the fluorescent lamp is above, the directivity of the light emitting means and the light receiving means of the HUB side transceiver 15 and the PC side transceiver 16 is wide in the horizontal direction and narrow in the vertical direction. By setting it to the maximum (horizontal direction), it is possible to maximize the two-way optical communication range (hereinafter referred to as the service area).

The HUB side transceiver 1 described with reference to FIGS.
By using the cylindrical lenses 19 and 21 in the light emitting means and the light receiving means of the transceiver 5 and the PC side transceiver 16, respectively, the above directional characteristics are secured and the service area is expanded. Then, the HUB side transceiver 15 and the PC
When the side transceiver 16 is in close proximity, the vertical angle between the light transmitting and receiving means becomes large, but the light amount increases due to the short communication distance (the light receiving amount is equal to the communication distance of 2).
Since it is inversely proportional to the power), reception is possible, and with such directional characteristics, it is possible to secure a service area from a long distance to a short distance.

Whether or not the HUB side transceiver 15 and the PC side transceiver 16 are within the range of the service area,
If a buzzer sounds or an LED or the like is used to visually indicate (hereinafter, collectively referred to as display means), it is possible to easily understand the optical communication range, and when communication cannot be performed outside the service area. It is even more convenient because it can be prevented from being mistaken for a failure. This display means may be provided in the PC-side transceiver 16, but due to the restrictions of the installation location and the power consumption, the size of the display is loose and the power supply of the HUB is easy.
It is better to provide the side transceiver 15.

A block diagram of FIG. 11 shows an example of the configuration when the display means is provided in the HUB side transceiver (first transceiver) 15. The optical signal received by the light receiving substrate 18 of the HUB side transceiver 15 is converted into an electric signal and supplied to the AGC amplifier 28. The AGC amplifier 28 amplifies the electric signal according to the reception level, supplies the electric signal to the binarization circuit 29, and outputs the electric signal to the HUB 14 via the connector. Further, the AGC amplifier 28 outputs an AGC control voltage that changes according to the reception level to one input terminal of the comparator 30.

Further, at the other input terminal of the comparator 30,
The threshold voltage set to the AGC control voltage at the reception level at which good reception is possible is supplied, and the comparison voltage compared with the AGC control voltage supplied to the one input terminal side is output. Then, this comparison voltage is inverted at a reception level at which good reception is impossible,
A user is informed that a communication channel is not established and transmission / reception cannot be performed by sounding a buzzer or illuminating an LED or the like (driving the display means 32) via the driver 31.
The display means 32 may be driven at the moment when good reception is possible or during the time when good reception is possible, and how to sound the buzzer and how to turn on the light emitting means such as an LED. The method is not limited to these methods and is free.

Furthermore, the insertion signals b and c as described with reference to FIGS. 5B and 5C are always output from the HUB side transceiver 15 so that the PC 17 can enter the service area. PC side transceiver 16 is HUB side transceiver 15
When receiving the optical signals (insertion signals b and c) from, the PC side transceiver 16 outputs the insertion signals b and c for the first time. In the HUB side transceiver 15, the PC
When the insertion signals b and c from the side transceiver 16 are received, the display means 32 may indicate that communication is possible.

In this case, since the PC side transceiver 16 does not emit light until the insertion signals b and c are received, the PC side transceiver 16 needs to be powered mainly from the PC 17 which is mainly used for battery drive. Electric power can be reduced as much as possible.

Next, FIGS. 12A to 12C show another embodiment of the optical wireless data transmission system which does not require the display means 32 because the communication path is surely established. Note that FIG. 7A is a plan view, FIG. 7B is a sectional view, and FIG. 7C is a front view.

The PC side transceiver 16 is provided with magnets (first magnets) 33a and 33b so as to slightly project from the entrance of the slot 25. Here, it is provided at both ends of the PC side transceiver 16. Then, at the position facing the magnets 33a and 33b of the HUB side transceiver 15,
Magnets of opposite polarity (second magnet) 34a, 34
b is provided vertically.

Further, the light transmitting / receiving means are arranged so as to have a positional relationship corresponding to each other, and here, when the magnets 33a, 33b and the magnets 34a, 34b are in contact with each other, the communication distance becomes the shortest. In addition, the light receiving board 18 of the HUB side transceiver 15 is placed at a position facing the LED 20 of the PC side transceiver 16, and the LED 20 of the HUB side transceiver 15 is located at a position facing the light receiving board 18 of the PC side transceiver 16. I will come. At this time, PC1
Since the height position of the slot 25 of No. 7 differs depending on the type of the PC 17, the magnets 33a and 33b of the HUB side transceiver 15 are long in the vertical direction, and the HUB side transceiver 1
By arranging a plurality of light-receiving substrates 18 and LEDs 20 of No. 5 in the vertical direction (three in the figure), various PCs 17
It corresponds to.

Then, the user uses the slot 2 of the PC 17
The optimum position is sought by sliding the front and rear sides of the HUB side transceiver 15 in contact with the side face having 5 and the light transmitting and receiving face of the HUB side transceiver 15. When the optimum position is reached, the magnets 33a, 33b, 34
By the suction force of a and 34b, the PC side transceiver 16 and the HU
Since the B-side transceiver 15 is fixed, it is possible to naturally establish a communication path capable of good transmission and reception.

In this case, even if the PC 17 is moved a little during use, the communication path is still established, and the PC 17 can be used with peace of mind regardless of the position of the PC 17. Further, since the magnets 33a, 33b, 34a, 34b are fixed by the attraction force, mechanical force is not applied to the connecting portion unlike the conventional connecting / disconnecting of the connector for fixing to the PC 17 by wire. There is no danger of destroying. Also, the work for establishing the communication path can be relatively easily performed.

It is convenient for the transmitting means and the receiving means of the PC side transceiver 16 to project a little from the slot 25 of the PC 17 because the service area is expanded. However, when the PC 17 is transported and stored with the PC-side transceiver 16 inserted in the slot 25, a part of the PC-side transceiver 16 protruding outside the slot 25 causes an accident such as damage. Therefore, it is not preferable.

Therefore, the first transmitter / receiver 16 of the PC side is configured so that it is accommodated in the slot 25 of the PC 17 during transportation and storage, and the service area is expanded when used.
And a second configuration example shown in FIGS. 13 (A), (B) and FIG.
Shown in (A) and (B).

FIG. 1 shows a first configuration example of the transceiver 16 on the PC side.
3 (A) and (B). It should be noted that the figure (A) shows the state during transportation and storage, and the figure (B) shows the state during use. In this configuration example, a mirror 36 that is pulled out by a handle 35 is provided on one side surface of the PC-side transceiver 16, and is housed in the slot 25 during transportation and storage as shown in FIG. At the time of use, as shown in FIG. 3B, the mirror 36 is pulled out from the slot 25 by pulling the handle 35, and the transmitted / received light is reflected by the mirror 36 to expand the horizontal service area. Has been done.

FIGS. 14A and 14B are plan views showing a second configuration example of the PC side transceiver 16, and FIG. 14A shows a state during transportation and storage. (B) is a diagram showing a state during use. In the present configuration example, a transmitting means and a receiving means are provided on the side surface of the PC-side transceiver 16, and these are drawn out by the handle 35. Then, during transportation and storage, as shown in FIG.
It fits in the slot 25, but when in use (B)
As shown in FIG. 3, the transmitting means and the receiving means are pulled out from the slot 25 by pulling the handle 35, and are projected to the outside of the PC 17 to expand the service area.

[0056]

According to the optical wireless data transmission system of the present invention,
The light emitting means and the light receiving means of the first transceiver can be optically separated, and the light emitting means and the light receiving means of the second transceiver can be optically separated to reproduce the clock signal from the signal itself. Since the bidirectional data transmission between the first transceiver and the second transceiver is performed by the optical signal that is intensity-modulated by the biphase code signal, the first transceiver and the second transceiver The configuration of the transceiver can be extremely simplified. As a result, it is possible to reduce the price and size. Moreover, the wired transmission path can be completely replaced by optical wireless communication.

In the case where the optical signal having the same amplitude as that during data transmission is transmitted during the non-data transmission period when the information data is packet-transmitted by the optical signal intensity-modulated by the bi-phase code signal In addition, the head of data can be correctly received by previously adjusting the amplification factor of the amplifier by AGC to the data signal level. Furthermore, when the optical signal transmitted during the non-data transmission period is an optical signal having a single frequency carrier, it is possible to minimize the influence of the time constant of the AGC and the transient response of the amplifier circuit.

Also, after the optical signal transmitted from the first transceiver during the non-data transmission period is received by the second transceiver, the optical signal transmitted from the second transceiver during the non-data transmission period is received. When the first transceiver is provided with display means for transmitting a signal and displaying that the optical signal is communicable when the first transceiver receives the optical signal, the power consumption of the second transceiver Can be minimized, which is extremely effective when the second transceiver is used by connecting it to an information device used in battery drive.

The light emitting means of the first transceiver is arranged at one of the upper end and the lower end of the first transceiver and the light receiving means is arranged at the other, and the light emitting means and the light receiving means of the second transceiver are arranged. If they are arranged close to each other, good transmission and reception can be performed when using the information device to which the second transceiver is connected on the desk.

Further, by setting the directional characteristics of the light emitting means and the light receiving means of the first transceiver and the second transceiver to be wide in the horizontal direction and narrow in the vertical direction, a service area where good transmission and reception can be performed can be achieved. Can be maximized.

Further, the second transmitter / receiver is constructed in a card shape in which the entire light emitting means and the light receiving means are inserted into the slot of the computer, and the end face thereof is flush with the side surface of the computer in which the slot is formed. Alternatively, the first magnet is provided so as to project to some extent, and the second magnet is provided at a position facing the first magnet on the side surface of the first transceiver where the light emitting means and the light receiving means are provided. When the communication path is formed by attracting the first and second magnets, the attractive force of the magnets fixes the first transceiver and the second transceiver, so that good transmission and reception is performed. It is possible to naturally establish a communication path that enables communication. In this case, even if the information device to which the second transceiver is connected is moved a little during use,
The communication path remains established and can be used with confidence regardless of the position of the information device. Furthermore, since it is fixed by the attractive force of the magnet, mechanical force is not applied to the connection part like when connecting and disconnecting the connector in order to fix it to the information device in the conventional wired manner, so there is a risk of destroying the connector etc. In addition, the work for establishing the communication path can be performed relatively easily.

When the first transceiver is provided with a display means for displaying whether or not the second transceiver is in the optical communication range, the optical communication range can be easily known and the service area is provided. It becomes even more convenient, for example, it is possible to prevent misunderstanding that it is out of order when communication is not possible.

If the optical wireless data transmitter / receiver is constructed in the form of a card to be inserted into the slot of the computer and only the light emitting means and the light receiving means are exposed to the outside of the slot, the service area is reduced. Can be expanded.

The optical wireless data transmitter / receiver, including the light emitting means and the light receiving means, is constructed in the form of a card to be inserted into the slot of the computer, and is used for transmission in order to expand the range of horizontal optical communication. When a mirror that reflects the optical signal is installed outside the slot so that it can be pulled out, it is stored in the slot during transportation and storage to prevent accidents such as damage, and when used, the mirror is pulled out to cover the service area. Can be expanded.

Further, the optical wireless data transmitter / receiver including the light emitting means and the light receiving means is constructed in the form of a card to be inserted into the slot of the computer, and the light emitting means and the light receiving means can be pulled out to the outside of the slot. Has an effect that it can be housed in a slot during transportation and storage to prevent accidents such as damage, and when used, the light emitting means and the light receiving means can be pulled out to expand the service area.

[Brief description of drawings]

1A to 1C are views for explaining a bi-phase code signal used in an embodiment of an optical wireless data transmission system of the present invention.

FIG. 2A is a block diagram showing an example of a Manchester code signal encoding circuit, and FIG. 2B is a block diagram showing an example of a Manchester code signal decoding circuit.

FIG. 3 is a graph showing the relationship between the transmission band and the signal level of the NRZ signal and the Manchester code signal.

FIG. 4 is a configuration diagram showing an example of a transmission side terminal and a reception side terminal.

5A is a state diagram showing a data transmission state on Ethernet, FIG. 5B is a state diagram showing a data transmission state of optical wireless transmission when power consumption is reduced, and FIG. It is a state diagram which shows the data transmission state of transmission.

FIG. 6 is a configuration diagram showing an example of a usage state of the optical wireless data transmission system of the present invention.

FIG. 7 is a diagram showing a configuration example of a first transceiver of the present invention, (A) is a plan view, (B) is a sectional view, and (C) is a front view.

8A and 8B are configuration diagrams showing a first embodiment of a second transceiver of the present invention, FIG. 8A is a perspective view of a PC, FIG. 8B is a plan view of a PC-side transceiver, and FIG. It is a sectional view of a PC side transceiver.

FIG. 9 is a configuration diagram showing a second embodiment of the second transceiver of the present invention, (A) is a plan view, (B) is a side view,
(C) is a front view.

FIG. 10 is a diagram showing a relative height position when the first transceiver and the second transceiver are placed on a desk for use, and FIG. 10A shows a case where the height position is substantially in the center. , (B) are the same as above, and (C) are the same as below.

FIG. 11 is a block diagram showing a configuration example when a display unit is provided in the first transceiver.

FIG. 12 is a configuration diagram showing another embodiment of the optical wireless data transmission system of the present invention, (A) is a plan view, (B) is a sectional view, and (C) is a front view.

FIG. 13 is a plan view showing a first configuration example of a second transceiver of the present invention, (A) showing a state during transportation and storage, and (B) showing a state during use. Is.

FIG. 14 is a plan view showing a second configuration example of the second transceiver of the present invention, (A) showing a state during transportation and storage, and (B) showing a state during use. Is.

[Explanation of Codes] 1 EX-OR circuit (exclusive OR circuit) 2 clock recovery circuit 3,11 transformer 4 receiver 5 LED driver 6 LED (light emitting diode) 7 pin photodiode 8 amplifier circuit (amplifier) 9 TTL level conversion Circuit 10 Driver 12 Ethernet 13 Transceiver 14 HUB 15, 15a to 15d HUB side transceiver (first transceiver) 16, 16a to 16d PC side transceiver (second transceiver) 17, 17a to 17d Personal computer (PC)

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Claims (11)

[Claims] 1. An optical wireless data transmission system for performing bidirectional data communication by an optical signal between a first transceiver and a second transceiver, wherein a light emitting means and a light receiving means of the first transceiver are provided. An optical signal that is optically separated, and the light emitting means and the light receiving means of the second transceiver are optically separated, and the intensity is modulated by a bi-phase code signal that can reproduce a clock signal from the signal itself. According to the optical wireless data transmission system, bidirectional data transmission is performed between the first transceiver and the second transceiver. 2. An optical signal having substantially the same amplitude as that during data transmission during a non-data transmission period when information data is packet-transmitted by an optical signal intensity-modulated by a bi-phase code signal. The optical wireless data transmission system according to claim 1. 3. The optical wireless data transmission system according to claim 2, wherein the optical signal transmitted during the non-data transmission period is an optical signal having a single frequency carrier. 4. The optical signal transmitted from the first transceiver during the non-data transmission period is received by the second transceiver, and then transmitted from the second transceiver during the non-data transmission period. 3. The first transceiver is provided with a display means for transmitting an optical signal and displaying that communication is possible when the first transceiver receives the optical signal.
Alternatively, the optical wireless data transmission system according to claim 3. 5. The light emitting means of the first transceiver is arranged at one of the upper end and the lower end of the first transceiver and the light receiving means is arranged at the other, and the light emitting means and the light receiving means of the second transceiver are provided. The two are arranged close to each other,
The optical wireless data transmission system according to claim 2, claim 3, or claim 4. 6. The directional characteristics of the light emitting means and the light receiving means of the first transceiver and the second transceiver are set wide in the horizontal direction and narrow in the vertical direction, respectively. The optical wireless data transmission system according to claim 3, claim 4 or claim 5. 7. The second transmitter / receiver is constructed in the form of a card including the light emitting means and the light receiving means, which is inserted into the slot of the computer, and the end face thereof is flush with the side face of the computer in which the slot is formed. Alternatively, the first magnet may be provided so as to project to some extent, and the second magnet may be provided at a position facing the first magnet on the side surface of the first transceiver where the light emitting means and the light receiving means are provided. The communication path is formed by attracting the first and second magnets.
The optical wireless data transmission system according to claim 2, claim 3, claim 4, claim 5, or claim 6. 8. A display device for displaying whether or not the second transceiver is in the optical communication range, wherein the display device is provided with a display device. An optical wireless data transceiver which is the first transceiver of the optical wireless data transmission system according to claim 5 or 6. 9. A card-like structure to be inserted into a slot of a computer, and only the light emitting means and the light receiving means are exposed to the outside of the slot. An optical wireless data transceiver which is a second transceiver of the optical wireless data transmission system according to claim 3, claim 4, claim 5, or claim 6. 10. The whole of the light emitting means and the light receiving means is formed into a card shape to be inserted into a slot of a computer, and reflects an optical signal used for transmission in order to widen an optical communication range in the horizontal direction. The optical wireless data transmission system according to any one of claims 1, 2, 3, 4, 5 and 6, wherein a mirror is provided so as to be drawn out of the slot. Optical wireless data transceiver that is the transceiver of. 11. A light-emitting means and a light-receiving means are configured as a whole into a slot of a computer, and the light-emitting means and the light-receiving means can be pulled out to the outside of the slot. An optical wireless data transceiver which is the second transceiver of the optical wireless data transmission system according to claim 1, claim 2, claim 3, claim 4, claim 5 or claim 6.