JPH09214437A - Bus type optical data transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the bus type optical data transmitter with simple configuration without attenuation of an optical signal during transmission. SOLUTION: An optical signal sent from a 2nd station Sn-1 to a 1st station Sn via a 1st optical fiber Fn-1 is converted into a 1st electric signal SGn-1 ,n by a 1st light emitting light receiving element PAn and fed to the 1st station Sn by a reception data input circuit RCn and fed to a 2nd light emitting light receiving element PBn as a 4th electric signal SGn ,n+1 by a transmission data output circuit TCn , and sent to a 3rd transmission Sn+1 . The optical signal sent from the 3rd station Sn+1 to the 1st station Sn via a 2nd optical fiber Fn is converted into a 3rd electric signal SGn+1 ,n , by the 2nd light emitting light receiving element PBn and fed to the 1st station Sn by a reception data input circuit RCn and fed to the 1st light emitting light receiving element PAn as the 2nd electric signal SGn ,n-1 by the transmission data output circuit TCn and sent to the 2nd station Sn-1 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bus type optical data transmission device for transmitting data between a plurality of stations via an optical fiber.

[0002]

2. Description of the Related Art An optical bus has been proposed for transmitting a large amount of data in a network between stations composed of data processing devices such as workstations and personal computers. For example, this is the optical bus described in FIG. 3 of JP-A-61-179627.

In such an optical bus, an optical element such as a half mirror is generally provided in the optical transmission path to take out a part of the light propagating in the optical transmission path to the station side,
Alternatively, an optical signal representing an output signal from the station is sent into the optical transmission line by using an optical element such as the half mirror.

[0004]

However, in the above conventional optical bus, the light propagating in the optical transmission line is attenuated to half each time it passes through the optical element such as the half mirror. As the number of stations connected to the optical bus increases, the optical signal propagating in the optical bus is significantly attenuated, and the transmission distance of the optical signal is limited.

It is also conceivable to insert repeaters in the optical bus at a predetermined interval in order to recover the attenuation of the optical signal propagating in the optical bus. Becomes complicated and expensive.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bus type optical data transmission apparatus having a simple structure and no attenuation of optical signals.

[0007]

In order to achieve such an object, the gist of the present invention is a bus type optical data transmission device which enables a plurality of stations to exchange data with each other. (A) a first optical fiber provided between a first station and a second station, and a first station and a third station for connecting the plurality of stations in series. A second optical fiber provided between the first optical fiber and the second optical fiber, and (b) is connected to the end of the first optical fiber and converts an optical signal transmitted through the first optical fiber into a first electric signal. In addition, the first light emitting / receiving element for converting the second electric signal into an optical signal and outputting the optical signal into the first optical fiber, and (c) the second optical fiber connected to the end of the second optical fiber, The optical signal transmitted through the optical fiber A second light emitting and receiving element for converting into a third electric signal and converting a fourth electric signal into an optical signal and outputting it into the second optical fiber; and (d) the first electric signal and the third electric signal. A reception data input circuit for supplying to the first station, and (e) supplying the transmission data and the first electric signal output from the first station to the second light emitting / receiving element as the fourth electric signal. A transmission data output circuit for supplying the transmission data output from the first station and the third electric signal to the first light emitting and receiving element as the second electric signal, respectively.

[0008]

As described above, the optical signal transmitted from the second station to the first station via the first optical fiber is converted into the first electric signal by the first light emitting and receiving element. After being processed, it is supplied to the first station by the reception data input circuit, and is also supplied to the second light emitting and receiving element as the fourth electric signal by the transmission data output circuit and transmitted to the third station.
The optical signal transmitted from the third station to the first station via the second optical fiber is
After being converted into the third electric signal by the second light emitting and receiving element,
The data is supplied to the station by the reception data input circuit, and is also supplied to the first light emitting / receiving element as the second electric signal by the transmission data output circuit, and is transmitted to the second station. Further, the transmission data output from the first station is supplied to the second light emitting / receiving element as a fourth electric signal, and at the same time, is supplied to the first light emitting / receiving element as a second electric signal. To the second station and the third station.

As a result, since the optical element such as the half mirror is not inserted in the optical transmission line, the signal transmitted through each optical fiber is hardly attenuated. Moreover, not only an optical element such as the half mirror but also a repeater is not required, so that the configuration is simple and the bus type optical data transmission device is inexpensive.

[0010]

Another aspect of the present invention is that the transmission data output circuit generates the second electric signal and the fourth electric signal by inverting the received first electric signal and third electric signal. is there. By doing so, there is an advantage that the pulse width distortion due to the response delay of the rising edge of the output signal of the light receiving element is suitably eliminated. Further, at this time, the reception data input circuit provided corresponding to every other station among the plurality of stations connected in series by the optical fiber outputs the first electric signal and the third electric signal. It is inverted and supplied to the first station. In this way, each station has the advantage of being supplied with the common first and third non-inverted electrical signals.

Also, preferably, the first and second optical fibers provided between the first station and the second station and between the first station and the third station are Each is a single optical fiber, and the first and second light emitting and receiving elements are the above-mentioned first and second optical fibers.
And a light receiving element and a light emitting element facing the end faces of the optical fiber and the second optical fiber, respectively.
By doing so, there is an advantage that the number of connecting devices for connecting the end portion of the optical fiber to the light emitting element and the light receiving element is halved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below in detail with reference to the drawings.

In FIG. 1, a plurality of stations S
_n (n = 1 to m, m = 8 in this embodiment) is a well-known data processing device such as a workstation or a personal computer, and is used for efficiently transmitting a large amount of data to each other. Further, they are mutually connected by the bus type optical data transmission device 10 to form a network between the stations S _n .

A plurality of bus type optical data transmission devices 10 are provided.
Station S_nIn order to connect
Number of stations S_nMultiple optical fibers installed between
Ba F _n(N = 1 to m-1). In this embodiment
Is each optical fiber F_nTransmits light in one direction
It is composed of a pair of optical fibers. This light
Fiber is optically excellent glass fiber or transparent resin fiber
It may have a single core or multiple cores.

[0015] The above each station S _n is two pairs of light-emitting light-receiving element PA _{n (n} = 1~m) and PB _{n (n} = 1~
m) and the two sets of light emitting and receiving elements PA _n and PB _n
Supplying electrical signals to the station S _n from and station set S 2 of the light-emitting light-receiving element an electrical signal from the _n PA _n
And PB _n , and an input / output circuit C _n (n = _{1 to} m) for supplying an electric signal from one of the two sets of light emitting / receiving elements PA _n and PB _{n to} the other. There is.

The light emitting / receiving element PA_nIs LED, LD
Light emitting element LA such as_nAnd PIN diode, APD
Light-receiving element DA such as iodine and phototransistor
_nAnd is composed of In addition, the light emitting / receiving element PB_n
Similarly to the above, the light emitting element LB _nAnd light receiving element DB_nWhen
It is composed of Station S_nLight emission of
Optical element PA_nAnd PB_nIn the light emitting element LA_n
And light receiving element DA_nIs a station adjacent to one side.
S_n-1Optical fiber F provided between_n-1End face of
Connected to each other by a predetermined connecting device
The light emitting element LB_nAnd light receiving element DB_nIs
Station S adjacent to one side_{n + 1}Provided between
Optical fiber F_nPredetermined connection facing the end face of
Each is connected by a device.

The input / output circuit C_nIs the received data input time
Road RC_nAnd transmission data output circuit TC _nAnd with
For example, it is configured as shown in FIG. For example, in Figure 2
Station S_TwoI / O circuit C connected to_Two
In the received data input circuit RC_TwoIs the optical fiber F
₁Is transmitted through the light receiving element DA_TwoConverted by
Electrical signal SG₁₂And optical fiber F_TwoTransmitted through
And light receiving element DB_TwoElectrical signal SG converted by₃₂
Above station S_TwoSupply to. In this example,
Received data input circuit RC_TwoIs a well-known N
It is composed of OR gate logic circuit elements.

[0018] The transmission data output circuit TC _2, said station S-emitting light-receiving element PB ₂ transmit data SG ₂ and the electrical signal SG ₁₂ outputted from the electric signal SG ₂₃ for sending to the adjacent station S ₃ side ₂ is supplied to the light emitting element LB _2, also transmits data SG ₂ and the electrical signal SG output from the station S ₂
An electric signal SG ₂₁ for sending ₃₂ to the adjacent station S _{1 is} supplied to the light emitting element LA ₂ of the light emitting and receiving element PA ₂ .

The transmission data output circuit TC ₂ has one well-known OR for supplying the transmission data SG ₂ and the electric signal SG ₁₂ to the light emitting element LB ₂ in order to realize the above function. The gate logic circuit element OR ₂₁ , the transmission data SG ₂ and the electric signal SG ₃₂ are sent to the light emitting element LA.
One well-known OR gate logic circuit element OR ₂₂ for supplying to ₂ and the transmission data SG ₂ (“H” level when it is “0”) output from the station S ₂ are inverted. The OR gate logic circuit elements OR ₂₁ and O
And an inverting circuit IV ₂ for supplying each to R ₂₂ . In this embodiment, the inverting circuit IV ₂ has one N
It is composed of OR gate logic circuit elements.

In this embodiment, a plurality of stations S
_nAmong them, the station S as shown in FIG._TwoTo
If it is the first station, the adjacent station
Station S₁And S_ThreeIs the second station and
Corresponding to the third station, the electrical signal SG₁₂Is
Station S₁From optical fiber F₁Is transmitted through
Light receiving element DA_TwoTo the first electrical signal converted by
Accordingly, the electrical signal SG₃₂Is station S_ThreeFrom light
F_TwoIs transmitted through and the light receiving element DB _TwoBy
Corresponding to the converted third electric signal, the electric signal SG
_{twenty three}Is the station S above_Three4th electrical message to send to
The electrical signal SG corresponding to_{twenty one}Is the station S above
₁Corresponds to the second electrical signal for sending to the side. Ma
Station S_TwoSets of light emitting and receiving elements provided in
PA_TwoAnd PB_TwoIs a first light emitting / receiving element and a second light emitting
It corresponds to each light receiving element.

Therefore, the bus type optical data transmission of this embodiment is performed.
The sending device 10 can be generally expressed as a predetermined first switch.
Station S_nAnd, for example, the second station on the right
S _n-1A first optical fiber F provided between_n-1,
And its first station S_nFor example, next to the left
Third station S_{n + 1}The second provided between
Optical fiber F_nAnd its first optical fiber F_n-1End of
Connected to the first optical fiber F_n-1Transmitted through
The optical signal to be transmitted is the first electrical signal SG_{n-1, n}When converted to
Second, the second electrical signal SG_{n, n-1}To an optical signal and
First optical fiber F_n-1First light emitting / receiving element for outputting inward
PA_nAnd the second optical fiber F_nConnected to the end of
Second optical fiber F_nThe optical signal transmitted through
3 electrical signal SG_{n + 1, n}Converted to and
No. SG_{n, n + 1}To an optical signal to convert the second optical fiber
F_nSecond light emitting / receiving element PB for outputting inward_nAnd the first electricity
Signal SG_{n-1, n}And the third electrical signal SG_{n + 1, n}The
First station S with the bell inverted_nSupply to
Signal data input circuit RC_nAnd the first station S _nOr
Transmission data SG output from_nAnd the first electrical signal SG
_{n-1, n}The fourth electrical signal SG_{n, n + 1}Anti that level as
Second light emitting / receiving element PB without being rotated_nSupply to the first
Station S of 1_nTransmission data SG output from_n
And the third electrical signal SG_{n + 1, n}The second electrical signal SG
_{n, n-1}As the first emission and reception without reversing the level
Element PA_nTransmission data output circuit TC to supply to each
_nAnd

The bus type of the present embodiment configured as described above
According to the optical data transmission device 10, the second station S
_n-1To the first station S_nTowards the first light
F_n-1The optical signal transmitted via the
Optical element PA_nDue to the first electrical signal SG_{n-1, n}Is converted to
Then, the received data input circuit RC_nBy the first station
S_nTo the transmission data output circuit T
C_nCauses the fourth electrical signal SG_{n, n + 1}Second light emission as
Element PB_nSupplied to the third station S _{n + 1}Toward
Once transmitted. Also, the third station S_{n + 1}Or
The first station S_nToward the second optical fiber
F_nThe optical signal transmitted via the second light emitting / receiving element P
B_nDue to the third electrical signal SG_{n + 1, n}After being converted to
Signal data input circuit RC_nBy the first station S_n
To the transmission data output circuit TC_nBy
Second electrical signal SG_{n, n-1}As the first light emitting / receiving element PA
_nSupplied to the second station S_n-1Toward
Sent. Furthermore, the first station S_nOutput from
Sent data SG_nIs the fourth electrical signal SG_{n, n + 1}age
The second light emitting / receiving element PB_nAt the same time it is supplied to
Electrical signal SG_{n, n-1}As the first light emitting / receiving element PA_nOffering
Is supplied to the second station S _n-1and
Third station S_{n + 1}Transmitted towards. this
The above bus type between specified stations
Through the optical data transmission device 10, full duplex communication or half 2
Heavy communication is possible.

Therefore, according to the present embodiment, the optical element such as the half mirror is not inserted in the optical transmission path, and the fourth electric signal S is passed every time the input / output circuit C _{n is} passed.
Since G _{n, n + 1} and the second electric signal SG _{n, n-1} are set to the level value of the digital signal, the signal transmitted via each optical fiber F _n of the bus type optical data transmission device 10 is Almost no attenuation. Moreover, not only an optical element such as the half mirror described above but also a repeater is unnecessary, so that the configuration is simple and the bus type optical data transmission device 10 is inexpensive.

Next, another embodiment of the present invention will be described. In the following description, the same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 3, the input / output circuits C _n provided in each of the plurality of stations S _n provided in the bus type optical data transmission device 20 are different. In this embodiment, every other input / output circuit, for example, an even numbered input / output circuit C _n (n = even) and an odd numbered input / output circuit C _n (n = odd) are used. Are different from each other.

In FIG. 3, even numbered inputs and outputs
Circuit C_TwoIs the received data input circuit RC as described above._Two
And transmission data output circuit TC_TwoIt is equipped with
Input circuit RC_TwoIs the optical fiber F₁Is transmitted through
And the light receiving element DA_TwoElectrical signal SG converted by₁₂You
And optical fiber F_TwoIs transmitted through and the light receiving element DB
_TwoElectrical signal SG converted by₃₂Invert that level
Let me Station S _TwoSupply to. Also, if the odd number is
Input / output circuit C attached_ThreeAlso, as described above, the received data
Input circuit RC_ThreeAnd transmission data output circuit TC_ThreeWith and
And reception data input circuit RC_ThreeIs the optical fiber F_TwoTo
Is transmitted through and the light receiving element DA_ThreeConverted by
Qi signal SG_{twenty three}And optical fiber F_ThreeIs transmitted through
Light receiving element DB_ThreeElectrical signal SG converted by₄₃To
Station S without inverting the level of_ThreeSupply to
I do.

The reception data input circuit RC ₂ is composed of one NOR gate logic circuit element as in the above, but the transmission data output circuit TC ₂ includes the transmission data SG ₂ and the transmission data SG ₂ from the station S _2. Electrical signal SG ₁₂
A NOR gate logic circuit element NOR ₂₁ for inverting its level and supplying it to the light emitting element LB ₂ , and the transmission data SG ₂ and the electrical signal SG _32.
One NOR gate logic circuit element N for supplying ₂
OR ₂₂ and the transmission data SG ₂ (“H” level when it is “0”) output from the station S ₂ are inverted to NOR gate logic circuit elements NOR ₂₁ and NOR.
_And an inverting circuit IV ₂ for supplying each of the signals to the respective ₂₂ .

The reception data input circuit RC ₃ is composed of two NAND gate logic circuit elements NAND connected in series.
It is composed of ₃₁ and NAND ₃₂ . NAND ₃₁ and NAND ₃₂ connected in series have one A
It has the same function as the ND gate logic element. Further, the transmission data output circuit TC _3; Station transmission from S ₃ data SG ₃ and electrical signals SG ₂₃ 1 N to be supplied to the light emitting element LB ₃ by inverting the level
AND gate logic circuit element NAND ₃₃ and one NAND gate logic circuit element NAND for supplying the transmission data SG ₃ and the electric signal SG ₄₃ to the light emitting element LA _3.
34 and. As a result, each electric signal is transmitted as shown in FIG.

Here, in general, the light emitting devices LA _n and L
B _n or the light receiving elements DA _n and DB _n have a characteristic that one of the rising delay and the falling delay is larger than the other, and at each station S _n , the optical signal transmitted toward it is First received
The rising portion of the electric signal SG or the third electric signal is delayed with respect to the falling portion, and as the transmission distance becomes longer, the pulse width distortion accumulates and increases (pulse width decreases), and the transmission distance is limited. However, according to this embodiment, the transmission data output circuit TC ₂ of the input / output circuit C ₂ outputs the electric signal SG _23, which is the inverted phase of the received electric signal SG ₁₂ , to the optical fiber F ₂ on the opposite side. Together with the input / output circuit C ₃
The received data input circuit RC ₃ of the received electrical signal SG
_Since the electrical signal SG _{34 of} which the phase of ₂₃ is inverted is output to the optical fiber F ₃ on the opposite side, the pulse width distortion does not increase, as shown in FIG. 4, for example. In FIG. 4, ΔT represents the response delay time of the light emitting / receiving element.

According to the present embodiment, as in the above-described embodiments, since the optical element such as the half mirror is not inserted in the optical transmission line, each optical fiber of the bus type optical data transmission device 20. There is almost no attenuation of the signal transmitted through F _n . Moreover, not only an optical element such as the half mirror described above but also a repeater is not required, so that the configuration is simple and the bus type optical data transmission device 20 is inexpensive. At the same time, even if a light receiving element having a large response delay at the rise of the output signal is used, there is an advantage that the pulse width distortion does not increase regardless of the transmission distance and the transmission distance is significantly lengthened.

Further, according to this embodiment, the transmission data output circuit TC _n inverts the received first electric signal SG _{n-1, n} and third electric signal SG _{n + 1, n} , thereby Two
Since the electrical signal SG _{n, n-1} and the fourth electrical signal SG _{n, n + 1} are generated and transmitted, a remarkable response delay is caused at the rising portions of the output signals of the light receiving elements DA _n and DB _n. There is an advantage that the pulse width distortion that occurs is suitably eliminated.

At this time, the optical fiber F_nBy
Multiple stations S connected in series_nOf
For every other station (even number in this embodiment)
Receiving data input circuit RC provided accordingly_n(N is an even
Number) is the first electrical signal SG _{n-1, n}And the third telegraph
No. SG_{n + 1, n}To reverse the first station S_nOffering
So each station is common, not inverted
First electrical signal SG of_{n-1, n}And the third electrical signal SG
_{n + 1, n}Has the advantage of being supplied.

FIG. 5 shows the light emitting and receiving elements PA _n and P.
The light emitting / receiving element 30 used in place of B _n is shown. In the figure, an annular projection 32 to which a connector provided at one end of the optical fiber F _n is connected is provided on one side surface of the main body, and a semicircular light emitting surface is provided inside the annular projection 32. The light emitting element 34 and the light receiving element 36 having a semicircular light receiving surface are arranged so that the light emitting surface and the light receiving surface form a circle concentric with the annular protrusion 32 and having a diameter smaller than that. . Optical fiber F of the above embodiment
_{Although n} is composed of one for each transmission direction, that is, two in total, according to the present embodiment, each optical fiber F _n
Is composed of one by one. FIG. 6 shows a bus type optical data transmission device 40 when the light emitting / receiving element 30 is used. According to this embodiment, at least half-duplex communication is possible between the predetermined stations via the bus type optical data transmission device 40, and in addition to the effects of the above-described embodiment, the optical fiber F _n Has the advantage of halving the number.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention is applied in other modes.

For example, in the above embodiment, the reception data
Data input circuit RC_nAnd transmission data output circuit TC
_nCan be constructed using other types of circuit elements. Need
Receive data input circuit RC_nIs the first electrical signal SG
_{n-1, n}And the third electrical signal SG_{n + 1, n}The first step
Option S_nAs long as it is supplied to
Data output circuit TC_nIs the first station S_nFrom
Output transmission data SG _nAnd the first electrical signal SG
_{n-1, n}The fourth electrical signal SG_{n, n + 1}As the second light emitting and receiving element
Child PB_nSupply to the first station S_nOutput from
Sent data SG_nAnd the third electrical signal SG_{n + 1, n}To
Second electric signal SG_{n, n-1}As the first light emitting / receiving element PA_n
To each of the above.

Although not provided in the reception data input circuit RC _n and the transmission data output circuit TC _n described above, amplifiers for amplifying signals are provided in the reception data input circuit RC _n and the transmission data output circuit TC _n. It can be provided in an appropriate place in the inside, especially in a place on the output side of the light receiving element DA _n or the light receiving element DB _n , if necessary.

Further, in the above-mentioned embodiment, the bus type optical data transmission devices 10, 20 and 40 have the stations S _n connected in a line, but the ends thereof are connected in a star shape. It doesn't matter.

The above description is merely an embodiment of the present invention, and the present invention can be variously modified without departing from the gist of the present invention.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an overall configuration of a bus type optical data transmission device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating in detail the configuration of an input / output circuit in the embodiment of FIG.

FIG. 3 is a view corresponding to FIG. 2 in another embodiment of the present invention.

FIG. 4 is a time chart explaining the operation in the embodiment of FIG.

FIG. 5 is a diagram illustrating a configuration of a light emitting / receiving element according to another embodiment of the present invention.

FIG. 6 is a diagram illustrating an overall configuration of a bus type optical data transmission device in the embodiment of FIG.

[Explanation of symbols]

10, 20, 40: bus type optical data transmission device S _n: Station F _n: an optical fiber PA _n, PB _n: emitting light receiving element LA _n, LB _n: the light emitting element DA _n, DB _n: the light-receiving element C _n: ON Output circuit RC _n : Received data input circuit TC _n : Transmitted data output circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location H04B 10/135 H04L 11/00 320 10/13 10/12 H04L 12/40

Claims (4)

[Claims] 1. A bus type optical data transmission device for enabling a plurality of stations to exchange data with each other, wherein a first optical fiber transmission device is provided for connecting the plurality of stations in series.
A first optical fiber provided between the first station and a second station, a second optical fiber provided between the first station and a third station, and the first optical fiber The optical signal connected to the end of the fiber and transmitted through the first optical fiber is converted into a first electric signal, and a second electric signal is converted into an optical signal to convert the first electric signal into the first electric signal.
A first light emitting / receiving element for outputting into the optical fiber, and an optical signal which is connected to an end portion of the second optical fiber and which is transmitted through the second optical fiber into a third electric signal. , A fourth electric signal is converted into an optical signal, and the second electric signal
Second light emitting / receiving element for outputting into the optical fiber, a reception data input circuit for supplying the first electric signal and the third electric signal to the first station, and transmission data output from the first station And the second electrical signal as the fourth electrical signal.
A transmission data output circuit that supplies the light emitting and receiving element and outputs the transmission data and the third electric signal output from the first station as the second electric signal to the first light receiving and receiving element, respectively. A bus type optical data transmission device characterized by: 2. The transmission data output circuit generates the second electric signal and the fourth electric signal by inverting the received first electric signal and third electric signal. Bus type optical data transmission device. 3. A reception data input circuit provided corresponding to every other station among the plurality of stations connected in series by an optical fiber.
3. The bus type optical data transmission device according to claim 2, wherein the electric signal and the third electric signal are inverted and supplied to the first station. 4. A first optical fiber and a second optical fiber provided between the first station and the second station and between the first station and the third station, respectively. 2. An optical fiber, wherein the first and second light emitting and receiving elements are respectively provided with a light receiving element and a light emitting element facing the end faces of the first optical fiber and the second optical fiber. 2. Bus type optical data transmission device.