JP2000068941A - Optical signal power amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To operate both systems simultaneously by extending a transmission range of the optical communication system and the electric communication system. SOLUTION: The 2-way optical signal power amplifier having two optical signal transmission/reception sections 10, 12 and a signal waveform shaping section 11, where an optical signal received from the one optical signal transmission/reception section is amplified up to a specified level by the signal waveform shaping section 11 and waveform-shaped and the result is outputted from the other optical signal transmission reception section is provided with a bus power supply section 18 that generates a 2-wire electric bus power supply that superimposes a signal on a power supply from an original power supply received externally, a terminator 19 that connects to the electric bus and shapes a signal waveform, an electric signal transmission/reception section 22 that sends/receives an electric signal with the electric bus, and transmission direction selection.waveform shaping means 20, 11 that discriminate a transmission reception section receiving first the signal among the electric signal transmission/ reception section 22 and the optical signal transmission/reception sections 10, 12 and transmit the signal after waveform shaping to the transmission/reception section other than the transmission/reception section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a meter for measuring, for example, a flow rate, a pressure, a temperature, etc. in a plant by a field device installed in a field and collectively processing and controlling data in a remote control room. The present invention relates to an optical signal power amplifier suitable for being applied to an instrumentation system. In particular, by amplifying and shaping the power level of an optical signal that is attenuated in an optical fiber, which is a data communication path, and converting the optical signal into an electric signal and connecting it to an electric bus system, The present invention relates to an optical signal power amplifier capable of mixing optical bus systems.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory diagram showing an example of use of a conventional optical signal power amplifier of this type, and FIG. 5 is a block diagram showing an internal configuration of the optical signal power amplifier. 4, one input / output terminal of an optical signal power amplifier 1 'is connected to a host device 4 in a control room via an optical fiber 2, and the other input / output terminal is an optical fiber 3, an optical splitter 5, and an optical fiber. 6
Is finally connected to the field device 7 '.

Here, the optical splitter 5 is an optical element using a waveguide, a mirror, and the like. It has no electrical energy source and evenly distributes an optical signal input from one input / output terminal to another input / output terminal. Normally, other devices except the host device 4 are often installed at a remote site called a field, and the optical fiber 2 connecting the host device 4 and the optical signal power amplifier 1 ′ has a length of several hundred meters to several meters. It is. In general, systems using electric buses have drawbacks such as being susceptible to noise and lightning, but optical field devices have particularly high security because the transmission medium is light and resistant to noise and lightning. Often applied to systems that require

In optical transmission using an optical fiber, signal distortion and attenuation are small, so that it can be used at a long distance.
This optical signal power amplifier 1 'is used in an optical instrumentation system to further extend its transmission distance. Further, the optical signal power amplifier 1 ′ receives power supply from the power supply device 8 via the power supply line 9, and does not have a power generation function, a battery, and the like inside.

The host device 4 performs bidirectional communication with the field device 7 ′ via the optical fiber 2, the optical signal power amplifier 1 ′, the optical fiber 3, the optical splitter 5, and the optical fiber 6. It monitors and controls various measured quantities such as temperature, pressure, and temperature. In this, the main function of the optical signal power amplifier 1 ′ is to shape a distorted signal waveform in the optical communication path of the optical fibers 2 and 3, and amplify the attenuated optical signal power to transmit each signal from the host device 4. The purpose is to extend the distance to the field device 7 'to a distant place.

In FIG. 5, power is supplied to an optical signal power amplifier 1 ′ through a power supply line 9.
After being insulated from the outside by 3, the circuit power supply unit 14 operates by generating a predetermined power supply voltage for driving the internal circuit of the device. The optical signal transmission / reception units 10 and 12 each include a so-called integrated light emitting / receiving element having both a light receiving element such as a photodiode and a light emitting element such as an LED, an amplifier circuit, and a light emission driving circuit. It has both a function of converting and a function of converting an electric signal into an optical signal.

When an optical signal is input from the optical fiber 2 to the optical signal transmitting / receiving unit 10, it is output as an electric signal to the signal waveform shaping unit 11 by the operation of the optical signal transmitting / receiving unit 10. Here, the electric signal output from the optical signal transmission / reception unit 10 includes an optical transmission path to the optical fiber 2 and jitter generated in the conversion process of the optical signal transmission / reception unit 10.

In general, when such an optical signal power amplifier is installed, the signal transmission form and the bit rate in the system are known in advance. After shaping the signal to be transmitted to the default signal width and bit rate originally transmitted,
Output to the optical signal transmitting / receiving unit 12. The optical signal transmitting / receiving unit 12 outputs the electric signal received from the signal waveform shaping unit 11 to the optical fiber 3 at a predetermined optical signal power level. By a series of these operations, the optical signal input from the optical fiber 2 is output to the optical fiber 3 after eliminating its jitter component, amplifying the optical power to a predetermined value.

Conversely, when an optical signal is input from the optical fiber 3, the optical signal shaped and amplified by the same action is transmitted from the optical fiber 2, but the description is omitted. With the above-described operation, the optical signal power amplifier 1 ′ operates as a device that amplifies the power of the optical signal in both directions.

[0010]

As described above, the main function of the conventional optical signal power amplifier is to perform signal waveform distortion shaping and optical signal power amplification in a bidirectional optical communication system. It has no function of connecting to an electric communication bus. Therefore, it cannot be used to extend the transmission distance by connecting to a field device compatible with an electric bus.

SUMMARY OF THE INVENTION An object of the present invention is to extend the transmission distance of an optical communication system and at the same time extend the transmission distance of an electric communication system, and to provide an optical communication system by interconnecting an optical bus and an electric bus. The present invention is to provide an optical signal power amplifier capable of coexisting with an electric communication system.

[0012]

According to an aspect of the present invention, there is provided an optical signal power amplifier, comprising: receiving means for converting an optical signal into an electric signal; and converting the electric signal into an optical signal and transmitting the signal. Two optical signal transmitting and receiving units comprising a transmitting means, and a signal waveform shaping unit for amplifying the electric signal received and converted by these optical signal transmitting and receiving units and shaping the waveform,
In a bidirectional optical signal power amplifier that amplifies the power of an optical signal input from one optical signal transmitting / receiving unit to a specified level by the signal waveform shaping unit, and outputs the waveform from the other optical signal transmitting / receiving unit, A power supply section for generating a two-wire electric bus power supply for superimposing a signal on a power supply from an external power supply, a terminator connected to an electric bus for shaping an electric bus signal waveform, An electric signal transmitting / receiving unit for transmitting / receiving an electric signal to / from the expression bus; and a transmitting / receiving unit that first receives a signal between the electric signal transmitting / receiving unit and the two optical signal transmitting / receiving units. Transmission direction selecting / waveform shaping means for sending the signal after waveform shaping to the transmitting / receiving unit of the above.

According to a second aspect of the present invention, one of the two optical signal transmitting / receiving units is connected to a host device via an optical fiber, and the other is connected to an optical field device via an optical fiber. The electric signal transmitting and receiving unit is connected to an electric field device via an electric bus.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, FIG. 1 is an explanatory diagram showing an example of use of the optical signal power amplifier 1 of this embodiment, FIG. 2 is a block diagram showing an internal configuration thereof, and FIG. 3 is a circuit configuration diagram. In these figures, the same components as those shown in FIGS. 4 and 5 are denoted by the same reference numerals.

In FIG. 1, one optical signal input / output terminal of an optical signal power amplifier 1 is connected to a host device 4 in a control room via an optical fiber 2, and the other optical signal input / output terminal is connected to an optical fiber 3 and an optical fiber. Finally, it is connected to a plurality of optical field devices 7 via a splitter 5 and an optical fiber 6. An electric signal input / output terminal newly provided in the optical signal power amplifier 1 is connected to a terminator 16 and a plurality of electric field devices 17 via a two-wire electric bus 15.

In FIG. 2, power is supplied to the optical signal power amplifier 1 from a main power supply via a power supply line 9, and after being insulated from the outside by an insulating section 13, an internal circuit of the device is controlled by a circuit power supply section 14. A predetermined power supply voltage for driving is generated. Further, a predetermined power supply voltage for the electric bus 15 is generated by a bus power supply section 18 connected to the insulating section 13.

Since the bus power supply unit 18 supplies power to the electric bus transmission / reception terminal via the terminator 19, the electric bus transmission / reception terminal operates as a power supply source for the two-wire electric bus 15. Here, the electric bus 15 can be configured by combining an inductance, a resistor, and a capacitor as long as it is a power source for a so-called field bus used in the field of instrumentation, for example.

An electric signal transmission / reception unit 22 is connected to the electric bus transmission / reception terminal via an insulating unit 21 so that transmission / reception at the physical layer level defined in the standard of the two-wire electric bus 15 can be performed. It has become. Electric signal transmitting / receiving unit 22
The circuit configuration is basically a well-known technique, although it depends on the bus system. Therefore, detailed description is omitted.

Since the reception outputs of the two optical signal transmitting / receiving units 10 and 12 and the electric signal transmitting / receiving unit 22 are all input to the transmission direction selecting unit 20 as shown in FIG. When input to the transmission / reception unit 10, the electric signal converted by the operation of the optical signal transmission / reception unit 10 is input to the retriggerable one-shot multivibrator 27 (see FIG. 3) of the transmission direction selection unit 20.

In FIG. 3, the multivibrator 2
The electric signal inputted to the multivibrator 2
7, a High output is generated for a certain period of time. Therefore, the other retriggerable one-shot multivibrators 26 and 28 are connected to the NOR gate 29,
The enable input operates in the non-operational direction by the action of 31, and during this time, even if signals are input to the multivibrators 26 and 28, their outputs remain LOW. Accordingly, the AND gates 32 and 34 also output LOW during this time.

On the other hand, since the signal in the operation direction is continuously supplied from the NOR gate 30 to the enable input of the multivibrator 27, while the signal is input within the extension time of the signal set in the multivibrator 27, , AND
Gate 33 sends the signal to a three-input OR gate 35. The output signal of the three-input OR gate 35 is sent to the signal waveform shaping unit 11 in FIG. The retriggerable one-shot multivibrator is provided for the purpose of extending the signal time and not accepting an input from another reception terminal during that time. It is also possible to extend the time.

As described above, the reason that the signal is not input from the receiving terminal to which the signal is initially input by the transmission direction selecting unit 20 is that the loopback signal (wraparound) when each input / output terminal outputs is output. In order to eliminate. The signal synchronized with the signal input from the AND gate 33 is output from the three-input OR gate 35 in FIG.
1, the signal includes an optical transmission path through the optical fiber 2 to the optical signal power amplifier 1 and a jitter generated in a conversion process in the optical signal transmitting / receiving unit 10 as described in the related art. . For this reason, the signal waveform shaping unit 11 shapes the signal input from the optical signal transmitting / receiving unit 10 into a default signal width and bit rate that are originally transmitted, and then outputs the signals to the AND gates 23, 24, and 25 in FIG. .

As shown in FIG. 3, the inverted signals of the multivibrators 26, 27, 28 of the transmission direction selector 20 are supplied from the NOT gates 36, 37, 38 to one input of each of the AND gates 23, 24, 25. Therefore, the output of the AND gate 24 is fixed at the LOW level, and the AND gates 23 and 2
From 5, the signals shaped by the signal waveform shaping unit 11 are output to the electric signal transmitting / receiving unit 22 and the optical signal transmitting / receiving unit 12, respectively. The electric signal transmitting / receiving unit 22 converts the input signal into a bus signal conforming to the physical layer form of the electric bus and outputs the converted signal to the insulating unit 21. The optical signal transmitting / receiving unit 12 converts the input signal into an optical bus. Is converted into an optical signal that conforms to the physical layer configuration of the above and is amplified to a predetermined power level, and is output to the optical fiber 3. Here, the transmission direction selection unit 20 and the signal waveform shaping unit 11 constitute a transmission direction selection / waveform shaping unit in claim 1.

The optical signal input from the optical fiber 2 by these series of operations eliminates its jitter component, and then the optical power is amplified to a predetermined value, and converted into an optical signal from the optical fiber 3 and converted into an electric signal. Output from the electric bus 15.

In the same manner, when an optical signal is inputted from the optical fiber 3 and when an electric signal is inputted from the electric bus 15, an electric signal shaped to another input / output terminal or a shaped signal is inputted. The amplified optical signal will be transmitted, but the description is omitted. As is clear from the above description, the optical signal power amplifier 1 is a device that amplifies the power of an optical signal in both directions and, at the same time, a converter that transmits and receives between an optical signal and an electric signal, that is, an optical type. It also operates as a signal converter for connecting the bus and the electric bus.

[0026]

As described above, according to the present invention, the transmission distance of the optical communication system is extended while the transmission distance of the electric communication system is extended. Mixing can also be made possible. In addition, since the transmission path extended by the optical signal power amplifier of the present invention is a communication path using light as a medium, a system that is more reliable against accidents such as lightning and noise than extending an electric bus. Can be built.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a usage example of an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of the embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a transmission direction selection unit in FIG. 2;

FIG. 4 is an explanatory diagram showing an example of use of a conventional technique.

FIG. 5 is a block diagram showing an internal configuration of a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical signal power amplifier 2, 3, 6 Optical fiber 4 Host device 5 Optical splitter 7 Optical field device 8 Power supply device 9 Power supply line 10, 12 Optical signal transmission / reception unit 13, 21 Insulation unit 14 Circuit power supply unit 15 Electric bus 16, 19 Terminator 17 Electric field device 18 Bus power supply unit 20 Transmission direction selection unit 22 Electric signal transmission / reception unit 23, 24, 25, 32, 33, 34 AND gate 26, 27, 28 Retriggerable one-shot multivibrator 29, 30, 31 NOR gate 35 3-input OR gate 36, 37, 38 NOT gate

Claims (2)

[Claims] 1. An optical signal transmitting and receiving unit comprising: a receiving unit for converting an optical signal into an electric signal; and a transmitting unit for converting an electric signal into an optical signal and sending the signal. A signal waveform shaping unit for amplifying the electrical signal and shaping the waveform, amplifying the power of the optical signal input from one of the optical signal transmitting and receiving units to a specified level by the signal waveform shaping unit, and shaping the waveform. A bidirectional optical signal power amplifier that outputs from the other optical signal transmitting and receiving unit, a power supply unit that generates a two-wire electric bus power supply for superimposing a signal on a power supply from a main power supply input from outside; A terminator connected to a bus for shaping an electric bus signal waveform; an electric signal transmitting / receiving unit for transmitting / receiving an electric signal to / from the electric bus; and an electric signal transmitting / receiving unit and the two optical signal transmitting / receiving units; of Transmitting direction selecting / waveform shaping means for judging a transmitting / receiving section which has received a signal first, and transmitting a signal after waveform shaping to a transmitting / receiving section other than the transmitting / receiving section, an optical signal power amplifier comprising: . 2. The optical signal power amplifier according to claim 1, wherein one of the two optical signal transmitting / receiving units is connected to a host device via an optical fiber, and the other is connected to an optical field device via an optical fiber. An optical signal power amplifier, wherein the electric signal transmitting / receiving unit is connected to an electric field device via an electric bus.