JPS58146153A - Optical transmission system - Google Patents

Abstract

PURPOSE:To obtain an optical transmission system transmitting an accurate physical quantity of signal with low power consumption, by operating a transmission terminal intermittently. CONSTITUTION:A transmission terminal 1 stores an electrical energy obtained from a reception terminal via an optical fiber 31 and a photoelectric conversion means 16 to a storage circuit 17 comprising capacitors and batteries, and the energy is used for the operating power supply of a circuit section. A clock circuit 18 is normally charged. For example, a switch 19 is closed by about 10sec per 1hr, the power is supplied to circuits section 11-15 for the time to activate the sections. During the power application, the physical quantity such as temperature from a sensor (not shown) is converted into an electric signal via the conversion circuit 11 and the amplifier 12 to illuminate a light emitting element 14 with pulse width, pulse intervals and the number of pulse relating to the measured physical quantity from the drive circuit 13. This optical signal is transmitted to the terminal 2 via an optical fiber 32. Since the terminal 1 is activated intermittently, average power consumption is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical transmission system that transmits various physical quantities such as temperature and pressure using optical signals. More specifically, the present invention relates to an optical transmission system in which power consumption on the transmission end side is reduced by intermittently operating the transmission end side.

Optical transmission lines such as optical fibers or semiconductor lasers,
BACKGROUND OF THE INVENTION As the development of various optical elements such as LEDs progresses, various optical measurement and transmission systems are being proposed in place of conventional systems.

The present invention is an attempt to realize an optical transmission system capable of reducing power consumption on the transmission end side in such a system.

FIG. 1 shows a configuration program showing an example of a system according to the present invention.
This is a diagram. In the figure, 1 is the transmission end.

2 is a receiving end, and 3 is an optical transmission line connecting the transmission end 1 and the receiving end 2, which is shown here as being composed of two optical fibers 31 and 32. At the transmission end 1, 11 is a transmission unit (a general representation of a conversion circuit that is given a physical quantity and converts it into an electrical signal), and 12 is an amplifier that amplifies the electrical signal from this conversion circuit 11.

Reference numeral 13 denotes a light emitting element drive circuit which inputs an output signal from an amplifier and drives the light emitting element 14, and drives the light emitting element 14 with a pulse width, a pulse interval, a pulse number, etc. related to the physical quantity to be measured. 15 is a drive circuit 1 connected in series with the light emitting element 14
This transistor is turned on by the output of 3. The light emitting device 14 is optically coupled to one end of an optical fiber 32, and the light output of the light emitting device 14 is transmitted to the receiving end via the optical fiber 32.

16 is a solar cell that converts light energy into electrical energy;
It is optically coupled to one end of the optical fiber 31 by photoelectric conversion means such as a photovoltaic cell. Reference numeral 17 denotes a storage circuit in which electrical energy from the photoelectric conversion means 16 is stored, and although a capacitor is used here, a storage battery may also be used. These photoelectric conversion means 16 and power storage circuit 17 constitute a power supply circuit of the transmission end 2. Reference numeral 18 denotes a clock circuit which is operated by the power supplied from the power storage circuit 17, and is operated for a predetermined time TL.
(for example, one hour) and outputs a drive signal to the power storage circuit 1.
The switch 19 provided at the output 94 of 7 is driven for a certain period of time Tm (for example, 10 seconds). This clock circuit is
The zero conversion circuit 11 uses a low power consumption circuit configured with C-MOS or the like, and uses an element such as an FET as the switch 19. Amplifier 12. Both the drive circuit 13 and the light emitting element 14 are connected to the output terminal +V of the power storage circuit 17 via a switch 19.
When conductive, it is operated by electric power from the power storage circuit 17 (photoelectric conversion circuit 16).

At the receiving end 2, the 21#'i light source
is optically coupled to the other end. As this light source, a laser light source 1 light emitting diode, an incandescent lamp, etc. can be used. 22 is a light receiving element, which is optically coupled to the other end of the optical fiber 32. This light-receiving element is a light-receiving diode or a phototransistor.

A photoconductive element or the like can be used.

The operation of the device configured as described above is as follows. The light source 21 of the receiving end 2 is operated and the optical energy from there is sent to the transmitting end 1 via the optical fiber 31.

At the transmission end 1, the photoelectric conversion means 16 connects the optical fiber 3
The light energy emitted from one end of the light beam is received and converted into electrical energy. This electrical energy is transferred to the storage circuit 1
7 and the clock circuit 18 is activated. This clock circuit switches the switch 1 for 10 seconds every hour, for example.
Drive 9. As a result, the conversion circuit 11. amplifier 1
2. The drive circuit 13 is connected to the circuit 1 in which the switch 19 is conductive.
Power is supplied for 0 seconds and it operates. That is, the conversion circuit 11 converts the electrical signal e corresponding to the physical quantity to be measured.
After being amplified by the amplifier 12, the driving circuit 13 causes the light emitting element 14 to emit light at a pulse width, pulse interval, or number of pulses related to the physical quantity to be measured. The optical signal from the light emitting element 14 is sent to the receiving end 2 via the optical fiber 32.

At the receiving end 2, the light receiving element 22 receives the optical signal transmitted through the optical fiber 32, converts it into an electrical signal, amplifies it, and processes the signal to obtain a physical quantity.

According to the device configured in this way, the power consumption on the transmission end 1 side is the insignificant power consumption in the clock circuit 18 and the conversion circuit 11 . Amplifier 12. The sum of the power consumed in a short period of time, for example, Tm = 10 seconds when the drive circuit 13 is in an operating state, and the power consumed during the time when the light emitting element 14 is emitting light within 10 seconds is calculated by a predetermined time TL. It is an average value, and if TtnlTL is made smaller, the power consumption can be reduced as a whole.

FIG. 2 is a configuration and connection diagram showing another embodiment of the present invention, specifically illustrating a case where temperature is measured by a thermocouple and this temperature signal is transmitted to the receiving end.

In the system of this embodiment, a measurement start pulse P8 indicating the start of one measurement is transmitted from the receiving end 2@ via the optical fiber 31 as shown in FIG. Reference pulse P generated later. An optical signal containing each intermittent pulse is sent to the transmission end 1. At the receiving end 2, 23 adds these pulses p8. to the optical signal from the light emitting element 21. It plays the role of superimposing the po. The first logic circuit 19&, which is operated by power from the power storage circuit 17, inputs the measurement start pulse Ps and the reference pulse Pc contained in the optical signal transmitted via the capacitor C□, and switches the switch 19. Conducts electricity for a certain period of time.

Amplifier 12. Amplifier A2 configuring the drive circuit 13. Comparator A3. Mono multi circuit MM, logic, circuit: L9b
While switch 19 and switch 19 are conductive, power is supplied from photoelectric conversion means 16 (power storage circuit 17) to operate. While these are in operation, amplifier 12 amplifies the signal ex from thermocouple 11. The logic circuit 19b receives the measurement start pulse p and the reference pulse Pc from the logic circuit 19a, and also receives the output signal of the comparator A3, and switches S1. S2 are driven to operate in opposite directions. That is, the switch S1 is made conductive for a certain period of time Ts from when the measurement start pulse Ps is first applied until the reference pulse P is applied. An integrator including an amplifier A2 and a capacitor C2 integrates the output voltage EX of the amplifier 12 for a certain period of time Ts during which the switch S1 is conductive. Subsequently, the switch S is turned OFF and the switch S2 is made conductive to discharge the output of the integrator until it reaches a predetermined reference voltage E8.

Figure 3 (b) shows the output voltage E of this integrator. FIG. Integrator, comparator A3. Cl thick circuit 19
b, the loose formed including the switches S□ and S2 is
Such an operation is performed every time a measurement pulse P8 is applied, and a fixed time T and a reference pulse P are applied.

from the integrator output voltage E. The duty ratio of the time TX until becomes the reference voltage E8 is the output voltage of the amplifier 12,
That is, it corresponds to the output signal e of the thermocouple 11. The logic circuit 19b and the monomulti circuit MM apply a reference pulse P to the light emitting element 14 via the transistor 5 as shown in FIG. 3(C). and the output voltage E of the integrator. becomes the reference voltage and the thin pulse width signal PK generated at the 9th point
Accordingly, the light pulse signal is driven to generate an optical pulse signal having an interval from this point. These pulse signals are transmitted to the receiving end 2 via the optical fiber 32, the pulse interval TX is detected at the receiving end 2, and the temperature is calculated by processing Tx and T8 obtained at the receiving end. You can know.

In each of the above embodiments, the transmission end and the reception end are connected via an optical fiber.
Instead of an optical fiber, communication may be made via a spatial transmission path, and the photoelectric conversion means 16 on the transmission end side may also be able to receive sunlight. In addition, the photoelectric conversion means 1
6. The power supply circuit consisting of the power storage circuit 17 may be replaced with a battery, and in this case, the battery can be used for a long period of time.Furthermore, in each of the above embodiments, the light emitting element 14 is used instead of a battery. Again, instead of this,
An optical control element such as a liquid crystal or PLZT that controls the amount of reflection or transmission of light may be used to control the light supplied from the receiving end and return it to the receiving end. Furthermore, at the transmission end, the circuits to which power is intermittently supplied via the switch do not have to be all the circuits that constitute the transmission end.
i/ may also be forced to be performed only on circuits with large power consumption.

As explained above, according to the present invention, the power consumption on the transmission end side is small, and therefore an optical transmission system that can be used for a long time with a power source including a charging conversion means and a battery can be realized.

[Brief explanation of the drawing]

FIG. 1 is a configuration block diagram showing an example of a system according to the present invention, FIG. 2 is a configuration and connection diagram showing another embodiment of the present invention,
@Figure 5 is a waveform diagram for explaining the operation of the system in Figure 2. 1... Transmission end, 2... Receiving end, 3... Optical transmission line,
DESCRIPTION OF SYMBOLS 11... Conversion circuit, 12... Amplifier, 13... Drive circuit, 14... Light emitting element, 15... Transistor, 16... Photoelectric conversion circuit, 17... Electric storage circuit, 18
... Clock circuit, 19... Switch, 21... Light source, 22... Light receiving element.

Claims (1)

[Scope of Claims] (1) In a system for transmitting an optical signal related to a measured physical quantity from a transmission end side to a reception end side, a conversion circuit for converting a measured physical quantity into an electrical signal on the transmission end side; an optical element that generates an optical signal related to the physical quantity; a drive circuit that inputs a signal from the conversion circuit to drive the optical element; a power supply circuit; 4111. An optical transmission system comprising an optical element and a switch for supplying at least one of a drive circuit, the switch being driven intermittently. (2) The optical transmission system according to claim 1, wherein the switch is intermittently driven by an output signal of a clock circuit operated by power from a power supply circuit. (3) The optical transmission system according to claim 1, wherein the switch is driven intermittently in relation to the signal transmitted from the receiving end side. (4) Optical transmission system according to claim 1, in which the power supply circuit includes charging conversion means for converting light energy and/or sunlight transmitted from the receiving end side into electrical energy. The optical transmission system according to claim 1, wherein the power supply circuit is constructed of a battery. (6) K to supply the reference clock signal from the receiving end to the transmission end to operate the circuit installed on the transmission end.
An optical transmission system according to claim 1.