JPS61269075A - Measuring instrument applying light - Google Patents

Abstract

PURPOSE:To enable both AC and DC components to be measured when a quantity to be measured is optically detected by making a signal processed by a differential integrator and a signal processed by a differential amplifier and processing both the signals for a division. CONSTITUTION:A light from a transmitter 1 is projected into a photosensor unit 15 including a Faraday element 5 and the light modulated by a magnetic field to be measured is received by a receiver 9. A differential amplifier 17 sums up the output of an amplifier 10 and of a differential integrator 16 and this sums up the output of the amplifier 10 and the output of the differential amplifier 17 divided by the gain thereof. The output of the differential amplifier 17 excluding a modulated component is divided by the output of the differential amplifier 17 proportional to the modulated component thereof by a divider 14 to obtain an output. Therefore, not only the phenomena the AC component of a quantity to be measured but also those of the DC component thereof can be measured without being affected by the change in a light transmitting path and the light transmitter.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention uses a material whose optical properties change depending on the quantity to be measured, such as an electric field or a magnetic field, and utilizes the change in light intensity to optically measure the quantity to be measured. The present invention relates to a measuring device that detects

[Conventional technology]

Figure 8 is a diagram showing the configuration of a conventional optical measurement device.
This shows a magnetic field measuring device that uses the Alladay effect. In the figure, h and t! It'i optical transmitter, (2) is an optical fiber, (31 is a lens, 141 is a polarizer, (6) is 7
A2 d element, (61 is analyzer, 17) f'i lens, 181 d optical 7 eyeper, (9) C optical receiver, tto+
is an amplifier, (11) is an integrator, 0 to coupling capacitors, (11 is an amplifier, and α4 is a divider.

Next, the operation will be explained. The light emitted from the optical transmitter 1!1 passes through the optical 7 eyeper (2), becomes a parallel beam at the lens (3), and enters the polarizer (4).It becomes linearly polarized light at the polarizer (4), and becomes a Faraday beam. When the light enters the element (5), if there is a magnetic field in a direction parallel to the traveling direction of the light, this magnetic field rotates the plane of polarization of the linearly polarized light due to the Faraday effect.Therefore, the analyzer (61) If the polarizer (41) and the analyzer (6) are set to transmit light from the plane (generally, the polarization planes of the polarizer (41) and the analyzer (6) make an angle of 45.0 so that the linearity is the best. The light is intensity-modulated by a magnetic field (arranged as shown in Fig. After amplification with an amplifier (lα,
On the other hand, in order to average the modulation components, an integrator (injected into the river,
On the other hand, in order to amplify only the modulation component, a coupling capacitor (1'4) is used to pass the AC component, and an amplifier (I is used to amplify it).The outputs of both of these are divided by a divider 04.This division By processing, the optical transmission path (for example, the optical 7-eyeper +21 +81 itself, and these and the lens +31171)
This compensates for errors due to loss changes and optical power changes at +11% optical transmission. This is the optical sensor M (
1119 (consisting of lens +31, polarizer (41, Faraday element TFI), analyzer (6), and lens 1f)) does not change the degree of light intensity modulation caused by the magnetic field.
Even if the optical power of the optical transmitter +11 becomes smaller or the loss in the optical transmission line increases, the average received light power (the amount after removing the modulation component, that is, equivalent to the output of the integrator (11) ) also becomes smaller, and as a result of division, a constant output is always obtained.

[Problem that the invention seeks to solve]

Since the conventional optical applied measuring device is configured as described above, it can only measure alternating current, and cannot measure quantities such as direct current pulses. It was developed to solve this problem, and provides an optical measuring device that can measure up to DC pulses.

[Means for solving problems]

The optical applied measurement device according to the present invention includes a differential integrator that operates with the output of an optical receiver as one input, and a differential integrator that operates with the output of the optical receiver and the output of the differential integrator as input. a differential amplifier whose output is divided by its own gain multiple as the other input of the differential integrator; and a divider which outputs the ratio of both outputs of the differential integrator and the differential amplifier. It is equipped with the following.

[Effect]

In this invention, the differential integrator integrates the difference between the output of the optical receiver and the modulation component and outputs an average value signal with the modulation component removed, and the differential amplifier integrates the difference between the output of the optical receiver and the modulation component. The difference from the average value is amplified and a signal proportional to only the modulation component is output.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. K1
In the figure, the same reference numerals as those in FIG. 8 indicate the same parts as in the prior art. 04m is a differential J integrator which inputs the difference between the output signal of the amplifier tlol and a signal obtained by dividing the output of a differential amplifier αη, which will be described later, by its gain A using a resistor all4. a? ) is a differential amplifier DC-coupled with the amplifier (lα), and the output signal of the amplifier (1 (1) and the differential integrator -
The difference between the output signal and the output signal is input.

Next, the operation will be explained. The operation from the optical transmitter +11 to the amplifier 001 is the same as the conventional one, and therefore will not be described here.

The differential amplifier 11η generates a voltage proportional to the output of the amplifier fill, that is, the combined optical power of the optical power when the optical sensor section is not modulated (average received optical power) and the optical power when the optical sensor section is modulated. t'' is one input, and the output of the differential integrator α is the other input, and the output of the differential integrator α is used as one input. The voltage with the output divided by its gain is used as another input and summed.
In this way, the differential divider 681 a outputs a voltage proportional to the optical power removed from the modulation component 1-*, and the differential amplifier +
171 outputs a voltage proportional to the modulation component, and by dividing both of them by the divider 04, it is possible to accurately generate DC voltage without being affected by fluctuations in the optical transmission line or the optical transmitter. Even pulse phenomena can be measured.

Note that the above example is an example of magnetic field measurement using the Faraday effect, but electric field measurement using the Pockels effect,
Voltage measurement, pressure and acceleration measurement using photoelastic effect,
The same effect can be achieved even when the intensity of the light is modulated based on the measured amount of ground cover. In addition, in this embodiment, the case where the DC gain is 1 is described as the differential integrator 01, but if the gain is other than 1, the output is set to 1 of the gain and summed to the differential amplifier aη. The same effect can be achieved even if

〔Effect of the invention〕

As described above, in this invention, a differential integrator removes the modulation component to output an average value signal, one differential amplifier outputs a signal proportional to the modulation component, and the two outputs are divided by a full divider. Since it is configured to calculate, not only the alternating current component but also the direct current component of the quantity to be measured can be measured.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a magnetic field measuring device according to an embodiment of the present invention, and FIG. 8 is a block diagram of a conventional magnetic field measuring device. In the figure, 1 is an optical transmitter, (91 is an optical receiver, l14 is a divider (, On is an optical sensor part, Q is a differential integrator, a'6 is
It is a t-x differential amplifier. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] (1) Equipped with an optical sensor section in which the amount of light transmitted changes according to a change in the amount to be measured, an optical transmitter that transmits light to this optical sensor section, and an optical receiver that receives the light transmitted through the optical sensor section. In the optical applied measurement device, a differential integrator operates with the output of the optical receiver as one input, a differential amplifier operates with the difference between the output of the optical receiver and the output of the differential integrator as input; The output of this differential amplifier divided by the gain multiple of the differential amplifier is set as the other input of the differential integrator, and the ratio of the outputs of the differential integrator and the differential amplifier is output. An optical application measuring device characterized by being equipped with a calculator.