JP2009020030A - Device for measuring underwater electromagnetic field - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for measuring underwater electromagnetic field, capable of stabilizing application of an alternating current signal under water, and correctly measuring the electric potential difference or magnetic field generated, accompanying the applied signal. <P>SOLUTION: Offset voltage Vso from an offset power supply 13 is superimposed on the alternating current signal Va, generated by an alternating current signal generator 11 of a signal transmitting system 10 by an amplifying circuit 14 to generate an output signal Vo; the output signal Vo is applied to the underwater 8 via electrodes 14 and 15 for signal application; the potential difference or the magnetic field produced concomitantly with the applied signal Vo is detected by the sensor element 21 of a signal receiving system 20; and the detected signal is recorded in a recorder 23 via an amplifying circuit 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an underwater electromagnetic field measuring apparatus that applies a signal from outside to water and measures a potential difference and a magnetic field generated accompanying the signal.

    In order to detect underwater (underwater) conditions and target bodies underwater (underwater), a potential difference or magnetic field in the water (underwater) is detected. Conventionally, as shown in FIG. 7, as a potential difference measuring device in the sea, a signal generating power supply device 1, signal voltage applying electrodes 2A and 2B connected to the signal generating power supply device 1, and electrodes for potential difference measurement A device comprising 3A, 3B and an amplification / display electronic circuit unit 4 is disclosed (for example, see Patent Document 1).

    In this potential difference measuring device, electrodes 2A and 2B and potential difference measuring electrodes 3A and 3B are provided in the sea 8 and a signal voltage is applied to the electrodes 2A and 2B from the signal generating power source device 1 to thereby generate the signal generating power source device 1. The positive electrode → the electrode 2A → the seawater 8 → the electrode 2B → the power is supplied through the path of the negative electrode of the signal generating power supply device 1. At this time, a current flows in the seawater having resistivity, and a potential difference signal corresponding to the current value output from the signal generating power supply device 1 is generated in the seawater. This potential difference signal is detected by electrodes 3A and 3B for potential difference measurement.

Further, an underwater electric field measuring device is disclosed in which a signal generating device is provided in a hull, an electric field sensor is provided in the sea, an electric field in the sea is measured by the electric field sensor, and a ship is extracted (see, for example, Patent Document 2).
Utility Model Registration No. 3123406 JP 2004-347453 A

    In the above-described conventional underwater electromagnetic field measurement device such as a potential difference measurement device, the signal applied to the water (underwater) from the signal generator can be an alternating current signal, a pulse signal, etc. in addition to direct current. Focused on the fact that AC signals have less noise such as drift during measurement compared to DC signals, and attempted to realize an underwater electromagnetic field measurement device that measures potential differences and magnetic fields in water using AC as a signal source. It was.

    In the course of the experiment, the signal generator applies the generated AC signal to the water from the two signal application electrodes installed in the water, and the signal receiver detects the potential difference and magnetic field that accompany the signals. In this case, when the waveform of the AC signal to be applied is shown in FIG. 6A, the waveform of the detected electric field signal is distorted as shown in FIG. 6B when the polarity of the AC signal is inverted. There was found. For this reason, there is a problem that the measurement of the potential difference and the magnetic field cannot be performed correctly.

    The present invention has been made paying attention to the above-described problems, and provides an underwater electromagnetic field measuring apparatus that stabilizes the application of an alternating current signal in water and can correctly measure a potential difference and a magnetic field that accompany the applied signal. For the purpose.

      The underwater electromagnetic field measuring apparatus according to the present invention is generated in association with a signal generator, a signal applying electrode for applying a signal generated by the signal generator into the water, and a signal generated by the signal generator. A signal receiver for detecting a potential difference and a magnetic field is characterized in that the signal generator outputs an alternating current with an offset greater than the peak value of the alternating current.

  According to the present invention, since an offset equal to or higher than the peak value of the alternating current is superimposed on the alternating current signal output from the signal generator, the underwater applied signal is not distorted. A signal can be used, and measurement with reduced influence of noise such as drift occurring during measurement can be performed as compared with the case of using direct current. Compared to the prior art, the potential difference and magnetic field in water can be measured more correctly.

    Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a schematic diagram for explaining an outline of an underwater electromagnetic field measuring apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing a circuit configuration of the underwater electromagnetic field measuring apparatus according to the embodiment. As shown in FIG. 1, the underwater electromagnetic field measuring apparatus according to this embodiment includes an AC signal generator 10 and signal application electrodes 12A and 12B for applying a signal generated from the AC signal generator 10 to water. And a signal receiver 20 for detecting a physical quantity such as a potential difference or a magnetic field generated accompanying signals applied to the water from the electrodes 12A and 12B.

    For example, when measuring an underwater potential difference with this underwater electromagnetic field measurement device, an alternating current signal is generated by the signal generator 10 using the electrodes 21A and 21B as the sensor elements 21 of the signal receiver 20, and used for signal application. Application to water through the electrodes 12A and 12B. As a result, an underwater current flows between the electrodes 12A and 12B, and a potential difference between the electrodes 21A and 21B generated in association with the current is detected by the circuit unit (controller) 20A of the signal receiver 20.

    However, the configuration of FIG. 1 is the same as that of the circuit shown in FIG. 7 in which the generated signal is an AC signal, and the feature of the present invention is the circuit configuration of the signal generator 1. Hereinafter, each circuit will be described with reference to the circuit of FIG.

    In this embodiment of the underwater electromagnetic field measuring apparatus, a signal transmission system (signal generator) 10 that generates an AC signal includes an AC signal transmitter 11, an offset voltage source 13, and an amplifier circuit 14. As shown in FIG. 3, the AC signal transmitter 11 outputs an AC signal Va that changes sine between + (plus) and − (minus) around the zero point. The offset voltage source 13 outputs an offset voltage Vos. The amplifier circuit 14 receives the AC signal Va from the AC signal transmitter 11 and the offset voltage Vos from the offset voltage source 13 as input, and superimposes the offset voltage Vos on the AC signal Va, as shown in FIG. A signal Vo that changes sine up and down around the minute Vos is output. The offset voltage Vos is set to be larger than the peak value Vm of the AC signal. The offset voltage Vos is configured to be changeable by a built-in volume.

  The signal reception system 20 is a circuit for detecting a physical quantity such as a potential difference and a magnetic field generated accompanying the signal output from the signal transmission system 10, and includes electrodes 21A and 21B that are sensor elements 21 that detect the potential difference. , An amplifier circuit 22 and a recorder 23 are provided.

    Here, in order to detect a potential difference (electric field) by the signal receiving system 20, two electrodes for detecting an electric field are used as sensor elements. However, when the signal receiving system 20 detects magnetism, the sensor element 21 is used. A magnetic sensor such as a fluxgate type is used. The amplifier circuit 22 has a filter function for amplifying the signal detected by the sensor element 21 and further extracting a target AC signal. The recorder 23 records the detection signal value output from the amplifier circuit 22.

  In this embodiment of the underwater electromagnetic field measuring apparatus, the waveform of the applied signal Vo output from the signal transmission system 10 is as shown in FIG. 4 for one cycle, and further, a predetermined number of cycles are shown. 5 (a). An applied signal Vo having this waveform is applied between the electrodes 12A and 12B, and the waveform of, for example, an electric field signal detected by the sensor element 21 accompanying the applied signal Vo is as shown in FIG. Become. When comparing the waveform of FIG. 5B with the waveform of FIG. 6B, in FIG. 6B, distortion occurs in the polarity switching portion, whereas FIG. In (b), since there is no signal polarity switching, no distortion occurs. Therefore, in this embodiment underwater magnetic field measurement apparatus, the electric field signal detected by the signal receiving system 20 can be stably measured without being distorted.

It is a schematic diagram for demonstrating schematically the underwater electromagnetic field measuring apparatus of one Embodiment of this invention. It is a block diagram which shows the circuit structure of the underwater electromagnetic field measuring apparatus of the embodiment. It is a wave form diagram for one period of AC signal Va output from the AC signal transmission system of the underwater electromagnetic field measuring apparatus of the same embodiment. It is a wave form diagram for one period of signal Vo output from the signal transmission system of the underwater electromagnetic field measuring device of the embodiment. It is a real waveform of the underwater electric field measuring apparatus of the embodiment, wherein (a) is a waveform diagram showing a signal Vo output from a signal transmission system, and (b) is a waveform diagram showing a signal detected by a signal reception system. . In the underwater electromagnetic field measuring apparatus shown in FIG. 1, it is an actual waveform at the time of outputting only an alternating current signal as a signal from a signal generator, Comprising: (a) is a waveform diagram of the signal output from the signal transmitter, (b) FIG. 4 is a waveform diagram showing a signal detected by a signal receiver. It is a block diagram which shows an example of the conventional potential difference measuring apparatus.

Explanation of symbols

10 Signal transmission system (signal generator)
11 AC Signal Transmitter 12A, 12B Signal Application Electrode 13 Offset Voltage Source 14 Amplifier Circuit 20 Signal Receiving System (Signal Receiver)
21 Sensor element 21A, 21B Potential difference detection electrode 22 Amplifier circuit 23 Recorder

Claims (1)

To detect a signal generator, a signal application electrode for applying a signal generated by the signal generator into the water, and a potential difference and a magnetic field that accompany the application of the signal generated by the signal generator In the underwater electromagnetic field measuring device composed of the signal receiver of
The underwater electromagnetic field measuring apparatus, wherein the signal generator outputs a signal in which an offset equal to or higher than a peak value of the alternating current is superimposed on the alternating current.

Images