CN115201510A - Front-end signal processing circuit suitable for marine electromagnetic sensor - Google Patents
Front-end signal processing circuit suitable for marine electromagnetic sensor Download PDFInfo
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- CN115201510A CN115201510A CN202210872418.6A CN202210872418A CN115201510A CN 115201510 A CN115201510 A CN 115201510A CN 202210872418 A CN202210872418 A CN 202210872418A CN 115201510 A CN115201510 A CN 115201510A
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- electromagnetic sensor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P1/00—Details of instruments
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
- H03H7/01—Frequency selective two-port networks
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- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
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Abstract
The invention discloses a front-end signal processing circuit suitable for a marine electromagnetic sensor, which relates to the technical field of electromagnetic principle flow velocity measurement and comprises the following components: the filter circuit, the amplifying circuit and the differential output circuit are connected in sequence; the input end of the filter circuit is connected with an electrode of the electromagnetic sensor; and the output end of the differential output circuit is connected with the electric connector of the electromagnetic sensor through a connecting cable. The invention improves the anti-interference capability of the electromagnetic sensor for the ship and realizes stable and reliable transmission of induced electromotive force.
Description
Technical Field
The invention relates to the technical field of electromagnetic principle flow velocity measurement, in particular to a front-end signal processing circuit suitable for a marine electromagnetic sensor.
Background
The electromagnetic principle device for measuring flow velocity, such as an electromagnetic log, is widely used for measuring velocity of ships and submarines.
The electromagnetic sensor is a sensitive element of the electromagnetic log, and an alternating magnetic field is applied to an excitation coil formed by silicon steel sheets, an electrode is used for picking up induced electromotive force caused by cutting magnetic lines by seawater, and the induced electromotive force is converted into an electric signal in direct proportion to the navigational speed. The electrodes of the electromagnetic sensor are easily corroded by seawater and covered by marine life, and weak induced electromotive force is easily submerged by noise due to electromagnetic interference of other equipment. In engineering practice, long-line transmission is adopted between the electromagnetic sensor and the signal processing circuit, which aggravates the trend.
The signal processing circuit is arranged in front, so that the anti-interference capability of the electromagnetic sensor can be improved, and the stable and reliable transmission of the induced electromotive force can be realized.
Therefore, how to improve the anti-interference capability of the marine electromagnetic sensor and realize stable and reliable transmission of the induced electromotive force is a problem to be solved urgently by those skilled in the art.
Disclosure of Invention
In view of this, the present invention provides a front-end signal processing circuit suitable for a marine electromagnetic sensor, which can effectively detect a signal from a noise signal, and achieve high measurement accuracy, high stability, and high reliability of the marine electromagnetic sensor.
In order to achieve the purpose, the invention adopts the following technical scheme:
a front-end signal processing circuit suitable for a marine electromagnetic sensor, comprising: the filter circuit, the amplifying circuit and the differential output circuit are connected in sequence; the input end of the filter circuit is connected with an electrode of the electromagnetic sensor; and the output end of the differential output circuit is connected with the electric connector of the electromagnetic sensor through a connecting cable.
Preferably, the filter circuit comprises an RLC low-pass filter circuit, and the RLC low-pass filter circuit comprises an inductor L1, a resistor R1, an inductor L2, a resistor R2, a capacitor C1, a capacitor C2, and a capacitor C3; one end of the inductor L1 is connected with a first input end of the filter circuit, the other end of the inductor L1 is connected with one end of the resistor R1, and the other end of the resistor R1 is respectively connected with a first end of the capacitor C1 and a first end of the capacitor C3; one end of the inductor L2 is connected with the second input end of the filter circuit, the other end of the inductor L2 is connected with one end of the resistor R2, the other end of the resistor R2 is connected with the second end of the capacitor C2 and the second end of the capacitor C3 respectively, and the first end of the capacitor C2 is connected with the second end of the capacitor C1 and then is grounded together.
Preferably, ferrite beads are used for the resistors R1 and R2.
Preferably, the amplifying circuit comprises a meter amplifying circuit.
Preferably, the differential output circuit comprises an operational amplifier circuit, a resistor R8, a resistor R9 and a capacitor C8, the resistor R9 and the capacitor C8 are connected between the reverse input end and the output end of the operational amplifier circuit, the resistor R9 and the capacitor C8 are connected in parallel, the resistor R8 is connected between the output end of the instrument amplifier circuit and the reverse input end of the operational amplifier circuit, and the output end of the operational amplifier circuit is connected to the reference voltage end of the instrument amplifier circuit.
Preferably, the connection cable includes a shielded twisted pair including a core composed of twisted pairs and a shield layer.
Preferably, the filter circuit, the amplifying circuit and the differential output circuit are integrated on a printed circuit board, the printed circuit board is installed inside a cavity of the electromagnetic sensor, and the distance from the circuit of the printed circuit board to the inner edge of the silicon steel sheet of the electromagnetic sensor is not less than 2.5 times the width of the silicon steel sheet.
Compared with the prior art, the invention discloses a front-end signal processing circuit suitable for a marine electromagnetic sensor, which has the following beneficial effects:
the invention can improve the anti-interference capability of the marine electromagnetic sensor and realize stable and reliable transmission of induced electromotive force.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic diagram of a front-end signal processing circuit schematic framework provided by the present invention;
FIG. 2 is a schematic diagram of a filter circuit according to the present invention;
FIG. 3 is a schematic diagram of an amplifying circuit and a differential output circuit according to the present invention;
fig. 4 is a schematic view of the overall structure of the marine electromagnetic sensor provided by the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, an embodiment of the present invention discloses a front-end signal processing circuit suitable for a marine electromagnetic sensor, including:
the filter circuit, the amplifying circuit and the differential output circuit are connected in sequence; the input end of the filter circuit is connected with an electrode of the electromagnetic sensor; and the output end of the differential output circuit is connected with the electric connector of the electromagnetic sensor through a connecting cable.
The marine electromagnetic sensor obtains a very weak measurement signal from an electrode of the marine electromagnetic sensor, generally in the microvolt level, and the measurement signal needs to be filtered and amplified for accurate measurement.
As shown in fig. 2, the filter circuit may be an RLC low-pass filter circuit, which includes an inductor L1, a resistor R1, an inductor L2, a resistor R2, a capacitor C1, a capacitor C2, and a capacitor C3; one end of the inductor L1 is connected with a first input end of the filter circuit, the other end of the inductor L1 is connected with one end of the resistor R1, and the other end of the resistor R1 is respectively connected with a first end of the capacitor C1 and a first end of the capacitor C3; one end of the inductor L2 is connected with the second input end of the filter circuit, the other end of the inductor L2 is connected with one end of the resistor R2, the other end of the resistor R2 is connected with the second end of the capacitor C2 and the second end of the capacitor C3 respectively, and the first end of the capacitor C2 is connected with the second end of the capacitor C1 and then grounded together.
In another embodiment, ferrite beads are used for the resistors R1 and R2. As an anti-interference component, the ferrite bead can present larger impedance when a high-frequency signal passes through, and present extremely low impedance when a low-frequency signal is input, so that the attenuation of the input high-frequency noise can be obviously caused, the low-frequency signal is not phase-shifted, and the subsequent circuit signal processing is facilitated.
In order to reduce the influence of the internal resistance of the two electrodes in seawater, which can change along with different sea areas, the input end of the amplifying circuit needs high input impedance and low bias input current. Meanwhile, in order to solve power frequency interference caused by coupling of power supply interference to an input loop and other interference (common mode interference) generated by alternating change of an excitation magnetic field, a differential circuit is adopted to reduce the influence of the common mode interference.
In an embodiment, the amplifying circuit is an instrument amplifying circuit, and as shown in fig. 3, the amplifying circuit is an integrated instrument operational amplifying circuit SGM620 chip.
In another embodiment, a meter amplifier circuit including 3 independent operational amplifier circuits may be used.
As shown in fig. 3, the differential output circuit mainly includes an operational amplifier circuit N2A, a resistor R8, a resistor R9, and a capacitor C8, the resistor R9 and the capacitor C8 are connected between the reverse input end and the output end of the operational amplifier circuit N2A, the resistor R9 and the capacitor C8 are connected between the output end of the meter amplifier circuit SGM620 chip and the reverse input end of the operational amplifier circuit N2A, the resistor R8 is connected between the output end of the meter amplifier circuit SGM620 chip and the reverse input end of the operational amplifier circuit N2A, and the output end of the operational amplifier circuit N2A is connected to the reference voltage end of the meter amplifier circuit SGM620 chip.
In the differential output circuit, the accurate control of the output voltage related to the reference voltage (pin 5 of N1) of the instrument amplification circuit SGM620 chip is utilized. The differential output is composed of the output end of the instrument amplifier and the output end of the operational amplification circuit, and the precision of the differential output is determined by the instrument amplification circuit and is not influenced by the operational amplification circuit and the resistor. Because the circuit is easily affected by stability, the capacitor C8 can limit the bandwidth of the operational amplifier circuit N2A to make the bandwidth stable, and the amplified signal is differentially output through the resistor R10 and the resistor R11 and is connected to the electric connector through a connecting cable.
In an embodiment, the connection cable connecting the electrical connector of the electromagnetic sensor and the output end of the differential circuit is a shielded twisted pair, and the shielded twisted pair includes a shielding layer and a core wire formed by the twisted pair. Crosstalk can be effectively minimized by using shielded twisted pair wires. The shielding wire is connected with the electromagnetic sensor shell, external interference signals are led into the ship body, and the influence of an external electromagnetic field on a circuit is reduced.
As shown in fig. 4, the filter circuit, the amplifier circuit and the differential output circuit are integrated on a printed circuit board 2, the printed circuit board 2 is installed inside a cavity of the electromagnetic sensor, a distance from a circuit of the printed circuit board 2 to an upper edge of a silicon steel sheet 3 inside the electromagnetic sensor is not less than 2.5 times a width of the silicon steel sheet, in the figure, 4 denotes an electrode of the electromagnetic sensor, 1 denotes a connection cable, and 5 denotes an electrical connector.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (7)
1. A front-end signal processing circuit adapted for a marine electromagnetic sensor, the front-end signal processing circuit comprising:
the filter circuit, the amplifying circuit and the differential output circuit are connected in sequence; the input end of the filter circuit is connected with an electrode of the electromagnetic sensor; and the output end of the differential output circuit is connected with the electric connector of the electromagnetic sensor through a connecting cable.
2. The front-end signal processing circuit suitable for the marine electromagnetic sensor according to claim 1, wherein the filter circuit comprises an RLC low-pass filter circuit, and the RLC low-pass filter circuit comprises an inductor L1, a resistor R1, an inductor L2, a resistor R2, a capacitor C1, a capacitor C2 and a capacitor C3; one end of the inductor L1 is connected with a first input end of the filter circuit, the other end of the inductor L1 is connected with one end of the resistor R1, and the other end of the resistor R1 is respectively connected with a first end of the capacitor C1 and a first end of the capacitor C3; one end of the inductor L2 is connected with the second input end of the filter circuit, the other end of the inductor L2 is connected with one end of the resistor R2, the other end of the resistor R2 is connected with the second end of the capacitor C2 and the second end of the capacitor C3 respectively, and the first end of the capacitor C2 is connected with the second end of the capacitor C1 and then is grounded together.
3. The front-end signal processing circuit suitable for the marine electromagnetic sensor according to claim 2, characterized in that the resistors R1 and R2 are ferrite beads.
4. The front-end signal processing circuit suitable for a marine electromagnetic sensor of claim 1, wherein the amplifying circuit comprises an instrument amplifying circuit.
5. The front-end signal processing circuit suitable for the marine electromagnetic sensor according to claim 4, wherein the differential output circuit comprises an operational amplifier circuit, a resistor R8, a resistor R9 and a capacitor C8, the resistor R9 and the capacitor C8 are connected between an inverting input end and an output end of the operational amplifier circuit, the resistor R9 is connected in parallel with the capacitor C8, the resistor R8 is connected between an output end of the instrument amplifier circuit and an inverting input end of the operational amplifier circuit, and an output end of the operational amplifier circuit is connected to a reference voltage end of the instrument amplifier circuit.
6. The front-end signal processing circuit for a marine electromagnetic sensor of claim 1, wherein the connecting cable comprises a shielded twisted pair comprising a core comprised of a twisted pair and a shielding layer.
7. The front-end signal processing circuit applicable to the marine electromagnetic sensor according to any one of claims 1 to 6, wherein the filter circuit, the amplifier circuit and the differential output circuit are integrated on a printed circuit board, the printed circuit board is installed inside a cavity of the electromagnetic sensor, and the distance from the printed circuit board to the edge of the silicon steel sheet inside the electromagnetic sensor is not less than 2.5 times the width of the silicon steel sheet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210872418.6A CN115201510A (en) | 2022-07-20 | 2022-07-20 | Front-end signal processing circuit suitable for marine electromagnetic sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210872418.6A CN115201510A (en) | 2022-07-20 | 2022-07-20 | Front-end signal processing circuit suitable for marine electromagnetic sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115201510A true CN115201510A (en) | 2022-10-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210872418.6A Pending CN115201510A (en) | 2022-07-20 | 2022-07-20 | Front-end signal processing circuit suitable for marine electromagnetic sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115201510A (en) |
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2022
- 2022-07-20 CN CN202210872418.6A patent/CN115201510A/en active Pending
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