underwater sound equipment

Underwater acoustic equipment is based on the sound wave can be in the water at a certain speed (seawater1500m/s; Fresh water 1400 m/s) travels a long distance, and it will reflect back when it meets the target. The most common underwater acoustic navigation and communication equipment are: echo depth meter, various types of sonar, etc.

Sonar is one of the indispensable electronic devices on modern large surface ships and submarines. The main functions of sonar are: to search and track underwater targets (submarines and mines), to identify the target as friend or foe, and to determine the movement elements of underwater targets, so as to be used for anti-submarine weapon shooting command. Secondly, underwater communication, mine detection, underwater situation detection to ensure the safe navigation of this ship.

The biggest feature of a submarine is its concealment. It needs to dive underwater for a long time in combat, which determines that it can't surface and use radar for observation, but can only rely on sonar for detection. Therefore, sonar is more important on the submarine and is called the "eyes and ears" of the submarine.

The working principle of sonar is the same as that of radar, which can be said to be a radar working at audio or super audio frequencies. The components of sonar station are very similar to those of radar station.

Because sonar works in the ultra-audio frequency range, its method of radiating signals is different from that of radar, which uses a parabolic antenna made of metal, while sonar uses an underwater acoustic transducer.

The underwater transducer works by using the piezoelectric effect of crystal (Shi Ying or potassium sodium tartrate) piezoelectric ceramics (barium titanate and lead zirconate titanate, etc.) or the magnetostrictive effect of iron-nickel alloy. The so-called piezoelectric effect is that the crystal is sliced in a certain direction, and pressure is exerted on the crystal slice, which will produce positive charges and negative charges on its two ends respectively. On the other hand, when a tensile force is applied to the crystal wafer, the opposite charges will be generated on its two end faces. Contrary to the piezoelectric effect, electrostrictive effect, that is, when alternating voltage is applied to two end faces of the crystal, the crystal will produce corresponding mechanical deformation. We use electrostrictive effect and piezoelectric effect to generate and receive ultrasonic waves.

When sonar emits ultrasonic waves, the ultrasonic oscillation voltage is applied to the two end faces of the crystal sheet. Then the thickness of the crystal will change with the ultrasonic oscillation voltage, resulting in ultrasonic vibration. The vibration of the crystal pushes the surrounding water to produce ultrasonic radiation.

When the ultrasonic wave propagates, it will reflect when it meets the target. The echo acts on the crystal of the underwater acoustic transducer, and electrical signals may be obtained on the two end faces of the underwater acoustic transducer due to the piezoelectric effect. Like radar antenna, underwater acoustic transducer should not only transmit and receive ultrasonic signals, but also have sharp directivity. Only in this way can the orientation of the target be determined. Sonar equipment uses many piezoelectric crystals to form a transducer array to obtain sharp directivity. Therefore, the underwater acoustic transducer of sonar has a large volume and is generally installed in the underwater part of the bow of the ship.

The working process of sonar can be described as follows:

Under the control of the transmitter controller, the transmitter generates high-power ultrasonic pulse oscillation, and the underwater acoustic transducer emits ultrasonic waves in a certain direction through the transceiver. In this direction, the ultrasonic wave will reflect back when it meets the target, and it will be received by the underwater acoustic transducer and become an electrical signal. Then it is sent to the receiver for amplification through the transceiver, and finally it is sent to the display to show the direction and distance of the target.

From the working process, the transmitter works when transmitting ultrasonic waves, and the receiver does not have to work; After the transmission, the receiver should work immediately to receive the ultrasonic waves reflected by the nearest target and the farthest target. Obviously, the transmitter and receiver work alternately. Therefore, the receiver and transmitter can share an expensive underwater acoustic transducer by using the transceiver conversion device.

Active sonar works in the above way, that is, sonar emits signals and then receives signals reflected by targets. In addition, there is a passive working mode, that is, only receiving the noise from the target itself (such as the sound from the propeller, etc.) to judge the direction of the target, which is also called noise lateral sonar. This kind of sonar is not captured by the local area because it emits sound waves, so the passive working mode is of special significance to improve the concealment of submarines.

The most basic principle of sonar

underwater sound equipment

Underwater acoustic equipment is based on the sound wave can be in the water at a certain speed (seawater1500m/s; Fresh water 1400 m/s) travels a long distance, and it will reflect back when it meets the target. The most common underwater acoustic navigation and communication equipment are: echo depth meter, various types of sonar, etc.

Sonar is one of the indispensable electronic devices on modern large surface ships and submarines. The main functions of sonar are: to search and track underwater targets (submarines and mines), to identify the target as friend or foe, and to determine the movement elements of underwater targets, so as to be used for anti-submarine weapon shooting command. Secondly, underwater communication, mine detection, underwater situation detection to ensure the safe navigation of this ship.

The biggest feature of a submarine is its concealment. It needs to dive underwater for a long time in combat, which determines that it can't surface and use radar for observation, but can only rely on sonar for detection. Therefore, sonar is more important on the submarine and is called the "eyes and ears" of the submarine.

The working principle of sonar is the same as that of radar, which can be said to be a radar working at audio or super audio frequencies. The components of sonar station are very similar to those of radar station.

Because sonar works in the ultra-audio frequency range, its method of radiating signals is different from that of radar, which uses a parabolic antenna made of metal, while sonar uses an underwater acoustic transducer.

The underwater transducer works by using the piezoelectric effect of crystal (Shi Ying or potassium sodium tartrate) piezoelectric ceramics (barium titanate and lead zirconate titanate, etc.) or the magnetostrictive effect of iron-nickel alloy. The so-called piezoelectric effect is that the crystal is sliced in a certain direction, and pressure is exerted on the crystal slice, which will produce positive charges and negative charges on its two ends respectively. On the other hand, when a tensile force is applied to the crystal wafer, the opposite charges will be generated on its two end faces. Contrary to the piezoelectric effect, electrostrictive effect, that is, when alternating voltage is applied to two end faces of the crystal, the crystal will produce corresponding mechanical deformation. We use electrostrictive effect and piezoelectric effect to generate and receive ultrasonic waves.

When sonar emits ultrasonic waves, the ultrasonic oscillation voltage is applied to the two end faces of the crystal sheet. Then the thickness of the crystal will change with the ultrasonic oscillation voltage, resulting in ultrasonic vibration. The vibration of the crystal pushes the surrounding water to produce ultrasonic radiation.

When the ultrasonic wave propagates, it will reflect when it meets the target. The echo acts on the crystal of the underwater acoustic transducer, and electrical signals may be obtained on the two end faces of the underwater acoustic transducer due to the piezoelectric effect. Like radar antenna, underwater acoustic transducer should not only transmit and receive ultrasonic signals, but also have sharp directivity. Only in this way can the orientation of the target be determined. Sonar equipment uses many piezoelectric crystals to form a transducer array to obtain sharp directivity. Therefore, the underwater acoustic transducer of sonar has a large volume and is generally installed in the underwater part of the bow of the ship.

The working process of sonar can be described as follows:

Under the control of the transmitter controller, the transmitter generates high-power ultrasonic pulse oscillation, and the underwater acoustic transducer emits ultrasonic waves in a certain direction through the transceiver. In this direction, the ultrasonic wave will reflect back when it meets the target, and it will be received by the underwater acoustic transducer and become an electrical signal. Then it is sent to the receiver for amplification through the transceiver, and finally it is sent to the display to show the direction and distance of the target.

From the working process, the transmitter works when transmitting ultrasonic waves, and the receiver does not have to work; After the transmission, the receiver should work immediately to receive the ultrasonic waves reflected by the nearest target and the farthest target. Obviously, the transmitter and receiver work alternately. Therefore, the receiver and transmitter can share an expensive underwater acoustic transducer by using the transceiver conversion device.

Active sonar works in the above way, that is, sonar emits signals and then receives signals reflected by targets. In addition, there is a passive working mode, that is, only receiving the noise from the target itself (such as the sound from the propeller, etc.) to judge the direction of the target, which is also called noise lateral sonar. This kind of sonar is not captured by the local area because it emits sound waves, so the passive working mode is of special significance to improve the concealment of submarines.

You can quote this article through this link: /tb.b? diaryId= 1 15 14295