JP4694442B2 - Ultrasonic transmitter and ultrasonic device - Google Patents

Description

  The present invention relates to an ultrasonic transmitter and an ultrasonic device that transmit ultrasonic waves, and more particularly to an ultrasonic transmitter and an ultrasonic device that are configured by arranging a plurality of transmitting elements in an arc or a partial spherical shape.

  In an ultrasonic device that transmits ultrasonic waves into the sea, receives echoes from the target, and detects targets in the water, if the target is near the seabed, the echo from the target will reverberate from the seabed. Detection becomes difficult because of being buried. In this way, when reverberation is the main factor that hinders target detection, target signal detection is achieved by transmitting and receiving broadband signals to improve the signal to reverberation ratio by the signal processing gain obtained by correlation processing on the received signal. Can be made easier.

  Transmission of a wideband signal can be realized by a transmission element using a method disclosed in Patent Document 1. Conventionally, in an ultrasonic transmitter of an ultrasonic device that transmits a broadband signal, the transmitting elements are arranged in a planar shape. However, in order to obtain a small and wide viewing angle, it was considered to arrange the transmitting elements in an arc shape in the horizontal plane. And found that it changed. This phenomenon is not a problem with ultrasonic devices that use relatively narrowband signals. However, when using wideband signals, the frequency characteristics of the transmitted signal differ for each direction, and depending on the direction, the signal processing gain due to the correlation processing described above. It was also found that was not enough. This will be described with reference to FIG. 1 and FIG.

  FIG. 1 is a diagram for explaining the horizontal transmission directivity of a transmitter in which N transmission elements are arranged in an arc shape in the horizontal direction and are stacked in 2M stages. In FIG. 1, the horizontal axis represents the azimuth (°), and the vertical axis represents the transmission level (dB). The parameter is the frequency, the rough broken line is the frequency (f0-18) kHz, the fine broken line is the frequency f0 kHz, and the solid line is the transmitted horizontal directivity at the frequency (f0 + 18) kHz. It can be seen that there is a ripple in the transmission horizontal directivity of each frequency, and the ripple state changes depending on the frequency.

  FIG. 2 is a diagram for explaining frequency characteristics in a specific direction. In FIG. 2, the horizontal axis represents frequency (kHz), and the vertical axis represents transmission level (dB). The parameter is an azimuth, and shows frequency characteristics in the azimuth φ and the azimuth θ in FIG. Since the ripple condition differs for each frequency, the frequency characteristics vary greatly for each direction.

  As an improvement measure, a method of reducing ripples and realizing flat directivity and uniform frequency characteristics by increasing the radius of curvature of the arc arrangement and increasing the number of elements arranged can be considered. However, it is contrary to the miniaturization that was the original purpose. In addition, the cost increases as the size of the transmitter increases.

JP-A-8-340597

  When a wideband signal is transmitted over a wide range by a transmitter in which a plurality of transmission elements are arranged in an arc or a partial spherical shape, the frequency characteristics change depending on the direction, and uniform frequency characteristics cannot be realized.

  The present invention provides an ultrasonic transmitter in which a plurality of transmission elements are arranged in an arc or a partial spherical shape in order to reduce transmission directivity ripple and achieve uniform frequency characteristics in each direction. The directional ripple peaks and valleys formed by the number of array elements in one column are canceled out by the directional ripple peaks and valleys formed by the number of element arrays in another column. By changing the arrangement every time, an ultrasonic transmitter and an ultrasonic device having a transmission directivity with less ripples are obtained.

  According to the present invention, in an ultrasonic wave transmitter and an ultrasonic device in which a plurality of wave transmitting elements are arranged in an arc or a partial spherical shape, a relatively small ultrasonic wave transmitter with less ripple directivity And can be realized with an ultrasonic device.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. Here, FIG. 3 is a front view of the transmitter. FIG. 4 is a diagram for explaining the transmission horizontal directivity of the transmitter at a specific frequency. FIG. 5 is a diagram for explaining the transmission horizontal directivity of the transmitter using the frequency as a parameter. FIG. 6 is a diagram for explaining frequency characteristics in a specific direction. FIG. 7 is a block diagram of the ultrasonic apparatus.

  In FIG. 3, the ultrasonic transmitter 10 is centered in an arc with (N−4) odd-numbered horizontal transmitting elements 1 and N even-numbered horizontal transmitting elements 1. It is configured by arranging and arranging 2M layers. The scale of the ultrasonic transmitter of the ultrasonic apparatus is determined by the scale of the ultrasonic apparatus, and in this embodiment, the number of transmitting elements is N × 2M. Although the number of transmitting elements in odd stages is four less than the number of transmitting elements in even stages, this value is obtained by simulation. That is, the horizontal transmission directivity with ripples of the N × M transmitter is obtained, and the (N−n) × M transmitter having the reverse transmission horizontal directivity of ripples is obtained. N = 4.

  Since FIG. 3 is a front view, the shape of the left and right wave transmitting elements arranged in an arc shape in the horizontal plane is vertically long. However, it is not expressed for the convenience of illustration. Moreover, although FIG. 3 is a part of the cylinder extended up and down, it may be a part of a sphere. In the case of a part of a sphere, not only the number of horizontal elements may be changed for each stage, but the number of vertical elements (the number of stages) may be changed for each horizontal arrangement. This is an easy assumption for those skilled in the art who understand this specification. Furthermore, in this specification, a column is an array including a column and a row.

  In FIG. 4, the horizontal axis represents the azimuth (°), and the vertical axis represents the transmission level (dB). EVEN, which is a fine broken line, is a transmission horizontal directivity of frequency f0 by N elements, and ODD, which is a rough broken line, is a transmission horizontal directivity of frequency f0 by (N-4) elements. The EVEN directivity ripple and the ODD directivity ripple are opposite to each other in the positions of the peaks and valleys. SUM is obtained as the directivity of the transmitter. FIG. 4 can be said to be the simulation result at f = f0 described in FIG.

  In FIG. 5, the horizontal axis represents the azimuth (°), and the vertical axis represents the transmission level (dB). The parameter is the frequency, the rough broken line is the frequency (f0-18) kHz, the fine broken line is the frequency f0 kHz, and the solid line is the transmitted horizontal directivity at the frequency (f0 + 18) kHz. Compared with FIG. 1, it can be seen that the ripple is reduced at each frequency.

  In FIG. 6, the horizontal axis represents frequency (kHz), and the vertical axis represents transmission level (dB). The parameter is an azimuth, and shows frequency characteristics in the azimuth φ and the azimuth θ in FIG. Compared to FIG. 2, it can be seen that the peaks and valleys of the characteristic change are small. In addition, with such a frequency characteristic, it is possible to obtain a flat characteristic with a waiting replica of the ultrasonic receiver. Further, the frequency characteristics can be further flattened by changing the characteristics of the transmission element.

  According to the above-described embodiment, an ultrasonic wave transmitter that widens the viewing angle in the horizontal direction without increasing the size of the ultrasonic wave transmitter, and realizes transmission directivity and uniform frequency characteristics with less ripples. Obtainable.

  In FIG. 7, an ultrasonic device 100 includes an ultrasonic transmitter 10 connected to a transmitter 30, an ultrasonic receiver 20 connected to a receiver 40, and a signal processor connected to the receiver 40. 50 and a control indicator 60. The transmitter 30 controls the ultrasonic transmitter 10, and the ultrasonic transmitter 10 performs electroacoustic conversion on transmission power input from the transmitter 30 and transmits ultrasonic waves. The ultrasonic receiver 20 performs acoustoelectric conversion on the received sound and sends an electric signal to the receiver 40. The signal processor 50 performs detection integration processing, correlation processing, and display processing on the electrical signal received from the receiver 40, and sends it to the control indicator 60. The control indicator 60 displays the received signal from the signal processor 50 and performs overall control of the ultrasonic apparatus 100.

  The ultrasonic wave transmitter 10 has a configuration in which N wave transmitting elements are arranged on a circumference in a horizontal plane and are stacked in 2M stages. Note that the ultrasonic transmitter 10 has 2N × M transmitting elements mounted thereon, but does not drive n end portions arranged at every other stage. As a result, it is possible to obtain an ultrasonic apparatus that widens the viewing angle in the horizontal direction and realizes transmission directivity and uniform frequency characteristics with less ripples without increasing the scale of the ultrasonic transmitter. In addition, in an ultrasonic device that transmits a wideband signal, a uniform frequency characteristic can be realized in each direction due to a low ripple directivity characteristic, so that a desired signal processing gain can be obtained by correlation processing.

It is a figure explaining the transmission horizontal directivity of the ultrasonic wave transmitter which arranged N number of wave transmission elements in the horizontal direction, and piled this up 2M steps. It is a figure explaining the frequency characteristic in a specific direction. It is a front view of an ultrasonic transmitter. It is a figure explaining the transmission horizontal directivity of the ultrasonic transmitter in a specific frequency. It is a figure explaining the transmission horizontal directivity of the ultrasonic transmitter which used the frequency as a parameter. It is a figure explaining the frequency characteristic in a specific direction. It is a block diagram of an ultrasonic device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Transmitting element, 10 ... Ultrasonic transmitter, 20 ... Ultrasonic receiver, 30 ... Transmitter, 40 ... Receiver, 50 ... Signal processor, 60 ... Control indicator, 100 ... Ultrasonic apparatus.

Claims (2)

In an ultrasonic transmitter configured by arranging a plurality of transmitting elements in an arc or a partial spherical shape,
An orientation corresponding to a directional ripple peak formed by the first number of transmitting elements in the first transmitting element array is formed by the second number of transmitting elements in the second transmitting element array. In order to correspond to the ripple valley in the directivity, the number of the second transmission elements, which is smaller than the number of the first transmission elements, is determined by simulation, and the first transmission element array and the second transmission element are determined. An ultrasonic transmitter characterized in that directivity ripple is reduced by interaction with a wave element array . A transmitter, an ultrasonic transmitter that converts the transmission power input from the transmitter into an electroacoustic signal and sends out an ultrasonic wave, and an ultrasonic wave reception device that converts the received sound into an electric signal and sends an electric signal to the receiver And a signal processor connected to the receiver for detecting and integrating electric signals received from the receiver, performing correlation processing and display processing, and sending them to a control indicator, and displaying a received signal from the signal processor In an ultrasonic device composed of a control indicator that performs overall control,
The ultrasonic transmitter includes a plurality of transmitting elements arranged in a circular arc or a partial spherical shape, and a directional ripple formed by the first number of transmitting elements in the first inverse wave element array. The azimuth corresponding to the crest is less than the first transmitting element number so that the directivity formed by the second transmitting element number of the second inverse wave element array corresponds to a ripple valley. An ultrasonic device characterized in that a second number of transmitting elements is determined by simulation, and directivity ripple is reduced by an interaction between the first transmitting element array and the second transmitting element array. .

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