JP3521887B2 - Underwater ultrasonic transducer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater ultrasonic transducer, and more particularly to an underwater ultrasonic transducer having two or more resonance frequency bands.

[0002]

2. Description of the Related Art Conventionally, an underwater ultrasonic wave transmitter / receiver is constructed, for example, as shown in FIG. In FIG.
The underwater ultrasonic wave transmitter / receiver 900 is configured to be used in a single resonance frequency band.
The transmission matching circuit group 920 and the reception circuit 930 are provided.

The vibrator main body 910 includes a number (M) of vibrators 911 to 91M arranged in conformity with the target performance. These oscillators 911 to 91M vibrate when the transmission signal from the transmitter 940 is supplied via the transmission matching circuit group 920, and generate ultrasonic waves in the water. Further, the reception signals received by the transducers 911 to 91M are transmitted to the reception circuit 930 via the transmission matching circuit group 920 and output to the receiver 950.

The transmission matching circuit group 920 is composed of a number (M) of transmission matching circuits 921 to 92M corresponding to each of the vibrators 911 to 91M constituting the vibrator main body 910. Here, each of the transmission matching circuits 921 to 92M has a matching transformer for impedance matching with the transmitter 940 adapted to a single band. As a result, a matching transformer is provided for each of the transducers 911 to 91M (or for each transmission channel).

The receiving circuit 930 includes the transducers 911 to 911.
The received signal from 91M is subjected to amplification processing or amplification / addition processing and output to the receiver 950.

On the other hand, in FIG. 7, an underwater ultrasonic wave transmitter / receiver 960 having two resonance frequency bands is used.
Is shown. In FIG. 7, an underwater ultrasonic transducer 9
60 has almost the same configuration as the above-mentioned underwater ultrasonic transducer 900, but has a different configuration in that a transmission matching circuit group 970 is provided instead of the transmission matching circuit group 920. The transmission matching circuit group 970 includes the transducers 911 to 9
The number (M) of transmission matching circuits 971 to 97 corresponding to 1M
It is composed of M.

Here, each transmission matching circuit 971-97M
Have the same configuration, the transmission matching circuit 97
The configuration of No. 1 will be described with reference to FIG. In FIG. 8, a transmission matching circuit 971 includes first and second matching transformers 981 and 982 for impedance matching with the transmitter 940 adapted to the transmission signals of the first and second bands from the transmitter 940, respectively. And a switch 980 for switching these matching transformers 981 and 982. As a result, a matching transformer is provided for each of the transducers 911 to 91M (or for each transmission channel).

Underwater ultrasonic transducer 9 having such a structure
According to 60, when receiving, in the same manner as in the case of the underwater ultrasonic wave transmitter / receiver 900, the transducers 911 to 9 1
The reception signal received at 1M is transmitted to the reception circuit 930 via the switch 980 of each transmission matching circuit 971 to 97M of the transmission matching circuit group 970 and either matching transformer 981 or 982, and is output to the receiver 950. It

On the other hand, at the time of transmission, a transmission signal from the transmitter 940 is supplied through the transmission matching circuit group 970, so that each of the transducers 911 to 91M vibrates and is superposed in water. Generates sound waves. Here, when the transmission signal of the first band is supplied from the transmitter 940, the transmitter 94
The control signal from 0 switches the switch 980 to the first matching transformer 981 side. As a result, the transmission signal in the first band from the transmitter 940 is transmitted to the transmission matching circuit group 9
The oscillators 911 to 91M are vibrated by being supplied to the oscillators 911 to 91M via the first matching transformer 981 of 70 and the switch 980, and ultrasonic waves are generated in water.

When the transmission signal of the second band is supplied from the transmitter 940, the switch 980 is switched to the second matching transformer 982 side by the control signal from the transmitter 940. As a result, the transmission signal of the second band from the transmitter 940 passes through the second matching transformer 982 of the transmission matching circuit group 970 and the switch 980 to each transducer 91.
1 to 91M so that each vibrator 911 to
91M vibrates and generates ultrasonic waves in the water. In this way, the transmission signal from the transmitter 940 is supplied to each of the transducers 911 to 91M via the matching transformer 981 or 982 corresponding to the band.

[0011]

By the way, in the underwater ultrasonic wave transmitter / receiver 960 having the two resonance frequency bands, the impedances of the transducers 911 to 91M are different for each resonance frequency band. Therefore, the impedance matching condition is also different. Therefore, with respect to the transmission matching circuit 970, it is necessary to prepare the configurations of the transmission matching circuits 971 to 97M suitable for the conditions of the respective resonance frequency bands. Therefore, the matching transformers 981 and 982 of the transmission matching circuits 971 to 97M with the transmitter 940 of the underwater ultrasonic wave transmitter / receiver 960 are required, and the matching transformer requires a system with a band multiple times, and each system. Since the interface of the transmission signal input line for inputting the transmission signal of the corresponding band is required, the interface scale is expanded.

Further, in each of the transmission matching circuits 971 to 97M, a switch 980 for switching the matching transformers 981 and 982 is directly connected to each of the transducers 911 to 91M. Here, the transducers 911 to 91M are
Generally, a piezoelectric type is used, which is driven by a high voltage. Therefore, as the switch 980, a large switch compatible with high voltage is used. Therefore, each of the transmission matching circuits 971 to 97M includes the large-sized switch 980, and thus becomes large.

Such a problem similarly occurs in an underwater ultrasonic wave transmitter / receiver having three or more resonance frequency bands, and the interface scale is further expanded corresponding to the number of bands. .

On the other hand, for example, JP-A-61-186
In 001 and JP-A-61-146002,
With regard to a phased array in which a plurality of antennas are connected in series, the connection of each antenna is turned on / off by a switch to perform phase matching so as to match the beam azimuth. Therefore, the impedance matching with the transmitter in the underwater ultrasonic transducer, which is the object of the present invention, has a different purpose and configuration.

The present invention has been made to solve the above-mentioned problems, and an underwater ultrasonic transducer having a resonance frequency band of two or more bands, which can be made compact by a simple structure. For the purpose of providing.

[0016]

In order to achieve this object, an underwater ultrasonic transducer according to claim 1 of the present invention comprises:
Via a plurality of transducers, a plurality of transmission matching circuits that respectively supply transmission signals of two or more bands input from the transmitter to each transducer, and a transmission matching circuit to which received signals from each transducer correspond. In the underwater ultrasonic transmitter / receiver having a resonance frequency band of two or more bands including the input receiving circuit, each of the transmission matching circuits has a first matching circuit whose output end is connected to the corresponding vibrator. The transformer and the first matching transformer are sequentially connected in series (N-1) (however,
N is a natural number of 2 or more) and the second to Nth switch circuits connected to each switch circuit in a short-circuitable manner.
And a matching transformer of
On / off control is performed by a control signal from the transmitter, the matching transformer corresponding to the time of turning off or on is disconnected, and the matching transformer corresponding to the time of turning on or off is connected in series.

When the underwater ultrasonic wave transmitter / receiver has such a configuration, by controlling the switch circuits in each transmission matching circuit on / off by the control signal from the transmitter, each transmission matching circuit is controlled to It is possible to connect only the matching transformer of 1 to the corresponding vibrator, or to connect the first matching transformer and any one other matching transformer to the vibrator. As a result, impedance matching can be performed on the transmission signal of each band from the transmitter. Therefore, the transmission signal of each band from the transmitter may be input to the transmission matching circuit through the interface of the common transmission signal input line, so that the transmission signal in the underwater ultrasonic transducer having a single band A transmission signal can be input through the same interface as the input line interface.

Further, since each switch circuit for switching connection or short circuit of the second to Nth matching transformers is connected to the corresponding vibrator through at least the first matching transformer, a low voltage is applied. Corresponding switch circuits can be used. As a result, each switch circuit can be small in size, so that the transmission matching circuit and the underwater ultrasonic transducer can be formed in a small size.

The underwater ultrasonic transducer according to claim 2 is:
Each of the switch circuits is controlled to be turned on or off so that all of them are turned on or off, or only one of them is turned on or off. When the underwater ultrasonic transmitter / receiver has such a configuration, only the first matching transformer or the first matching transformer and the selected one matching transformer are provided in the corresponding transmission matching circuit for each transducer. Are connected, and N resonance frequency bands corresponding to the number of matching transformers can be supported.

The underwater ultrasonic transducer according to claim 3 is
Each of the switch circuits is configured to be on / off controlled so that all of them are turned off or on, or at least one of them is turned on or off. When the underwater ultrasonic transmitter / receiver has such a configuration, only the first matching transformer or the first matching transformer and at least one matching selected in the corresponding transmission matching circuit for each transducer. Since the transformers are connected, the combination of the matching transformers can support a larger number of resonance frequency bands as compared with the number of the matching transformers.

The underwater ultrasonic transducer according to claim 4 is:
The first matching transformer is configured to correspond to the lowest frequency band among the two or more resonance frequency bands used. The underwater ultrasonic transducer according to claim 5,
The first to N-th matching transformers are configured so as to be compatible with frequency bands that are sequentially higher.

When the underwater ultrasonic wave transmitter / receiver has such a structure, the matching transformer corresponding to the lowest resonance frequency band is connected to the vibrator side, and the impedance of each resonance frequency band is switched by switching the switch circuit. Matching will be ensured.

The underwater ultrasonic transducer according to claim 6 is:
The reception signal from each transducer is input to the reception circuit via the first matching transformer of each transmission matching circuit. With this configuration of the underwater ultrasonic transducer, the received signal is input to the receiving circuit without passing through other matching transformers other than the first matching transformer, so deterioration of the received signal is minimized. Can be suppressed.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a first embodiment of an underwater ultrasonic transducer according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a configuration of the underwater ultrasonic transducer, and FIG. 2 is a block diagram showing a detailed configuration of a transmission matching circuit in the underwater ultrasonic transducer. In FIG. 1, an underwater ultrasonic wave transmitter / receiver 100 is configured as an underwater ultrasonic wave transmitter / receiver having two or more resonance frequency bands, and includes a transducer body 110, a transmission matching circuit group 120, and a receiving circuit 130.
Is equipped with.

The vibrator main body 110 includes a number (M) of vibrators 111 to 11M arranged in conformity with the target performance. These vibrators 111 to 11M vibrate when a transmission signal from the transmitter 140 is supplied via the transmission matching circuit group 120, and generate ultrasonic waves in water. Further, the reception signals received by the transducers 111 to 11M are transmitted to the reception circuit 130 via the transmission matching circuit group 120 and output to the receiver 150.

The transmission matching circuit group 120 is composed of a number (M) of transmission matching circuits 121 to 12M corresponding to the respective vibrators 111 to 11M constituting the vibrator main body 110.

The receiving circuit 130 includes the transducers 111 to 111.
The received signal from 11M is amplified or amplified / added, and is output to the receiver 150.

Here, each of the transmission matching circuits 121 to 12M.
Have the same configuration, the transmission matching circuit 12
The configuration of No. 1 will be described with reference to FIG. In FIG. 2, the transmission matching circuit 121 is sequentially connected in series to the first matching transformer 161 whose output end is connected to the corresponding vibrator, and the first matching transformer 161 (N-1). Switch circuits 172, third switch circuits 172, third switch circuits 173, ..., Nth switch circuits 17N and each switch circuit 172 to 17N
, (N-1) matching transformers, that is, second matching transformer 162, third matching transformer 163, ..., Nth matching transformer 1
6N is provided. Here, N is a natural number of 2 or more. The received signals from the transducers 111 to 11M are configured to be directly transmitted to the receiving circuit 130 only through the first matching transformer 161.

Here, each matching transformer 161 to 16N
Are set such that the corresponding frequency bands are sequentially increased from the vibrators 111 to 11M side. In that case, the 1st matching transformer 161 is comprised so that it may match the impedance matching with respect to the transmission signal of a 1st band, and the 2nd-Nth matching transformers 162-16N may be changed.
By combining with the first matching transformer 161, respectively,
It is configured to match impedance matching for transmission signals in the second to Nth bands.

The switch circuits 172 to 17N are
When turned on, the matching transformers 162 to 162 respectively connected
16N is connected in series between the first matching transformer 161 and the transmitter 140, and when off, these matching transformers 162 to 16N are switched by a control signal from the transmitter 140 so as to be disconnected and short-circuited. It is configured to be controlled. In addition, each switch circuit 172
˜17N, only one of them is turned on by the control signal from the transmitter 140.

Next, the above-mentioned underwater ultrasonic wave transmitter / receiver 10
The operation of 0 will be described. First, at the time of reception, the reception signals received by the transducers 111 to 11M are transmitted to the reception circuit 130 via the corresponding transmission matching circuits 121 to 12M of the transmission matching circuit group 120 and output to the receiver 150. To be done. At that time, the received signals are transmitted matching circuits 121 to 1
In 2M, regardless of whether each of the switch circuits 172 to 17N is turned on or off, it is transmitted to the receiving circuit 130 through only the first matching transformer 161 and not the other matching transformers 162 to 16N. Alternatively, noise mixing is suppressed to a minimum.

On the other hand, at the time of transmission, when the transmission signal from the transmitter 140 is supplied through the transmission matching circuit group 120, each of the vibrators 111 to 11M vibrates, and the ultrasonic waves are superposed in water. Generates sound waves. Here, when the transmission signal of the first band is supplied from the transmitter 140, as shown in FIG. 3, all the switch circuits 172 to 17N are turned off, that is, corresponding to the control signal from the transmitter 140. The matching transformers 162 to 16N are separated from each other and set to a short circuit state. As a result, the transmission signal of the first band from the transmitter 140 has the second to Nth matching transformers 162 to 162.
Each switch circuit 172 to 17N without passing through 16N
Through the first matching transformer 161 and
By being supplied to each of the vibrators 111 to 11M, each of the vibrators 111 to 11M vibrates in the first band and generates ultrasonic waves in water.

When the transmission signal of the second band is supplied from the transmitter 140, as shown in FIG.
By the control signal from 0, only the switch circuit 172 is turned on, and the second matching transformer 162 is connected,
Further, the other switch circuits 173 to 17N are turned off and the corresponding matching transformers 163 to 16N are cut off to be in a short-circuit state. This allows the transmitter 1 to be combined by the combination of the first matching transformer 161 and the second matching transformer 162.
Impedance matching is performed on the second band transmission signal from 40. Therefore, the transmission signal of the second band from the transmitter 140 is the third to Nth matching transformer 163.
Each switch circuit 173-17 without passing through 16N
Each of the vibrators 111 to 11 passes through N, and further passes through the second matching transformer 162 and the first matching transformer 161.
By being supplied to M, each of the transducers 111 to 11M vibrates in the second band and generates ultrasonic waves in water.

Further, when the transmitter 140 supplies the transmission signal in any of the third to Nth bands, the control signal from the transmitter 140 similarly causes any one of the switch circuits 173 to 17N to be transmitted. Only one of them is turned on and the corresponding matching transformer is connected, and the other switch circuit is turned off to set the corresponding matching transformer to a short-circuited state. As a result, impedance matching is performed on the transmission signal of the third to Nth band from the transmitter 140 by the combination of the first matching transformer 161 and any one of the matching transformers 163 to 16N. Therefore, the transmission signal from the transmitter 140 passes through any one of the matching transformers 163 to 16N and the first matching transformer 161 connected by any of the turned-on switch circuits 173 to 17N and passes through each transducer 1.
11 to 11M so that each oscillator 111
11M vibrates in any of the third to Nth bands to generate ultrasonic waves in the water.

In this way, the transmission signal from the transmitter 140 is switched on and off only in the first matching transformer 161 or in the first matching transformer 161 and the band of the transmission signal, and the switch circuits 172 to 17N are controlled. Is supplied to each of the transducers 111 to 11M via any one of the matching transformers 172 to 17N connected by any of the above. Therefore, since the interface of the transmission signal input line from the transmitter 140 does not need to be provided for each band, only a single interface is required and the expansion of the interface can be suppressed. Furthermore, the switch circuit 17
Since 2 to 17N are connected to the vibrators 111 to 11M via the first matching transformer 161, they may be small switch circuits corresponding to low voltage. Therefore, the switch circuits 172 to 17N, the transmission matching circuits 121 to 12N, and the underwater ultrasonic transducer 100 can be configured in a small size.

[Second Embodiment] Next, a second embodiment of the underwater ultrasonic transducer according to the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing a detailed configuration of a transmission matching circuit in the underwater ultrasonic transducer. In FIG. 5, the underwater ultrasonic wave transmitter / receiver 200 is configured in substantially the same manner as the underwater ultrasonic wave transmitter / receiver 100 shown in FIG. 1, and the same components are designated by the same reference numerals and their description is omitted. Is omitted. Here, the underwater ultrasonic transducer 20
0 is a switch circuit 172 to a transmission matching circuit 121 to 12N of the underwater ultrasonic transducer 100 shown in FIG.
Switch circuits 272 to 27N are provided instead of 17N.

Here, each switch circuit 272 to 27N
Are connected to the matching transformers 16 when turned on.
2 to 16N are connected to the first matching transformer 161 and the transmitter 14
The matching transformers 162 to 16N are connected in series between 0 and 0, and are switched and controlled by a control signal from the transmitter 140 so as to disconnect and short-circuit these matching transformers 162 to 16N when off. In this case, each of the switch circuits 272 to 27N is independently turned on / off by a control signal from the transmitter 140. As a result, not only one switch circuit 272 to 27N but also an arbitrary plurality of switch circuits can be turned on.

At this time, the first matching transformer 161 is configured so as to match impedance matching with respect to the transmission signal in the first band, and the second to Nth matching transformers 162 to 16N are respectively the first matching transformer. One matching transformer 1
Any number of combinations with 61 are configured to adapt to impedance matching for transmission signals in other bands.

Next, the above-mentioned underwater ultrasonic transducer 20
The operation of 0 will be described. First, at the time of reception, similarly to the underwater ultrasonic wave transmitter / receiver 100 described above, the reception signals received by the transducers 111 to 11M correspond to the corresponding transmission matching circuits 121 to 12M of the transmission matching circuit group 120. Is transmitted to the receiving circuit 130 via the signal and output to the receiver 150. At this time, the received signals are transmitted matching circuits 121 to 12
In M, the signal is transmitted to the receiving circuit 130 through only the first matching transformer 161 and regardless of the on / off state of each of the switch circuits 272 to 27N without passing through the other matching transformers 162 to 16N. Deterioration or noise mixing is suppressed to the minimum.

On the other hand, at the time of transmission, the transmitter 140
When the transmission signal of the first band is supplied from the switch circuit 2 in the same manner as the underwater ultrasonic wave transmitter / receiver 100 described above, all the switch circuits 2 are controlled by the control signal from the transmitter 140.
72 to 27N is off, that is, the corresponding matching transformer 1
62 to 16N is set to a short-circuited state. Thereby, the transmission signal of the first band from the transmitter 140 is
The oscillators 111 to 1 pass through the switch circuits 272 to 27N without passing through the second to Nth matching transformers 162 to 16N, and further through the first matching transformer 161.
Each oscillator 111 to 11M is supplied to 1M.
Vibrates in the first band to generate ultrasonic waves in the water.

When the transmission signal of the third band is supplied from the transmitter 140, as shown in FIG.
The switch circuit 272 and the switch circuit 273 are turned on by the control signal from 0, and the matching transformers 162, 16
3 in the connected state, and other switch circuits 274-2
7N is turned off and the corresponding matching transformers 164-16
It becomes a short circuit state with N disconnected. As a result, the transmitter 140 is combined with the first matching transformer 161, the second matching transformer 162, and the third matching transformer 163.
Impedance matching is performed on the transmission signal in the third band. Therefore, the transmission signal of the third band from the transmitter 140 is the fourth to Nth matching transformers 164-1.
It passes through each switch circuit 274-27N without passing through 6N, further passes through the third matching transformer 163, the second matching transformer 162, and the first matching transformer 161, and is supplied to each vibrator 111-11M. By doing
Each of the vibrators 111 to 11M vibrates in the third band to generate ultrasonic waves in water.

Further, when the transmitter 140 supplies the transmission signals in the fourth or more bands, the transmitter 14 is similarly processed.
Switch circuits 272 to 27N depending on the control signal from 0.
Is turned on to connect the corresponding matching transformer, and the other switch circuit is turned off to set the corresponding matching transformer in a short-circuited state. Thereby, impedance matching with respect to the transmission signals of the fourth or more bands from the transmitter 140 is performed by a combination of at least one of the first matching transformer 161 and the matching transformers 163 to 16N. Therefore, the transmission signal from the transmitter 140 is supplied to each of the transducers 111 to 11M through at least one of the matching transformers 162 to 16N and the first matching transformer 161 which are connected by the turned-on switch circuit. By
Each of the oscillators 111 to 11M vibrates in the fourth or more band,
Generates ultrasonic waves in the water.

In this way, while operating in the same manner as the above-mentioned underwater ultrasonic transducer 100, only the first matching transformer 161 or the first matching transformer 161 and the second matching transformers 162 to N-th. Matching transformers 161 to 16N by at least one combination of matching transformers 16N.
Impedance matching can be performed for transmission signals in a number of bands greater than the number of 16N. Therefore, as compared with the number of bands of the transmission signal, it is possible to perform impedance matching on the transmission signal of each band with a smaller number of matching transformers and switch circuits, so that the underwater ultrasonic transducer 200 is provided. Can be made even smaller.

In the above-described embodiment, N matching transformers 161 to 16N and (N-1) switch circuits 172 to 17N or 272 to 27N are provided, but N is an arbitrary number of 2 or more. Therefore, the present invention can be applied to an underwater ultrasonic transducer having two or more resonance frequency bands. Further, each of the switch circuits 172 to 17N or 272 to 27N is configured to disconnect the matching transformer corresponding to the OFF state and connect the matching transformer corresponding to the ON state, but the invention is not limited to this, and the matching transformer corresponding to the ON state is not limited thereto. It may be configured to disconnect the transformer and connect the corresponding matching transformer when turned off.

[0045]

As described above, according to the present invention, the first matching is performed in each transmission matching circuit by on / off controlling each switch circuit in each transmission matching circuit by the control signal from the transmitter. It is possible to connect only the transformer to the corresponding oscillator, or to connect the first matching transformer and any other matching transformer to the oscillator. As a result, impedance matching can be performed on the transmission signal of each band from the transmitter. Therefore, the transmission signal of each band from the transmitter may be input to the transmission matching circuit through the interface of the common transmission signal input line, so that the transmission signal in the underwater ultrasonic transducer having a single band A transmission signal can be input through the same interface as the input line interface. Also, the second ~
Since each switch circuit that switches connection or short circuit of the Nth matching transformer is connected to the corresponding oscillator through at least the first matching transformer, use a switch circuit corresponding to low voltage. You can As a result, each switch circuit can be small in size, so that the transmission matching circuit and the underwater ultrasonic transducer can be formed in a small size.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of an underwater ultrasonic transducer according to the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a transmission matching circuit in the underwater ultrasonic wave transceiver of FIG.

FIG. 3 is a block diagram showing an operating state of the transmission matching circuit of FIG. 2 in a first band.

FIG. 4 is a block diagram showing an operating state of the transmission matching circuit of FIG. 2 in a second band.

FIG. 5 is a block diagram showing an operating state of a transmission matching circuit in a second embodiment of the underwater ultrasonic wave transceiver according to the present invention.

FIG. 6 is a block diagram showing a configuration of an example of a conventional underwater ultrasonic transducer having a single band.

FIG. 7 is a block diagram showing a configuration of an example of a conventional underwater ultrasonic wave transmitter / receiver having two bands.

8 is a block diagram showing a detailed configuration of a transmission matching circuit in the underwater ultrasonic wave transceiver of FIG. 7. FIG.

[Explanation of symbols]

100 Underwater Ultrasonic Transducer 110 oscillator body 111-11M oscillator 120 Transmission matching circuit group 121-12M transmission matching circuit 130 receiver circuit 140 transmitter 150 receiver 161-16N matching transformer 172-17N switch circuit 200 Underwater ultrasonic transducer 272-27N switch circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04R 1/22 330 G01S 7/521 H04R 3/00 330

Claims (6)

(57) [Claims] 1. A plurality of transducers, a plurality of transmission matching circuits that respectively supply transmission signals of two or more bands input from a transmitter to each transducer, and a reception signal from each transducer correspond to each other. A receiving circuit that is input via a transmission matching circuit, and an underwater ultrasonic transducer having a resonance frequency band of two or more bands, wherein each of the transmission matching circuits has an output end connected to a corresponding transducer. A first matching transformer, (N-1) switch circuits sequentially connected in series to the first matching transformer, and second to short-circuitable respective switch circuits. An Nth matching transformer is provided, and each of the switch circuits is ON / OFF controlled by a control signal from a transmitter that supplies transmission signals of a plurality of bands to disconnect the matching transformer corresponding to OFF or ON, and Other ultrasonic transducer for underwater, characterized in that to connect the matching transformer corresponding to the OFF in series. 2. The underwater ultrasonic wave transmission / reception according to claim 1, wherein each of the switch circuits is on / off controlled so that all of them are turned on or off, or only one of them is turned on or off. Wave instrument. 3. The on / off control is performed so that each of the switch circuits is turned off or turned on, or at least one of the switch circuits is turned on or off.
The underwater ultrasonic wave transmitter / receiver described in. 4. The underwater use according to claim 1, wherein the first matching transformer corresponds to the lowest frequency band among the resonance frequency bands of two or more bands used. Ultrasonic transducer. 5. The underwater ultrasonic transducer according to any one of claims 1 to 4, wherein the first to Nth matching transformers correspond to frequency bands which become higher sequentially. . 6. The reception signal from each transducer is input to the reception circuit via the first matching transformer of each transmission matching circuit, according to claim 1. Underwater ultrasonic transducer.