JPH10290495A - Sound signal transmission method, its equipment, sound signal reception method, its equipment and sound wave signal transmission/reception processing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit or receive a sound signal without resonance and to attain electric control easily with less noise. SOLUTION: The sound signal transmitter is made up of a transmission element that is a magnetostriction element made of a super magnetostriction material, a drive coil 3a wound on the transmission element 1 is the lengthwise direction, a bias power supply 3b and a signal source 3c connected in series between both ends of the drive coil 3a. The transmission element 1 is made by using the magnetostriction element made of a super magnetostriction material whose displacement is larger than that of a piezoelectric element or the like, the transmission element 1 is driven without resonance and a sound signal is sent. Thus, the transmission element 1 is driven and the sound signal is sent with proper energy, and the mechanical resonance frequency does not exist in the audible range and the ultrasonic range by selecting properly the size of the transmission element 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for transmitting a sound wave signal used for a sensor for obtaining various kinds of information such as the presence or absence, position, and speed of an object by a sound wave, and a sound wave signal receiving method. And a device and a sound wave signal transmission / reception processing system using the same.

[0002]

2. Description of the Related Art Conventionally, various sensors have been proposed in which sound waves are radiated into various propagation media such as gas, liquid, and solid, and information on an object to be measured is obtained by measuring the propagation state. (For example, see JP-A-7-218)
477, JP-A-4-313999, JP-A-4-313998, JP-A-5-49649 and JP-A-2-269914.

For example, a sound wave is transmitted to an object to be measured, a reflected wave from the object to be measured is received, and a delay time from the start of the transmission to the start of the reception is measured. A sensor that measures the distance to the object to be measured based on time, a sensor that detects the presence or absence of an object based on the presence or absence of a reflected wave as this application, and other sound waves transmitted into a solid are reflected by a scratch in the solid Flaw detector that non-destructively inspects flaws in solids, and the fact that the transmission frequency and reception frequency change according to the speed of movement of an object (Doppler effect). A sensor that measures the moving speed of the object based on the frequency, or a barrier that measures the internal structure of the living body by receiving reflected sound waves transmitted inside the living body and reflected at the reflectance boundary, There are sensors that can be detected.

By the way, the sound wave signals in the above-mentioned various conventional sensors are transmitted by a method in which vibration is propagated to a sound wave propagation medium by mechanically vibrating a vibration plate with a piezoelectric element or the like. In this case, the electric signal for driving the piezoelectric element or the like is merely a signal for giving a trigger for mechanical resonance, and the transmission and reception of the sound wave signal are performed with a large amplitude generated by mechanical resonance. Therefore, the essential part controlling the transmission and reception of the sound wave signal is mechanical control.

[0005] As a circuit configuration for transmitting a sound wave signal by the above-described resonance system, there is, for example, one shown in FIG. 14 or FIG. 14, the transmitting circuit 22 drives the transmitting element 20 based on a signal of a fixed frequency output from the oscillation circuit 24, and transmits a sound wave signal into a propagation medium and reflects the sound signal on an object. The reflected signal (sound wave signal) received is received by the wave receiving element 21, converted into an electric signal by the wave receiving circuit 23, and subjected to various signal processings by the post-processing circuit 25, and the presence or absence and moving speed of the object. Etc. are required. In addition,
FIG. 15 shows an example in which a wave transmitting element and a wave receiving element are shared by one wave transmitting / receiving element 26, and the switching circuit 27 switches and connects the wave transmitting circuit 22 and the wave receiving circuit 23. It has become.

FIG. 16A shows the structure of a piezoelectric ultrasonic transducer which has been frequently used as a transmitting element or a receiving element. The bottom of the aluminum case 30 formed into a bottomed cylindrical shape is thin (thickness = about 0.1 mm).
65 [mm]), a thin plate-shaped piezoelectric ceramic 31 (thickness =
(Approximately 0.25 [mm]) is adhered and fixed. Terminal 3 for applying a voltage to the piezoelectric ceramic 31 from outside
2 protrudes from the substrate 33 and is connected to the piezoelectric ceramic 31 by a lead wire 34. Reference numeral 35 denotes a holding member for holding the lead wire 34, and reference numeral 36 denotes a member (cotton) for reducing vibration inside the aluminum case 30. A board 33 is provided in the opening of the aluminum case 30 and a terminal 32 is provided.
Are sealed with an epoxy adhesive 37 in a state where they protrude out of the aluminum case 30. When a voltage V is applied as shown in FIG. 3B, the piezoelectric ceramic 31 vibrates in the horizontal direction, and the vibration is
Is converted into a vertical vibration and a sound wave (ultrasonic wave) is transmitted. The resonance frequency at this time is determined by a frequency constant described later and the dimensions of the aluminum case 30 and the like.
A frequency of about [kHz] is generally used.

[0007] In addition, distortion due to an applied magnetic field (magnetostriction)
In some cases, a case or the like is vibrated to emit a sound wave. In general, materials often used for sound wave generation include ferrite and nickel as magnetostrictive materials, and piezoelectric ceramics (PZT = lead zircon titanate) and piezoelectric rubber (PVDF = polyvinyldene fluoride) as electrostrictive materials. . However, since a large amount of energy is required to generate a sound wave by forcibly vibrating these materials, the amount of vibration amplitude is obtained by using mechanical resonance as described above in order to save supplied energy. In. Note that the amount of vibration amplitude corresponds to the sound pressure of the transmitted sound wave, and greatly affects the output voltage during reception.

As described above, conventionally, a structure that mechanically resonates in both the electrostrictive system and the magnetostrictive system has been adopted.
The frequency of the sound wave in such a resonance system is determined by a fundamental standing wave determined by its structural dimensions and the acoustic velocity inside the material. For example, in the case of an ultrasonic transducer using the piezoelectric ceramic 31, the frequency constant is 1600.
[MHz], if the length is 16 [mm], the vibration in the thickness direction of the piezoelectric ceramic 31 is 100 [k].
[Hz]. The frequency constant is a numerical value indicating the relationship between the size of the piezoelectric ceramic 31 and the resonance frequency.

Further, the energy required when utilizing resonance is 1 / Q energy when vibrating non-resonantly (Q is a Q factor indicating the sharpness of resonance). That is,
Sound waves can be transmitted efficiently by employing a transmission method utilizing resonance. The Q factor varies depending on the material, but is about 1000 in the case of piezoelectric ceramic. Also, in the case of the magnetostrictive system, the frequency that can be calculated from the speed of sound waves inside the material is the fundamental frequency of resonance, with the material length being half the wavelength. In general, in addition to the electrostrictive method and the magnetostrictive method, the sound wave generator using the above-described resonance method can be used as a wave receiving element in addition to the wave transmitting element. This is because a voltage or a current is generated in the material by applying an external vibration equal to the mechanical resonance frequency.

As described above, since the sound wave is conventionally transmitted and received by the resonance method, as shown in FIG. 17, a frequency corresponding to the resonance frequency of the element, for example, a resonance frequency of 40 [kHz] is obtained until a stable resonance is achieved as shown in FIG. A pulse signal having a period of 25 [μs] is continuously applied to the element over a plurality of periods. This is due solely to the requirements of the transmitting or receiving element. Furthermore, even if the transmission electric signal is stopped in the case of transmission, or if the sound wave is stopped in the case of reception, vibration due to mechanical resonance remains (this is referred to as "reverberation"). It takes considerable time to completely stop. Therefore, the next operation such as signal processing is executed after waiting a considerable time after transmitting the sound wave.

By the way, the Doppler effect generally refers to a phenomenon in which the frequency of a sound wave reflected by an object moving with respect to an observer is different from the frequency of a transmitted sound wave. On the other hand, since the transmission and reception of sound waves in the above-described conventional example are performed by mechanical resonance, even if a sound wave is transmitted by applying a signal of a predetermined frequency to the transmitting element, the reflected sound waves reflected by the object are reflected. Is shifted from the frequency of the transmitted sound wave, the receiving element may not be able to receive the reflected sound wave. That is, although depending on the frequency shift amount of the sound wave signal, the sound wave is received by the wave receiving element at a frequency other than its resonance frequency, and the efficiency of converting the received wave signal into an electric signal is extremely reduced. Therefore, when measuring the moving speed of the object using the Doppler effect, the measurable speed range is largely limited by the resonance frequency of the wave receiving element, and the measurement accuracy is low.

In the conventional method of transmitting and receiving waves utilizing mechanical resonance, even if a signal whose amplitude is modulated is applied to a transmitting element, for example, the amplitude of the resonance vibration is the same as that of the applied modulation signal. Does not change. Therefore, in the above-described conventional resonance method, the sound wave signal transmitted from the transmitting element cannot be controlled by the electric signal applied to the transmitting element. Therefore, there has been no idea of applying an analog-modulated signal to the transmitting element and transmitting the signal, and receiving the analog-modulated sound wave by the receiving element.

By the way, in order to make the directional characteristics of the transmitting element and the receiving element desired characteristics, in the conventional resonance method, there is a method of changing the shapes of the transmitting surface and the receiving surface of the transmitting element and the receiving element. However, it is not a practical method because the structure itself needs to be changed. Therefore, conventionally, a desired directional characteristic is obtained by arranging a horn 38 in front of the transmitting surface and the receiving surface as shown in FIG. 18, and when the directional characteristic is changed, a shape matching the directional characteristic is obtained. I was replacing it with a horn. That is, when the horn is not wired in front of the wave transmitting surface or the wave receiving surface as shown in FIG. 19, the sound wave is spread in a wide space. The direction of transmitting the sound wave can be concentrated in the front direction.

[0014]

However, in the case of the above-mentioned conventional resonance system, there are the following problems. First, since only sound waves having a frequency substantially equal to the resonance frequency uniquely determined by the structure can be transmitted and received, the structure of the element itself must be changed in order to transmit and receive sound waves of another frequency. Must.

Further, as shown in FIG. 17B, a time of about several ms is required until mechanical resonance reaches a stable region, and a signal for instructing to transmit a sound wave is stopped. However, as shown in FIG. 3C, it takes several milliseconds for the sound wave to actually stop due to reverberation. Depending on the applied electric signal, it cannot be controlled on the order of μs. In the case of a system configuration having a transmitting element and a receiving element independently, the resonance frequencies of the elements must be matched. For example, the physical frequency must be adjusted by measuring the resonance frequency of a single element, which causes an increase in unit cost.
Furthermore, the dimensions including the element change due to the temperature and humidity, which affects the resonance frequency, and the change in the resonance frequency changes the magnitude of the output of the element. And
Because of the resonance system, the amount of output change with respect to environmental changes, that is, frequency changes, is very large.

Further, since the frequency of the transmitted and received sound waves is only the resonance frequency determined by the structure, when a sound wave of the same frequency is generated by another sound wave generator, the sound wave is generated by the own apparatus or the sound wave from another apparatus. A great deal of effort is required to distinguish between them, and various attempts have been made, for example, as described in JP-A-60-91281 or JP-A-58-122482. Neither of them has taken complete measures.

On the other hand, it is conceivable to avoid the above-mentioned problem of the resonance system by driving the magnetostrictive material, the piezoelectric material, and the like used in the conventional resonance system without resonance.
It has the following problems. For example, the forced vibration displacement of the piezoelectric ceramic 31 shown in FIG.
(D: piezoelectric constant = 200 × 10 ⁻¹² [m / V]), to obtain a displacement of 1 μm, the applied voltage must be 5 μm.
About 000 [V] is required, and a booster circuit must be provided for the conventional device (see FIG. 20). Further, even if the shape is set so that the vibration in the desired direction becomes non-resonant, resonance vibration may occur in an undesired direction depending on the shape and size of the material and the frequency of the applied signal voltage. If sound waves due to this vibration leak in an undesired direction, they become noise sources. Therefore, in order to prevent resonance in all shape directions within a wide frequency band to be used, there is a problem that the dimensional design of the element itself becomes very complicated.

In the case of a generally used magnetostrictive element (ferrite, nickel, etc.), as shown in FIG. 21, if the strain is 20 [ppm], at least 50 [mm] is required to displace 1 [μm]. Material length is required. However, when the sound velocity in the magnetostrictive element is ferrite, it is about 5
000 [m / s], and the frequency at which the material length is equal to the half-wavelength of the sound wave is the basic resonance frequency. In this case, the resonance frequency is about 50 [kHz], and the resonance slightly exceeds the audible range. There will be a point. Therefore, there is a drawback that when a conventional magnetostrictive element is used to transmit a sound wave in a non-resonant manner, a structural resonance frequency exists in the ultrasonic region of the transmitted sound wave. Also, using the magnetostrictive element in a region where the relationship between the magnetic field and the distortion is not linear means that the sound pressure of the sound wave does not change in a sinusoidal manner even if the magnetic field is changed in a sinusoidal manner. There is a disadvantage that it becomes complicated. However, if an attempt is made to use the magnetostrictive element in a portion where the relationship between the magnetic field and the strain is linear, there is a problem that the material length becomes longer and the structural resonance frequency further decreases, which causes inconvenience.

The above-mentioned vibration displacement of 1 [μm]
When the propagation medium is air at room temperature and humidity, the vibration frequency is 40 [k
Hz] when vibrating with a point sound source at a distance of 30 [cm].
And the sound pressure is 120 [dB] (0 [dB] = 0.00002)
[Pa]), which is almost equal to a resonance type transmitting element and receiving element using a piezoelectric ceramic which is conventionally marketed for aerial ultrasonic waves.

By the way, when measuring the distance to an object based on a time delay from the transmission of a sound wave signal to the reception of a reflected sound wave signal, the distance between the transmitting element, the object, and the receiving element is measured. Is expressed by the distance L = VT (V: sound velocity in the propagation medium, T: time from the start of transmission to the start of reception), but the time until the above-mentioned stable resonance and the reverberation after the sound wave stop command are given. At a distance equivalent to the time plus the time,
When the same element is used for both transmission and reception, measurement becomes impossible. A method for reducing such reverberation is disclosed in JP-A-4-70585 and JP-A-64-448.
No. 76, and the like, and a method for improving the short-range measurement area as described above are proposed in Japanese Utility Model Laid-Open Nos. 59-149071 and 63-168875. However, when sound waves are transmitted and received in the air, even when various measures are taken at a resonance frequency of 40 [kHz], the area within the above 30 [cm] is almost an unmeasurable area.

As described above, since conventionally, only a single-frequency sound wave was transmitted by mechanical resonance, there was no idea of modulating the sound wave. Therefore, the signal processing method is based on the method of measuring the delay time from the start of transmission to the start of reception and calculating the distance from the transmission time. On the other hand, in the application of the sensor, there is an object which cannot be measured without a sound wave. For example, when trying to obtain information on an optically transparent object such as glass or a liquid, it is impossible to measure with a commonly used optical sensor, and sensing with sound waves is important in such a field. It can be a scheme.

Conventionally, when the directional characteristics of a sound wave are to be set to desired characteristics, a horn 3 as shown in FIG.
8 and other members other than the transmitting element and the receiving element are required, and there is a problem that the transmitting apparatus or the receiving apparatus becomes structurally large. Further, there is a problem that changing the directivity characteristics requires replacement of members, which is troublesome. The inventions of claims 1 to 12 have been made in view of the above problems, and an object of the invention is to enable transmission or reception of a sound wave signal without resonance, to reduce noise, and to reduce electrical noise. It is an object of the present invention to provide a sound wave signal transmitting method and apparatus which can be easily controlled, a sound wave signal receiving method and a sound wave signal transmitting / receiving processing system using them.

The inventions of claims 13 to 17 have been made in view of the above problems, and an object of the invention is to modulate a sound wave signal to obtain information on an object by a signal processing method different from the conventional method. A method and apparatus for transmitting a sound signal, a method and apparatus for receiving a sound signal, and a system for transmitting and receiving a sound signal using the same.

The inventions of claims 18 and 19 have been made in view of the above problems, and an object of the invention is to provide a method and an apparatus for transmitting a sound wave signal in which the directional characteristics can be easily set and changed, and the sound wave. It is an object of the present invention to provide a signal receiving method, a device thereof, and a sound wave transmitting / receiving processing system using the same.

[0025]

According to a first aspect of the present invention, there is provided a magnetostrictive element formed of a giant magnetostrictive material comprising a binary alloy of a rare earth element and an iron group element. A magnetostrictive element formed of a giant magnetostrictive material having a large displacement amount, characterized in that a pressure change is generated in the acoustic wave propagation medium by driving the wave transmitting element in a non-resonant manner and a sound wave signal is transmitted. When used for a transmitting element, a sound wave signal can be transmitted with an appropriate amount of energy, and if the dimensions of the transmitting element are set to an appropriate size, the mechanical resonance frequency can be in the audible range or the ultrasonic range. Can be eliminated. As a result, the transmission of the sound wave signal can be electrically controlled, and the responsiveness of the sound wave signal is improved.

According to a second aspect of the present invention, there is provided a wave transmitting element formed of a giant magnetostrictive material comprising a binary alloy of a rare earth element and an iron group element, A driving means for driving by resonance, wherein the driving means drives the wave transmitting element to generate a pressure change in a sound wave propagation medium to transmit a sound wave signal, and a giant magnetostrictive material having a large displacement amount. By using the magnetostrictive element formed by
If the driving means is driven with an appropriate amount of energy, the sound wave signal can be transmitted, and if the size of the transmitting element is set to an appropriate size, the mechanical resonance frequency becomes in the audible range or the ultrasonic range. Can be absent. As a result, the transmission of the sound wave signal can be controlled by the electric drive signal from the driving means, and the responsiveness of the sound wave signal is improved.

According to a third aspect of the present invention, in order to achieve the above object, a magnetostrictive element formed of a giant magnetostrictive material made of a binary alloy of a rare earth element and an iron group element is used as a wave receiving element, It is characterized in that the pressure change of the sound wave propagation medium is detected non-resonantly by the wave receiving element and converted into an electric signal, and a magnetostrictive element formed of a giant magnetostrictive material having a large displacement amount is used as the wave receiving element. It is possible to convert a received sound wave signal into an electric signal of an appropriate level and output the same, and if the dimensions of the wave receiving element are set to an appropriate size, the mechanical resonance frequency can be in the audible range or the ultrasonic range. Can be eliminated. As a result, the reception of the sound wave signal can be electrically controlled, and the responsiveness of the sound wave signal is improved.

According to a fourth aspect of the present invention, there is provided a wave receiving element formed of a giant magnetostrictive material comprising a binary alloy of a rare earth element and an iron group element, and Signal converting means for converting a pressure change of a sound wave propagation medium due to a sound signal detected at a non-resonance into an electric signal, wherein a magnetostrictive element formed of a giant magnetostrictive material having a large displacement amount is used as a wave receiving element. By using, the sound wave signal received by the receiving element can be converted into an electric signal of an appropriate level by the signal converting means and output, and if the dimensions of the receiving element are made appropriate, The mechanical resonance frequency can be eliminated from the audible range and the ultrasonic range. As a result, the reception of the sound wave signal can be electrically controlled, and the responsiveness of the sound wave signal is improved.

According to a fifth aspect of the present invention, there is provided a wave transmitting element formed of a giant magnetostrictive material comprising a binary alloy of a rare earth element and an iron group element, and a non-resonant wave transmitting element. A sound wave signal transmitting device including a driving unit driven by a device, and a pressure change of a sound wave propagating medium due to a sound wave signal formed of the giant magnetostrictive material and transmitted from the wave transmitting element and reflected by an object. A sound receiving element including a wave receiving element that detects by resonance, a signal conversion unit that converts a pressure change of a sound wave propagation medium detected by the wave receiving element into an electric signal, and at least the sound wave signal receiving apparatus Signal processing means for performing processing for obtaining information on the object based on the electric signal converted by the signal conversion means to perform, the sound wave signal transmitting device and the sound wave signal receiving device Super magnet with large displacement Since the magnetostrictive element formed of a material is used for the wave transmitting device and wave receiving element, it is possible to electrically control the transmit and reception of the acoustic signal, the response of the acoustic signal is improved.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the sound wave signal comprises a sound wave in an audible region. The invention of claim 7 is the invention of claims 1 to 5
In any one of the inventions, the sound wave signal comprises a sound wave in an ultrasonic region. The invention according to claim 8 is the invention according to any one of claims 1 or 2 or 5 to 7, wherein the driving unit supplies an electric signal having a predetermined periodic waveform to the transmitting element for driving. Features.

According to a ninth aspect of the present invention, in the invention of the eighth aspect, the driving means drives the transmitting element by supplying the electric signal for one cycle to the transmitting element. Claim 10
According to a third aspect of the present invention, in any one of the third to seventh aspects of the present invention, the signal conversion unit converts a pressure change of a sound wave propagation medium having a predetermined periodic waveform detected by the wave receiving element into an electric signal. It is characterized by the following.

An eleventh aspect of the present invention is characterized in that, in the tenth aspect of the present invention, the signal converting means converts a pressure change of the sound wave propagation medium having the waveform for one cycle into an electric signal. According to a twelfth aspect of the present invention, in the invention according to any one of the fifth to eleventh aspects, the driving unit applies an electric signal having a predetermined periodic waveform to the transmitting element to drive the transmitting element. A sound wave signal is transmitted from the object, and the reflected sound wave signal of the sound wave signal reflected by the moving or stationary object is converted into an electric signal by the wave receiving device, and the reflected sound wave is converted by the signal processing unit. A signal frequency is obtained, and information on the moving speed of the object is obtained from the frequency of the sound wave signal transmitted from the wave transmitting device and the frequency of the reflected sound wave signal. There is no need to adjust the characteristics of the transmitting element and receiving element between the signal receiving devices, and the level fluctuation of the sound wave signal received in response to environmental changes such as temperature and humidity is suppressed. Object movement with higher accuracy Speed of information can be obtained.

According to a thirteenth aspect of the present invention, in the fifth aspect of the present invention, the driving means applies an electric signal obtained by analog-modulating a carrier wave with a modulating wave to the transmitting element to drive the transmitting element, so that the acoustic wave signal is transmitted from the transmitting apparatus. The reflected wave signal of the sound wave signal reflected by the moving or stationary object is converted into an electric signal by the wave receiving device, and the reflected wave signal is modulated by the signal processing unit. It is characterized by obtaining information about the object from the wave component, it is possible to obtain information of the object in a method different from the conventional, accurate and fast response of the object without being affected by external acoustic noise Information is obtained.

According to a fourteenth aspect, in the thirteenth aspect, the signal processing means includes a modulating component of the sound wave signal transmitted from the wave transmitting device and a reflected sound wave signal received by the wave receiving device. The time interval in the same phase of the modulation component is obtained, multiplying the time interval by the medium propagation velocity of the sound signal, to obtain information on the distance to the moving or stationary object, The distance information to the object can be obtained by a different method, and the distance information to the object can be obtained accurately and quickly without being affected by external acoustic noise.

According to a fifteenth aspect of the present invention, in the thirteenth aspect, the signal processing means includes a modulating component of the sound wave signal transmitted from the wave transmitting device and a reflected sound wave signal received by the wave receiving device. The time interval in the same phase of the modulation component is obtained, and the time interval is multiplied by the medium propagation velocity of the sound signal to calculate the distance to the moving or stationary object, and a plurality of times with a predetermined time difference. Dividing the difference between the distances obtained by the crossing by the time difference to obtain information on the moving speed of the object, it is possible to obtain information on the moving speed of the object by a method different from the conventional method. Thus, information on the moving speed of the target object can be obtained accurately and with a fast response without being affected by external acoustic noise.

According to a sixteenth aspect, in the thirteenth aspect, the signal processing means includes a modulating component of the sound wave signal transmitted from the wave transmitting device and a reflected sound wave signal received by the wave receiving device. The frequency of the modulation component of the sound wave signal transmitted from the transmitting device and the frequency of the modulation component of the reflected sound wave signal to obtain information on the moving speed of the object. Thus, the information on the moving speed of the object can be obtained by a method different from the conventional method, and the information on the moving speed of the object can be obtained accurately and quickly without being affected by external acoustic noise.

The invention of claim 17 is the invention of claim 15 or 16
In the invention, the signal processing means obtains information on the moving acceleration of the object by dividing the difference between the moving speeds obtained a plurality of times with a predetermined time difference by the time difference, The information on the moving acceleration of the object can be obtained by a method different from that of the first embodiment, and the information on the moving acceleration of the object can be obtained accurately and quickly without being affected by external acoustic noise.

According to an eighteenth aspect of the present invention, in any one of the first or second or fifth to seventeenth aspects, the wavelength of the sound wave signal transmitted from the wave transmitting element and the shape of the sound wave transmitting surface of the sound wave transmitting element are formed. And a sine wave signal having a frequency at which a desired directional characteristic can be obtained is given from the driving means to the transmitting element to drive the directional characteristic. Can be set and changed.

A nineteenth aspect of the present invention is the invention according to any one of the third to seventeenth aspects, wherein the sound wave receiving surface of the wave receiving element with respect to the wavelength of the sound wave signal so as to obtain a desired directional characteristic of the wave receiving element. Is determined, and the directional characteristics at the time of receiving a sound wave signal can be easily set and changed.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. (Embodiment 1) As shown in FIG. 1, a sound wave signal transmitting apparatus according to the present embodiment has a magnetostrictive element formed of a giant magnetostrictive material as a transmitting element 1, and a driving coil 3a extending longitudinally around the transmitting element 1. The driving coil 3a is configured such that a bias power source 3b and a signal source 3c are connected in series at both ends of the driving coil 3a. Further, as shown in FIG. 2, the acoustic wave signal receiving device is configured such that a magnetostrictive element also formed of a giant magnetostrictive material is used as the receiving element 2, and a detection coil 4a is wound around the receiving element 2 along the longitudinal direction. A bias power supply 4b and a detection transformer 4c are connected in series to both ends of the drive coil 4a.

The giant magnetostrictive materials forming the transmitting element 1 and the receiving element 2 are Tb (terbium), Sm (samarium),
Rare earth elements such as Dy (dysprosium) and Fe
It is made of a binary alloy of an iron group element such as (iron), Co (cobalt), Ni (nickel) and has a magnetic field-magnetostriction characteristic as shown in FIG. 199
October 2006 (Vol.44, No.11) 48-53, published by Nikkan Kogyo Shimbun). In addition, as an application of the magnetostrictive element formed of such a giant magnetostrictive material, a low-frequency actuator is generally mainly assumed.

In general, a magnetostrictive element has a Joule effect and a billiard effect. The Joule effect refers to a phenomenon in which when a magnetic field H is applied to a magnetostrictive element, a change in size (magnetostriction Δl / l) corresponding to the magnitude of the magnetic field H occurs. Using the Joule effect, the magnitude of the magnetic field H applied to the magnetostrictive element (transmitting element 1) is changed by changing the amount of current flowing through the driving coil 3a, and thereby the magnetostriction Δl / 1 is generated, and the magnetostriction becomes a pressure change of air as a propagation medium, and a sound wave signal is transmitted. That is, as shown in FIG. 3, a bias magnetic field H _DC is applied to the transmitting element 1 by flowing a bias current I _DC from the bias power supply 3c to the drive coil 3a.
And, for example, a sinusoidal signal current I _AC from the signal source 3 c to the drive coil 3 around the bias current I _DC.
a, the magnetic field H _AC applied to the transmitting element 1 also changes sinusoidally according to the signal current I _AC . As a result, a displacement (magnetostriction) that changes sinusoidally in accordance with the signal current I _AC occurs in the transmitting element 1, and the displacement is propagated in the air, so that a sinusoidal sound signal is transmitted. is there.

On the other hand, the Villari effect is a phenomenon in which when the size of the magnetostrictive element changes due to the application of a force, the amount of magnetization of the magnetostrictive element changes in proportion to the change in the size. With such magnetization of the magnetostrictive element (wave receiving element 2) is changed, the detection coil 4a is induced voltage E _AC is generated in accordance with the amount of change. That is, since the sound wave signal is a change in the pressure of air as a propagation medium, when the wave receiving element 2 composed of a magnetostrictive element receives a sound wave signal, the change in the pressure causes the wave receiving element 2 to be displaced, and the amount of magnetization is reduced. Change. As a result, it is possible to convert the signal current I _AC flowing through the sound wave signal reception in the detection coil 4a through the change in the magnetization of wave receiving element 2.

Here, the basic relational expression in the magnetostrictive element forming the transmitting element 1 and the receiving element 2 is as follows. S = sH · T10 d · H B = d · T10 μT · H where S: magnetostriction, H: magnetic field strength, sH: reciprocal of Young's modulus, T: mechanical stress, B: magnetic flux density, μT : Permeability. Also, the giant magnetostrictive material has a magnetic field-magnetostrictive characteristic as shown in FIG. As described above, while applying a bias magnetic field H ₁ in the magnetostrictive element with the bias power supply 3b, or permanent magnets and supplies the alternating current (signal current) I _AC to drive coils 3a, AC to the magnetostrictive element a magnetic field H ₂
Is applied. Magnetic field upon application of a bias magnetic field H ₁ -
The slope of the magnetostrictive characteristic curve is d, and the length of the magnetostrictive element is l =
2 [mm], H ₁ = 250 [Oe], H ₂ = 250 [O
e) _{Let p - p} and mechanical stress T = 0. Here, from the above equation, the magnetostriction generated in the magnetostrictive element is S = d · H ₂ , and the amount of distortion Δl is obtained by Δl = l · S. Specifically, FIG.
Since the inclination d is 2 × 10 ⁻⁸ [m / A], the distortion amount Δl ≒ 1 [μm]. Then, if the frequency of the alternating magnetic field H _2, for example, in the extent 50 [kHz], 50 [kH
z] is output. That is, the frequency of the sound wave signal transmitted from the transmitting element 1 is not determined by the structural factors of the transmitting element 1 as in the conventional resonance system, but is a signal current flowing from the signal source 3c to the driving coil 3a. it can be electrically determined by the frequency of the I _AC. That is, by changing the frequency of the signal current I _AC , a sound wave signal of an arbitrary frequency can be transmitted, and this is clear from the above principle.

In this embodiment, the acoustic wave velocity in the giant magnetostrictive material is 2500 [m / s], and the mechanical characteristics of the transmitting element 1 when the length of the transmitting element 1 is 5 [mm]. Since the wavelength is 10 [mm], the theoretical resonance frequency f ₀ is f ₀ = 625 [kHz]. At present, the resonance frequency f ₀ is one order of magnitude higher than the sound wave frequency of an ultrasonic vibrator using a piezoelectric ceramic which is currently generally used is about 40 [kHz].
If the frequency band of the signal current I _AC flowing to the
Obviously, the transmitting element 1 can be driven non-resonantly without mechanical resonance.

On the other hand, the wave receiving element 2 of the present embodiment can receive a sound wave signal as follows. First, when the both ends of the detection coil 4a are short-circuited, the magnetic flux density B = 0 from the above equation, so that the magnetic field H = −d · T / μ
It becomes T ₀ . Furthermore, the current I generated in the detection coil 4a
And the magnetic field H, a relationship of H = n · I (n = N / l, N: the total number of turns of the detection coil 4a) is established.
= D / μT × 1 / N × T. Here, μT = 4π ×
10 ^-7 × relative magnetic permeability, relative magnetic permeability = 8. Therefore, it is obvious from the above principle that the wave receiving element 2 can receive a wave regardless of the frequency of the sound wave signal.

FIG. 5 shows the basic configuration of a sound wave signal transmission / reception processing system using the above-mentioned transmission element 1 and reception element 2. Wave transmitting circuit 3 including drive coil 3a and bias power supply 3c
On the other hand, a continuous signal current is supplied from the continuous oscillation circuit 5, and a sound wave signal is transmitted from the transmitting element 1. Then, the sound wave signal transmitted from the wave transmitting element 1 and reflected back to the object is received by the wave receiving element 2, and is converted into an electric signal by the wave receiving circuit 4 having the detection coil 4a and the like, and the signal is processed. Circuit 6
Is output to Note that the oscillation frequency in the continuous oscillation circuit 5 can be changed by the transmission frequency setting unit 7, and information on the transmission frequency is also given to the signal processing circuit 6.

The signal processing circuit 6 obtains, for example, a difference between the transmission start time of the sound wave signal from the wave transmitting element 1 and the reception start time of the reflected sound wave signal by the wave receiving element 2, and determines the difference. For example, the distance to the object is obtained by multiplying the propagation speed of the sound wave signal in the air). Note that the information on the target object obtained by the signal processing circuit 6 is not limited to the information on the distance, and by performing appropriate signal processing,
For example, it is possible to obtain various information such as the existence or nonexistence of the object, the moving speed or the moving acceleration of the object.

As described above, according to the present embodiment, the wave transmitting element 1 and the wave receiving element 2 are formed using a magnetostrictive element made of a giant magnetostrictive material having a larger displacement than a piezoelectric element or the like. 1 is driven non-resonantly to transmit a sound wave signal, and the wave receiving element 2 is configured to receive a sound wave signal non-resonantly. If the wave can be transmitted with an appropriate amount of energy and the size of the wave transmitting element 1 is made appropriate, the mechanical resonance frequency does not exist in the audible region or the ultrasonic region. In addition, even if the amount of energy of the sound wave signal is not so large, the wave receiving element 2 can convert the received sound wave signal into an electric signal of an appropriate level and output the electric signal. As a result, it becomes possible to electrically control the transmission and reception of the sound wave signal,
For example, by changing the frequency of the signal current flowing through the drive coil 3a, it is possible to easily set or change the sound signal to an arbitrary frequency. Also, a filter is connected to the detection coil 4a, and the pass band of the filter is set to volume or the like. In this case, the frequency of the sound wave signal received by the wave receiving element 2 can be easily set and changed. As described above, a sound wave signal of an arbitrary frequency can be transmitted and received by electrical control such as adjustment of a signal current, so that the structures of the transmitting element 1 and the receiving element 2 are adjusted as in a conventional resonance system. This is no longer necessary, and the change in the output level of the wave transmitting element 1 and the wave receiving element 2 with respect to the change in temperature and humidity is not so large as that of the conventional resonance system and is so small that it can be ignored.

By the way, when the transmitting surface of the transmitting element 1 and the receiving surface of the receiving element 2 are substantially circular with a radius a, the transmitting and receiving angles are set at an angle θ from the normal direction of the transmitting and receiving surfaces. When the direction is defined, the sound velocity is v ₀ , the sound frequency is fa, and the wavelength of the sound signal is λ, k = 2π · fa / v ₀ = 2π / λ
Then, the directional characteristics D of the transmitting element 1 and the receiving element 2 are represented by the following equations (where J ₁ (x) is a first-order Bessel function). Since this is obvious in the field of acoustic engineering, detailed description is omitted.

D (θ) = | 2J ₁ (k × a × sin (θ)) / (k × a × sin (θ)) | By the above equation, the radius a of the transmitting and receiving surfaces and the sound signal 6A to 6D show the directional characteristics obtained for various combinations of the wavelength λ. That is, when a / λ = 0.2 as shown in FIG.
As shown in FIGS. 8B to 8D, the stronger the value of a / λ, the stronger the directivity characteristics. When transmitting a sound wave signal, the wavelength of the sound wave signal is actually changed by appropriately setting the frequency of the signal current flowing through the drive coil 3a to easily change and adjust to a desired directional characteristic. be able to.

(Embodiment 2) FIG. 7 shows Embodiment 2 of the present invention.
1 is a block diagram of a sound wave transmission / reception processing system in FIG. However, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only the configuration and operation that characterize the present embodiment will be described. In the present embodiment, a signal having an arbitrary waveform such as a triangular wave,
It is characterized in that a single pulsed sound wave signal is output by outputting to the drive coil 3a only for a period. That is, as shown in FIG. 7, a single oscillation circuit 8 is provided in place of the continuous oscillation circuit 5 in the configuration of the first embodiment, and when the start of signal output is instructed from the transmission start instruction unit 9, the single oscillation circuit By outputting a drive signal for one cycle of the rectangular wave as shown in FIG. 8A to the drive coil 3a from the circuit 8 via the wave transmitting circuit 3, the rectangular wave as shown in FIG. Of 1
The sound wave signal for the period is transmitted.

In this embodiment as well, as in the first embodiment, the sound wave signal is transmitted by driving the wave transmitting element 1 non-resonantly. The element 1 transmits a sound wave signal in response. Therefore, there is no need to repeatedly input a drive signal having the same waveform a plurality of times until the sound wave signal is stabilized unlike the conventional resonance method. That is, in the conventional resonance method, the resonance frequency is 40 [kHz].
z], it was necessary to continuously output a number of pulses of a rectangular wave signal having a pulse width of 25 [μs] (FIG. 17).
(See (a)), in the case of the present embodiment, a sound wave signal can be transmitted only by applying a pulse signal for one cycle. In addition, immediately after the input of the driving signal is stopped, the transmission of the sound wave signal from the wave transmitting element 1 is also stopped. Therefore, the reverberation as in the related art does not occur even if no special measures are taken. Because the signal is stable, there is no conventional waiting time. Therefore, there is an advantage that the response speed of the system is faster than that of the conventional system that performs the transmission and reception of the resonance method.

On the other hand, since a stable sound wave signal is transmitted from the beginning and reverberation does not occur, the receiving element 2 also has the configuration shown in FIG.
As shown in the figure, a single sound wave signal can be received, and a detectable distance (a recent detection distance) such as a moving speed of an object and presence or absence can be greatly reduced as compared with the conventional resonance method. Furthermore, even when the transmitting element 1 and the receiving element 2 are shared by one element, the receiving distance can be immediately obtained at the same time as the end of the transmitting operation. is there.

(Embodiment 3) FIG. 9 shows Embodiment 3 of the present invention.
1 is a block diagram of a sound wave transmission / reception processing system in FIG. However, components common to the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the signal processing circuit 10 of the present embodiment, the frequency of the sound wave signal to be transmitted and received is measured, and the moving speed of the target object is obtained from the measured frequency using the Doppler effect. A DSP equipped with a frequency counter or a frequency-voltage conversion circuit, etc.
(Digital signal processor) and the like. However, the frequency of the transmitted sound signal need not be measured, and the frequency data provided by the transmission frequency setting unit 7 may be used.

For example, the frequency of the transmitted sound signal (frequency of the signal current flowing through the drive coil 3a) is fa, the speed of the sound signal in the propagation medium is v ₀ , and the frequency of the received sound signal (wave receiving circuit 4). the frequency) of the signal output fb, when the moving speed v ₁ of the object from the frequency shift due to Doppler effect is represented by the following formula. The moving speed v ₁ of the object is positive when the direction in which the object moves away from the wave receiving element 2 is positive.
The direction of approach is negative.

Fb = (v ₀ + v ₁ ) / (v ₀ −v ₁ ) × fa From the above equation, the moving speed v ₁ of the object can be obtained by the following equation. v ₁ = (fb−fa) / (fa + fb) × v ₀ ... The above formula and the above are only slightly corrected for the difference in the transmission direction or reception direction of the sound wave signal and the moving direction of the object. And a detailed description is omitted.

(Embodiment 4) FIG. 10 is a block diagram of a sound wave signal transmission / reception processing system according to Embodiment 4 of the present invention. However, components common to the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the present embodiment, the modulated sound wave signal is transmitted and the modulated wave component is extracted from the received sound wave signal, and the distance to the object is determined by the signal processing circuit 15 from the transmitted and received modulated wave components. We are trying to calculate. Therefore, a carrier wave generating circuit 12 for generating a carrier wave signal, a modulated wave generating circuit 13 for generating a modulated wave signal, and a carrier wave signal inputted from the carrier wave generating circuit 12 based on the modulated wave signal inputted from the modulated wave generating circuit 13 A modulation circuit 11 that modulates and outputs the modulated wave signal to the transmission circuit 3 and a modulation wave extraction circuit 14 that extracts the component of the modulation wave signal (modulation wave component) from the output signal from the reception circuit 4
And However, the outputs of the carrier wave generation circuit 12 and the modulation wave generation circuit 13 are also supplied to a modulation wave extraction circuit 14, and a modulation wave component is extracted based on the output. In the present embodiment, the carrier signal has a frequency fc = 5.
0 [kHz], frequency fm of the modulated wave signal = 100 [H
z], the modulation circuit 11 performs amplitude modulation.

In FIG. 11, the modulated wave signal output from the modulated wave generation circuit 13 and the signal of the modulated wave component extracted by the modulated wave extraction circuit 14 from the sound wave signal received by the receiving element 2 are the same. It is shown on the time axis. The signal processing circuit 15 measures a time interval when both signals have the same phase. For example, the signal processing circuit 15 records the time for each zero cross of each signal, and obtains the time interval t from the difference between the transmission zero cross time and the reception zero cross time.
Do with. Assuming that the speed of the sound wave signal in the propagation medium is c, the distance L to the object A is L = ct / 2 as shown in FIG.
Can be obtained by For example, the sound speed c at normal temperature is c =
340 [m / s], the frequency of the modulated wave is 100
If the time interval t = 2 [ms] in the case of [Hz], the distance L to the object A at that time is L = 0.3
4 [m]. Further, as shown in FIG. 13, the measurement of the distance L to the object A is repeatedly performed, and the difference L _{2 in the} distance is measured.
By dividing −L ₁ by the measurement time interval T ₂ −T ₁ , the moving speed v of the object A becomes v = (L ₂ −L ₁ ) / (T
₂ −T ₁ ). Further, the moving acceleration of the object A can also be obtained by differentiating the obtained moving speed v with time. In the present embodiment, the distance from the zero-crossing time interval to the object A is obtained. However, by measuring the frequency of the modulated wave, the moving speed of the object A can be calculated from the frequency shift due to the Doppler effect. It is also possible to ask.

As described above, according to the present embodiment, information on the distance to the object A and the moving speed can be obtained by a method different from that of the related art, and can be accurately performed without being affected by external acoustic noise. In addition, information on the distance and the moving speed of the target A can be obtained with a fast response.

[0061]

According to the first aspect of the present invention, a magnetostrictive element formed of a giant magnetostrictive material composed of a binary alloy of a rare earth element and an iron group element is used as a transmitting element, and the transmitting element is driven without resonance. This causes a pressure change in the sound wave propagation medium to transmit a sound wave signal, so that a magnetostrictive element formed of a giant magnetostrictive material having a large displacement amount is used for the wave transmitting element, so that the sound wave signal can be transmitted with an appropriate amount of energy. When the size of the transmitting element is appropriately sized, the mechanical resonance frequency can be prevented from being present in the audible region or the ultrasonic region, and as a result, the sound wave signal can be transmitted. It is possible to electrically control the transmission, and there is an effect that the response of the sound wave signal is improved.

According to a second aspect of the present invention, there is provided a transmitting element formed of a giant magnetostrictive material comprising a binary alloy of a rare earth element and an iron group element, and a driving means for driving the transmitting element non-resonantly. Prepared,
Since the drive unit drives the wave transmitting element to generate a pressure change in the sound wave propagation medium to transmit the sound wave signal, a magnetostrictive element formed of a giant magnetostrictive material having a large displacement is used for the wave transmitting element. If the driving means is driven with an appropriate amount of energy, the sound wave signal can be transmitted. If the dimensions of the transmitting element are set to an appropriate size, the mechanical resonance frequency becomes audible or ultrasonic. Can no longer exist in the area,
As a result, the transmission of the sound wave signal can be controlled by the electric drive signal from the driving means, and the response of the sound wave signal is improved.

According to a third aspect of the present invention, a magnetostrictive element formed of a giant magnetostrictive material made of a binary alloy of a rare earth element and an iron group element is used as a wave receiving element, and the pressure change of a sound wave propagation medium caused by a sound wave signal is measured. Since the receiving element detects non-resonance and converts it into an electric signal, the magnetostrictive element formed of a giant magnetostrictive material having a large displacement is used for the receiving element, so that the received sound wave signal can be adjusted to an appropriate level. It can be converted to an electrical signal and output, and if the dimensions of the wave receiving element are made appropriate,
The mechanical resonance frequency can be eliminated from the audible range and the ultrasonic range. As a result, it is possible to electrically control the reception of the sound wave signal, and the responsiveness of the sound wave signal is improved. effective.

According to a fourth aspect of the present invention, there is provided a wave receiving element formed of a giant magnetostrictive material comprising a binary alloy of a rare earth element and an iron group element, and a sound wave signal detected non-resonantly by the wave receiving element. Signal conversion means for converting a change in pressure of the sound wave propagation medium into an electric signal, so that a magnetostrictive element formed of a giant magnetostrictive material having a large displacement amount is used as the wave receiving element, and the wave is received by the wave receiving element. The sound wave signal can be converted into an electric signal of an appropriate level by the signal conversion means and output, and if the dimensions of the wave receiving element are set to an appropriate size, the mechanical resonance frequency can be in the audible range or the ultrasonic wave. Can no longer exist in the area,
As a result, it is possible to electrically control the reception of the sound wave signal, and the response of the sound wave signal is improved.

According to a fifth aspect of the present invention, there is provided a wave transmitting element formed of a giant magnetostrictive material made of a binary alloy of a rare earth element and an iron group element, and driving means for driving the wave transmitting element without resonance. A sound wave signal transmitting device, a wave receiving element that is formed of the giant magnetostrictive material and detects a non-resonant change in pressure of a sound wave propagation medium due to a sound wave signal transmitted from the wave transmitting element and reflected by an object, A sound signal receiving device including a signal converting device for converting a change in pressure of the sound wave propagation medium detected by the wave receiving element into an electric signal, and at least a signal converted by the signal converting device included in the sound signal receiving device. Signal processing means for performing a process for obtaining information on the object based on the electric signal, so that the sound wave signal transmitting device and the sound wave signal receiving device are formed of a giant magnetostrictive material having a large displacement. Magnetostrictive element to transmitting element Because it used the wave receiving element each time,
The transmission and reception of the sound wave signal can be electrically controlled, and the responsiveness of the sound wave signal is improved.

According to a twelfth aspect of the present invention, the driving unit transmits an electric signal having a predetermined periodic waveform to the transmitting element to drive the transmitting element, thereby transmitting an acoustic signal from the transmitting apparatus and moving the transmitting element. Or the reflected sound wave signal of the sound wave signal reflected by the stationary object is converted into an electric signal by the wave receiving device, and the frequency of the reflected sound wave signal is obtained by the signal processing means, Since information on the moving speed of the object is obtained from the frequency of the sound wave signal transmitted from the device and the frequency of the reflected sound wave signal, a transmitting element and a receiving device are provided between the sound wave signal transmitting device and the sound wave signal receiving device. There is no need to adjust the characteristics of the wave element, and the fluctuations in the level of the received sound wave signal due to environmental changes such as temperature and humidity are suppressed, and information on the moving speed of the object can be obtained more accurately than in the conventional resonance method. Has the effect of being obtained. .

According to a thirteenth aspect of the present invention, the driving means transmits an acoustic signal from the transmitting device by applying an electric signal obtained by analogly modulating a carrier wave with a modulating wave to the transmitting element to drive the moving device. The reflected wave signal of the sound wave signal reflected by the stationary object is converted into an electric signal by the wave receiving device, and the signal processing means relates to the object from a modulated wave component of the reflected sound signal. Since the information is obtained, the information of the object can be obtained by a method different from the conventional method, and there is an effect that the information of the object can be obtained with high accuracy and fast response without being affected by external acoustic noise.

[0068] According to a fourteenth aspect of the present invention, the signal processing means has the same phase of the modulation component of the sound wave signal transmitted from the wave transmitting device and the modulation component of the reflected sound wave signal received by the wave receiving device. The time interval is obtained, and the time interval is multiplied by the medium propagation velocity of the sound wave signal to obtain information on the distance to the moving or stationary object, so that the distance information to the object is obtained by a method different from the conventional method. Thus, there is an effect that distance information to an object can be obtained with high accuracy and a quick response without being affected by external acoustic noise.

According to a fifteenth aspect of the present invention, the signal processing means may be configured so that the modulated component of the sound wave signal transmitted from the transmitting device and the modulated component of the reflected sound signal received by the receiving device have the same phase. Obtain a time interval, multiply the time interval by the medium propagation velocity of the sound signal, calculate the distance to the moving or stationary object, and obtain each of the distances obtained a plurality of times with a predetermined time difference By dividing the difference by the time difference, the information on the moving speed of the object can be obtained, so that the information on the moving speed of the object can be obtained by a method different from the conventional method, without being affected by external acoustic noise. Thus, there is an effect that information on the moving speed of the target object can be obtained with high accuracy and fast response.

According to a sixteenth aspect of the present invention, the signal processing means converts each frequency of the modulation component of the sound wave signal transmitted from the wave transmitting device and the frequency of the modulation component of the reflected sound wave signal received by the wave receiving device. The information on the moving speed of the object is obtained from the frequency of the modulation component of the sound wave signal transmitted from the transmission device and the frequency of the modulation component of the reflected sound signal. The information on the moving speed of the target object can be obtained with high accuracy and fast response without being affected by external acoustic noise.

According to a seventeenth aspect of the present invention, the signal processing means obtains information on the moving acceleration of the object by dividing the difference between the moving speeds obtained a plurality of times with a predetermined time difference by the time difference. Therefore, the information of the moving acceleration of the object can be obtained by a method different from the conventional method, and the effect that the information of the moving acceleration of the object can be obtained accurately and quickly without being affected by external acoustic noise can be obtained. is there.

According to the eighteenth aspect of the present invention, a frequency at which a desired directional characteristic can be obtained is obtained from a directional characteristic determined by a wavelength of a sound wave signal transmitted from the transmitting element and a shape of a sound wave transmitting surface of the transmitting element. Since the sine wave signal is supplied from the driving unit to the transmitting element and driven, there is an effect that the directivity characteristic when transmitting the sound wave signal can be easily set and changed.

According to a nineteenth aspect of the present invention, the shape of the sound wave receiving surface of the wave receiving element with respect to the wavelength of the sound wave signal is determined so that desired directional characteristics of the wave receiving element can be obtained. There is an effect that the directional characteristics at the time of receiving waves can be easily set and changed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a sound wave signal transmitting device according to a first embodiment.

FIG. 2 is a circuit diagram showing the sound wave signal receiving device in the above.

FIG. 3 is an explanatory diagram for explaining the operation of transmitting and receiving a sound wave signal in the above.

FIG. 4 is a diagram showing a magnetic field-magnetostriction characteristic of the transmitting element and the receiving element in the above.

FIG. 5 is a block diagram showing a system configuration of the above.

FIGS. 6A to 6D are diagrams showing directivity characteristics of a transmitting element and a receiving element in the above.

FIG. 7 is a block diagram illustrating a system configuration according to a second embodiment.

FIG. 8 is an explanatory diagram for explaining the operation of the above.

FIG. 9 is a block diagram illustrating a system configuration according to a third embodiment.

FIG. 10 is a block diagram illustrating a system configuration according to a fourth embodiment.

FIG. 11 is a signal waveform diagram for explaining the above operation.

FIG. 12 is a diagram for explaining the operation of the above.

FIG. 13 is a diagram for explaining the operation of the above.

FIG. 14 is a block diagram showing a conventional system configuration.

FIG. 15 is a block diagram showing another conventional system configuration.

FIG. 16 shows the piezoelectric ultrasonic vibrator in Embodiment 1;
(A) is a side sectional view, and (b) is a schematic circuit diagram.

FIG. 17 is a waveform chart for explaining the above operation.

FIG. 18 is a cross-sectional view showing a structure for obtaining a desired directional characteristic in the above.

FIG. 19 is a cross-sectional view showing a structure for obtaining a desired directional characteristic in the above.

20 (a) and (b) are explanatory diagrams for explaining the operation of the ultrasonic transducer in the above.

FIG. 21 is a diagram showing a magnetic field-magnetostriction characteristic of a conventional magnetostrictive material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmitting element 2 Receiving element 3 Transmitting circuit 3a Drive coil 3b Bias power supply 3c Signal source 4 Transmitting circuit 4a Detection coil 4b Bias power supply 4c Detection transformer

Claims (19)

[Claims] A magnetostrictive element formed of a giant magnetostrictive material made of a binary alloy of a rare earth element and an iron group element as a transmitting element;
A sound signal transmitting method, wherein the sound transmitting element is driven non-resonantly to generate a pressure change in a sound wave propagating medium to transmit a sound wave signal. 2. A transmitting element comprising a giant magnetostrictive material comprising a binary alloy of a rare earth element and an iron group element, and driving means for driving the transmitting element non-resonantly, wherein the driving means A sound signal transmitting device that drives the wave transmitting element to generate a pressure change in a sound wave propagation medium to transmit a sound signal. 3. A wave receiving element, comprising: a magnetostrictive element formed of a giant magnetostrictive material comprising a binary alloy of a rare earth element and an iron group element;
A sound wave signal receiving method, wherein a change in pressure of a sound wave propagation medium due to a sound wave signal is detected by the wave receiving element without resonance and converted into an electric signal. 4. A wave receiving element formed of a giant magnetostrictive material made of a binary alloy of a rare earth element and an iron group element, and a pressure of a sound wave propagating medium by a sound wave signal detected non-resonantly by the wave receiving element. A sound wave signal receiving device comprising: signal conversion means for converting a change into an electric signal. 5. A sound wave transmitting device comprising a wave transmitting element formed of a giant magnetostrictive material made of a binary alloy of a rare earth element and an iron group element, and a driving means for driving the wave transmitting element non-resonantly. And a non-resonant wave receiving element formed of the giant magnetostrictive material and detecting a pressure change of a sound wave propagation medium due to a sound wave signal transmitted from the wave transmitting element and reflected by an object, and the wave receiving element. Signal receiving device comprising a signal converting means for converting a pressure change of the detected sound wave propagating medium into an electric signal, based on at least the electric signal converted by the signal converting means provided in the sound signal receiving device. Signal processing means for performing processing for obtaining information on the object. 6. The sound wave signal transmitting method and device, the sound wave signal receiving method and device, and the sound wave signal transmitting method and device according to claim 1, wherein the sound wave signal comprises a sound wave in an audible region. Sound wave transmission / reception processing system using a computer. 7. The sound wave signal transmitting method and apparatus, the sound wave signal receiving method and the apparatus, and the sound wave signal transmitting method according to claim 1, wherein the sound wave signal comprises a sound wave in an ultrasonic region. A sound wave transmission and reception processing system using these. 8. The apparatus according to claim 1, wherein the driving means drives the transmitting element by supplying an electric signal having a predetermined periodic waveform to the transmitting element. A method and apparatus for transmitting a sound wave signal and a sound wave transmission and reception processing system using the same. 9. The sound wave signal transmitting method and apparatus according to claim 8, wherein said driving means supplies said one period of electric signal to said transmitting element to drive said transmitting element. Sound wave transmission and reception processing system. 10. The apparatus according to claim 3, wherein said signal converting means converts a pressure change of a sound wave propagation medium having a predetermined periodic waveform detected by said wave receiving element into an electric signal. A method and apparatus for receiving a sound wave signal according to any one of the preceding claims, and a sound wave transmission / reception processing system using the same. 11. The method and apparatus for receiving a sound wave signal according to claim 10, wherein said signal converting means converts a pressure change of the sound wave propagation medium having the waveform for one cycle into an electric signal. A sound wave transmission and reception processing system using these. 12. An acoustic signal is transmitted from the transmitting device by applying an electric signal having a predetermined periodic waveform to the transmitting device by the driving means to drive the transmitting device, and the moving device is stationary or moving. The reflected sound wave signal of the sound wave signal reflected by the object is converted into an electric signal by the wave receiving device, and the frequency of the reflected sound wave signal is obtained by the signal processing unit,
The sound wave signal according to any one of claims 5 to 11, wherein information on a moving speed of the object is obtained from a frequency of the sound wave signal transmitted from the wave transmitting device and a frequency of the reflected sound wave signal. Transmission and reception processing system. 13. The transmitting device transmits an acoustic signal from the transmitting device by applying an electric signal obtained by analogly modulating a carrier with a modulating wave to the transmitting device, and the driving unit moves or stands still. The reflected wave signal of the sound wave signal reflected by the object is converted into an electric signal by the wave receiving device, and the signal processing means obtains information on the object from a modulated wave component of the reflected sound signal. The sound wave transmission / reception processing system according to claim 5, characterized in that: 14. The signal processing means obtains a time interval in the same phase between a modulation component of a sound wave signal transmitted from the wave transmitting device and a modulation component of a reflected sound wave signal received by the wave receiving device, 14. The sound wave transmission / reception processing system according to claim 13, wherein the time interval is multiplied by a medium propagation speed of the sound wave signal to obtain information on a distance to the moving or stationary object. 15. The signal processing means obtains a time interval in the same phase between a modulation component of a sound wave signal transmitted from the wave transmitting device and a modulation component of a reflected sound wave signal received by the wave receiving device, The time interval is multiplied by the medium propagation speed of the sound wave signal to calculate the distance to the moving or stationary object, and the difference between the distances obtained a plurality of times at a predetermined time difference is calculated as the time difference. 14. The sound wave signal transmission / reception processing system according to claim 13, wherein information on the moving speed of the object is obtained by dividing by the following formula. 16. The signal processing means obtains each frequency of a modulation component of a sound wave signal transmitted from the wave transmitting device and a modulation component of a reflected sound wave signal received by the wave receiving device. 14. The sound wave signal transmission / reception process according to claim 13, wherein information on the moving speed of the object is obtained from the frequency of the modulation component of the sound wave signal transmitted from the apparatus and the frequency of the modulation component of the reflected sound wave signal. system. 17. The information processing apparatus according to claim 17, wherein the signal processing unit divides the difference between the moving speeds obtained a plurality of times with a predetermined time difference by the time difference to obtain information on the moving acceleration of the object. The sound wave transmission and reception processing system according to claim 15. 18. A sine wave signal having a frequency at which a desired directional characteristic is obtained from a directional characteristic determined by a wavelength of a sound wave signal transmitted from the transmitting element and a shape of a sound wave transmitting surface of the transmitting element. 18. A method and apparatus for transmitting a sound wave signal according to claim 1, wherein said wave transmitting element is supplied from a driving means to said wave transmitting element, and a sound wave transmitting and receiving process using said apparatus. system. 19. The sound receiving element according to claim 3, wherein a shape of a sound wave receiving surface of the wave receiving element with respect to a wavelength of the sound wave signal is determined so as to obtain a desired directional characteristic of the wave receiving element. 7. A method and apparatus for receiving a sound wave signal according to any one of the above, and a sound wave transmission and reception processing system using the same.