JPH0194282A - Wave transmitting and receiving apparatus - Google Patents

Abstract

PURPOSE:To perform highly accurate measurement by reducing a side lobe level viewed on the basis of receiving output, by allowing the direction of the min. value between the lobes of one directional pattern to be present in the vicinity direction of the max. value of the other pattern. CONSTITUTION:An acoustic insulator 5 is inserted between a transmitting vibrator 3 and a receiving vibrator 4 and the vibrators 3, 4 are mounted so that the center axis thereof coincides with the center axis of a wave reflecting cone 6. The length l2 of the vibrator 4 in the axial direction thereof is shorter than the length l1 of the vibrator 3 in the axial direction thereof. The central part of the main lobe of the directional pattern (first pattern) formed by the transmitting vibrator 3 and the wave reflecting cone 6 is allowed to coincide with that of the main lobe of the directional pattern (second pattern) formed by the vibrator 4 and the reflecting cone 6. Further, the length l2 of the vibrator 4 in the axial direction thereof is determined so that the position of the max. value of the first side lobe of the second pattern comes to the position showing the min. value between the main lobe and first side lobe of the first pattern. By this constitution, a lower order side lobe level becoming the practical trouble of a synthetic pattern can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wave transmitting/receiving device, and in particular to reducing the sidelobe level of the received output of a wave receiver.

[Prior Art] Conventionally, there is a wave transmitting/receiving device used in ultrasonic distance measuring devices, ultrasonic level meters, etc. as shown in FIG.

In Fig. 5, numeral 1 has a time axis generation function and generates a reference signal that serves as a reference for time measurement, and numeral 2 receives the reference signal generated by the drive portion 1 and generates electrical vibrations at a nearly constant frequency. 3 is a cylindrical wave transmitting oscillator (hereinafter referred to as a wave transmitting oscillator) that converts the electric vibrations sent from the oscillator 2 into ultrasonic waves and transmitting the same; 4a is a wave transmitting oscillator 3;
A cylindrical transducer (hereinafter referred to as a receiving transducer) of the receiver receives the ultrasonic waves transmitted by the receiver, and 5 is an acoustic transducer provided between the transmitting transducer 3 and the receiving transducer 4a. The insulating material 6 is a conical wave reflecting tube with a right angle center angle. As shown in FIG. 6, the transmitting transducer 3 and the receiving transducer 4a have an outer diameter of
A vibrator having the same inner diameter, length p, ρ2, and material is used, and is attached to the wave reflecting tube 6 so that its center axis coincides with the center axis of the wave reflecting tube 6.

7 is a transmitted wave emitted from the wave transmitting transducer 3, reflected by the reflecting surface of the wave reflecting tube 6, and traveling parallel to the central axis of the wave reflecting tube 6; 8 is a transmitted wave in the ultrasonic transmission medium. 9 is an existing reflecting object; 9 is a reflected wave that is reflected by the reflecting object 8 and travels parallel to and in the opposite direction to the transmitted wave 7; 10 is an amplifier; 11 is a processing unit that performs signal processing such as amplitude comparison of electric vibrations sent from the amplifier 10. It is.

In the wave transmitting/receiving device configured as described above, the oscillating unit 2 generates electrical vibrations in synchronization with the reference signal sent from the driving unit 1, and the electrical vibrations are sent to the wave transmitting oscillator 3 to generate pulses. is converted into ultrasonic waves. This ultrasonic wave is radiated from the side surface of the wave transmitting transducer 3, and the inner diameter φ1 of the reflecting surface of the wave reflecting cylinder 6 corresponds to the length Ω1 of the wave transmitting transducer 3.
1 and the outer diameter φ1o and is transmitted.

This transmitted wave 7 propagates through the medium and is reflected by a reflecting object 8, which is the object to be measured.The inner diameter φ21 and outer diameter of the reflecting surface of the wave reflecting tube 6 correspond to the length ρ2 of the wave receiving vibrator 4a. After being reflected within a region determined within φ2o, the wave is received by the wave receiving vibrator 4a and converted into electric vibration by the wave receiving vibrator 4.

This electric vibration is amplified by an amplifier 10 and sent to a processing unit 11 which has started time measurement in response to a reference signal generated by the drive unit 1 in advance when transmitting the ultrasonic wave.

The amplitude of this electric vibration is compared with a predetermined threshold, and when the amplitude of the electric vibration exceeds the threshold, timekeeping is stopped and a measurement signal is sent.

FIG. 7 shows an example of the directivity pattern of the above-mentioned wave transmitting/receiving device.
indicates a directivity pattern (hereinafter referred to as a first pattern) formed by the wave receiving vibrator 4a and a directivity pattern formed by the wave reflection cylinder 6 (hereinafter referred to as a second pattern). Note that e may be the first pattern and d may be the first pattern.

As shown in FIG. 7, when an ultrasonic wave having a first pattern d is transmitted and a reflected wave 9 of this ultrasonic wave is received by the wave reflecting tube 6 and the wave receiving transducer 4a having a second pattern e, ,
The receiving output of the wave receiving transducer 4a is divided into the first pattern d and the second pattern d.
A composite pattern f corresponding to the value obtained by adding the pattern e is obtained. The first side rope of this composite pattern f
Since the levels are combined in the rope parts where the levels are mutually high, the level is about -20 dB in the case shown in FIG. 7.

[Problems to be Solved by the Invention] In the above-mentioned conventional wave transmitting/receiving device, the side ropes of the composite pattern f are synergized by the rope portions of the first pattern d and the second pattern e whose levels are high. Because of this, the side rope level of the composite pattern f is high, which poses a problem in that it interferes with measurements using the original = 4 - main rope.

The present invention was made to solve this problem, and its purpose is to provide a wave transmitting and receiving device that can reduce the sidelobe level of the received output of a wave receiver and perform measurements with high accuracy. It is something to do.

[Means for Solving the Problems] The wave transmitting/receiving device according to the present invention has a directivity pattern formed by a first cylindrical vibrator and a wave reflecting tube, or a directivity pattern formed by a first cylindrical vibrator and a wave reflecting cylinder. Within the range where the directional pattern formed by the cylinder has side ropes with high strength, the direction of the minimum value between the ropes of one directional pattern is in the vicinity of the maximum value of the other directional pattern. It is characterized by what it did.

[Function] In this invention, the directional pattern formed by the first cylindrical vibrator and the wave reflecting tube, and the side rope of the directional pattern formed by the second cylindrical vibrator and the wave reflecting tube. The side lobe level of the receiver's received output is determined by adding the local minimum value between the ropes of the - side directional pattern and the local maximum value of the side lobe of the other directional pattern, or a value in the vicinity thereof, with a difference in direction. Reduce.

[Embodiment FIG. 1 is a block diagram showing an embodiment of the present invention.
In the figure, numbers 1 to 3.5 to 11 are exactly the same as the conventional example shown in FIG. Reference numeral 4 denotes a receiver transducer (hereinafter referred to as a delivery transducer) that receives reflected waves 9 reflected by an ultrasonic reflector 8 transmitted from the transmitting transducer 3 and converts them into electrical vibrations. .

An acoustic insulating material 5 is inserted between the wave transmitting vibrator 3 and the wave receiving vibrator 4, and the wave transmitting vibrator 3 and the wave receiving vibrator 4 are
As shown in the figure, it is attached to the wave reflecting shade 6 so that its central axis coincides with the central axis of the wave reflecting shade 6.

The axial length ρ2 of the transmission transducer 4 is the transmission transducer 3.
is shorter than the axial length pl, and the directivity pattern (hereinafter referred to as
The directivity pattern formed by the wave receiving transducer 4 and the wave reflecting shade 6 (hereinafter referred to as the second pattern) are different from each other in a constant relationship.

FIG. 3 shows an example of the first pattern and the second pattern, and in FIG. 3, a is the first pattern and b is the second pattern. As shown in Fig. 3, the central portions of the main ropes of the first pattern a and the second pattern b almost coincide, and the center portions of the main ropes of the first pattern a and the first side ropes are located at the minimum value. The axial length ρ of the wave receiving transducer 4 is adjusted so that the position of the maximum value of the first side rope of the second pattern b is located.
2 is the standard.

In the wave transmitting/receiving device configured as described above, the ultrasonic waves emitted from the wave transmitting transducer 3 are reflected by the reflecting surface of the wave reflecting shade 6 and enter the medium as transmitted waves 7 shown in the first pattern a. Sent. This transmitted wave 7 propagates through the medium, is reflected by a reflecting object 8, and becomes a reflected wave 9. This reflected wave 9 is reflected within the area defined by the inner diameter φ21 and the outer diameter φ2o corresponding to the length Ω2 of the wave receiving vibrator 4 on the reflecting surface of the wave reflecting shade 6, and is received by the delivery vibrator 4. The waves are converted into electrical vibrations.

The receiving output of the delivery transducer 4 that received this ultrasonic wave is the first one.
A composite pattern C is obtained by combining the pattern a and the second pattern b. In this case, the first pattern a and the second pattern
Since the central parts of the main ropes in pattern B are almost the same, a composite pattern C can be obtained by combining the central parts of the rain ropes.
main rope level can be maintained at a constant level. - On the other hand, since the direction of the minimum value between the main rope and the first side rope of the first pattern a is almost the same as the direction of the maximum value of the first side rope of the second pattern b, these are synergized. It is possible to reduce the side lobe level of the lower order which is a practical problem in the composite pattern C obtained by the method. In other words, in the case shown in FIG. 3, the composite pattern C
The first side rope level of is about -25 dB,
This can be improved by about 5 dB compared to the conventional example shown in FIG. In this case, the main rope of composite pattern C is slightly wider than that of the conventional example shown in Fig. 7, but =
8 - There are no particular problems in practical use.

In the above embodiment, the first pattern a and the second pattern b were made different by changing the axial length pl of the wave transmitting vibrator 3 and the axial length Ω2 of the delivery vibrator 4. Although the case has been explained, even if the inner and outer diameters of the wave transmitting vibrator 3 and the wave receiving vibrator 4, the distance between both vibrators 3 and 4, or the thickness of the acoustic insulating material 5 are changed, the above-mentioned embodiments will work. The same effect can be achieved.

Further, in the above embodiment, a case has been described in which the reflected wave of the ultrasonic wave reflected by the reflecting object 8 is received by the delivery transducer 4, but as shown in FIG. Even if there is no transmitting wave, the transmitting wave 7 transmitted from the transmitting vibrator 3 can be directly received by combining the receiver's wave reflection shade 6a and the delivery vibrator 4 in addition to the wave transmitting one. By receiving the signal using the digital vibrator 4, the same effect as in the above embodiment can be achieved.

In each of the above embodiments, even if the transmitting transducer 3 and the delivery transducer 4 have different shapes and dimensions, the transducers have a certain frequency band, so they cannot be used at the same frequency for transmitting and receiving. does not cause any practical problems.

Further, in each of the above embodiments, the case where ultrasonic waves are propagated has been described, but the present invention can also be applied to wave propagation other than ultrasonic waves in the same manner as in each of the above embodiments.

[Effects of the Invention] As explained above, the present invention has a directivity pattern formed by the first cylindrical vibrator and the wave reflecting tube, and a directivity pattern formed by the second cylindrical vibrator and the wave reflecting tube. By making a difference in the position of the side ropes from the pattern and multiplying the minimum value between the ropes of one directional pattern and the maximum value of the side ropes of the other directional pattern, the low-order side of the receiver's received output is Since the rope level is reduced, it is possible to prevent side ropes of the received output from interfering with measurements, etc.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a sectional view showing the transducer of the above embodiment, FIG. 3 is a state diagram showing the directivity pattern of the above embodiment, and FIG. A block diagram showing another embodiment, FIG. 5 is a block diagram showing a conventional example,
FIG. 6 is a sectional view showing a conventional transducer, and FIG. 7 is a state diagram showing a directivity pattern of the conventional example. DESCRIPTION OF SYMBOLS 1... Drive part, 2... Oscillator, 3... Vibrator for wave transmission, 4.4a... Vibrator for wave reception, 5... Acoustic insulation material, 6.8a... Wave motion Reflection tube, 10...Amplifier, 1
1... Processing section, a, d... First pattern, b, e
... second pattern, c, f... composite pattern.

Claims (2)

[Claims] (1), the first transmitting wave having a nearly constant frequency
A cylindrical oscillator, a second cylindrical oscillator that receives the waves transmitted from the first cylindrical oscillator, and a conical shape with a right angle center angle, and are provided for both transmission and reception or separately for transmission and reception. A wave transmitting/receiving device comprising: a wave reflecting shade; the first cylindrical oscillator and the second cylindrical oscillator are arranged so that their respective central axes are shared with the central axis of the wave reflecting shade; In the wave device, the directivity pattern formed by the first cylindrical vibrator and the wave reflecting shade (hereinafter referred to as the first pattern), or the directivity formed by the second cylindrical vibrator and the wave reflecting shade Within the range where side ropes with high strength exist in the pattern (hereinafter referred to as the second pattern), the direction of the minimum value between the ropes of one directional pattern is near the maximum value of the side ropes of the other directional pattern. A wave transmitting/receiving device characterized in that the wave transmitting/receiving device exists in a direction. (2) The direction of the side ropes of the first pattern and the second pattern is determined by at least the length in the central axis direction, the outer diameter, and the inner diameter of the first cylindrical vibrator and the second cylindrical vibrator. Claim 1 that differs by making one thing different
The wave transceiver device described in .