JPS60125578A - Device for forming directional receiving beam to acoustic wave coming from near position - Google Patents

Abstract

PURPOSE:To attain accurately the azimuth of a detected object, which exists in a near position by forming the arrangement of arranged vibrators into the same shape as a spherical wave of the acoustic wave coming from the near position. CONSTITUTION:A recording circuit 6 reads out stored data of eight channels in accordance with the counted value of a counter 8, and read-out stored data are transmitted as square waves of eight channels from latch circuits 901-908. Square wave train data of eight channels having phase relations related to the azimuth and the distance of a sound source are transmitted from a storage circuit 7 through latch circuits 161-168. Square wave trains of eight channels transmitted from circuits 161-168 are sent to exclusive OR gates 311-318 together with square wave trains of circuits 901-908 with respect to individual channels. Outputs of these gates are led to mixing circuits 201-208 through filters 321-328 and preamplifiers 301-308 to make phases of received signals in ultrasonic oscillators T1-T8 equal to the phase of the spherical wave due to sounds in the near position.

Description

Detailed Description of the Invention: a3 Technical Field of the Invention This invention relates to forming a directional receiving beam when receiving an ultrasonic signal, and in particular, to forming a directional receiving beam when receiving an ultrasonic signal. The present invention relates to a device for forming a suitable directional reception beam.

b. Prior Art As is well known, an underwater detection device transmits ultrasonic pulses and receives reflected waves from a detected object. Then, the distance to the object to be detected is measured based on the time from when the detection pulse is transmitted until the reflected wave is received, and the direction of the object to be detected is measured based on the arrival direction of one foul wave.

The arrival direction of the detected object is determined by forming a directional receiving beam. The directional reception beam is most commonly generated by phase-combining the reception signals of a plurality of ultrasonic transducers.

For example, as shown in Fig. 1, this phase synthesis is performed by arranging a plurality of ultrasonic transducers and appropriately shifting the phase of the received signal of each transducer to form an equal phase wavefront in a specific direction. conduct.

A sound wave arriving from a sufficiently far distance with respect to the transducer array length 2 mm can be regarded as a plane wave with an equal phase wavefront Fw. Therefore, when receiving a sound wave arriving from the θ direction with respect to the front, by tilting the transducer array plane "T" by θ to FT' and making it parallel to the equal phase wavefront Fw of the sound wave, the synthetic reception of the transducer can be achieved. The wave sensitivity can be maximized in the θ direction. That is, a directional reception beam can be formed in the θ direction.

In the above, the phase correction amount of each transducer for phase shift synthesis by tilting the transducer array plane 1T to FT' is, for example, the correction amount φ of the transducer T with respect to the transducer Ti at the center position.
is 2π.

φ, = □ sentence + Sin.

It is expressed as λ. However, distance indicates the distance from the central vibrator Ti to the vibrator T.

C0 Disadvantages of the Prior Art As mentioned above, when the source of the conventional sound wave is sufficiently far away, its equiphase wavefront can be regarded as a plane wave. However, as shown in Figure 2, when the distance #D to the sound source cannot be ignored with respect to the transducer array length 2 mm, it must be taken into account that the equiphase wavefront Fw of the arriving sound wave is a spherical wave. . Therefore, as in the past, the wave receiving surface of the oscillator "T" is
By simply tilting the transducer by θ like T', the wave receiving surface of the transducer cannot be made parallel to the equiphase wavefront of the sound wave, and the maximum receiving sensitivity cannot be achieved for the sound source in the θ direction.

d0 Purpose of the Invention This invention provides that when the equiphase wavefront of a sound wave arriving from a sound source located at a short distance must be considered as a spherical wave,
By correcting the phase of each transducer's received signal so that the transducer array plane is the same as the spherical wave formed by the equal-phase wavefront of the incoming sound wave, the maximum receiving sensitivity for the incoming sound wave is achieved. The purpose is to

e0 Principle of the Invention As shown in Fig. 3, when the sound source Q is in front of the transducer array, the received signals of each transducer T to τn are transmitted from each transducer to a spherical equiphase wavefront FT''. It is sufficient to perform phase correction according to the distance.For example, in the case of the transducer T, the distance Δd to the equal phase wavefront Fv' is Δd, = rT−v17
-D, so the phase correction amount Δφ is -φ, = 2
x (nπ1·−D) (1) Represented by λ.

Next, as shown in Fig. 4, when the sound source Q is located in the θ direction with respect to the front, first,
If the sound source Q is positioned in front of the central transducer Ti by tilting it by θ, the FT
Phase correction may be performed in accordance with the distance from the transducer position replaced on the 'plane' 2, that is, the projection position on the FT' plane, to the spherical equiphase wavefront Fw. For example, in the case of transducer T, the phase correction amount Δφθ, for tilting the equal-phase receiving surface "T" by 0 to Fv' is, and the transducer T1 position converted onto the FT" plane is:

Intersection point Th + of the perpendicular lines drawn from the transducer T to the FT plane
Therefore, as is clear from FIG. 3, the phase correction at the Tow position to match the equal phase receiving surface on the F plane with the equal phase wave front Fw on the spherical surface is as follows. expressed. Therefore, the total phase correction amount φ of the vibrator T is expressed as φ, =Δφθ, +Δφ H+ (4) from equations (2) and (3).

As is clear from the above, the present invention corrects the phase of the array transducer so that the transducer array plane is located in front of the sound source when the source of the incoming sound wave is located at a short distance, and further , distributed at the front position, and by performing phase correction corresponding to the distance from each converted transducer position to the spherical equiphase wavefront of the incoming sound wave, a directional receiving beam is formed for the incoming sound wave from a nearby sound source. .

f0 Embodiment of the invention In FIG. 5, T to T represent ultrasonic transducers,
They are arranged linearly on a common plane FT. Note that the vibrator array does not necessarily have to be arranged in a planar shape, and may be spherical or curved, but for convenience of explanation, it is assumed that the transducer array is arranged in a planar shape.

The received signals of the ultrasonic transducers T, T8 are guided to the respective mixing circuits 201 to 208 via the respective preamplifiers 111 101 to 108, and then to the other preamplifiers 3.
They are mixed separately with the signal waves sent out from 01 to 308, respectively. The mixed outputs of the mixing circuits 201 to 208 are added together in an adding circuit 4, and then guided to a filter 5, where signal components of specific frequencies are extracted.

Then, a directional reception beam in a specific direction is formed by the output signal of the filter 5.

This will be explained below.

Pre-multiple ID devices 301-308 each output a frequency signal having a specific phase relationship. When this frequency signal is mixed with the reception signals of the ultrasonic transducers T to T8 in the mixing circuits 201 to 208, the phase of each mixed output is regulated in accordance with the phase relationship of the frequency signals, This allows the received signals of the ultrasonic transducers T to T1 to be transferred equivalently. The amount of transfer at this time is determined by the phase of the frequency signals sent from the preamplifiers 301 to 308.
When the phase of the frequency signal output from the J unit 301 is changed by Δφ, the phase of the output signal of the mixing circuit 201 is changed by Δφ, thereby changing the received signal of the ultrasonic transducer T by Δφ.
It is possible to obtain an effect equivalent to transferring only

Therefore, Tokuko Showa 5E! As described in Japanese Patent No. 545110, if the phases of the frequency signal outputs of the preamplifiers 301 to 308 are changed in a specific relationship, for example, when the phase of each frequency signal is linearly changed by a fixed amount, the ultrasonic signal T , ~Tll
A signal obtained by equivalently transferring the received signal by a fixed amount can be obtained on the output side of the mixing circuits 201 to 208. By combining these signals and extracting specific frequency components, it is possible to form a received beam having directivity in a specific direction.

In the above, if the phase relationship of the frequency signals guided to the mixing circuits 201 to 208 is changed while maintaining a constant relationship, the pointing direction of the directional reception beam can be changed. The applicant has filed a patent application for this type of device in 1986-1.
No. 21439 was provided. This device temporally changes the phase of the frequency signals guided to the mixing circuits 201 to 208, that is, the frequency of the frequency signals is temporally changed to change the directivity direction of the received beam. In this case, as shown in FIG. 1, the patent application No. 57-1214313 considers the equal-phase wave fronts of the ultrasound waves arriving at the ultrasound transducers T to T8 as plane waves, and the directivity direction is changed temporally. It forms a changing directional receiving beam.

This invention was proposed in Japanese Patent Application No. 57-121439, and uses this technique to form a directional receiving beam for a sound source at a short distance position Q as shown in FIG.

This will be explained below. When the respective stored data is read from the memory circuits 6 and 7, eight channels of rectangular wave trains are sent out.

The rectangular wave train generated by the memory circuit 6 tilts the array plane FT of the ultrasonic transducers T to Tn in FIG. By, equal phase receiving surface FT
Phase correction is performed from the ultrasonic transducer replaced above to the spherical wave Fw. For example, since the ultrasonic transducer T is given at the TH1 position on the equal phase receiving surface FT',
It is sufficient to perform phase correction corresponding to the distance Δd from the TH+ position to the spherical wave Fw.

First, to explain the rectangular wave train generated by the memory circuit 6, the memory address in the memory circuit 6 is specified by the count value of the counter 8, and the stored data of 8 channels is read out in binary values at each memory address. be done. The read storage data is latched by latch circuits 901 to 808, and eight channels of rectangular waves are sent out from latch circuits 901 to 808. The latch circuits f301 to f908 are constructed by a latch pulse generation circuit 1O in Japanese Patent Application No. 57-1214.
The data stored in the storage circuit 6 is latched as explained in No. 39. Further, the latch pulse generation circuit 10 generates a latch pulse by combining the pulse train sent from the frequency dividing circuit 11 to the counter 8 and the frequency-divided pulse of the clock pulse source 12 whose frequency is divided by the frequency dividing circuit 11.

FIG. 6 CII to 0.8 are latch circuits 901 to 90B
shows a rectangular wave train sent out by the rectangular wave train C11 to C11.
1 is generated so that the phase thereof is sequentially different by Δφ. Then, the rectangular wave trains CI to C1° are generated such that their phase differences Δφ change over time. This operation is
As explained in No. 7-121438, the rectangular wave train C1,
This is done by temporally changing the repetition frequency of C19 to C19.

Therefore, the rectangular wave train C1I of the latch circuits 901 to 908
By guiding C18 to mixing circuits 201 to 208, the equal phase wavefronts FT of ultrasonic transducers T to Tll are
As shown in FIG. 4, the rectangular wave trains C1 to CIR are tilted by an angle 0 corresponding to the CIR phase difference Δφ, and the tilt angle θ is adjusted by 1 in accordance with the phase change of the rectangular wave trains C11 to C10. change to

In the above, the storage capacity of the memory circuit 6 includes the change time of the directional received beam formed by the ultrasonic transducers T to Tll, the repetition frequency of the rectangular wave trains C1 to C1°, and the repetition frequency of the rectangular wave trains C1l to C1B. It is determined by the phase accuracy when generating . For example, when detecting ultrasonic pulses arriving at ultrasonic transducers T to Tll with a distance resolution of 0.5 m, the ultrasonic signals arriving from each direction while the ultrasound propagates for 0.5 m are time-series. There must be. Therefore, the repetition frequency of the rectangular wave sequences C1 to C1s is 1Hk)Iz.

(Since the ultrasonic propagation time of 1.5 m is BBB, full sec, a capacity of 8 bits is required per rectangular wave of 1 channel. Therefore, in order to generate a rectangular wave train of 8 channels, a capacity of 8 bytes is required. In addition, the counter 8 requires a counting capacity of at least 8182 or more, and the clock frequency input to the counter 8 is given by 192k)IzX84=12288kHz, so the frequency divider circuit 11 uses The frequency of the pulse train of the source 12 may be divided to send out a pulse train of 12288 kHz.

Next, the rectangular wave generated by the memory circuit 7 will be explained. In the memory circuit 7, a memory address is specified by the count value of the counter 13 and numerical data of the memory circuits 14 and 15, and the memory data is read out. Like the memory circuit 6, the memory circuit 7 sends out 8 channels of memory data for each memory address, and the sent memory data is latched by the launch circuits 181 to 168, and an 8 channel rectangular wave train is sent out. . This rectangular wave train, as shown in FIG.
A spherical equiphase wavefront F from the position replaced with T ′J2
The received signals of the ultrasonic transducers T, . . . are transferred by a phase amount corresponding to the distance to w. Then, by moving the vibrator, which has been replaced on the equal phase wave receiving surface FT' in the 0 direction, the transducer is further replaced to a position on the spherical equal phase receiving surface Fw. As a result, a directional receiving beam for the sound source Q is formed.

In Fig. 4, the distance from the transducer position on the equal-phase receiving surface FT' to the spherical equal-phase wavefront Fw changes depending on the inclination angle θ of the equal-phase receiving surface FT', and at the same time changes depending on the distance to the sound source. also changes.

Therefore, the rectangular waves sent out from the latch circuits 181 to 168 change their phases in response to changes in the inclination angle θ of the equal-phase wave receiving surface FT', and at the same time correspond to changes in the distance to the sound source Q. Even if we do, we have to change it. Therefore, when such a rectangular wave train is generated by the memory circuit 7, the memory circuit 7 must have a large capacity. For example, latch circuits 161 to 188 to 88k
Assuming that a rectangular wave train of Hz is to be generated with a phase accuracy of 100 Hz, in order to transmit the rectangular wave train for 688.7 JLsec to obtain a distance resolution of 0.5 m4, the storage capacity of each channel is required to generate a rectangular wave train of It is necessary every time. Then, the rectangular wave of each channel must be newly generated every time the distance to the sound source changes, so when detecting 100 m with a distance resolution of 0.5 m, 200 types of rectangular waves are generated. must be able to generate. Therefore, the capacity required for one channel of square waves is 3754 x 200 = 750800 (bits), so in order to generate 8 channels of square waves, 7
50 bytes of storage capacity is required. If such a large capacity storage circuit is used, the configuration of the storage circuit 7 will become very large, which is not very practical.

The memory circuit 7 is not limited to a large-capacity one as described above, but is also a very small-capacity memory circuit, for example, when generating a rectangular wave train of 88 kHz, a memory capacity of 8 bytes is used.

The rectangular wave trains sent out from the latch circuits 181 to 188 are
As explained above, strictly speaking, the equal phase receiving surface FT'
The angle of inclination θ must be changed according to the distance to the sound source Q. However, in reality, one type of rectangular wave train may be used in common for the inclination angle 0 of the equiphase receiving surface FT' and the constant change range of the distance to the sound source Q. The range of variation that can be commonly used in this case can be determined experimentally or empirically. In other words, when one type of rectangular wave train is used and the inclination angle θ of the equal-phase receiving surface FT' and the sound source distance are changed, the range of change can be set so that the receiving beam maintains predetermined characteristics. .

The memory circuit 7 in FIG. 5 has a detection range of ±6 in the center direction.
Divide the detection section of 60° into 8 sections with respect to 0°,
An example is shown in which a common rectangular wave train is used for each section, and in the distance direction, the detection range of 100+a is divided into 16 sections for i river, and a common rectangular wave train is used for each section.

FIG. 7 shows an example of the configuration of the memory circuit 7, which has a capacity of 8 bytes, and the stored data is sent out as rectangular wave train data of 8 channels for each memory address.

The memory address (0 to 8181) of the memory circuit 7 is a 13-digit 2
Specified in base numbers. The lower six digits of the 13-digit binary number are specified by the counter 13, the first three digits are specified by the storage circuit 14, and the upper four digits are specified by the storage circuit 15.

Therefore, in the memory circuit 7, storage addresses of 184'' are sequentially specified by the count value of the counter 13, and each time the specified value of the memory circuit 14 changes, the address specified by the counter 13 changes at an interval of 64 addresses. Further, each time the designated numerical value of the memory circuit 15 changes, the memory address changes at an interval of r512 J addresses. For example, the specified number of memory circuits 15 (fi is roooOJ, the specified number of memory circuits 14 is roooJ
At this time, in the memory circuit 7, the memory addresses "0" to "63" are repeatedly designated by the 51 value of the counter 13. Then, the designated value of the memory circuit 14 is rool.
When it changes to J, the storage addresses "64" to "127" are repeatedly specified. Furthermore, the memory circuit 15
When the specified numerical value changes to rooolJ, the specified address in the memory circuit 7 changes by address r512J, and counter 1
The memory addresses r512J to r5754 are repeatedly designated by the count value of 3.

In the above, the counter 13 is composed of a 64-decimal counter and counts the pulse train sent out from the frequency dividing circuit 18. The output pulses of the frequency divider circuit 19 are set so that one period of the rectangular wave train sent out by the latch circuits 181 to 188 ends when the count value of the counter 13 is reached. For example, considering the repetition frequency of the rectangular wave trains sent from the latch circuits 181 to 16 days, the period of the output pulse of the frequency dividing circuit 19 is given by = 177, El(n 5ee). Therefore, the frequency dividing circuit 19 divides the clock pulse train of the pulse source 12 to 17? , B n5ec is set.

In the counter 13, stored data for one cycle of the eight-channel rectangular wave train is read out from the storage circuit 7 every time the count value is overwritten. The stored data read from the storage circuit 7 is latched by the latch circuits 181 to 168, and eight channels of rectangular wave trains are sent out from the latch circuits 161 to 168. This rectangular wave train is repeatedly read out as long as the specified numerical values in the memory circuits 14 and 15 do not change. The phase relationship between the rectangular wave trains of each channel is specified by the memory circuits 14 and 15. That is, the memory circuit 1 corresponding to the inclination angle θ of the equal phase receiving surface Fv'' in FIG.
The specified value of 4 is 1l (i=0.l, 2...7)
, the specified value of the memory circuit 15 corresponding to the distance to the sound source Q is j, (j=o, 1, 2...15), then the value of the memory circuit 7 read out by the counter 13 is The memory address is from address (512j+84i) to ((512j
It is represented by the address +84 i)+84)).

The stored data corresponding to this storage address is read out, and an 8-channel rectangular wave train is sent out from the latch circuits 181 to 18B. At this time, the rectangular wave train of each channel is stored in the memory circuit 7 so that it has a phase relationship that makes the equal-phase receiving surface "T' in the θ direction in FIG. 4 match the spherical equal-phase receiving surface Fw. From address (512J+64i) (
It is written between addresses (512j + E14i) + 84).

As is clear from the above, the memory circuit 14 specifies the inclination angle θ of the equal-phase wave receiving surface F, and specifies the angle based on the count value of the counter 17. The counter 17 counts the angular pulses led from the scanning circuit 21 via the frequency dividing circuit 20. These angular pulses are associated with pixel scanning of the display 22, for example, one angular pulse is counted by the counter 17 for every 1" of pixel scanning. Also, the counter 17
starts counting at the same time as the scanning line of the display 22 starts scanning. Therefore, the counted value of the counter 17 changes with respect to the pixel scanning angle of the display 22, and when the pixel scanning of the display 22'' changes from -60'' to +60'' with respect to the center direction N, the count value of the counter 17 changes with respect to the pixel scanning angle of the display 22. Count value is from "0" to r120J
changes up to. In response to this change in the 1 value of the counter 17, the memory circuit 14 changes the specified value in 3 binary digits as shown in FIG.

As is clear from Figure 8, the count value changes from rOJ to r4J.
The storage circuit 14 specifies the numerical value roo'OJ while the value changes to . Therefore, during this period, latch circuits 1fll to 18
The rectangular wave train sent out from 8 is kept in a constant phase relationship,
The phase relationship of each channel is set so that phase correction is performed for the sound source in the 57.9" direction. In the same manner,
In response to changes in the count value, the designated numerical values change as shown in Figure wS8, and the beam directions corresponding to each designated numerical value are set.

The counter 17 starts counting at the same time as each scanning line of the display 22 starts scanning, and the count value is reset by an output pulse sent from the scanning circuit 21 every time the scanning ends.

Therefore, the counter 17 sends the count value corresponding to the scanning position on each scanning line of the display 22 to the memory circuit 14, and the memory circuit 14 receives the designation determined as shown in FIG. 8 based on the count value number. Send a numerical value. Note that, at the same time as the counter 17 is reset, the counters 13 and 8 are also reset.

In the above, the reset signal for the counter 17 is generated within the scanning circuit 21. In the scanning circuit 21, the counter 211 counts the noggle train of the clock pulse source 212, and the pixel scanning of the display 22 is performed in accordance with the counted value.
be exposed. The count value of the counter 211 is sent to a sine wave voltage generation circuit 213 and a cosine wave voltage generation circuit 214, and a sine wave voltage and a cosine wave voltage corresponding to the count value of the counter 211 are sent out from each. The sine wave voltage and cosine wave voltage are guided to the X-axis deflection circuit 23 and the Y-axis deflection circuit 24 through modulation circuits 215 and 216, respectively. Therefore, arc-shaped scanning lines 25 are formed on the display 22. And this scanning line is the counter 211
While counting and looking at the counted value, - with respect to the central direction N
The sine wave voltage generation circuit 213 and the cosine wave voltage generation circuit 214 are configured to be formed from the BO° position to the +60'' position.The sine wave voltage generation circuit 243 and the cosine wave voltage generation circuit 214 are /A conversion circuit is used to generate a sine wave voltage corresponding to the count value of the counter 211,
Sends out a cosine wave voltage. Counter 211 then sends out an output pulse each time each scan line 25 is formed, and counters 17, 13 and 8 are reset by this output pulse. Further, this output pulse is led to the counter 18 via the gate circuit 26 and is counted by 51.

The scanning time of the scanning line 25 on the display 22 is determined by the distance resolution to be displayed.
When displaying with a distance resolution of 51, each scan line is 88B,
Formed every 7 JL sec. Therefore, scanning circuit 2
The counter 211 at 1 sends out an output pulse every 86B,7 seconds, and this pulse interval corresponds to 0.5 cm on the display 22.

The count value of the counter 18 is reset every time an output pulse is sent from the transmitter 27. Therefore, counter 1
The count value of 8 corresponds to the distance to the detected object after the detection pulse is transmitted by the display 27. Note 1. The transmitter 27 sends out an output pulse every time the transmitter 28 sends an ultrasonic pulse in a wide range of directions. This output pulse is sent to the sawtooth wave generation circuit 217 of the scanning circuit 21 to generate a sawtooth wave. This sawtooth wave is guided to amplitude modulation circuits 215 and 216, and changes each of the sine wave voltage and cosine wave voltage sent out from the sine wave voltage generation circuit 213 and the cosine wave voltage generation circuit 214 in a sawtooth shape. the result,
Concentric scanning lines are formed on the display 22.

Further, the number of scanning lines on the display 22 changes due to a change in the peak value of the sawtooth wave, and the distance range displayed on the display 22 changes.

As mentioned above, the count value of the counter 18 is reset by the output pulse of the transmitter 27, and the count value is reset by 0.5 of the detection distance.
The pulse waves sent out from the operating circuit 21 are counted every m. Therefore, the count value of the counter 18 changes in accordance with the detection distance on the display 22. The count value of the counter 18 is sent to the storage circuit 15, which converts the count value into a 4-digit binary number and sends it out.

FIG. 9 shows the memory circuit 15 for the count value of the counter 18.
This shows the relationship between the converted numerical values. For example, during 6 when the count value changes from rOJ to "6", the memory circuit 15 stores r0OOOJ.
Sends a 4-digit binary number. The upper four digits of the memory address of the memory circuit 7 are designated by this four-digit numerical value. Therefore, the memory circuit 7 stores this four-digit designated address r0O
Eight channels of rectangular wave train data determined by OOJ and a three-digit designated address of the memory circuit 14 are sent out. Then, as mentioned above, the specified address of the memory circuit 15 is r0O
At the time of OOJ, the memory circuit 7 sends out rectangular wave train data when the sound source distance is 31 in FIG. Similarly, when the count value of the counter 18 reaches "7", the memory address 1 is
5 sends out the numerical value r0001J, and the storage circuit 7 sends out rectangular wave train data for the sound source of 3.5■ corresponding to the specified address r0001J. After that, do the same and set counter 1.
The designated address of the memory circuit 7 changes sequentially in accordance with the count value of B, and when the count value reaches a specific value, the counter 18 sends out an output pulse, and this output pulse inverts the flip-flop 28. Based on that, the gate circuit 26
is blocked. Therefore, the counter 18 stops counting after that, and the previous IT value is held. 9th
In the figure, an output pulse is sent out when the numeric value of 1 is rllll19J, and the memory circuit 15 stores the numeric value [11OIJ
hold. Then, the memory circuit 7 has a sound source distance @:98.5
Send rectangular wave train data for m. Note that the flip-flop 28 is reset at the same time as the counter 18 is reset by a transmission pulse from the transmitter 27.
The gate circuit 26 is made conductive.

'' - As described above, eight channels of rectangular wave train data having a phase relationship related to the direction and distance of the sound source are sent out from the storage circuit 7, and are sent out from the latch circuits 161 to 168 to 8.
A rectangular wave train of the channel is transmitted. Note that the latch circuits 181 to 168 perform latch operations using latch pulses sent from the latch pulse generation circuit 30, and the latch pulse generation circuit 30 uses the pulse train guided to the counter 13 and the frequency-divided pulses from the frequency divider circuit 18. and sends out a latch pulse.

The eight channels of rectangular wave trains sent out from the latch circuits 181 to 188 are combined with the rectangular wave trains of the latch circuits 901 to 908 to an exclusive OR gate 31 for each channel.
1 to 318. For example, a rectangular wave train of the latch circuits 161 and 901 is guided to the exclusive OR gate 311. exclusive OR gate 311
Each of 318 to 318 sends out the multiplication output of the input signal. That is, it performs the same function as the mixing circuits 210 to 208. Therefore, exclusive OR gates 311 to 31
The rectangular wave train sent from B is.

A rectangular wave train in which the phase relationship of the rectangular wave trains of the latch circuits 161 to 188 is superimposed on the phase relationship of the rectangular wave trains of the latch circuits 801 to 808 is sent out. For example, in Figure 4,
The received signal of the transducer T is transferred to the equal phase receiving surface FT' in the 0 direction.
A rectangular wave train that performs phase correction on the upper position THI and further performs phase correction on the spherical equiphase wavefront Fw is sent out from the exclusive OR game 311.

Each output of the exclusive OR gates 311 to 31B is guided to filters 321 to 328 to extract a specific frequency signal. For example, latch circuits, circuits 801 to 90
8 rectangular wave train is 192kHz, rat circuit 161 to 1
When the rectangular wave train of 68 is 88kHz, the filter 301
328 extracts the frequency signal of the sum component 280k)lz of each frequency signal. And filters 321 to 32
The extracted signals No. 8 have a phase relationship in which the phase of the rectangular wave train of the latch circuits 901 to 908 is superimposed on the phase of the rectangular wave train of the latch circuits 181 to 188.

Therefore, by guiding the extracted signals of the filters 321 to 328 to the mixing circuits 201 to 208 via the preamplifiers 301 to 308, the received signals of the ultrasonic transducers T1 to T9 can be changed as shown in FIG. As shown in FIG. After the directional reception beam signal for the sound source Q is extracted by a filter, it is guided to the luminance terminal of the display 22 via the ring 11 device 33. As a result, a bright spot is displayed on the display 22 at the direction and distance position corresponding to the sound source Q on the rask.

Effects of the g0 Invention Since the array shape of the array transducer can be formed to have the same shape as the spherical wave of the sound wave arriving from a short distance position, it is possible to configure the orientation of a detected object existing at a short distance position with high precision. can.

h0 Other Embodiments of the Invention In FIG. 1θ, the same numbers as in FIG. 15 perform the same operations.

In Fig. 1θ, 64 ultrasonic transducers T to T
1.4 are arranged in a straight line at regular intervals on the array plane T.The 84 oscillators are combined into 8 blocks of 4 each, and the vibrations for each prong are As shown in FIG. 11, eight directional receiving beams B, . and the directivity direction changes accordingly.

The directivity directions of the directional reception beams B to B9 are determined by the phase relationship of the 4-channel rectangular wave trains sent out from the latch circuits 341 to 344, and by changing the phase relationship of the 4-channel rectangular wave trains. , the pointing direction is changed in conjunction.

The latch circuits 341 to 344 output a rectangular wave train by latching the data stored in the storage circuit 36 read by the counter 35. Note that counter 35 is reset together with counters 8.13 and 17.

The four-channel rectangular wave trains sent out from the latch circuits 341 to 344 are commonly guided to eight sets of blocks each consisting of four sets of MX to MX-mixing circuits. Therefore, by guiding the mixed outputs of the mixing circuits MX to MxG4 to adder circuits AD to AD8 for each block and extracting specific frequency signals by filters F to FIl,
Directional receiving beams B through Bll as shown in FIG. 11 can be formed from each of the filters F through Fll. For example, the filters F to F receive the received signals of the ultrasonic transducers T to T1.4 at 100 kHz, and the rectangular wave trains sent out from the latch circuits 341 to 344 to 75 kHz.
z, its sum frequency component of 175 kHz is extracted.

The storage capacity of the storage circuit 36 is determined by the frequency of the rectangular wave train to be generated and the phase accuracy of the generated rectangular wave train.

In the case of sec, the capacity required to generate one channel of rectangular wave is calculated as follows. Therefore, the capacity required to generate a 4-channel square wave is (4X 3200) bits, and the counter 35 is at least r 3200J
A larger counting capacity is required. Further, the period of the clock input to the counter 35 is stopped at =208Cn8ec).

Therefore, the 1 frequency divider circuit 38 divides the frequency of the pulse train of the clock pulse source 12 and sends a 208 nsec clock pulse to the counter 35. Further, the latch pulse generation circuit 37 generates a latch pulse by combining the output pulse of the frequency dividing circuit 38 and the frequency divided pulse, and causes the latch circuits 341 to 344 to perform a latch operation using the latch pulse.

As a result of the above, the directivity direction of the received beams sent out from the filters F to TIl changes in conjunction with the phase changes of the rectangular wave trains sent out from the latch circuits 341 to 344. The range of change in the pointing direction is set to be similar to the range of change in the directional reception beam formed by the ultrasonic transducer shown in FIG. For example, in FIG. 5, when the directional received beam changes within a range of ±6o with respect to the central azimuth N, the filters F to F in FIG. The received beam signal sent from the preamplifier 30 is guided to the mixing circuits 201 to 20B.
It is mixed with the frequency signals sent out from 1 to 308. Mixing circuits 201 to 208 perform mixing operations in the same manner as in FIG. 5, and send their respective mixed outputs to adder circuit 4.

Therefore, in FIG. 1θ, instead of receiving signals from the ultrasonic transducers T to T8 shown in FIG.
guided by. The directivity direction of each directional receiving beam is controlled in conjunction with the directivity direction controlled by the rectangular wave train sent out from the latch circuits 8ol to 9°8.

As a result, the directional received beams added by the adding circuit 4 and sent out from the filter 5 form a received beam with a very sharp directivity angle compared to the one shown in FIG. i5.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the principle of the conventional device, FIG. 2 is a diagram for explaining the drawbacks of the conventional device, FIGS. 3 and 4 are diagrams for explaining the present invention in detail, 5 shows an embodiment of the present invention, FIG. 6 is a waveform diagram for explaining its operation, FIG. 7 is a diagram for explaining the configuration of its memory circuit, and FIGS. 8 and 9 are memory circuit diagrams. FIG. 1θ, which is a diagram for explaining the operation of the circuit, shows another embodiment, and FIG. 11 is a diagram for explaining the receiving beam formed by the ultrasonic transducer. T, to Tll... Ultrasonic transducer, 101 to 108... Front amplifier 11" device, 2o1 to 208
...Mixing circuit, 301 to 308...
Pre-multiplier, 4.Old...addition circuit, 5...
Filters, 6 and 7... Memory circuit, 8...
... Counter, 801 to 808, old... latch circuit.・10・・・Latch pulse generation circuit, 11・Old・
・Frequency divider circuit, 12...Clock pulse source, 13
······counter. 14 and 15... Memory circuits, 161 to 168
...Latch circuit, 17 and 18 old counter, frequency divider circuit for 18 and 2o, 21...
・Scanning circuit, 211... Counter, 212.
・・・・・・Clock pulse source, 213・Old・・Sine wave voltage generation circuit, 214・・・・Cosine wave voltage generation circuit,
215 and 21B... amplitude modulation circuit, 217.
Old... sawtooth generation circuit, 218... control circuit,
22...Display device, 23 and 24...Modulation circuit, 25...Scanning line, 26...Gate circuit, 27...Transmission Vessel, 28...
Transmitter, 28...Flip-flop, 30...
...Latch pulse generation circuit, 311 to 318...
・Exclusive OR gates, 321 to 328・
... filter, 33 ... increase 11] device,
341 to 344... Latch circuit, 35...
...Counter, 36...Memory circuit, 37.
... Latch pulse generation circuit, 38 ... Frequency division circuit, T to Tr, 4. Old ... Ultrasonic transducer, P
A. 〜PA1.4・・・・・・Preamplifier, MX, 〜M
x,...Mixed circuit, AD to ADll...
... Addition circuit, F, to F8 ... Filter patent applicant Furuno Electric Co., Ltd. Figure 9 Figure 11

Claims (2)

[Claims] (1) A plurality of ultrasonic receivers arranged in a straight line, and transmitting the received signal of each of the plurality of ultrasonic receivers from the receiving surface of each receiver to the transducer array direction. a first phase shifting means that shifts the phase by a distance corresponding to the distance to the equal phase wavefront tilted by a specific angle; 2. The distance from the position on the equiphase wavefront tilted by the specified angle to the sound source of the received signal and the equiphase wavefront formed on the equidistant line from the sound source. and second phase shifting means for shifting the phase by an amount corresponding to the distance difference between the second phase and the second phase.
Above 1. A short distance position characterized in that a directional received beam in the direction of the sound source is formed by combining received signals of each of the plurality of ultrasonic transducers phase-shifted by the second phase shifting means. A directional receiving beam forming device for incoming sound waves. (2) The ultrasonic receiver is configured by arranging a plurality of ultrasonic transducers, and is configured to combine and extract received signals of the plurality of ultrasonic transducers, and Directional reception beam formation for sound waves arriving from a short distance position according to claim 1, wherein the wave signal is formed to form directivity in the direction of an equal phase wave front tilted by the specific angle. Device.