JPS58109867A - Sound detection device for wide-range underwater detector - Google Patents

Abstract

PURPOSE:To obtain an audible sound in response to the moving state of an object to be detected through a simple circuit, by detecting consecutively the frequency component of a reflected wave coming from a specific direction and converting the frequency component into an audible sound. CONSTITUTION:A switch circuit 3 switches the receiving signal of the oscillator which performs the phase synthesization among the receiving signals of ultrasonic oscillators T1-T36 and then transmits the receiving signal to a phase synthesizing circuit 5. The direction of the received beam is changed by varying the combination of those oscillators. The circuit 5 transmits the phase synthesization to the signal received from the circuit 3 and forms a wave receiving beam which has the directivity in a specific direction. The wave receiving signal of each direction is displayed to a display 7. On the other hand, the circuit 5 transmits the wave receiving signals of each direction in time series. A sample holding circuit 11 samples the wave receiving signals and holds the sampling voltage for a period until the next wave receiving signal of the same direction is sampled. As a result, the wave receiving signals of designated directions are consecutively delivered from the circuit 11. Then a sound is delivered through a speaker 22 and via a mixing circuit 18.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an underwater detection device that performs underwater detection by transmitting and receiving ultrasonic pulses in a wide range of directions, and relates to a device that converts reflected waves returning from a specific direction into audible sounds and listens to them.

A platform that detects a wide area underwater, generally sends and receives omnidirectional ultrasonic pulses in a wide range of directions, and when receiving waves, forms directional reception beams in each direction and returns from each direction. A method is used in which the reflected waves are received by respective interdigital reception beams.

When forming a directional receiving beam, phase synthesis is relatively often used.

That is, a large number of oscillators are arranged in a wide range of directions, and the received signals of several of the oscillators are phase-combined to form a receiving beam having directivity in one direction.

Directional receive beams must be formed in each direction. When forming directional reception beams in each direction, a method in which the phase synthesis circuits are prepared in correspondence with each direction, and directional reception beams in each direction are prepared in advance by each phase synthesis circuit; A method is used in which a single phase synthesis circuit is commonly used and the combinations of vibrators for phase synthesis are switched corresponding to each direction.

In a system using a large number of phase synthesis circuits, independent directional reception beams are formed for each direction, so it is relatively easy to convert a reception signal in a specific direction into an audible sound. When converting an audible sound, an audible sound of about 1KH2 is generally generated by taking a beat with an approximate frequency signal.

The frequency of the audible sound after conversion changes in accordance with the frequency change of the received signal, so when the received signal is subjected to the Doppler effect due to the relative speed with the detected object, the height of the audible sound changes. changes. This allows you to intuitively know whether the detected object is moving away from you or approaching you.

However, when a large number of phase synthesis circuits are used as described above, a large number of phase shifters such as delay circuits must be used. A phase shifter is required for each vibrator, and a plurality of phase shift signals having different amounts of phase shift must be generated for each vibrator. Therefore, phase synthesizers tend to be extremely complex and expensive.

In contrast, if one phase synthesis circuit is used commonly for all of the oscillators to form a directional receiving beam in each direction while changing the combination of oscillators for phase synthesis, the combination of oscillators is Although the switching circuit for switching is reliable, the configuration of the phase shifter can be made relatively simple. In this case, in the directional receiving beam sent out from the phase synthesis circuit, receiving signals in each direction are sent out in time series. Therefore, when a received signal in one direction is extracted, the extracted signal is transmitted discontinuously, so even if it is converted into an audible sound, it is difficult to hear an audible sound that corresponds to the relative movement of the detected object. Not exposed.

This invention relates to frequency components of reflected waves returning from a specific direction in an underwater detection device that changes the direction of a directional receiving beam by switching the combination of transducers using one phase synthesis circuit in common. To provide a device that can continuously detect and convert sound into audible sound and listen to the sound.

Examples of the present invention will be described below.

In FIG. 1, T1 to T- indicate ultrasonic transducers,
As shown in FIG. 2, they are arranged at regular intervals on the circumference. The transmission output of the transmitter 2 is applied to each of the ultrasonic transducers T1 to T, 6 via transmission/reception switching circuits 101 to 136. Therefore, the ultrasonic transducers T1 to 'rss are simultaneously excited and transmit ultrasonic waves in all directions around the circumference.

The reflected waves reflected by the detection object and returning from each direction are received by the ultrasonic transducer whose directivity angle includes the directions.

Each of the ultrasonic transducers T8 to T'ms has a relatively wide directivity angle. For example, when a reflected wave arrives from the 0□ direction in FIG. 2, the transducers ThT, , T1, T ,,
The wave is received by T.

The received signals of the ultrasonic transducers T1 to T are sent from the transmission/reception switching circuits 101 to 136 to the switching circuit 3 and the selection circuit 4, respectively.
sent to.

The switching circuit 3 switches the received signal of the transducer that performs phase synthesis among the received signals of the ultrasound imagers T1 to TH, and sends it to the phase synthesis circuit 5. The phase synthesis circuit 5 phase-synthesizes the received signals of the vibrators sent from the switching circuit 3 to form a received beam having directivity in a specific direction. For example, the second
In the figure, when forming a directional receiving beam in the θ1 direction, the ultrasonic transducer T1% TI, T, , T, , T, ρ
Phase-synthesizes the received signals.

Phase synthesis is performed using the oscillators 'r1, 'r arranged on the circumference.
, , T, , T, %T, the respective received signals are suitably shifted in phase so that the receiving surfaces of , , T, %T, coincide with equal-phase wave fronts with equal constraints.

After the receiving signal in the 01 direction is sent out from the phase combining circuit 5, the switching circuit 3 selects the receiving signal of the other transducer and guides it to the phase combining circuit 1!85, thereby converting the directional receiving signal in the other direction. Form a wave beam. To cut the received signal, for example, to form a received beam in the θ1 direction, use the transducers T, T, T.
When transmitting a receiving signal of 1, T, ,T, and forming a receiving beam in the direction θ, the transducer 'I'5sT1, T1,
The received signals of Ts and T4 are transmitted. Thereafter, by changing the combination of transducers in the same manner, the directivity direction of the received beam is changed.

The received signals in each direction sent out from the subphase combining circuit 5 are amplified by the amplification device 6 and then sent out to the display 7. The display 7 is, for example, a cathode ray tube display, and the received signal is guided to its luminance terminal. Further, the display device 7 undergoes pixel scanning by a scanning circuit 8. Pixel scanning is performed in a spiral manner in response to switching of the direction of receiving beam by the switching circuit 3. On the other hand, the above switching operation of the switching circuit 3 is performed on the switching control surface W! ! It is carried out based on 9. The switching control of the switching control circuit 9 and the pixel scanning of the scanning circuit 8 are performed by the synchronous circuit 1.
0 and are performed in synchronization with each other.

That is, the direction of the received beam determined by the switching circuit 43 and the position on the display screen determined by pixel scanning by the scanning circuit 8 are made to correspond to each other. Further, the direction switching of the received beam by the switching circuit 3 is performed so that reflected waves from substantially equidistant positions are sent out while the received beams in each direction are switched in one round.

The synchronization circuit 10 synchronizes the switching control circuit 9 and the scanning circuit 8 while also controlling the transmitter 2. That is, the synchronous circuit 10
First, the transmitter 2 is driven to transmit ultrasonic pulses from the supertotal wave transducers T0 to T'ss, and after λ, the running time f! I
8 to start pixel scanning, and at the same time, the switching control circuit 9 is caused to perform switching and control. As a result, the received signals in each direction are displayed on the display screen of the display 7 in the corresponding directions and positions.

While the reflected waves returning from each direction are displayed as described above, the output of the phase synthesis circuit 5 is also sent to the sample and hold circuit 11.

The sample and hold circuit 11 samples all output signal levels of the phase synthesis circuit 5 based on the sampling pulse generation circuit 12, and holds the sampled voltage until the next sampling is performed.

The sampling pulse generation circuit 12 sends out a sampling pulse every time the matching circuit 13 sends out an output. The coincidence circuit 13 connects the output of the switching control circuit 9 and the direction setting circuit 14.
When both outputs match, the matching output is sent. That is, since the switching control circuit 9 sends out the switching output of the switching selection circuit 3, the entire arrival direction of the received beam can be known from the output of the switching control circuit 9. On the other hand, the azimuth setting circuit 14 specifies the azimuth of the received beam to be listened to, and sends out the specified azimuth data corresponding to the azimuth output of the switching control circuit 9. The coincidence circuit 13 operates when the azimuth output of the switching control circuit 9 matches the designated azimuth of the azimuth setting circuit 14, and therefore, when a received signal corresponding to the designated azimuth of the azimuth setting circuit 14 is sent out from the phase synthesis circuit 14. ,
Send match output. Sampling pulse generation circuit 12
sends out a sampling pulse based on this coincidence output, and the sample hold circuit 11 samples the output signal of the phase synthesis circuit 5. Since the phase synthesis circuit 5 sends out the received signals in each direction in time series, the sample and hold times are
, :311 samples the received signal in the specified direction and then samples the received signal in the same direction (
8), hold the sampling voltage. The rice polishing and sample hold circuit 11 continuously sends out received signals in the specified direction. On the other hand, the direction data from the direction setting circuit 14 is also sent to the selection circuit 4, and Among the received signals, a received signal in a specified azimuth direction is selected.

Since the reflected waves from the specified direction are received at different times depending on the distance to the reflecting object, it is possible to know from the output of the sample and hold circuit 11 when the received signal in the specified direction arrives.
It is possible to detect the frequency component of a received signal arriving from a designated direction.

The selection signal of the selection circuit 4 is shaped by the shaping circuit 16.

FIG. 3a shows the shaped wave of the shaping circuit 16, and the same figure shows the output signal r of the sample and hold circuit 11. Note that the shaped wave a has a period t that changes in accordance with the speed of movement of the object to be detected, as in the conventional underwater detection device.

The shaped wave a is sent to the switching circuit 15, and conduction is established between the input and output of the switching circuit 15 during each high level period. Therefore, from the switching circuit 15,
As shown, the amplitude of the shaped wave a is determined by the sample and hold circuit 11
A switching waveform is sent out that changes according to the output speed of the switch. This switching waveform C is sent to the filter circuit 17 and a specific frequency signal is extracted. Filter circuit 17
The center frequency of the passband is set equal to the transmission frequency of the ultrasonic pulse, and the frequency shift of the received signal is set to be included within the passband. As a result, the filter circuit 17 sends out a frequency signal whose amplitude changes in accordance with the output of the sample and hold circuit 11 and whose frequency matches the selection signal of the selection circuit 40, as shown in FIG. 3d. This frequency signal d matches the received signal in the direction specified by the direction setting circuit 14.

The output signal d of the filter circuit 17 is mixed with the oscillation signal of the source oscillator 19 in a mixing circuit wr18. The oscillation frequency of the oscillator 19 is set to a frequency that differs from the transmission frequency of the ultrasonic pulse by an amount of audible sound.

The output of the mixing circuit 18 is sent to the filter circuit 2o, and the frequency components of the audible sound are selected from the mixed output.

The selection signal of the filter circuit 2o is amplified by the amplifier 21 and then announced as an audible sound from the speaker 22. As is clear from the above, the intensity of this audible sound changes depending on the amplitude of the received signal, and the intensity of the sound changes depending on the frequency displacement of the received signal, and therefore the relative moving speed of the detected object. It changes depending on.

Therefore, by listening to this, it is possible to intuitively know the change in the position of the detected object.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 2 is a diagram for explaining the arrangement of the ultrasonic transducers, and FIG. 3 is a diagram for explaining the operation. Applicant Furuno Electric Co., Ltd. 1st Item 2nd Item// 3rd Item αJ

Claims (1)

[Claims] Ultrasonic pulses are transmitted and received in a wide range of directions, and the reflected waves returning from the object to be explored in each direction are displayed in the 6th position on the display.
In this device, a suitable number of oscillators among the large number of oscillators arranged in the above wide range of directions receive the waves. A phase combining circuit that combines the phases of signals with each other to form a received beam having directivity in one direction; and a phase combining circuit that sequentially switches combinations of oscillators that perform phase combining. a switching circuit that sequentially changes the pointing direction of the receiving beam sent out from the switching circuit; and a display that displays the receiving signal sent out from the phase synthesis circuit in association with the pointing direction of the receiving beam determined by the switching circuit. an extraction circuit for extracting an output signal corresponding to an anti-IR wave in a specific direction of the reflected wave displayed on the display from among the output signals of the phase synthesis (b) path; and an extraction signal of the extraction circuit. a control circuit for controlling the amplitude of the received signal of the vibrator which receives the reflected wave in the specific direction among the plurality of vibrators, and converting the output signal of the amplitude control circuit into an audible sound. A listening device in a wide range underwater detection device, comprising a conversion circuit for converting the sound.