JPS6246280A - Receiver for hydrospace detector - Google Patents

Abstract

PURPOSE:To prevent an ultrasonic wave from being transmitted in unnecessary directions by pulse-modulating exciting signals by using pulse waves wherein a rise and a fall edge gently change. CONSTITUTION:Exciting signals generated by a transmitted signal generator 2 are led to an ultrasonic wave transmitter and receiver 1 via a transmission and reception changeover device 3 (301-308). That is, in the transmitted signal generator 2, the data stored in a ROM 203 are latched [204 (2041-2048)] to make a latch circuit 204 output an eight phase rectangular waveform, which is led to a power amplifier 216 (2161-2168) via a bribe amplifier 215 (2151-2158), wherein the rectangular waveform is pulse-modulated by a pulse wave released from a pulse control circuit 217 to form the exciting signals. Therefore, since the rise and the fall edge of each ultrasonic oscillator 100 (101-108) are excited by a smoothly changing pulse-modulated wave, ultrasonic wave signals transmitted from the oscillators 100 have stable phases. So the synthetic directional characteristics of the ultrasonic wave signals can be maintained in a direction determined in advance.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an underwater detection device that instantly detects a wide range of directions by transmitting and receiving ultrasonic pulses in a wide range of directions underwater. Regarding a transmitting device that transmits ultrasonic pulses in a wide range of directions, the applicant previously provided a patent application filed in 1983.
0-119325 and Japanese Patent Application No. Sho GO-128949.

(Conventional device) The applicant has proposed a device of this type in Japanese Patent Application No. 1193/1986.
No. 25 and Japanese Patent Application No. Sho GO-128949.

As shown in Fig. 2, this device divides a wide range angle 0 for underwater detection into multiple range angles θ1, 02, and θ3.04, and sets frequencies f, , f2, and ff for each divided range angle.
transmits and receives ultrasonic pulses. Then, the frequencies f1 and f2 of the received signal of the reflected wave returning from each divided range direction are
, f3, f4 as a common frequency f. The received signal is then converted into a signal and processed.

In this way, since the frequency of the ultrasonic pulse differs for each divided range angle, the transmitted and received signals of each section will not be mixed with the transmitted and received signals of other sections.

Therefore, when a directional receiving beam having receiving sensitivity in a specific direction is formed, the sub-pole beam of the directional receiving beam is not affected by reflected signals returning from other directions.

Kitaki's patent application No. Showa EiO-119325 and patent application No. 1193
No. 0-128949, frequencies f1, f2 . f3
．． The f4 ultrasound pulse is performed using a common ultrasound transmitter.

An ultrasonic transmitter has a large number of ultrasonic transducers arranged.

By appropriately combining the phases of each excitation signal that excites each ultrasonic transducer and setting a specific phase relationship, the combined directivity direction of the transmitted signal can be set at each division range angle of 01.0□ and 03.04. It is designed to be formed every time. Note that it is known to appropriately combine the phases of excitation signals that excite each vibrator to obtain a desired composite directivity characteristic (1).

Therefore, each division range angle 04.02.03.04
In order to transmit an ultra-11 wave signal in the range direction, it is necessary that the phase relationship of the ultrasonic signals transmitted from each ultrasonic transducer is maintained in the same phase relationship as the phase relationship of the excitation signal. If the phase relationship between the respective ultrasound signals is disrupted, transmission directional characteristics of the ultrasound signals will be formed in directions other than the desired direction.

Further, in the above, the ultrasonic signal transmitted into the water is an ultrasonic pulse in which the excitation signal is pulse-modulated. However, when the excitation signal is pulse-modulated using a pulse wave, the ultrasonic transducer's response to sudden waveform changes at the rise or fall of the pulse wave causes This causes complex phase fluctuations. This phase variation causes the phase relationship of the ultrasound signals to differ from the predetermined phase relationship.

Moreover, an ultrasonic signal of an unnecessary frequency is generated due to one phase variation. Therefore, unnecessary ultrasonic signals are transmitted in other directions different from the predetermined division range angle.

(Problems to be Solved by the Invention) In the case of pulse modulating the excitation signal of an ultrasonic transducer, the present invention solves the following problems even at the rise and fall of the pulse modulated wave.
By maintaining the phase relationship of the ultrasonic signals transmitted from the ultrasonic transducer to a preset phase relationship, ultrasonic waves are prevented from being transmitted in unnecessary directions.

(Means and operations for solving the problem of m points) As a final means to solve the problem, the rising part of the pulse wave that performs pulse modulation changes gradually, and the falling part gradually changes. A pulse wave control circuit is used to control the pulse waveform. Then, the rising and falling parts gradually increase.
By pulse modulating the excitation signals using a gradually changing pulse wave, the phase relationship of each of the excitation signals is maintained at a constant phase relationship. .

(Example) In Fig. 1, ■ indicates an ultrasonic transducer, which is constructed by arranging a large number of ultrasonic transducers.
The ultrasonic transducers +01 to +108 are arranged and configured.

An excitation signal output from the transmission signal generator 2 is guided to the ultrasonic transducer 1 via transmission/reception switching devices 301 to 308.

The transmission signal generator 2 outputs a pulse-modulated excitation signal corresponding to each of the ultrasonic transducers 101 to 108, as shown in FIG. 3e. The rising and falling parts of the pulse-modulated excitation signal are controlled so that the waveform changes smoothly, thereby preventing the phase fluctuation of the ultrasonic transmission signal as described above.

The transmission signal generator 2 is based on a patent application filed in 1986 by the applicant.
-119325 or patent application No. 130-128949
The data stored in the read-only memory 203 is latched by the latch circuits 204 to 2048, so that the latch circuits 2041 to 2048
An eight-phase rectangular wave train is output. This rectangular wave train passes through drive amplifiers 2151 to 2158 to power amplifier 2.
When guided by 162168, drive amplifier 215□
215o to 215o, the excitation signal shown in FIG. 3e is formed by pulse modulation by the pulse wave (FIG. 3d) output from the pulse control circuit 217.

The excitation signal e has one frequency f, , f2 . f3. f4
0 frequencies f1, f2 . The frequency signals of f3 and f4 are based on patent application Sho GO-1.
As explained in No. 19325 or Japanese Patent Application No. 80-128949, each time the count value of the counter 208 changes, the decoder 212 changes the count value of the counter 201 to 2. The frequency of the read-only memory 2 is changed by changing the output value of the value setter 207.
03 is generated by switching the readout area.

That is, the counter 208 is a quaternary counter in this embodiment, and the gate 20
The clock pulses of the clock pulse generator 210 passing through the clock pulse generator 210 (FIG. 3b) are counted. In addition, gate 209
counter 2 after keying pulse a is output.
08 conducts while performing 4a counting.

When the karantoi direct of the counter 208 changes, the result (+
ri, the setter 207 switches the readout area of the read-only memory 203, while the decoder 212 switches the readout area of the read-only memory 203 sequentially.
4 The clocks with different frequencies output from the frequency circuit 202 are sequentially switched and guided to the counter 201. Therefore, in the read-only memory 203, the counter 208 is switched to the counter [
Each time data is read out from a different readout area using clocks with different clock frequencies, the launch circuits 2041 to 2048 read out data tα.

As a result, rectangular wave signals of one frequency f1, f2, f3, and f4 are sequentially output from the latch circuits 204□ to 2048.

Note that the latch circuits 2041 to 2048 latch stored data using latch pulses output from the latch pulse generation circuit 205, and the latch pulse generation circuit 205 is connected to the glock pulse source 206 that outputs the clock to the frequency dividing circuit 202. A latch pulse is generated using the clock and the clock output from the OR circuit 213 to the counter 201.

”, the counting operation of the counter 208 is as follows:
Each time a keying pulse a is output, it is done within a relatively short time, and therefore within this short time the frequencies f1, f2, f
3. The rectangular wave train of f4 is the latch circuit 2041 to 2048.
are output in chronological order. Further, the output pulse b of the gate 209 is guided to the pulse wave generator 214 and is shown in FIG.
A pulse wave of is output from the pulse wave generator 214. The pulse wave C is outputted in accordance with the count of the counter 208. Figure 3C' shows the pulse wave C expanded in the time axis direction.The pulse wave C' is guided to the pulse control circuit 217, and its rising and falling parts are as shown in Figure 3d. It is controlled to have gradual increases and decreases. Then, this controlled pulse wave is transmitted to the drive amplifier 215.
Latch circuits 2o41 to 2 are guided by I to 2158.
Pulse modulate the rectangular burst output from o48. Therefore, as shown in FIG. 3e, the drive amplifiers 2151 to 21511 output pulse-modulated rectangular bursts of frequencies f1, f2, f3, and f4.

The pulse-modulated rectangular wave train e is amplified in power by power amplifiers 216° to 218o, and then guided from transmission/reception switching devices 301 to 308 to each of the ultrasonic transducers 101 to 108 to cause each transducer to Excite. Therefore, since each of the ultrasonic transducers 101 to 108 is excited by a pulse modulated wave whose rising and falling parts change smoothly, the ultrasonic transducers 101 to +08 transmitted from each ultrasonic transducer 101 to The sonic signal is a pulse change: an ultrasonic signal whose phase is stable even at the rising or falling portion of the A wave is transmitted. Note that the composite directivity characteristics of the ultrasound signals transmitted from the ultrasound transducers 101 to 108 are determined by the phase relationship of the respective excitation signals. The phase relationship of the excitation signals is determined by the data stored in the read-only memory 203, as disclosed in Japanese Patent Application No. 60-119325 or Japanese Patent Application No. GO-128949. By inserting the frequency f2. A composite directional characteristic based on the excitation signals of f3 and f4 can be set in each direction of 02.03.04.

FIG. 4 shows a specific example of the pulse control circuit 217.

In Fig. 4, the pulse wave shown in Fig. 3 C' is introduced to the input terminal P, and the pulse wave whose rising and falling parts shown in Fig. 3 d are smoothly DIM is introduced from the output terminal P. is output.

The pulse wave C' applied to the input terminal P is inverted in the inversion rotation A, and then guided to the base of the transistor Q4 via the resistor R1 and the base of the transistor Q4 via the resistor R2. Therefore, transistors % and Q4 are turned off when the pulse wave C' is at a high level, and turned on when the pulse wave C' is at a low level. When transistors Q2 and Q4 are OFF, transistor 9<ON, and capacitor C1 is charged via resistor R5 by time constant C1R5.

Conversely, when transistor "2' Q4 is turned ON, transistor Q1% is turned OFF, and the charging electrode of capacitor CI is discharged by time constant ClR6 via resistor R6. Therefore, a pulse wave C' is applied to input terminal P. When applied,
What is the charging voltage of capacitor 01?

As shown in FIG. 3d, the time constant at the time of rising is C, and the time constant at R5 is changed by C1R6.

Charging time constant C, R5, discharging time constant C of capacitor C1
, R6 are determined in consideration of the response characteristics of the ultrasonic transducer. That is, the time constants C, R, , C, R, 6 are set to be larger than the response delay time of the ultrasonic transducer to the excitation voltage.

The charged voltage of the capacitor C1 is led to the output terminal P from the emitter of the transistor Q5 with a low impedance. Therefore, from the output terminal P, as shown in FIG. 3d,
A controlled pulse wave is output so that the rising and falling parts gradually increase and decrease.

As described above, from the ultrasonic transducer 1 to the dividing range angle θ1
．． The ultrasonic pulses transmitted in the directions 02, θ3, and 04 are reflected by objects underwater, and the reflected waves are received by the ultrasonic transducer 1.

The ultrasonic signal received by the ultrasonic transducer 1 is guided to the phase shifter 5 via the transmitter/receiver switchers 301 to 308.

In the phase shifter 5, each of the ultrasonic transducers 101 to 108 is set to 0.
After frequency-converting the received signals that have received the reflected waves returning in each direction η1 of □, 0□, and 03.04 into a common frequency signal, the phase shift of each received signal is controlled and sent to the adder 8. Output. Frequency conversion of the received signal is performed based on the mixed signal output from the mixed signal generator 6. Further, phase shift control of the received signal is performed based on a phase shift signal output from the phase shift controller 7. In addition, the phase shifter 5 mixed signal generator 6 and the phase shift system g! Specific examples and functions of J device 7 can be found in the patent application Sho GO.
119325 and Japanese Patent Application No. Sho EiO-128949, the explanation will be omitted.

The received signals of each of the ultrasonic transducers 101 to 10B whose phase has been controlled by the phase shifter 5 are guided to the adder 8 and added together. Therefore, since the adder circuit 8 outputs a composite signal obtained by phase-shifting and combining the received signals of the six ultrasonic transducers 101 to 108, it has directivity in one specific direction, and the direction of the directivity is detected. A directional received beam that changes at high speed within the range angle θ is output.

The output of the adder circuit 8 is guided to a filter 9 to extract a specific frequency signal. The extracted signal from the filter 9 is amplified by an image intensifier 10 and then led to a display 11.The 0 display 11 is, for example, a cathode ray tube display, and the pixel operation of the electron beam is performed by a sweep circuit 12. The brightness of the electron beam is modulated by the output of the video intensifier 10.

Further, the sweep circuit 12 performs pixel operations based on the keying pulse generator in synchronization with the phase shifting operation of the phase shifting VJ controller 7. Therefore, on the display screen of the display 11, the detected object underwater is displayed. The reflected waves returning from the detected object are displayed on one display screen at one position in the direction corresponding to the detected object.

(Effects of the Invention) As described above, according to the present invention, the underwater detection range angle is divided into 81 range angles, and the composite directional characteristics of a plurality of ultrasonic transducers are used to make each divided range angle When transmitting ultrasonic pulses with different frequencies in a time series within an extremely short period of time, the rising and falling parts of the pulse wave that pulse-modulates the excitation signal of each ultrasonic transducer may be gradually increased or decreased. Waveform control is performed so that the Therefore, at the rising or falling part of the pulse modulated wave,
The ultrasonic transducer can be excited each time the transfer of the ultrasonic signal transmitted from the ultrasonic transducer follows the phase shift of the Kimoto signal. As a result, it is possible to maintain the phase shift relationship of the ultrasonic signals transmitted from the plurality of ultrasonic transducers to be the same as the phase shift relationship of the excitation signal that excites each transducer.

Therefore, the composite directivity characteristic of the a-sound wave signal can be maintained in a predetermined directivity direction, and it is possible to prevent ultrasonic waves from being transmitted in unnecessary directions. Therefore, it is possible to realize an underwater detection device suitable for use when dividing the detection range angle into a plurality of sections and transmitting ultrasonic pulses of different frequencies for each range angle.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the present invention, Fig. 2 is a diagram for explaining the situation of underwater detection, Fig. 3 is a diagram for explaining the operation of the embodiment, and Fig. 4 is a diagram for explaining the operation of the embodiment. A specific example of a pulse control circuit will be shown. ■... Ultrasonic transducer, 2... Transmission signal generator, 4... Keying pulse generator, 5
... Phase shifter, 6... Mixed signal generator,
7... Phase shift controller, 8... Adder, 9
・・・・・・Filter, lO・・・・Image increase [1
〕vessel. II... Display unit, 12... Sweep circuit,
101 to 108... Ultrasonic transducer, 201.
... Counter, 202 ... Frequency divider circuit,
203...Read-only memory, 204! ~2
04o...Latch circuit, 205...Latch pulse generator, 20G...Clock pulse source, 207...Numeric value setter, 208...
・Counter, 209...Gate.

Claims (1)

[Claims] In an underwater detection device that performs underwater detection by dividing an underwater wide-range detection range angle θ into a plurality of range angles and transmitting ultrasonic pulses of different frequencies for each range angle, An ultrasonic transmitter configured by an array of transducers, and an excitation signal generated corresponding to each of the large number of ultrasonic transducers, each of the excitation signals having a common frequency and each phase. an excitation signal generation circuit whose relationship is set to a specific phase relationship, and which generates the excitation signal by sequentially switching the frequency and phase relationship of the excitation signal to a plurality of types corresponding to each of the divided range angles, and the excitation signal. a pulse modulation circuit that pulse modulates and outputs each of the excitation signals each time the frequency and phase relationship of the excitation signals are switched and output; and a pulse wave generation circuit that performs the pulse modulation, the pulse wave generating circuit comprising: and a pulse wave generation circuit that generates a pulse wave in which the pulse wave gradually changes and the falling part changes gradually, and the pulse wave generating circuit generates a pulse wave in which the pulse wave changes gradually and the falling part changes gradually, and the pulse wave generating circuit generates a pulse wave in which the pulse wave changes gradually and the falling part changes gradually. A transmitting device in a wide-angle underwater detection device characterized by excitation.