JP3050204B2 - Underwater depth multi-stage acoustic measurement buoy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater multi-stage acoustic measuring buoy, and more particularly to an underwater multi-stage acoustic measuring buoy having a depth detecting function.

[0002]

2. Description of the Related Art Conventionally, this type of underwater depth multi-stage acoustic measurement buoy is disclosed in, for example, Japanese Patent Laid-Open No. 60-152965, in which a temperature sensor attached to the buoy is temporarily suspended to a predetermined position. The temperature information is transmitted wirelessly, the depth of the buoy transceiver described later is determined based on the temperature information, and the position of the transducer is switched to that depth by wireless control, so that a more distant target can be obtained. The purpose is to detect.

FIG. 5 is a block diagram showing an example of a conventional underwater depth multi-stage acoustic measurement buoy disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 60-152965.

In FIG. 5, a conventional underwater depth multi-stage acoustic measurement buoy includes a transducer 101 for transmitting and receiving sound for measurement, and a transducer suspension cable for suspending the transducer 101. 102 and a predetermined position of the transducer suspension cable 102 in several stages.
A fixed tap 103 for determining the depth of the transducer 101 by fixing it, a drum 104 around which the transducer suspended cable 102 and the fixed tap 103 are wound, and a transducer depth switching mechanism connecting the fixed tap 103 105,
A transmitter / receiver depth switching circuit 106 for transmitting a signal for disconnecting the fixed tap 103, a power supply 107 for operating the transmitter / receiver depth switching circuit 106, and a transmitter / receiver An antenna 108 for transmitting and receiving wirelessly via a suspension cable 102;
Transmission / reception switching circuit 1 for switching between transmission and reception of sound by the
09, a temperature sensor 110 for measuring the water temperature, and a temperature sensor suspension cable 111 which is a cable for the temperature sensor.
And a temperature information transmission circuit 112 for transmitting a temperature sensor signal to the transmission / reception switching circuit 109 via the temperature sensor suspension cable 111.

Next, the operation of the above conventional example will be described.
When the underwater depth multi-stage acoustic measurement buoy is put on the sea surface, the temperature sensor 110 is hung by the temperature sensor hanging cable 111, and sinks to a predetermined constant depth under the sea.

At the time of subsidence, temperature information output from the temperature sensor 110 is processed by a temperature information transmission circuit 112 via a temperature sensor suspension cable 111, and the transmission / reception switching circuit 1
09 from the antenna 108.

The signal transmitted from the antenna is received externally, the optimum depth of the underwater depth multi-stage acoustic measurement buoy is calculated, and a control signal for setting the optimum depth is transmitted. The control signal is received by the antenna 108 of the underwater depth multistage acoustic measurement buoy, and is input to the transducer depth switching circuit 106 via the transmission / reception switching circuit 109. The transducer depth switching circuit 106 transmits a switching signal for disconnecting the corresponding fixed tap 103 to the transducer depth switching mechanism 105.

[0008] Until the switching signal is transmitted, the transducer 10
1 is a diagram showing the relationship between the transmitter / receiver depth switching mechanism 105 and the fixed tap 103 at the shortest point of the transmitter / receiver suspension cable 102 at a plurality of predetermined depths. The vessel 101 is fixed at the shallowest depth among predetermined depths.

When the switching signal is transmitted, the selected fixed tap 103 is cut off, and the transceiver suspension cable 102 is disconnected.
Of the fixed tap 10 which has not been cut
3 to the position of the transducer hanging cable 102 to reach the selected depth.

[0010]

However, the prior art described above has the following drawbacks.

A first problem is that it is not possible to confirm whether or not the depth has been set after switching the depth.

As a result, there is a possibility that depth switching is not performed even if depth switching is performed, or that the depth cannot be recognized even if another depth is set, and measurement at the optimum depth is not performed. There is.

One of the reasons is that depth detection components such as a depth sensor for detecting depth are expensive components, and when excellent environmental performance is required, the shape and size must be increased. That is, it cannot be used. The underwater depth multi-stage acoustic measurement buoy is required to be inexpensive because it is a consumable.

Further, since it may be used by being dropped from an aircraft or the like, it must be excellent in environmental performance such as shock, vibration and temperature.

The other is that even if the underwater depth multi-stage acoustic measurement buoy detects the depth of the transducer and transmits the information wirelessly, the underwater depth multi-stage acoustic measurement buoy receives the radio signal. A device for processing the signal of the depth information is required on the side of the conventional signal processing device for processing, but this is not provided in the conventional device.

Although it is necessary to add a device for processing the signal of depth information to the conventional device, there is a possibility that the device cannot be added due to a space problem because the device is larger than the conventional device.

The present invention has been made in view of the above-mentioned circumstances, and has been made to solve the above-mentioned drawbacks inherent in the conventional technology. Therefore, an object of the present invention is to provide a small-sized, inexpensive, excellent environmental performance, and a circuit scale. Another object of the present invention is to provide a novel underwater depth multi-stage acoustic measurement buoy having a small depth and a depth detector that can be processed by an existing signal processing device.

[0018]

In order to achieve the above object, the underwater depth multi-stage acoustic measurement buoy according to the present invention is required to have a low-cost structure because it is a consumable. In addition, since it may be used by dropping it from an aircraft,
It must have excellent environmental performance such as shock, vibration and temperature. For this purpose, the underwater depth multi-stage acoustic measurement buoy of the present invention is provided with a small, inexpensive depth detector having excellent environmental performance.

Specifically, a signal for disconnecting the suspension of the suspension cable by the depth switching signal is used, and the frequency is changed in the frequency band used for measurement for a certain period of time during the depth switching according to the location to be disconnected. Detector to transmit by using (11 in FIG. 1)
Having.

In order to explain the present invention in more detail, the underwater depth multi-stage acoustic buoy according to the present invention is an underwater depth multi-stage acoustic buoy in which a floating part and an underwater part are connected by a suspension cable. A control circuit for controlling signal transmission and reception between the underwater part and the levitation having a receiving means for receiving a depth switching control signal and a transmitting means for transmitting an information signal to the outside, and measuring sound. A depth switching circuit for controlling a depth switching mechanism and a sensor to be performed, and depth detection means for generating a depth information signal based on a switching operation of the depth switching mechanism. The depth detection is performed by generating the depth information and transmitting the information via the floating portion.

The depth information of each stage is generated by signals having different frequencies set in accordance with the depth of each stage.

Further, the depth information of each stage is transmitted in the same form as the acoustic measurement signal during the depth switching by using the depth switching control signal at each depth.

The depth detecting means includes a timer for counting the fixed time set by the control circuit so as to transmit the generated depth information signal at each stage only for a fixed time within the depth switching time; A latch circuit for latching a depth switching signal supplied from a circuit, an oscillator control circuit controlled by the depth switching signal, a frequency signal of a predetermined frequency controlled by the control signal of the oscillator control circuit and the timer And a waveform shaping circuit for shaping the output of the oscillator to generate a sine wave signal and outputting the sine wave signal to the control circuit.

A plurality of taps are provided at substantially equal intervals along the lower part of the suspension cable between the suspension cable and the depth switching mechanism in the underwater part, and the upper tap is provided. The suspension cable sinks down to the position of the next tap every time it is cut.

A counter for measuring the number of times a depth switching control signal is received is provided between the depth switching circuit and the depth switching mechanism, and the output of the counter is input to the depth detecting means, and the number of times of the depth switching signal is Thus, a depth detection is performed by transmitting a signal of depth information.

Further, according to the number of depth switching signals,
The signal of the depth information is transmitted in the same form as the acoustic measurement signal during the depth switching.

[0027]

According to the present invention, depth switching is carried out without using a depth sensor, and by changing the extension length of the suspension cable by cutting the holding of the suspension cable by a conventional acoustic measurement buoy. Focusing on the fact that the depth is confirmed by transmitting the cutting point by a signal, the depth detection is small and inexpensive, and has no problem with environmental performance.

Further, the signal of the depth information is executed during the depth switching without performing the sound measurement, and the signal from the underwater depth multi-stage sound measurement buoy is received by using the signal of the same frequency band as the signal of the sound measurement. In addition, the depth can be detected without changing the processing device that performs the processing.

[0029]

Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of First Embodiment] FIG. 1 (a)
FIG. 1 is a block diagram showing a first embodiment of the present invention, and FIG. 2B is a schematic layout diagram showing the first embodiment of the present invention.

Referring to FIGS. 1 (a) and 1 (b), a multi-stage underwater depth sound measurement buoy floats on the sea surface and transmits and receives information by radio, and a buoyant part 1 is positioned underwater to measure sound. An underwater part 2 and a suspension cable 3 connecting the floating part 1 and the underwater part 2 are constituted.

The underwater section 2 comprises a probe section 4, a depth switching mechanism 5 attached to the probe section 4, and a probe section by fixing the depth switching mechanism 5 at an intermediate length of the suspension cable 3. A tap 6 for setting the depth of the suspension cable 4 to a midway length of the suspension cable 3, a tap group 7 provided with a plurality of the taps 6 at different positions within the length of the suspension cable 3, and a suspension cable 3 And a cable pack 8 in which the tap group 7 is wound.

The depth switching mechanism 5 has a single tap 6
One is provided. Therefore, as many depth switching mechanisms 5 as the number of taps 6 in the tap group 7 are provided.

The probe unit 4 measures the sound and receives or transmits the sound. The sensor unit 9 transmits a signal to the depth switching mechanism 5 to cut off the tap 6 of the tap group 7. A depth detector 11 for detecting a depth from a signal of the depth switching circuit 10, a sensor unit 9, and a depth detector 11
And a control circuit 12 for controlling a signal to be sent to the depth switching circuit 10.

The depth switching circuit 10 controls the presence or absence of a DC voltage in the depth switching mechanism 5 connected to each of the taps 6 (hereinafter, DC voltage is present: "H" signal, DC voltage is not present).
The tap 6 to which the “H” signal has been transmitted is disconnected, and the tap 6 to which the “L” signal has been transmitted is not disconnected, thereby performing depth switching.

The levitation 1 includes a transmitter 13 for wirelessly transmitting a signal from the sensor unit 9 or a signal from the depth detector 11 via the suspension cable 3, a transmission antenna 14, and a control signal for depth switching or the like. The receiver 15 is configured to receive a signal wirelessly and send it to the depth switching circuit 10 via the suspension cable 3, and a receiving antenna 16.

Next, a detailed configuration of the depth detector 11 will be described.

FIG. 2 is a block diagram showing a configuration example of the depth detector 11 in the embodiment according to the present invention.

In FIG. 2, the depth detector 11 includes a latch circuit 17, an oscillator control circuit 18, a timer 19, an oscillator 20, a waveform shaping oscillator 21, a waveform shaping circuit 22, and an LP.
F23.

An "H" or "L" signal sent from the depth switching circuit 10 to the depth switching mechanism 5 is also sent to the latch circuit 17, and a control signal predetermined by the signal is sent to the oscillator control circuit 18. . The oscillator control circuit 18
The oscillator 20 transmits a predetermined frequency in the frequency band of the signal transmitted from the sensor unit 9 only for the time width determined by the timer 19 according to the control signal.

The signal from the waveform shaping oscillator 21 is synthesized by the waveform shaping circuit 22 to make the waveform a sine waveform, which is transmitted to the control circuit 12 via the LPF 23.

[Operation of First Embodiment] Next, the operation of the first embodiment will be described.

When the underwater depth multi-stage acoustic measurement buoy is put on the sea surface, the suspension cable 3 is drawn out from the cable pack 8 and the underwater part 2 is suspended. In the tap group 7 connected in the middle of the suspension cable 3, the underwater part 2 is suspended by the connection of the depth switching mechanism 5 at the tap 6 connected to the place closest to the levitation 1. Stop.

At the depth, acoustic measurement is performed by the sensor unit 9, and the sound volume measurement information is wirelessly transmitted from the transmitter 13 and the transmission antenna 14 via the suspension cable 3.

The control signal for depth switching transmitted by radio is received by the receiving antenna 16 and the receiver 15 and transmitted to the control circuit 12 via the suspension cable 3 to perform depth switching.

Next, the depth switching and the operation of the depth detector 11 will be described with reference to FIGS.

FIG. 2 is a block diagram showing a specific example of the depth detector 11, and FIG. 3 is a sequence diagram for explaining the operation of the present invention.

Referring to FIG. 3, a control signal is transmitted from control circuit 12 to depth switching circuit 10. An “H” signal is transmitted when the tap 6 is disconnected from the depth switching circuit 5 to the depth switching mechanism 5 according to the form of the control signal, and an “L” signal is transmitted when the tap 6 is not disconnected. The tap 6 is cut, and the underwater part 2 sinks to the depth of the uncut tap.

The "H" or "L" signal sent from the depth switching circuit 10 is also sent to the depth detector 11, where the latch circuit 17 outputs the "H" or "L" signal. The oscillator control circuit 18 and the oscillator 20 generate one determined frequency in the same frequency band as the sensor unit 9, and generate a sine waveform from the waveform shaping oscillator 21, the waveform shaping circuit 22, and the LPF 23, The timer 19 transmits only a certain time within the depth switching time.

By this, a signal in the same frequency band as the sensor information is transmitted during a time period during which sound measurement is not performed during depth switching, so that the frequency can be checked.
You can see which taps were cut and how far they sank.

Next, the effect of the first embodiment of the present invention will be described.

In the first embodiment of the present invention, the depth sensor is not used, and the underwater part 2 extends the suspension cable 3 connecting the floating part 1 and the underwater part 2 to thereby obtain the depth of the underwater part. Is set, it can be said that the length of the suspended cable being extended = depth. Therefore, by using the conventional depth switching signal, a signal in the frequency band used for sound measurement is generated, and is sent during depth switching in which sound measurement is not performed. For underwater depth multi-stage acoustic measurement buoys that are inexpensive and require environmental resistance, the depth can be checked only by adding a small circuit.

[Second Embodiment] Next, a second embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 4A is a block diagram showing a second embodiment according to the present invention, and FIG. 4B is a schematic layout diagram showing a second embodiment according to the present invention.

Referring to FIGS. 4A and 4B, the second embodiment according to the present invention is described above in that a counter 24 is provided in front of the depth detector 11 and the depth switching mechanism 5. This is different from the first embodiment.

In the case where the control signal of the depth switching is one mode or the number is small, and the depth switching is performed more than the number,
Rather than determining the depth according to the form of the transmitted control signal, depth switching is performed according to the number of times the control signal is received. In that case, a counter 24 is provided after the signal sent from the depth switching circuit 10 and the counter 24
Is changed according to the number of times and input to the depth switching mechanism 5 and the depth detector 11.

The second embodiment according to the present invention, in addition to the effects of the first embodiment, is that more depth switching and depth detection are possible regardless of the number of control signals.

[0058]

Next, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIGS. 1 (a) and 1 (b), one embodiment of a multi-stage underwater depth-type acoustic measurement buoy is a floating part 1 which floats on the sea surface and wirelessly transmits and receives information, and is located underwater. It comprises an underwater part 2 for acoustic measurement, and a suspension cable 3 connecting the floating part 1 and the underwater part 2.

The underwater section 2 fixes the probe section 4, a depth switching mechanism 5 attached to the probe section 4, and a depth switching mechanism 5 at an intermediate length of the suspension cable 3. A tap 6 for setting the depth of the suspension cable 3 to a depth halfway along the suspension cable 3, a tap group 7 provided with a plurality of taps 6 at different positions within the length of the suspension cable 3,
The cable pack 8 includes the suspension cable 3 and the tap group 7.

The depth switching mechanism 5 has a single tap 6
, One depth switching mechanism 5 is provided. Therefore, as many depth switching mechanisms 5 as the number of taps 6 in the tap group 7 are provided.

The probe unit 4 measures the sound, and receives or transmits the sound. The sensor unit 9 transmits a signal to the depth switching mechanism 5 and disconnects the tap 6 of the tap group 7. , A depth detector 11 for detecting a depth from a signal of a depth switching circuit 10, a sensor unit 9, and a depth detector 1
1 is provided with a control circuit 12 for controlling a signal from the control unit 1 and a signal to be sent to the depth switching circuit 10.

The depth switching circuit 10 transmits an “H” or “L” signal to the depth switching mechanism 5 connected to each of the taps 6, and the tap 6 to which the “H” signal has been transmitted is disconnected, and the “L” signal is transmitted. The depth switching is performed by not disconnecting the tap 6 to which the signal has been sent.

The levitation 1 includes a transmitter 13 for wirelessly transmitting a signal from the sensor unit 9 or a signal from the depth detector 11 via the suspension cable 3, a transmission antenna 14, and a control signal for depth switching or the like. It comprises a transmitter 15 that receives wirelessly and sends it to the depth switching circuit 10 via the suspension cable 3, and a receiving antenna 16.

Next, a detailed configuration of the depth detector 11 will be described.

FIG. 2 is a block diagram showing a configuration example of the depth detector 11 according to the embodiment of the present invention.

In FIG. 2, a depth detector 11 includes a latch circuit 17 for latching a depth switching signal from the depth switching circuit 10, an oscillator control circuit 18, a timer 19, an oscillator 20, and a waveform shaping oscillator 21. , Waveform shaping circuit 22
And an LPF 23.

An “H” or “L” signal sent from the depth switching circuit 10 to the depth switching mechanism 5 is also sent to the latch circuit 17, and a predetermined control signal is transmitted to the oscillator control circuit 18 based on the signal. . The oscillator control circuit 18
The oscillator 20 transmits a predetermined frequency in the frequency band of the signal transmitted from the sensor unit 9 only for the time width determined by the timer 19 according to the control signal. The signal from the waveform shaping oscillator 21 is combined by the waveform shaping circuit 22 to make the waveform a sine waveform and the LPF 23
To the control circuit 12 via the.

[Operation of Embodiment] Next, the operation of this embodiment will be described.

Referring to FIG. 1, when the underwater depth multistage acoustic measurement buoy is put on the sea surface, the suspension cable 3 is drawn out from the cable pack 8 and the underwater part 2 is suspended. Among the tap group 7 connected in the middle of the suspension cable 3, the tap 6 connected to the place closest to the levitation 1.
At this point, suspension of the underwater part 2 is stopped by the connection of the depth switching mechanism 5.

Acoustic measurement is performed by the sensor unit 9 at that depth, and information is shifted from the transmitter 13 and the transmitting antenna 14 via the hanging cable 3 in the frequency band of, for example, 1 kHz ± 500 Hz, and is wirelessly transmitted. To send.

On the other hand, a depth switching control signal transmitted wirelessly by an aircraft or the like is received by the receiving antenna 16 and the receiver 15 and transmitted to the control circuit 12 via the suspension cable 3 to perform depth switching.

Next, the depth switching and the operation of the depth detector 11 will be described with reference to FIGS.

FIGS. 3A and 3B are diagrams for explaining the operation of the present invention. FIG. 3A is an operation sequence diagram, and FIG.
(A) is a block diagram showing only the probe unit 4 extracted, and (c) is an output state of the depth switching circuit 10 and an output frequency of the depth detector 11 corresponding to the underwater depths A, B, C, and D. It is a table showing the relationship.

In the system of the present embodiment, the underwater part 2 is selected by a selected one of a plurality (four in this embodiment) of taps 6 attached in the lower part of the suspension cable 3.
Is fixed, and when an electric signal flows into the tap 6, the corresponding tap 6 is cut and the suspension cable 6
Is carried out, and the next attached tap 6
By submerging to the depth, the depth switching is executed.

The electric signal flowing through each tap 6 is converted into a different predetermined frequency by the tap at each stage, and those frequency signals are transmitted to the signal processor within the time during which the suspension cable 3 is extended. .

In this embodiment shown in FIGS. 3A to 3C, the case where the number of taps 6 is four, that is, 6A to 6D, is shown. Of course you can.

Referring to FIGS. 1 to 3, a control signal is transmitted from the control circuit 12 to the depth switching circuit 10. An “H” signal is transmitted when the tap 6 is disconnected from the depth switching circuit 5 to the depth switching mechanism 5 according to the form of the control signal, and an “L” signal is transmitted when the tap 6 is not disconnected.
When the “H” signal is supplied and the tap 6 is cut, the underwater part 2 sinks to the depth of the tap closest to the floating part 1 that has not been cut.

The "H" or "L" signal sent from the depth switching circuit 10 is also sent to the depth detector 11, where the latch circuit 17 outputs a "H" or "L" signal in the form of an "H" or "L" signal. In the same frequency band as the sensor section 9 by the oscillator control circuit 18 and the oscillator 20, as shown in FIGS. 3A and 3C, when the first tap A6 is cut (B), 600 Hz is set to 700H when the first and second taps A6 and B6 are cut (C).
z is set to 800 Hz when the first to third taps A6, B6, and C6 are cut (D), and a combination of other taps is cut (for example, the first and third taps are cut).
, A sine waveform is generated from the waveform shaping oscillator 21, the waveform shaping circuit 22, and the LPF 23, and the timer 19 transmits the sine waveform only for a certain time within the depth switching time.

As a result, a signal in the same frequency band as the sensor information is transmitted during a time period during which sound measurement is not performed while the depth is being changed.
It is possible to check which tap has been cut and which depth has sunk.

[0081]

The present invention is constructed and operates as described above. According to the present invention, the following effects can be obtained.

The first effect is that by enabling depth detection, it is possible to confirm that the optimum depth has been set, and the reliability of acoustic measurement is higher than before.

The reason is that a signal of a frequency band used for acoustic measurement is generated by using a conventional depth switching signal from the viewpoint that a suspended cable length being extended = depth without using a depth sensor. By sending during the depth switching without performing sound measurement, it is possible to detect the depth of underwater depth multi-stage sound measurement buoys that require miniaturization, low cost and environmental resistance performance without additional processing equipment. is there.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment according to the present invention.

FIG. 2 is a detailed block diagram showing a specific example of the depth detector shown in FIG.

FIG. 3 is a diagram for explaining the operation of the present invention.

FIG. 4 is a block diagram showing a second embodiment according to the present invention.

FIG. 5 is a block diagram showing an example of a conventional underwater depth multi-stage acoustic measurement buoy.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Floating part 2 ... Underwater part 3 ... Hanging cable 4 ... Probe part 5 ... Depth switching mechanism 6 ... Tap 7 ... Tap group 8 ... Cable pack 9 ... Sensor part 10 ... Depth switching circuit 11 ... Depth detector 12 ... Control Circuit 13 ... Transmitter 14 ... Transmit antenna 15 ... Receiver 16 ... Receive antenna 17 ... Latch circuit 18 ... Oscillator control circuit 19 ... Timer 20 ... Oscillator 21 ... Waveform shaping oscillator 22 ... Wave shape shaping circuit 23 ... LPF 24 ... Counter 101 ... Transducer 102 Transceiver hanging cable 103 Fixed tap 104 Drum 105 Transceiver depth switching mechanism 106 Transducer depth switching circuit 107 Power supply 108 Antenna 109 Transmission / reception switching circuit 110 Temperature sensor 111: temperature sensor suspension cable 112: temperature information transmission circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-274482 (JP, A) JP-A-60-98374 (JP, A) JP-A-60-152965 (JP, A) 198844 (JP, A) JP-A-9-156584 (JP, A) JP-A-9-281220 (JP, A) JP-A-4-32086 (JP, U) JP-A 64-48686 (JP, U) Jpn. Sho 62-49722 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S ⁷ /52-7/64 G01S 15/00-15/96 B63B 22/00

Claims (5)

(57) [Claims] 1. An underwater depth multi-stage acoustic buoy in which a levitation part and an underwater part are connected by a suspension cable, a receiving means for receiving a depth switching control signal to the levitation part and a transmission means for transmitting an information signal to the outside. Having a control circuit for controlling signal transfer between the underwater part and the floating part, a sensor for measuring sound, a depth switching circuit for controlling a depth switching mechanism, and a switching operation of the depth switching mechanism. Based on the depth of each step
Depth detection means for generating a depth information signal based on signals having different frequencies set correspondingly, and using the depth switching control signal at each depth to generate depth information of each stage and sound during the depth switching. An underwater depth multi-stage acoustic measurement buoy, wherein depth detection is performed by transmitting the measurement signal in the same form via the levitation. 2. The timer according to claim 2, wherein the depth detection unit counts the predetermined time set by the control circuit so as to transmit the generated depth information signal at each stage only for a predetermined time within a depth switching time. A latch circuit for latching a depth switching signal supplied from the depth switching circuit, an oscillator control circuit controlled by the depth switching signal, and a predetermined frequency controlled by the control signal of the oscillator control circuit and the timer. 2. The oscillator according to claim 1, further comprising: an oscillator that outputs a frequency signal for the predetermined time, and a waveform shaping circuit that shapes a waveform of an output of the oscillator to generate a sine wave signal and outputs the signal to the control circuit. Underwater depth multi-stage acoustic measurement buoy. 3. A plurality of taps are provided at substantially equal intervals along a lower portion of the suspension cable between the suspension cable and the depth switching mechanism in the underwater portion, and an upper tap is provided. 2. The underwater depth multi-stage acoustic measurement buoy according to claim 1, wherein the suspension cable sinks down to the position of the next tap each time it is cut. 4. A counter for measuring the number of times a depth switching control signal is received is provided between the depth switching circuit and the depth switching mechanism, and an output of the counter is input to the depth detecting means, and a depth switching signal is output. The underwater depth multi-stage acoustic measurement buoy according to claim 1, wherein the depth detection is performed by transmitting a signal of the depth information according to the number of times of the depth measurement. 5. The underwater depth multi-stage sound according to claim 4 , further comprising transmitting the signal of the depth information in the same form as the sound measurement signal during the depth switching according to the number of times of the depth switching signal. Measurement buoy.