[0089] Figures 1 and 2 show schematic diagrams of the underwater acoustic communication and alarm method and device configuration principles of the present invention. The underwater acoustic communication and alarm devices A and B using the same communication and alarm system and using water as the transmission medium must be configured for the water system vehicle and the surface command ship or the dock control station. The underwater acoustic emission system A2 of the device A is sent via the carrier frequency The modulated voice or telegram or dual-frequency alarm coded signal is converted into an underwater acoustic carrier frequency signal through the underwater acoustic system A4 as electro-acoustic energy, and transmitted through the water medium, reaching the underwater acoustic system B4 of the device B and performing acoustic-electrical The energy is converted into a carrier frequency electrical signal and sent to the underwater acoustic receiving system B3, which demodulates the received modulated voice or telegram or dual-frequency alarm signal, and restores it to an audio voice or an orderly interval alarm tone or alarm tone. Aural or visual instructions are given through the terminal to complete the transmission of device A information to device B.
[0090] Similarly, device B transmits, device A receives, and completes the transmission of device B information to device A, thereby realizing time asynchronous two-way communication, communicating between underwater vehicles and the water surface where the underwater vehicle and the transducer are under the waterline Telephone, telegraph communication or alarm between navigation bodies or terminal control stations.
[0091] When an underwater vehicle encounters an accident or a shipwreck, the underwater acoustic emission system A2 and the underwater acoustic system A4 of the underwater acoustic communication and alarm device A will send out underwater acoustic alarm signals. At this time, the relevant underwater navigation in the same monitored water area The underwater acoustic system B4 and the underwater acoustic receiving system B3 of the underwater acoustic communication and alarm device B of the body or surface vehicle or the dock console station can receive the alarm signal of the underwater crashed vehicle. The alarm signal is for the implementation of search and rescue. Provide effective hydroacoustic positioning information.
[0092] Figure 3 shows a schematic block diagram of the composition of the device using the underwater acoustic communication and alarm method of the present invention. The underwater acoustic communication and alarm device at least includes a console 1, an underwater acoustic emission system 2, an underwater acoustic receiving system 3, and an underwater acoustic System 4, terminal box 5, recording system 6 and power supply 7.
[0093] The technical solutions and embodiments are described in further detail below in conjunction with Figs. 4-11.
[0094] 4 and 5 are schematic diagrams of the console panel and the terminal box panel of the embodiment of the underwater acoustic communication and alarm device of the present invention.
[0095] The console 1 is provided with a power K1 switch 11, a working mode K2 switch 12, a power selection K3 switch 13, a working state K4 switch 14, an indication group 15, and an alarm A1 button 16. The working mode K2 can be set to three modes of "talk", "report" and "alarm". This embodiment adopts two methods of "talk" and "alarm". The power selector switch K3 sets two gears of "full" power and "small" power. The working state switch K4 sets two states of "work" and "self-check".
[0096] The alarm button A1 is a self-locking button. In the working mode K2, it is set to the "alarm" gear. Press the self-locking alarm button A1 to keep "alarm" and start to emit water sound alarm signals continuously at fixed intervals. Press the alarm button A1 again, Unlock to cancel the "alarm".
[0097] The terminal box 5 is provided with a recording K5 switch 56, a volume adjustment K6 switch 53, a speaker 51, a handheld microphone 54, a microphone jack 55, an earphone 59 and an earphone jack 52. The recording switch K5 is set with three gears of "record", "play" and "off", and the handheld microphone 54 has a speaking button 57.
[0098] Fig. 6 is a functional block diagram of the underwater acoustic emission system of an embodiment of the underwater acoustic communication and alarm device of the present invention. The hydroacoustic emission system 2 includes a communication signal source 21, an alarm signal source 22, a band-pass filter 23, a single-sideband demodulation circuit 24, a power amplifier input signal voltage divider 25, a transmission power-up controller 26, a linear power amplifier 27, and Power matching circuit 28.
[0099] The working mode switch K2 can be set to "talk", "announcement", and "alarm". In this embodiment, the working mode switch K2 sets two working modes of "talk" and "alarm". The communication signal source 21 of the hydroacoustic emission system 2 selects a telephone. Signal source; the output ends of the telephone signal source 21 and the alarm signal source 22 are connected to the operating mode K2 of the console 1, and the input end of the band-pass filter 23 is connected to the common end of the operating mode K2 switch 12, and the operating mode switch K2 is set to "Speak" or "Alarm" block, select the call signal source or alarm signal source to connect to the input end of the band-pass filter 23 of the hydroacoustic emission system 2; the output end of the hydroacoustic emission system 2 is connected to the working state K4 of the console 1 The switch 14 is controlled, and the working state switch K4 is placed in the "working" gear and the "self-checking" gear, and the output end of the power matching circuit 28 of the underwater acoustic emission system 2 is selected to be connected to the transducer or the dummy load of the underwater acoustic system 4, At the same time, the self-check sampling signal or transducer signal on the dummy load is controlled to be sent to the input end of the hydroacoustic receiving system 3; the transmission power of the hydroacoustic emission system 2 is controlled by the power selection K4 switch 14 of the console 1, and the hydroacoustic emission The two output terminals of “large” and “small” of the power amplifier input signal voltage divider 25 of system 2 are respectively connected to the “full” power stage or “small” power stage contact of the power selector switch K3, which are set by the power selector switch K3 The "full" power gear or "small" power gear controls the large or small input signal of the linear power amplifier 27 of the hydroacoustic emission system 2 to control its output "full" power or "small" power.
[0100] The control contact of the microphone jack 55 of the terminal box and the control contact of the console alarm A1 button 16 are respectively connected to the OR gate input terminal of the transmitter power-up controller 26 of the hydroacoustic emission system 2 and the power-up controller 26 The output terminal is connected to the power terminal of the linear power amplifier 27, and the output terminal of the linear power amplifier 27 is connected to the input terminal of the power matching circuit 28.
[0101] When the working mode switch K2 is placed in the "talk" position, press the microphone button 57, the voice signal passes through the voice amplifier, the working mode switch K2 "talk" contact and the bandpass filter 23, and the single sideband modulation circuit 24 is connected. , Through the single sideband modulator 241 and f 0 The carrier frequency local oscillator modulation and the single sideband modulation output filtered by the single sideband filter 242 are controlled by the transmit signal voltage divider 25 and the power selection switch K3, and the single sideband modulation telephone signal is added to the signal end of the linear power amplifier 27, While pressing the microphone button 57, one contact of the button 57 is connected to the +5V power supply, and the other contact is connected to the calling control line F1, and +5V is added to the input of the transmitter power-on controller 26, one of the two OR gates Terminal, the transmitter power-on controller 26 controls the voltage V F It is applied to the linear power amplifier 27, which is amplified by the linear power amplifier 27 and matched by the power matching circuit 28 to transmit the underwater acoustic single-sideband modulation telephone signal to the underwater acoustic system load. When the microphone button is released, the transmission of underwater single-sideband modulation telephone signals is immediately stopped.
[0102] Alarm working mode and communication working mode are public water acoustic emission system 2 except for the signal source. When the working mode switch K2 is set to "alarm", press the alarm button A1, the contact of the "alarm" button is closed, and the alarm signal passes The working mode switch K2 turns on the band-pass filter 23 and the single-sideband modulation circuit 24, and the single-sideband modulator 241 is connected to f 0 The carrier frequency local oscillator modulation and the single sideband modulation output filtered by the single sideband filter 242 are controlled by the transmit signal voltage divider 25 and the power selection switch K3, and the single sideband modulation alarm signal is added to the signal terminal of the linear power amplifier 27, While pressing the alarm button A1, one contact of the alarm button A1 is connected to the +5V power supply, and the other contact is connected to the alarm control line F2, and +5V is added to the input of the transmitter power-on controller 26, one of the two OR gates Terminal, the transmitter power-on controller 26 controls the high-voltage V F It is applied to the linear power amplifier 27, which is amplified by the linear power amplifier 27 and matched with the power matching circuit 28 to transmit the underwater acoustic single-sideband modulation alarm signal to the underwater acoustic system load. When the alarm button A1 is pressed again, it immediately stops transmitting the underwater acoustic single-sideband modulation alarm signal.
[0103]Power selection K3 switch 13, set the "full" power and "small" power two gears, the common end of the power selection switch K3 is connected to the signal input end of the linear power amplifier 27, and the "full" power gear contact is connected to the signal voltage divider large signal output The “small” power switch contact is connected to the small signal output terminal of the signal voltage divider; by selecting and controlling the input signal amplitude of the hydroacoustic emission system 2 linear power amplifier 27, the “full” power or “small” power transmission can be controlled. When placed in the "full" power range, the linear power amplifier amplification is the optimal power, when placed in the "small" power range, the linear power amplifier amplification is 1/10 of the optimal power, which is conducive to saving power consumption. Can greatly extend the working time, in the case of "alarm", can win valuable time for search and rescue work, in the "self-check" state, put in the "small" power gear, 1/10 power has met the self-check requirements .
[0104] Single sideband modulator 241, single sideband filter 242 and f 0 The carrier frequency local oscillator 243 constitutes the single-sideband modulation circuit 24, and the voice or alarm coded audio output by the band-pass filter 23 and f 0 F of the carrier frequency local oscillator 243 output 0 The carrier frequency is input to the signal input terminal and the carrier frequency input terminal of the single-sideband modulator 241. After being modulated by the single-sideband modulator 241, the upper and lower sideband carrier frequency signals that carry the same modulation information are output. The filter 242 filters, and its passband is f 0 +300Hz~f 0 +3kHz, the lower sideband modulation frequency signal is filtered out, the single sideband modulation circuit 24 outputs the upper sideband modulation carrier frequency signal, and the bandwidth of the modulation carrier frequency signal sent to the linear power amplifier 27 is compressed by half, saving transmission power consumption and improving transmission efficiency .
[0105] Fig. 7 shows the principle block diagram of the underwater acoustic receiving system and the recording system of the embodiment of the underwater acoustic communication and alarm device of the present invention. The working process of the underwater acoustic receiving system 3 is described in detail with reference to FIGS. 4, 5, and 7. The underwater acoustic receiving system 3 is composed of a preamplifier 31, an AGC automatic gain control amplifier 32, a single sideband demodulation circuit 33, a bandpass filter 34, an audio amplifier 35, and a listening audio power amplifier 36. The input end of the underwater sound receiving system 3 is connected to the underwater sound system 4 via the operating state switch K4 of the console 1.
[0106] The two working modes of telephone and alarm share a set of underwater sound receiving system. When working mode K2 is set to "talk", it can receive the telephone or alarm signal transmitted from underwater and through the underwater sound system 4, and deal with it accordingly. . The output of the single-sideband demodulation circuit 33 is sequentially connected to the bandpass filter 34 and the audio amplifier 35, the input of the listening audio power amplifier 36 is connected through the volume adjustment of the terminal box 5, and the output audio signal is connected to the speaker and earphone of the terminal box 5. After filtering by the single sideband filter 331, the passband is f 0 +300Hz~f 0 The +3kHz single-sideband carrier frequency signal is sent to the signal input terminal of the single-sideband modulator 332 and the carrier frequency local oscillator 333 sends f 0 The carrier frequency is demodulated by the unilateral demodulation circuit 33 and filtered by the band-pass filter 34 to output a signal carrying audio information, amplified by the audio amplifier 35 and adjusted by the volume adjustment switch K6 of the terminal box 5, and then listened to the audio amplifier 36 Amplify, send to the speaker earphone of terminal box 5 or listen.
[0107] The signal + terminals of the speaker 51 and the earphone 59 are respectively connected to the normally closed contact and the normally open contact of the earphone jack 52, the signal-terminal is connected in parallel, and the common terminal and the signal-terminal of the earphone jack 52 are respectively connected to the underwater sound receiving system 3 The output + terminal and-terminal of the listening audio power amplifier 36 are used for listening with the speaker 51 when the earphone is not plugged in. When the earphone 59 plug 60 is inserted into the earphone jack 52, the speaker is disconnected and the earphone 59 is used for listening.
[0108] The working process of the recording system 6 is described in detail with reference to Figs. 4, 5, 7, and 8. The recording K5 switch 56 of the terminal box 5 has three gears of "record", "play" and "off"; the recording signal input line 67 of the watertight cable 63 is connected to the underwater sound receiving system 3 through the recording divider 62 to listen to the audio power amplifier 36 At the output end, the contact of the recording switch K5 "recording" block is connected to the +5V power supply, and the common contact is connected to the power supply end of the recorder 61 through the power line 69 of the watertight cable 63; a set of contacts of the recording switch K5 "playing" block is connected with The “recording” block contact is connected to the +5V power supply, and the other set of contacts connects the recording playback output 63 of the recorder 61 to the input of the audio amplifier 35 of the underwater sound receiving system 3 through the recording signal outlet 68 of the watertight cable 63, The playback recording signal is adjusted by the volume K6, listening to the audio power amplifier 36, and listening through the speaker 51 or earphone 59; when the recording switch K5 is set to "off", the +5V power supply is disconnected, and the recorder 61 stops recording.
[0109] The recording system 6 shares the audio amplification and listening channel circuit of the underwater sound receiving system 3. After the device is turned on, when the recording switch K5 is switched from "off" to "recording", the power supply of the control recorder is turned on, the recording system is turned on, and the recording system is switched on. The audio signal output by the listening audio amplifier 36 of the underwater sound receiving system 3 is recorded synchronously with the time; when it is placed in the "play" gear, the power supply of the recorder is controlled and the audio recording signal of the recorder is transmitted from the recording playback output terminal 63 through the recording switch K5 The "play" block contact sends the water sound receiving system 3 to amplify the listening circuit and play it back through the speaker 51 or earphone 59; when the recording switch K5 is placed in the "off" block, the power supply of the recorder is disconnected and the recording system is closed.
[0110] Fig. 8 shows a structural schematic diagram of an embodiment of a recorder with a watertight and pressure-resistant shell of the underwater acoustic communication and alarm device of the present invention. The external structure of the watertight and pressure-resistant housing 65 of the recorder 61 can be rectangular, square, or circular in addition to the oval shape in this embodiment. The watertight pressure box shell 65 and the watertight pipe connection 64 are made of steel, and the tape recorder is reinforced with pressure-resistant hard foam plastic to withstand pressure and compression to prevent shock.
[0111] Fig. 9 is a functional block diagram of the underwater acoustic system of an embodiment of the underwater acoustic communication and alarm device of the present invention. Fig. 9 is used in conjunction with Figs. 4-7 to describe the working process of the underwater acoustic system.
[0112] The underwater sound system 4 includes a transducer 41, a working state converter 42, a dummy load 44, and a self-check sampling circuit 45; the main task of the underwater sound system 4 is to realize the conversion of sound-electricity and electro-acoustic energy. The transducer 41 is an important part of the sound-energy conversion of the device. It usually adopts a transceiving dual-purpose omnidirectional underwater acoustic transducer or two separate transceiving underwater acoustic transducers. The miniaturized device preferably adopts a transceiving dual-purpose omnidirectional cylindrical transducer. The transducer 41 is installed on the bridge or bow of the underwater vehicle, and the transducer 41 is installed on the lifting equipment on the surface command ship or dock console station. The transducer is placed in the diversion fluid, which is in the water. The working depth is at least 1 to 3 meters; the sound-electric and electro-acoustic energy conversion of the dual-purpose omnidirectional cylindrical transducer 41 is the working state converter 42 and the working state switch K4 controlled by the working state switch K4 of the console 1 The automatic transceiving adapter 43 is implemented. The transmitting load adapter 421 and the receiving signal adapter 422 of the working state converter 42 are relay contact groups, and the working state switch K4 of the console 1 controls the conversion of the “self-check” and “work” gears; The connection circuit 43 is a group of diode switch circuits, which are automatically switched by the strength of the signal added to the switch diode group;
[0113] When the working state switch K4 of the console 1 is set to the "working" gear, the transmitting load adapter 421 of the working state converter 42 relay turns on the transmitting signal end of the automatic transmitting and receiving switch circuit 43. The energy device 41, if the console 1 has the control of speaking or alarming, the power transmission carrier frequency signal output by the hydroacoustic emission system 2 is added to the transceiver automatic switching circuit 43, so that the switch diode group is turned on, so the hydroacoustic emission system 2 The output power transmission carrier frequency signal is directly connected to the underwater acoustic transducer 41 through the normally closed contact of the transmission load adapter 421. The underwater acoustic transducer 41 converts the power transmission carrier frequency signal electro-acoustic into an acoustic signal through the water medium. The spherical wave is radiated out, and while the switch diode group of the automatic transmitting and receiving circuit 43 is turned on, the input terminal of the underwater acoustic receiving system 3 is short-circuited and shielded.
[0114] If the console 1 does not have a call or alarm control, the output of the hydroacoustic emission system 2 also has no power to transmit the carrier frequency signal to the automatic transceiver circuit 43, so that the switch diode group is cut off, and the output of the hydroacoustic emission system 2 is disconnected from the water. The connection of the acoustic transducer 41, the underwater acoustic transducer 41 is connected to the input terminal of the underwater acoustic receiving system 3 through the normally closed contact of the transmitting load adapter 421, through the receiving and sending automatic switching circuit 43 and the receiving signal adapter 422, For example, the hydroacoustic transducer 41 receives the hydroacoustic telephone or alarm carrier frequency signal, and converts the carrier frequency signal acousto-electrical into an electrical signal, and then transmits the normally closed contact of the load adapter 421, the transceiver automatic switching circuit 43 and The receiving signal adapter 422 is sent to the input terminal of the underwater acoustic receiving system 3 for processing.
[0115] When the operating state switch K4 of the console 1 is placed in the "self-check" gear, the common contact of the transmitting load adapter 421 of the operating state converter 42 is controlled to switch to make the normally open contact closed, and the dummy load 44 is connected. At the same time, the control The common contact of the receiving signal adapter 422 of the working state converter 42 is switched to close the normally open contact, and the input terminal of the underwater acoustic receiving system 3 is switched to the self-check sampling circuit 45. If the handheld microphone button is pressed to speak or the alarm button, the hydroacoustic emission system 2 outputs a carrier frequency transmission signal according to the relevant working mode, and the power carrier frequency transmission signal turns on the switch diode group of the automatic transmission and reception circuit 43, which is added to the dummy load 44 and On the self-check sampling circuit 45, the self-check sampling circuit 45 obtains the corresponding self-check sampling signal and adds it to the input terminal of the underwater acoustic receiving system 3, so that the received signal of the corresponding working mode is simulated and sent to the underwater acoustic receiving system 3 for processing. The processing functions of the transmitting system and the receiving system of the working mode are fully self-checked.
[0116] Figure 10 shows a block diagram of the principle of automatic power conversion and charging control of the underwater acoustic communication and alarm device of the present invention. The power automatic control converter 73 uses a DC relay J1, and the voltmeter, ammeter and indicator light constitute the indicator group of the console 1 15. The device load 102 includes the electrical loads of each system of the device. The AC rectifier power supply 71 has multiple sets of DC outputs after rectification. The principle block diagram of the embodiment shows one channel of 24V, and the other channels have the same DC output. The AC 220V is connected to the input terminal of the AC rectifier power supply 71 of the power supply 7 from the power grid distribution switch K through the parallel voltmeter and series ammeter, and the output terminal of the AC rectification power supply 71 is connected to the K of the power supply K1 switch 11 1-1 , K 2-2 And power supply automatic control converter 73 relay J1 wire package, relay J1 normally open contact Z 1-1 Connect the K of the power switch K1 1-0 , Relay J1 normally closed contact Z 1-2 Connect the K of the power switch K1 2-1 ,Relay J1 common contact Z 1-0 Connect the device load 102; the DC+ terminal of the standby DC power supply 72 is connected to the common terminal K of the power switch K1 2-0 , Power supply automatic control converter 73 relay J1 normally closed contact Z 1-2 Connect the K of the power switch K1 2-1.
[0117] When the power distribution switch K~ is turned on, the switch 11 of the power supply K1 is set to the "on" position, a set of DC output of the AC rectifier power supply 71 is added to the wire package of the relay J1, and the wire package is energized to make the normally open contact Z 1-1 Closed, the power supply 71 outputs 24V DC through the K of the power switch K1 1-1 With K 1-0 And normally open contact Z 1-1 Supply power to the device load; when the power switch K1 is set to "off", the K of the power switch K1 1-0 Disconnect with K 1-1 Connection, because K 1-0 Disconnect from the AC rectifier power supply 71, although the wire package of the relay J1 is still energized and the Z 1-1 Closed, the device load 102 passes Z 1-0 And Z 1-1 Connect K 1-0 , Because K 1-0 The connection with the AC rectifier power supply 71 has been disconnected, and the power supply to the device load is turned off.
[0118] When the power switch K1 is set to "on", but when the AC stops power distribution or loses power, the output of the AC rectifier power supply 71 is 0, and the wire package of the relay J1 loses power and makes the normally closed contact Z 1-2 Closed, the standby DC power supply 72 outputs 24V DC through the K of the power switch K1 2-0 And K 2-1And normally closed contact Z 1-2 The device load 102 is supplied with power, and the power supply is automatically converted from the AC rectifier power supply 71 to the standby DC power supply 72 to supply power to the device load, which can meet the requirements of the device for receiving and low-power transmission within a certain period of time.
[0119] In the case of maintaining 220V AC power distribution and closing the power distribution switch 101, when the power switch K1 is set to "off", the output of the AC rectifier power supply 71 causes the relay J1 line to be energized and the normally open contact Z 1-1 Closed, Z of the power supply automatic control converter 73 1-1 By K 1-0 Connect K 1-2 The open circuit cuts off the AC rectifier power supply 71 to supply power to the device load. At the same time, the normally closed contact Z 1-2 Turn on, also cut off the standby DC power supply 72 to supply power to the device load; at this time, the switch K1 is at "off", 2-0 And K 2-2 Connected, the AC rectifier power supply 71 outputs K through the power switch K1 1-1 And the K shorted to it 2-2 And K 2-0 The DC+ terminal of the backup DC power supply 72 is automatically turned on, and the AC rectifier power supply 71 charges the backup DC power supply 72.
[0120] When the device is not working, the AC rectifier power supply 71 can automatically charge the backup DC power supply 72, but after turning off the power distribution switch K~, the AC rectifier power supply 71 stops charging the backup DC power supply 72.
[0121] Fig. 11 is a block diagram of the communication signal source and alarm signal source of the embodiment of the underwater acoustic communication and alarm device of the present invention, and Fig. 12 is a schematic diagram of the waveform formation of the alarm signal encoding of the underwater acoustic communication and alarm device of the present invention, showing the alarm signal code The forming process and its waveforms, in conjunction with Figs. 4-7 and Figs. 11 and 12, describe the working process of the communication signal source 21 and the formation process of the alarm signal code.
[0122] Close the power switch K1 of the underwater acoustic communication and alarm device, set the working mode K2 to "talk", insert the plug 58 of the microphone 54 on the terminal box into the microphone jack 55, press and hold the speaking button 57 of the handheld microphone 54 to talk, and the voice signal After the voice amplifier of the communication signal source 21 and the "talk" contact of the working mode switch K2, the 300Hz~3000Hz voice is sent to the bandpass filter 23 and filtered, and the voice is added to the modulator 241 to f 0 Carrier frequency 243 is modulated, and the modulator output is filtered by a single sideband filter 242 to obtain the upper sideband signal f 0 +300Hz~f0+3000Hz, through the signal voltage divider 25 and the power selector switch K3 low power gear, send the linear power amplifier 27, press and hold the hand-held microphone button 57 when talking, the 5V voice control F 1 The linear power amplifier 27 amplifies the automatic transmission and reception switching circuit and the power matching network, and adds them to the omni-directional transducer, and the electric energy is converted into a modulated acoustic signal that is radiated into the water by acoustic energy. The transducer of the device is an omnidirectional transducer with a combined transceiver. At the same time, close the power switch of another communication and alarm device, and set the working mode to "talk". The transducer receives the modulated acoustic signal from the water medium, and then the transducer is converted into sound and electricity, sending and receiving automatically. The switching circuit is switched, the contact of the "talk" working mode switch is added to the preamplifier, automatic gain control amplifier circuit, upper sideband filter to filter, and then through the demodulator, filter 300Hz~3000Hz, the voice signal is restored , After listening to power amplifier amplification and voltage divider equalization, added to the speakers and earphones for the operator to listen. The same voice signal is attenuated by the voltage divider and sent to the recorder for recording.
[0123] The alarm signal source 22 includes an alarm signal encoder 221 with an encoding selector switch 222, two fixed audio oscillators and modulators, and an output OR gate 223. The alarm signal encoder 221 outputs two alarm encoder signals and two The audio oscillator output is added to the signal end and the local oscillator end of the modulator, and the two modulator outputs are sent to the two input ends of the OR gate. The output of the OR gate is two audio modulated alarm signals in an orderly manner according to the coding interval.
[0124] When the working mode is set to "Alarm" mode, the alarm signal source can automatically generate a variety of alarm signal codes. The alarm signal source generates an alarm signal according to the set number. The alarm button A1 is a self-locking button. Press the alarm button for the first time and continue to alarm. Press the alarm button to stop the alarm. When the alarm button is pressed, the dual-frequency alternate coded pulse signal passes through the telephone transmission channel, and the transducer radiates the modulated alarm sound signal into the water. When the working mode of A device is set to "telephone" mode, the alarm signal can be heard through its transducer and the above-mentioned telephone receiving channel. At the same time, the alarm signal is attenuated by the voltage divider and sent to the recorder for recording.
