Method for transmitting and receiving data through the transmission of acoustic signals in a fluid within a conduit, system, and transceiver for implementing the said method

Abstract

A method and system for the transmission and reception of data transmitted through modulation on a carrier wave consisting of an acoustic wave within a liquid inside conduits, the method comprising: at least a first and at least a second transmission / reception unit positioned at two points separated by a section of a conduit filled with a fluid that serves as the propagation medium for the said acoustic wave; performing a setup cycle in which the actual transfer function of the acoustic waves is determined as a function of frequency within the said conduit segment; determining a frequency range for the said acoustic wave where the amplitude of the signal generated by the wave after traversing the said conduit section exceeds a certain minimum threshold value; setting an operating frequency for the acoustic wave, which is intermediate to the limits of the said frequency range and corresponds to the frequency at which the amplitude of the said acoustic wave reaches a maximum value; in one of the said units operating for data transmission, generating a carrier acoustic wave at the said operating frequency and amplitude-modulating the said acoustic wave with the data to be transmitted, and in the other of the said two units operating as a reception unit, demodulating the said wave to extract the transmitted data.

Description

[0001] Method for transmitting and receiving data through the transmission of acoustic signals in a fluid within a conduit , system, and transceiver for implementing the said method .

[0002] DESCRIPTION

[0003] The present invention relates to a system and a method for communication between transceiver units through acoustic waves in liquids , particularly in liquids contained within conduits .

[0004] In the prior art , a system is known for transmi tting / receiving information using acoustic waves through potable water contained in its distribution conduits . The system comprises acoustic reception / transmission units specifically designed for use in water distribution networks , these units including : an electroacoustic transmission transducer designed to be immersed in a fluid, converting an electrical signal into an acoustic signal ; an electroacoustic reception transducer that converts a received acoustic signal into an electrical signal ; a control unit configured to process the received and transmitted electrical signals ; a power supply source ; the control unit comprising a demodulation section for the electrical signal received from the electroacoustic reception transducer , the said section extracting from the received signal an information-encoding signal transmitted by modulating the acoustic frequency carrier ; the control unit comprising a modulation section for modulating an acoustic frequency carrier with an information-encoding signal .

[0005] Acoustic data transmission occurs by modulating the data onto an acoustic carrier , preferably using amplitude modulation , and by demodulating the said data from the said carrier .

[0006] The solutions known in the prior art , while demonstrating the feasibility of the system and method, have not yet achieved a level of refinement that makes them practically usable in current applications .

[0007] Document CN105871475 describes a method of hidden underwater acoustic communication resembling whale sounds , based on adaptive interference cancellation . Communication occurs between a transmitting unit and a receiving unit that are not connected by a conduit containing water or fluid but are instead immersed in an open volume of space containing the said fluid .

[0008] The method described in this document falls within the scope of traditional hidden underwater acoustic communication methods , which involve introducing communication signals into the underwater acoustic environment in the form of "noise" or acoustic effects that simulate acoustic signals emitted , for example , by animals such as dolphins or whales .

[0009] The aim is to generate a carrier on which communication data are modulated, with the said carrier simulating natural noise or acoustic effects , such that the said carrier is not easily recognized as a communication data transmission signal .

[0010] It does not consider data transmission through a fluid contained in a confined environment that has a single communication interface with a transmitting station and a receiving station , respectively, and is therefore unsuitable for producing the desired technical effects described herein .

[0011] The article titled "Development of an Underground Through-Soil Wireless Acoustic Communication System, " by Sijung Yang et al . , IEEE Wireless Communications , February 2020 , pages 154 to 161 , describes a method for communication through the transmission of acoustic waves through soil . In this case as well , there are no constrained or bounded propagation paths between the transmitting unit and the receiving unit , as these are essentially positioned in an open area . Consequently, acoustic signals can propagate in all directions and encounter fewer interferences from conduits that constrain propagation directions and generate reflection surfaces . This document , therefore , does not introduce any additional technical concepts compared to the previous prior art document and is also unsuitable for guiding a skilled person in the art toward achieving the technical advantages of the present invention .

[0012] The present invention aims to improve the systems and methods according to the prior art , particularly as described above , by enabling enhanced communication performance , including better signal reception quality, without requiring increased costs .

[0013] In combination with the above , the present invention also seeks to develop a transmission and / or reception unit that is more efficient in terms of energy consumption and the power of the transmitted and / or received signals .

[0014] Another object of the present invention is to provide a data transmission / reception system applicable in the field of monitoring the operating conditions of a water network or a section of a conduit .

[0015] The present invention achieves the aforementioned objects with a method for transmitting and receiving data transmitted by modulation on a carrier consisting of an acoustic wave within a liquid inside conduits , the method comprising :

[0016] At least a first and a second transmission / reception unit , positioned at two spaced points along a conduit filled with a fluid, in particular water , the two points defining a section of the conduit in which at least the fluid contained within serves as the propagation medium for the said acoustic wave ;

[0017] Performing a setting cycle , during which the effective transfer function of the acoustic waves is determined as a function of frequency for the section of the conduit between the two positioning points of the said first and second units ;

[0018] Determining a frequency range for the said acoustic wave , for which frequencies the amplitude of the signal generated by the said acoustic wave after passing through the fluid in the said section of the conduit has a value which is above a certain minimum threshold value ;

[0019] Setting a working frequency of the acoustic wave , which is intermediate to the limit values of the said frequency range and, optionally, corresponds to the frequency at which the amplitude of the said acoustic wave reaches a maximum value after passing through the fluid in the said section of the conduit ;

[0020] In one of the said units operating for data transmission , generating an acoustic carrier wave having the said working frequency and modulating the amplitude of the said acoustic wave with the data to be transmitted; In the other of the said two units operating as a receiving unit, demodulating the said wave to extract the transmitted data.

[0021] In the present description and in the claims , the terms conduit, pipeline, duct, or tube refer to an element comprising a wall with an annular cross-section closed upon itself, i.e. extending for 360° and which defines an opening, the said wall also having a predetermined length along the axis of the said opening.

[0022] Regarding the propagation of the acoustic wave, it should be specified that, in general, the acoustic wave propagates through the fluid, i.e. , the water in the pipe, the pipe itself, and the surrounding ground. Therefore, the definition of the propagation fluid of the acoustic wave should be interpreted as optionally including the pipe itself and the surrounding ground. However, it must also be considered that the portion of acoustic energy propagating through the fluid constitutes a significant, if not predominant, component over the portions of acoustic energy propagating through the pipe and the surrounding ground.

[0023] In combination or alternatively, the said method provides an additional setting phase, during which it is determined the presence of background noise in the said section of the conduit, and / or in combination, one or more of the parameters characterizing the said background noise from the following list: intensity, type, spectrum of the frequencies of the said noise, i.e. the spectral signature of the background noise, said background noise being detected by at least one of the said transmission / reception units in the absence of data transmission and / or of the acoustic carrier alone, and the said working frequency being further selected among the frequencies at which the intensity of the background noise is lower. According to a further alternative , which may be provided in combination with one or more of the preceding alternatives , the detection of background noise in the said section is performed over a period of several days , identifying the time slots in which the background noise is minimal and / or below a certain intensity or amplitude , and selecting one or more of the said time slots in which the background noise is minimal and / or below a certain intensity or amplitude for data transmission .

[0024] According to one characteristic, data transmission takes place during the time slots where the background noise is minimal for important data , while non-critical data are also transmitted during the time slots where the background noise exceeds the minimum intensity .

[0025] According to a preferred embodiment , the method provides for generating , as the acoustic carrier wave , a continuous wave (CW) on which the data to be transmitted are modulated using a modulation type referred to as OOK (On- Off-Keying) , the said data being converted i . e . encoded into a sequence of binary data .

[0026] In one embodiment , the said OOK modulation involves transmitting bits with a value of " 1" and a value of "0 , " the bit with a value of " 1" being transmitted as a sinusoidal wave of predetermined duration and frequency, while the bit with a value of "0" is constituted by a constant signal with an amplitude of "0" and a predetermined duration , optionally of the same duration as the bit with a value of " 1 . "

[0027] In combination , the demodulation of the received acoustic signal is performed by reconstructing the pulse train corresponding to the bits with a value of " 1 , " analyzing the said bit stream, and inserting , following the said analysis , the bits with a value of "0" for reconstructing the entire sequence .

[0028] According to an embodiment , which is provided in combination with any one or more of the preceding embodiments , the generation of the acoustic wave at the working frequency on which the binary sequence is modulated using OOK modulation comprises the steps of :

[0029] - Generating an electromagnetic or electrical signal corresponding to a carrier wave at the predetermined working frequency and modulating the data converted into a binary sequence onto the said carrier wave using the said OOK modulation ;

[0030] - Amplifying the said carrier wave modulated with the said binary sequence corresponding to the data to be transmitted and using the said signal as a drive signal for an electroacoustic transducer , also referred to as an acoustic projector , which generates the said acoustic wave , i . e . , a pressure wave modulated with the binary sequence corresponding to the data in the fluid contained in the said section of the conduit .

[0031] According to an embodiment , which is provided in combination with any one or more of the preceding embodiments , upon reception , the said pressure wave that has passed through the said section of the conduit is acquired by the said electroacoustic reception transducer , such as a hydrophone , and converted into an electromagnetic signal , which is subsequently conditioned and then converted into a digital signal and demodulated to extract the bit sequences corresponding to the transmitted data .

[0032] According to yet another embodiment , the determination of the working frequency range is performed using the first transmission unit to generate a pressure wave corresponding to a so-called CW wave , the frequency of the said CW wave being variable and being generated, for a sequence of predetermined time intervals , a CW wave with a different frequency for each interval of the said sequence , while the second unit acquires the CW waves for each time interval and measures the amplitude of the said CW wave for each time interval of the sequence , with a comparator provided to compare the amplitude of the received CW waves at each time interval and corresponding frequency with a minimum amplitude threshold value , the working frequency range being defined based on the limit frequencies for which the amplitude exceeds or is at least equal to the said threshold, and a working frequency value being further defined, corresponding to the frequency at which the received amplitude is maximum and / or near a maximum.

[0033] The invention also relates to a system for implementing the said method, the system comprising :

[0034] - At least a first and at least a second transmission / reception unit , each comprising at least one electroacoustic transmission transducer and at least one hydrophone , which are positioned at two points at a certain distance from each other along a section of the conduit for a fluid, the said conduit being filled with the said fluid, with the said electroacoustic transmission transducers and the said receiving hydrophones being in contact with the said fluid for transmitting pressure waves at acoustic frequencies and receiving pressure waves at the said acoustic frequencies .

[0035] Each of the said first and second transmission and reception units being provided with :

[0036] A control unit configured to generate a carrier wave with a predetermined acoustic frequency; - An input for data , commands , or information in the form of binary data sequences , or alternatively, an input for a signal converter related to data , information , or commands into binary data sequences ;

[0037] - A modulator for the said binary data onto the said carrier wave ;

[0038] - Optionally, an amplifier for the said modulated carrier wave to the power level required for driving an electroacoustic transmission transducer that transforms the said modulated carrier wave into a pressure wave in the fluid of the conduit section ;

[0039] - A reception unit for a pressure wave at the carrier wave frequency upon which are modulated binary sequences corresponding to the data , information , and / or commands , with an input for the output signal of a hydrophone in contact with the fluid of the said conduit ;

[0040] - A signal conditioning unit for the signal acquired by the reception unit , with an output connection to a demodulation unit for demodulating the binary signal sequences modulated on the carrier wave .

[0041] - Alternatively or in combination , one or more of the following units may also be included :

[0042] A memory unit ;

[0043] A displaying unit on a display;

[0044] A transmission unit to a remote unit for processing , storing , or displaying the said data .

[0045] According to the present invention , the unit of at least one of the said transmission / reception units comprises a setting subunit , the said setting subunit being configured to perform a procedure for measuring parameters characterizing the propagation conditions of the pressure wave in the fluid, the said subunit being further configured to define the transmission and / or reception conditions based on the said parameters characterizing the propagation conditions in the fluid, such as , in particular , one or more time periods for enabling / disabling transmission and / or for the transmission of only certain types of data and / or a predetermined frequency range of the carrier wave and / or a predetermined power or intensity of the carrier wave .

[0046] In one embodiment , the said setting subunit is configured to perform a procedure for measuring parameters characterizing acoustic noise , such as , for example , the intensity and the frequency band of the said noise , in the fluid in contact with the said hydrophone , the said intensity and / or frequency data being acquired over a predetermined period of at least one day or several days , and the temporal trend, particularly on an hourly basis within a day and / or across several days , being determined for the parameters characterizing the noise , while the setting unit sets a transmission / reception activation / deactivation timer , which activates and / or deactivates transmission and / or reception in synchronization with the said temporal trend of the said noise characterization parameters .

[0047] According to an additional feature , which may be provided in combination with or alternatively to the preceding , the setting subunits of the control units of at least two transmission and reception units are configured to measure parameters characterizing the transfer function of the pressure wave between one of the said two units operating in transmission and the other of the said two units operating in reception , the frequency of the acoustic carrier wave and / or the intensity being defined based on the said transfer function , and / or the received pressure wave being conditioned to extract the data modulated on it based on the said transfer function .

[0048] In one embodiment , when the setting subunit is configured to perform both the determination of the noise characterization parameters and the transfer function , the parameters of the acoustic carrier wave are defined based on both the noise and the transfer function , in particular selecting the frequency and intensity of the said carrier wave that optimize both the transfer function and the signal - to-noise ratio .

[0049] The setting subsections may be equipped with dedicated hardware or may alternatively be implemented as a program encoding instructions for performing the functions described above , the said program, when executed by the corresponding control unit , enabling the said control unit to perform the functions of the said setting subunit as described above .

[0050] According to an additional feature , the said transmission and reception units also comprise wired or wireless , i . e via radio , communication subunits , with remote monitoring units capable of performing one or more of the various activities listed below as non-limiting examples , such as functional and diagnostic monitoring of the transmission and reception units , further processing and storage of transmitted data , execution of maintenance and updating of the firmware of the control units and / or the setting subunits , and other activities .

[0051] According to another additional feature , it is possible to provide for the communication units of the control units of the said reception units to be placed in communication with each other directly and / or through the remote monitoring units , for example , to perform comparative measurements of noise data and / or transfer functions , alternately using one or the other of the transmission and reception units located at the ends of a section of the fluid conduit .

[0052] In the aforementioned case , the noise in the propagation fluid present in the conduit and the transfer function are measured using the hardware provided for the control units in combination with software encoding the instructions for performing the specific steps for detecting noise and its characterization , as well as for measuring and characterizing the transfer function . This avoids the need to use configurations of the said reception and transmission units specifically dedicated to performing noise detection and characterization in the conduit and / or to detecting the transfer function , which are provided as alternative devices to the reception and transmission units .

[0053] The invention includes additional features that are the subject of the dependent claims .

[0054] The aforementioned features and advantages of the present invention will become clearer from the following description of some exemplary embodiments illustrated in the attached drawings , in which :

[0055] Figure 1 shows a non-limiting example of a water distribution network where , at two spaced points connected by a conduit section , a first and a second transmission and reception unit are installed, indicated as Node " 1" and Node w 2n

[0056] - Figure 2 schematically shows the communication system comprising the conduit section and the two transmission and reception units from Figure 1 , along with additional elements of the said system.

[0057] - Figure 3 shows the interface component with the conduit and the fluid contained therein according to an embodiment of the transmission and reception units provided in the system of the present invention .

[0058] - Figure 4 shows the component from Figure 3 in an exploded view .

[0059] - Figures 5 and 6 show flowcharts for an exemplary embodiment of the transmission method and the reception method, respectively .

[0060] - Figure 7 shows a block diagram of an example of the electronic hardware of a transmission and reception unit .

[0061] - Figure 8 graphically represents the acoustic wave according to the On-Off-Keying modulation type used in the system according to the present invention .

[0062] - Figure 9 shows an example of a transfer curve measured in a conduit section between two transmission and reception units , such as for example provided in Figures 1 and 2 .

[0063] - Figures 10 and 11 respectively show the drive voltage of the electroacoustic actuator , the voltage detected by the hydrophone in the transmission and reception unit from which the transmission originates , defined as the local node , the voltage generated by the pressure wave at the hydrophone of the transmission and reception unit intended to receive the signal that has passed through the conduit section , and the corresponding demodulated signal , with reference to a carrier wave frequency of 40 Hz .

[0064] - Figures 12 and 13 are analogous to Figures 10 and 11 but refer to a carrier wave frequency of 70 Hz .

[0065] - Figures 14 and 15 are analogous to Figures 10 and 11 but refer to a carrier wave frequency of 120 Hz .

[0066] - Figure 16 shows a graph of the effective noise value (intensity) over a time span of several months .

[0067] - Figure 17 shows the spectrogram of noise at a specified date and with reference to various times . - Figure 18 shows the trend of the effective noise value for different time slots over 24 hours .

[0068] Figure 1 shows a territorial map featuring a water distribution network . At the ends of a segment 3 of a conduit in the distribution network , there are respectively provided a first node 1 and a second node 2 , at which are respectively provided a transmission unit and a reception unit for data by means of the propagation of acoustic waves in the fluid contained within the said conduit .

[0069] The illustrated example refers to a minimal configuration of the system, which may include a plurality of transmission and reception units distributed along the conduits of the water network , delimiting a succession of conduit segments and transmitting data sequentially from one to another of the transmission and reception units distributed along the conduit itself .

[0070] As shown in Figure 2 , considering only a single segment of the water conduit indicated as 3 , transmission takes place from a node 1 to a node 2 , at which a reception unit and a transmission unit are respectively provided, with the transmission between an upstream node not illustrated, located before node 1 , and a downstream node not illustrated , located after node 2 , each of which comprises a transmission and reception unit , being carried out in an identical manner to the transmission from node 1 to node 2 explicitly illustrated in the example .

[0071] The fluid is , in particular , water , as indicated by 4 . Furthermore , in addition to the hardware components of the transmission and reception units , which will be described in greater detail later and which operate for the modulation of data onto the acoustic carrier , the generation of the pressure wave in the fluid, the reception of the said wave , and the extraction of the data through its demodulation , each transmission and reception unit can be associated with a remote processing unit 5 , 6 with which it communicates , for example , via Wi-Fi communication protocols , the said units also communicating with each other and with other data processing units , for example , residing in the cloud 7 .

[0072] The transmission and reception units for data modulated on an acoustic carrier wave , which travels as a pressure wave from one node to another , comprise an interface section with the conduit and, in particular , with the fluid, and a control unit An example of these is shown with reference to Figures 3 , 4 , and 7 .

[0073] The interface component with the fluid, shown in Figures 3 and 4 , comprises a sleeve 11 for connection to the conduit , which has a threaded sealing coupling end 111 designed to engage with a threaded fitting not illustrated of the conduit , located at the ends of the segment 3 of the conduit .

[0074] The sleeve 11 has an intermediate section for coupling a hydrophone . The hydrophone 121 is supported by a housing 12 , which has a screw- threaded engagement with a radial threaded hole 113 provided in the intermediate section of the sleeve 11 . The hydrophone housing 12 includes an axial support protruding to a certain extent beyond the threaded section of the housing , the said extent being configured such that the hydrophone sensor is positioned within the passageway of the sleeve and is thus immersed in the fluid .

[0075] From the housing 12 , cables extend to carry the electrical signal generated by the hydrophone sensor , which are connected to the control unit for the functionalities described below .

[0076] An end section 112 of the sleeve 11 , opposite the threaded coupling 111 to the conduit 3 , has an internal thread for sealingly coupling with a support housing 14 for an actuator 15 of a membrane 13 . The said membrane and actuator form the electroacoustic transducer that converts the electromagnetic signal into a pressure wave in the fluid .

[0077] In the exemplary, non-limiting embodiment described here , a flexible , disc-shaped membrane is peripherally clamped between an internal radial shoulder of the section 112 of the sleeve 11 and an annular front edge of the threaded terminal 141 of the support housing 14 of the electromechanical actuator 15 .

[0078] The said annular front edge of the threaded terminal 141 of the support housing 14 delimits an axial cavity 144 , in the central region of which a coaxial hole 142 is provided . The coaxial hole 142 is provided for the passage of an axial pusher 153. In the assembled condition , the axial pusher 153 is mechanically connected via a joint 152 to the shaft 151 of the electromagnetic actuator 15 .

[0079] The electromagnetic actuator 15 may consist of an electromagnet , such as a coil wound coaxially around the shaft 151 , which induces an alternating axial motion of the shaft based on a power signal supplied to the said electromagnet through the command signal power line 154 .

[0080] In the assembled condition , as shown in Figure 2 , the pusher 153 acts on the membrane 13 , causing axial oscillations in both axial directions of the conduit 3 and the oscillations of the membrane in the fluid generate , in turn , the pressure wave in the fluid, which wave is a transposition of the electromagnetic carrier wave on which the binary signals encoding the data or information to be transmitted are modulated and which electromagnetic signals , suitably amplified to the required power level , constitute the power supply signals for the electromechanical transducer .

[0081] The alternating movement of the membrane can be driven in one direction by the pusher 153 and in the opposite direction by the intrinsic elasticity of the membrane and / or by a return elastic element , alternatively the membrane system 13 , pusher 153 , joint 152 , and shaft 151 of the electromechanical actuator 15 is a rigid mechanical system, i . e . all individual parts are mechanically connected to each other , with the pusher 153 mechanically connected to the membrane 13 by coupling terminals not illustrated in detail but well within the technical knowledge of a person skilled in the art .

[0082] With reference to the control unit component , it comprises a microprocessor 60 that executes software or firmware encoding the instructions to enable the said microprocessor to command the various units and subunits to perform the steps of the transmission and reception method according to one or more of the variants described below .

[0083] In the specific example , the data provided to the processor relate to physical parameters present in the fluid, such as the temperature of the fluid, which in this case is water (TH2O) , the hydrostatic pressure PI in the fluid, the power supply voltage of the transmission and reception unit VPS , and its current consumption IPS . These data are purely exemplary; some or all of them may be omitted or replaced by other measurement parameters supplied to the control unit for transmission to the other transmission and reception unit located at node 2 .

[0084] The signals from the sensors , indicated collectively as 62 , and / or from other unillustrated sources are provided to the microprocessor 60 through a multiplexer 61 .

[0085] To transmit data , the microcontroller 60 generates a so-called continuous wave (CW) signal , which is modulated with the data encoded as binary sequences using On-Off Keying (OOK) modulation . This type of modulation converts the binary data sequence to be transmitted into a waveform applied to the input of the audio amplifier 64 , wherein a bit at level ' 1 ' is transmitted as a sinusoidal wave with predetermined duration Tp and frequency fp , while a bit at level ' O ' is transmitted as a constant signal at level 0 with a duration equal to Ts , as shown in Figure 8 .

[0086] Optionally, as shown in Figure 7 , the modulated signal is further converted into an analog signal using a converter 63 before amplification to the power levels required to drive the electromechanical actuator 15 .

[0087] The control unit further includes a demodulator that converts the signal received by the hydrophone of the transmission and reception unit located at the other node 2 of the conduit segment 4 and which is intended to receive the acoustic pressure wave propagated through the fluid . The received signal detected by the hydrophone at node 2 corresponds to the transmitted signal , degraded by the presence of noise and distortion in the original sequence of Os and Is , and by the transfer function characteristic of the conduit segment 3 connecting the two nodes .

[0088] As shown in Figure 7 , the transmission and reception units have , downstream of the hydrophone 121 , a signal conditioning chain for the electromagnetic signal generated by the hydrophone 121 upon receiving the pressure wave .

[0089] In the illustrated example , the conditioning chain includes , by way of non-limiting example , an attenuator 69 , one or more filters 68 , an amplifier 67 , and an analog-to- digital converter that transforms analog signals into digital signals and provides them to the microprocessor 60 for demodulation and the extraction of the binary sequences encoding the transmitted data . In this case , and as a nonlimiting example , the data consist of the values measured by the sensors 62 .

[0090] Specifically, the conditioning chain is configured to reconstruct the pulse train corresponding to the transmitted bits at value ' 1 . ' The bit stream is then analyzed, inserting the bits at value ' O ' not detected by the demodulator to reconstruct the entire sequence .

[0091] As is evident , in the configuration of the transmission and reception units in the non-limiting example illustrated, the system allows interrogation of a node mounted on the conduit concerning conditions defined by predetermined physical / chemi cal parameters detected by one or more sensors and the transmission of said information to a subsequent node located at a certain distance at the opposite end of the common conduit segment , at the ends of which the said transmission and reception units are provided .

[0092] According to yet another feature , which may optionally also be provided separately, the microprocessor may be connected to a communication subunit 70 , which interfaces with a wireless transmission / reception unit , such as a modem operating on the cellular network , i . e . a GSM modem or similar , as indicated by 74 . Through this modem, the transmission and reception units can connect to a computer network in which one or more remote processors are provided to perform various operations , such as diagnostic monitoring operations , maintenance and / or software updates , and / or operations for collecting transmitted and / or received data and further processing the said data .

[0093] A power supply source , for example , a battery, is indicated as 71 . Using one or more DC-DC converters , indicated as 72 and 73 , the battery output voltage is converted to different voltages , in this case , output voltages of 5V, 3.3V, and 1 . 8V, intended for the various components of the control unit .

[0094] Figure 5 shows a flowchart for the data processing method for transmission . Step 50 initializes the control unit . Step 51 involves populating the data packet for transmission , i . e . , generating the binary sequences encoding the data to be transmitted . The modulator 52 modulates the said binary data sequences onto the carrier , as previously described, using OOK modulation . The signal is then transmitted bit by bit , and in step 53 , it is verified whether all the bits of the data packet have been sent , completing this transmission step only when all bits of the packet have been transmitted . If so , as shown in the flowchart in Figure 5 , it becomes possible to populate a packet with new data to be transmitted . In the case where not all the bits of a packet have been transmitted, the transmission of the next bit of the packet is carried out .

[0095] Transmission takes place by providing the modulated carrier wave as a command signal to the electromechanical transducer , optionally after conversion to analog format and amplification to the power level necessary to drive the said electroacoustic transducer .

[0096] Figure 6 shows a flowchart of the reception and reconstruction method for the signal received by the hydrophone of a remote transmission and reception unit , such as the one located at node 2 of the system described in this exemplary embodiment .

[0097] Step 80 involves initializing the peripherals controlled by the microprocessor 60 . The pressure wave generated in the fluid by the electroacoustic transducer of the transmission and reception unit , for example , at node 1 , is detected by the hydrophone or another microphone 121 of the transmission and reception unit at node 2 , i . e . , the opposite end of conduit segment 3.

[0098] The signal , after being subjected to a conditioning process , is demodulated, as indicated in step 82 .

[0099] In one embodiment , the conditioning and demodulation operation involves converting the signal acquired by the microphone , corresponding to the signal transmitted by the transmission and reception unit at node 1 , which signal has been degraded by noise and distortion , back into the original sequence of "0" and "1 . " To this end, the signal is conditioned using digital filters to reconstruct the pulse train corresponding to the transmitted bits at value ’ 1 . ’ The bit stream is then analyzed, inserting the bits at value ’ 0 ’ not detected by the demodulator to reconstruct the entire sequence .

[0100] The process is executed as shown in steps 83 and 84 for each bit of the received signal . If this condition is not met , the process repeats for additional bits ; otherwise , if all bits have been received, the data packet is populated as indicated in step 84 . Verification of whether all bits for a data packet have been received can be repeated again , as indicated in step 85 . If the condition is met , i . e . if all bits have been received, the entire data packet is considered complete and received, as indicated in step 86. Otherwise , steps 81 through 85 are repeated until the condition is satisfied, and the process continues to step 66.

[0101] As is clearly evident from the preceding description , the transmission and reception system and method provide for the definition of a specific frequency for the acoustic carrier wave and, additionally, for the received signal to be conditioned during reception , meaning it is processed in such a way as to compensate for its degradation during propagation through the fluid between node 1 of the transmitter and node 2 of the receiver , for example , using digital filters and an amplifier .

[0102] The operating frequency, i . e . , the carrier wave frequency, and the settings for the digital filters and signal amplifier during reception are determined based on prior and / or optionally repeated periodic measurements of the transfer function of the carrier wave between node 1 for transmission and node 2 for reception and / or noise parameters present in the fluid of the conduit segment which overlaps with the pressure wave at the said operating frequency and is further modulated with the binary signals encoding the data , information , or commands to be transmitted from one transmission and reception unit to another .

[0103] From the description of the construction of the transmission and reception units , it is evident that these units can be controlled via control software containing executable instructions for the microprocessor 60 to modify or set the carrier wave frequency to a selectable value within a predefined frequency range between a maximum and minimum value .

[0104] Additionally, since the said transmission and reception units can be connected to at least one remote control center , the system according to the present invention may include setup software for the transmission and reception units , allowing measurement of various characteristic and systematic parameters of the transmission fluids and / or the conduits containing the said fluids .

[0105] In particular , one embodiment of the system according to the present invention provides that the microprocessor 60 can load and execute setup software for selecting the carrier wave frequency and / or optionally its intensity or power .

[0106] In this case , the transmission and reception unit at one node and the unit at another node are used to measure the transfer function of the fluid for a pressure wave having a predetermined frequency, which can be selected within a predefined range .

[0107] The setup software executed by the microprocessor 60 includes instructions to generate and transmit , by of the transmission and reception units , in particular , successive pressure waves and / or a sequence of pressure waves . Each wave or sequence of pressure waves has a different frequency that is incremented relative to the previous wave so that the frequencies used for the said pressure waves or the said sequence of pressure waves cover , in steps of a predetermined frequency difference , the entire range of possible frequencies .

[0108] The transmission unit intended to receive the pressure waves , located at a remote node , such as node 2 in the specific illustrated example , receives the said pressure waves , converts them into electromagnetic signals , and records the intensity and frequency of the received wave .

[0109] This information can be processed in a cloud server for storage and for generating a characteristic curve of the conduit and fluid situated between the two nodes 1 and 2 and the associated transmission and reception units . The said characteristic curve represents the transfer function of the acoustic wave from the transmission and reception unit that generated it to the unit that received it . Based on the characteristics of the said transfer function , the method provides for defining at least one operating frequency for the carrier wave that minimizes intensity loss during propagation and where the transmission efficiency is relatively stable over a certain frequency range .

[0110] As shown in the example of Figure 9 , a transfer function has a central zone where the attenuation of the carrier wave intensity is substantially stable with respect to frequency . The control software thus includes instructions to analyze the transfer function and to identify frequency ranges where no substantial variations in the attenuation of the transmitted signal have been detected, defining the operating frequency as a selectable frequency within those frequency ranges .

[0111] In the example of Figure 9 , it is evident that conditions of substantial stability or constancy in the attenuation of the transmitted wave exist for carrier waves with frequencies between approximately 40 Hz and 120 Hz .

[0112] Regarding the performance of the transmission and reception units at different operating frequencies of the carrier wave , experiments were conducted setting the operating frequency respectively to the lower limit of the detected frequency range , i . e . , 40 Hz , to the upper limit , i . e . , 120 Hz , and to an intermediate value between the two , i . e . , 70 Hz .

[0113] Figures 10 , 12 , and 14 show graphs representing the temporal behavior of the signal corresponding to the drive voltage of the electroacoustic actuator and the voltage measured by the hydrophone mounted on the same transmission and reception unit to whose actuator the said drive voltage was applied and respectively for carrier wave frequencies of 40 Hz , 70 Hz , and 120 Hz . This measurement serves as a reference and comparison value for the results of the measurements taken with the transmission and reception unit located at the opposite end of the conduit segment 3 , connecting the two units .

[0114] The curves in Figures 11 , 13 , and 15 show, respectively, for carrier waves with frequencies of 40 Hz , 70 Hz , and 120 Hz , the voltage detected by the hydrophone of the remote transmission and reception unit relative to the unit that transmitted the said wave , i . e . , located at the opposite end of the conduit segment 3 , and the corresponding waveforms obtained after demodulation , i . e . , the waveforms of the demodulated signal .

[0115] Thanks to the recorded data , it is possible to select the best carrier wave frequency or a range of optimal frequencies for the carrier wave for transmission along the conduit segment 3 connecting the two transmission and reception units .

[0116] In one embodiment , the software executed by the microprocessor may include instructions for the automatic determination of the frequency based on the numerical data of the measured curves . Alternatively, this selection can be made manually by an operator .

[0117] As is evident from the examples of graphs described above , the waveforms of the received and decoded signal exhibit differences compared to the original square waveform of the transmitted carrier .

[0118] The information regarding this variation in the waveform of the received and demodulated signal can be used to manually or automatically configure filters and / or signal amplifiers to compensate for the said waveform variations .

[0119] According to yet another feature , which may be provided either separately or in combination with the previous feature regarding the definition and use of the transfer function for configuration , the system and method according to the present invention further provide for the transmission and reception units , or at least one of them, to be configured to detect the background noise present in the fluid within the conduit .

[0120] In this case , the setup software , loadable and executable by the microprocessor 60 , allows detection , in the absence of pressure wave transmissions from other nodes i . e . of other transmission and reception units connected to the same conduit filled with the fluid, of the background noise simply by acquiring , through the hydrophone 121 , the acoustic signals present in the conduit .

[0121] The control software for the transmission and reception units may further include instructions to inhibit pressure wave transmission and to acquire reception signals from the hydrophone over a predetermined period of time .

[0122] The measured parameters can include , for example , the intensity of the received signals over the acquisition time within a predetermined time interval and / or the acquisition of the spectrogram of the background noise , also in relation to time within the said predetermined time interval or a part thereof .

[0123] Thanks to these measurements , it is possible to determine , either automatically or manually by an operator , both the frequency band of the background noise and the trend of the background noise intensity over a predetermined time period, such as 24 hours in a day and / or over the days of the week .

[0124] By comparing the background noise frequencies at which the noise consistently exhibits relatively high intensity that significantly interferes with the acoustic wave at the operating frequency selected solely based on the transfer function , the system allows the said operating frequency to be adjusted, considering optimization with respect to both the transfer function and with respect to the background noise . This operation can be performed automatically by including corresponding instructions in the control software , or it can also be carried out manually by the user .

[0125] Additionally, the temporal trend of the background noise allows for defining transmission time windows , which can be used to transmit data of low importance , for instance when the noise is more intense , while more critical data can be transmitted during periods when the noise has lower intensity .

[0126] Figure 18 shows the temporal trend of the noise with reference to different time slots throughout the day .

[0127] In this case , for example , the system may include a programmable clock , which is controlled by the control software to set the time instants for activating and / or deactivating the transmission and / or reception capability of the transmission and reception units and / or to send activation and / or deactivation notifications to remote terminals of users and / or control personnel .

[0128] Regarding manual configuration actions by service personnel or users , such as setting the operating frequency and / or configuring filters and / or setting activation and deactivation times for transmission and / or reception , the system may provide for the microprocessor 60 to be equipped with a bidirectional communication section , for example , of a wireless type operating according to at least one wireless transmission and reception protocol , which bidirectional transmission section allows for the transfer of setting data and / or transmission and / or reception signals to a remote unit of the user or service personnel , which remote unit includes a human-machine interface for viewing the said data and inputting configuration commands to be transmitted to the said transmission and reception units .

[0129] As is evident from the preceding description , the hardware configuration of the system, i . e . , of the transmission and reception units , allows for the functionalities of the said units to be configured in any desired manner to meet operational requirements simply by generating software containing instructions for the said microprocessor , enabling it to execute the said functions and / or control its peripherals for performing the said functions .

Claims

CLAIMS1 . Method for transmitting and receiving data transmitted by modulation on a carrier consisting of an acoustic wave and within a liquid inside conduits or pipes , the method comprising :- at least a first and a second reception / transmission unit positioned at two points spaced apart in a conduit filled with a fluid, particularly water , the two points defining a section of the conduit in which the fluid contained therein serves as a propagation medium for the said acoustic wave ;- performing a setting cycle in which the effective transfer function of the acoustic waves is determined as a function of frequency, for the section of the conduit between the two positioning points of the said first and second units ;- determining a frequency range for the said acoustic wave for which frequencies the amplitude of the signal generated by the said acoustic wave after passing through the fluid in the said section of the conduit has a value exceeding a certain minimum threshold value ;- setting a working frequency of the acoustic wave that is intermediate to the limit values of the said frequency range and optionally corresponds to the frequency at which the amplitude of the said acoustic wave reaches a maximum value after passing through the fluid in the said section of the conduit ;- in one of the said units operating as a data transmitter , generating an acoustic carrier wave with the said working frequency and modulating the said acoustic wave in amplitude with the data to be transmi tted ;in the other of the said two units operating as a receiving unit , demodulating the said wave to extract the said data .2 . Method according to claim 1 , characterized by including a further setting phase in which it is determined the presence of background noise in the said section of the conduit and / or one or more of the parameters characterizing the said background noise , included in the following list : intensity, type , frequency or frequency band, spectrum of the frequencies of the said background noise , also referred to as spectral signature , the said background noise being detected by at least one of the said transmission / reception units in the absence of data transmission and / or the acoustic carrier alone , and the said working frequency being further selected among the frequencies at which the intensity of the background noise is lower .3 . Method according to claims 1 or 2 , wherein the detection of background noise in the said section is performed over a time period of several days , identifying the time slots in which the background noise is minimal and / or below a certain intensity or amplitude , and selecting one or more of said time slots in which the background noise is minimal and / or below a certain intensity or amplitude for data transmission .4 . Method according to one or more of the preceding claims , wherein the said method includes generating as the acoustic carrier wave a so-called CW-type wave on which the data to be transmitted are modulated using a modulation type referred to as OOK (On-Off-Keying) , the said data being converted, i . e . , encoded, into a sequence of binary data .5 . Method according to claim 4 , wherein the said OOKmodulation involves transmitting bits with a value of " 1" and a value of "0" , the bit with a value of " 1" being transmitted as a sinusoidal wave of predetermined duration and predetermined frequency, while the bit with a value of "0" consists of a constant signal with an amplitude of "0" and a predetermined duration , preferably of the same duration as the bit with a value of " 1" .6 . Method according to claim 4 or 5 , wherein the demodulation of the received acoustic signal is carried out by reconstructing the pulse train corresponding to the bits with a value of " 1" , analyzing the said bit flow, and inserting , as a result of the said analysis , the bits with a value of "0" to reconstruct the entire sequence .7 . Method according to one or more of the preceding claims , wherein the generation of the acoustic wave at the working frequency on which the binary sequence is modulated using OOK modulation includes the steps of : generating an electromagnetic or electrical signal corresponding to a carrier wave at the predetermined working frequency and modulating the data converted into a binary sequence onto the said carrier wave using the said OOK modulation , amplifying the said carrier wave modulated with the said binary sequence corresponding to the data to be transmitted and using the said signal as a driving signal for an electroacoustic transducer , also referred to as an acoustic projector , which generates the said acoustic wave , i . e . , a pressure wave modulated with the binary sequence corresponding to the data in the fluid contained in the said section of the conduit .8 . Method according to one or more of the preceding claims , wherein upon reception the said pressure wave that has passed through the said section of the conduit is acquired using a hydrophone and converted into an electromagneticsignal , which in turn is conditioned and subsequently converted into a digital signal and demodulated for extracting the bit sequences corresponding to the transmitted data .9 . Method according to one or more of the preceding claims , wherein the determination of the working frequency range is performed using the first transmission unit to generate a pressure wave corresponding to a so-called CW wave , the frequency of the said CW wave being variable and being generated for a sequence of predetermined time intervals a CW wave having a different frequency for each time interval of the said sequence , while the second unit acquires the CW waves for each time interval and measures the amplitude of the said CW wave for each time interval of the sequence of the said time intervals , a comparator being provided to compare the amplitude of the CW waves received for each time interval and at the corresponding frequency with a minimum amplitude threshold value , being the working frequency range defined based on the limit frequencies for which the amplitude is above or at least equal to the said threshold value , and being further defined a working frequency value corresponding to the working frequency at which the amplitude in reception is maximum and / or close to a maximum.10 . System for implementing the said method, the system comprising : at least a first and a second transmission / reception unit , each comprising at least one electroacoustic transmission transducer and at least one hydrophone , which units are positioned at two points spaced apart along a section of conduit for a fluid, the said conduit being filled with the said fluid, with the said electroacoustic transmission transducers and the saidreception hydrophones being in contact with the said fluid for transmitting pressure waves at acoustic frequencies and for receiving pressure waves at the said acoustic frequencies ; each of the said first and second transmission / reception units being provided with :- a control unit configured to generate a carrier wave with a predetermined acoustic frequency;- an input for data , commands , or information in the form of binary data sequences , or alternatively an input for a signal converter relating to data , information , or commands into binary data sequences ;- a modulator for the said binary data onto the said carrier wave ;- optionally, an amplifier for the said modulated carrier wave to the power input of the driving signal of an electroacoustic transmission transducer , which transforms the said modulated carrier wave into a pressure wave in the fluid of the conduit section ;- a reception unit for a pressure wave at the carrier wave frequency, modulated with the binary sequences corresponding to the data , information , and / or commands , with an input for the output signal of a hydrophone in contact with the fluid of the said conduit ;- a signal conditioning unit for the signal acquired by the reception unit , with an output connection to a demodulation unit for demodulating the binary signal sequences modulated on the carrier wave ;- alternatively or in combination , one or more of the following units : a memory unit ; a display unit for visual representation ;a transmission unit for a remote unit capable of processing , storing , and visualizing the said data .11 . System according to claim 10 , wherein at least one of the said transmission / reception units comprises a setting subunit , the said setting subunit being configured to execute a procedure for measuring parameters that characterize the propagation conditions of the pressure wave in the fluid, the said subunit being further configured to define the transmission and / or reception conditions based on the said parameters characterizing the propagation conditions of the pressure wave in the fluid, such as in particular one or more temporal periods for enabling / disabling transmission and / or for transmitting only certain types of data , and / or a predetermined frequency range of the carrier wave and / or a predetermined power or intensity of the carrier wave .12 . System according to claim 11 , wherein the said setting subunit is configured to execute a procedure for measuring acoustic noise parameters , such as the intensity and the frequency of the said noise in the fluid in contact with the said hydrophone , the said intensity and / or frequency data being acquired over a predetermined time period of at least one day or several days , and the temporal trend, particularly on an hourly basis during a day and / or over multiple days for periods longer than one day, being determined for noise characterization parameters , while the setting unit sets a transmission / reception activation / deactivation timer , which activates and / or deactivates transmission and / or reception in synchronization with the said temporal trend of the said noise characterization parameters .

13. System according to one or more of claims 10 to 12 ,wherein the setting subunits of the control units of at least two transmission and reception units are configured to measure the parameters that characterize the transfer function of the pressure wave between one of the said two units operating in transmission and the other of the said two units operating in reception , the frequency of the acoustic carrier wave and / or the intensity being defined based on the said transfer function , and / or the received pressure wave being conditioned to extract the data modulated on it based on the said transfer function .14 . System according to one or more of claims 10 to 13 , wherein the setting subunit is configured to execute both the determination of the noise characterization parameters and the transfer function , the parameters of the acoustic carrier wave being defined based on both the noise and the transfer function , selecting the frequency and intensity of the said carrier wave that optimizes both the transfer function and the signal-to-noise ratio , the said setting subsections being optionally provided with dedicated hardware or being in the form of a program encoding instructions for performing the functions described above which program, when executed by the corresponding control unit , enables the said control unit to perform the functions of the said setting subunit as described above .15 . System according to one or more of claims 10 to 14 , wherein the said transmission and reception units also include wired or wireless , i . e . radio-based, communication subunits , with remote monitoring units that can perform one or more of the various activities listed below as non-limiting examples , such as functional and diagnostic monitoring of the reception and transmission units , further processing and storage of the transmitteddata , execution of maintenance and updating of the firmware of the control units and / or the setting subunits , and other activities .

16. System according to one or more of claims 10 to 15 , wherein the communication units of the control units of the said transmission and reception units can be placed in communication with each other directly and / or through the remote monitoring units , to perform comparative measurements of noise data and / or transfer functions , alternately using one or the other of the reception and transmission units located at the ends of a section of fluid conduit , the noise in the propagation fluid present in the conduit and / or the transfer function being measured using the hardware provided for the control units in combination with software that encodes the instructions to execute the specific steps for noise detection and its characterization and for the measurement and characterization of the transfer function , thus avoiding the need to use configurations of the said reception and transmission units that are specific for performing the detection and characterization of noise in the conduit and / or for detecting the transfer function and are provided as alternative devices to the reception and transmission units .

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