System and method for detecting the position of an autonomous device

Abstract

The present description relates to a device (40) comprising: - a first electro-acoustic transducer (44) comprising N electro-acoustic elements (E1, E2, EN), each electro-acoustic element being configured to emit and receive first ultrasonic waves; - a first terminal (B1), a second terminal (B2), and a third terminal (B3); - for each electro-acoustic element, a phase shift circuit (D1, D2, DN) connected to the electro-acoustic element and configured to apply a phase shift to a first analogue signal (S) received from the first terminal (B1) for controlling the electro-acoustic element; - for each electro-acoustic element, a switch (SW1, SW2, SWN) connecting the first terminal (B1) either to the electro-acoustic element or to the phase shift circuit connected to the electro-acoustic element; and - a multiplexer (51) configured to connect the first terminal (B1) to the second terminal (B2) in a first operating mode or to the third terminal (B3) in a second operating mode.

Description

B23499 PCT – UTET1 DESCRIPTION TITLE: System and method for detecting the position of an autonomous device. This patent application claims priority from French patent application FR24 / 07124, which will be considered an integral part of this description. Technical field

[0001] This description generally relates to a system and method for detecting the position of a self-contained device, in particular an implantable medical device. Prior art

[0002] An implantable medical device may include an actuator or sensor powered by an energy storage element. It is desirable to be able to recharge the energy storage element remotely, i.e., without an electrical connection to the autonomous device. It may also be desirable to be able to remotely transmit data to the implantable medical device and / or receive data transmitted by the implantable medical device.

[0003] The exact position of the implantable medical device within the user's body is generally not known precisely. Therefore, it may be necessary to implement a method for detecting the position of the implantable medical device before the charging and / or data transfer operation.

[0004] Furthermore, it is desirable that the operation of detecting the position of the implantable medical device and the operation of charging and / or transferring data can be implemented simply by a user and without requiring excessive immobilization of the user. B23499 PCT – UTET1 Summary of the invention

[0005] An embodiment overcomes all or part of the disadvantages of known systems and methods for tracking the position of an autonomous device, in particular an implantable medical device.

[0006] One embodiment provides a device comprising: - a first electro-acoustic transducer comprising N electro-acoustic elements, N being an integer greater than or equal to 3, each electro-acoustic element being configured to emit and receive first ultrasonic waves; - a first terminal, a second terminal, and a third terminal; - for each electro-acoustic element, a phase-shifting circuit connected to the electro-acoustic element and configured to apply a phase shift to a first analog signal received from the first terminal for the control of the electro-acoustic element; - for each electro-acoustic element, a switch connecting the first terminal either to the electro-acoustic element or to the phase-shifting circuit connected to the electro-acoustic element; and - a multiplexer configured to connect the first terminal to the second terminal in a first operating mode or to the third terminal in a second operating mode..

[0007] According to one embodiment, the device further comprises: - a first electronic circuit configured to receive a second analog signal at the second terminal in the first operating mode; and - a second electronic circuit configured to provide the B23499 PCT – UTET1 first analog signal to the third terminal in the second operating mode.

[0008] According to one embodiment, the device further comprises a third electronic circuit configured, in the first operating mode, to successively close each switch, the other switches being open, and, in the second operating mode, to keep all the switches open.

[0009] According to one embodiment, the device further includes a fourth electronic circuit configured to provide control signals, not all identical, simultaneously to all the phase-shifting circuits.

[0010] According to one embodiment, the first electroacoustic transducer comprises, in addition to the N electroacoustic elements, further: - at least three additional electroacoustic elements; - a first additional terminal, and a second additional terminal; - for each additional electroacoustic element, a phase-shifting circuit connected to the additional electroacoustic element and configured to apply a phase shift to a first analog signal received from the first additional terminal for controlling the additional electroacoustic element; - for each additional electroacoustic element, a switch connecting the first additional terminal either to the additional electroacoustic element or to the phase-shifting circuit connected to the additional electroacoustic element; and - an additional multiplexer configured to connect the first additional terminal to the second terminal. B23499 PCT – UTET1 additional in the first operating mode or at the third terminal in the second operating mode.

[0011] According to one embodiment, the device further includes a first additional electronic circuit configured to receive a second additional analog signal at the second additional terminal in the first operating mode.

[0012] One embodiment also provides for a system comprising the device as defined above and a self-contained device, the self-contained device comprising a second electro-acoustic transducer and an electrical energy storage element, the second electro-acoustic transducer being configured to convert the first ultrasonic waves into a third analog signal for recharging the electrical energy storage element.

[0013] According to one embodiment, the second electro-acoustic transducer is configured to emit periodic bursts of second ultrasonic waves.

[0014] According to one embodiment, the autonomous device is an implantable medical device comprising a sensor and / or an actuator powered by the electrical energy storage element.

[0015] One embodiment also provides a method for operating the system as defined above, comprising, in the first mode of operation, the supply of bursts of third ultrasonic waves by the second electro-acoustic transducer, the supply by each electro-acoustic element of a fourth analog signal comprising a packet of oscillations upon reception of each burst of third ultrasonic waves, and the storage of the second analog signal obtained by closing B23499 PCT – UTET1 successively each of a part or all of the switches, the other switches being open, the determination from the second analog signal of the electro-acoustic element, called the reference electro-acoustic element, among the N electro-acoustic elements providing the maximum intensity oscillation packets and the determination, for each electro-acoustic element other than the reference electro-acoustic element, of a shift between the oscillation packet provided by said electro-acoustic element upon reception of one of the bursts of third ultrasonic waves and the oscillation packet of the reference electro-acoustic element upon reception of said burst of third ultrasonic waves.

[0016] According to one embodiment, the method comprises determining, for each electro-acoustic element, a delay to be applied by the phase-shifting circuit connected to said electro-acoustic element from the offset associated with the electro-acoustic element and the maximum offset among the N electro-acoustic elements, and, in the second mode of operation, supplying the first analog signal to the first terminal and applying the delay by the phase-shifting circuit to said second signal to control said electro-acoustic element.

[0017] According to one embodiment, the bursts of third ultrasonic waves are emitted periodically.

[0018] According to one embodiment, the second analog signal is obtained by successively closing each of a part of the switches, the other switches being open, and the offsets for the electro-acoustic elements associated with switches that have not been closed to obtain the second analog signal are determined by interpolation. B23499 PCT – UTET1

[0019] According to one embodiment, the second additional analog signal and the second additional analog signal are provided at least partially simultaneously. Brief description of the drawings

[0020] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the attached figures, among which:

[0021] Figure 1 represents, in a partial and schematic way, an embodiment of a charging system for an implantable medical device and of data exchange with the implantable medical device comprising a mobile charging device and a charging station;

[0022] Figure 2 represents an electrical diagram of one embodiment of the implantable medical device of the system of Figure 1;

[0023] Figure 3 and Figure 4 are respectively a partial and schematic perspective view and top view of an embodiment of the mobile charging device of the system of Figure 1;

[0024] Figure 5 represents an electrical diagram of one embodiment of the mobile charging device of the system of Figure 1;

[0025] Figure 6 is a block diagram illustrating one embodiment of an operating method for the mobile charging device of Figure 5;

[0026] Figure 7 illustrates a step in the implementation of the operating process of the mobile charging device according to the block diagram in Figure 6;

[0027] Figure 8 shows timing diagrams of a signal used by the implantable medical device and of signals B23499 PCT – UTET1 measured by the mobile charging device at one stage of the embodiment of the operating method of the mobile charging device according to the block diagram in Figure 6;

[0028] Figure 9 illustrates another step in the implementation of the operating process of the mobile charging device according to the block diagram in Figure 6;

[0029] Figure 10 represents timing diagrams of signals used by the mobile charging device at one stage of the embodiment of the mobile charging device's operating process, according to the block diagram in Figure 6; and

[0030] Figure 11 shows an electrical diagram of another embodiment of the mobile charging device of the system in Figure 1. Description of embodiments

[0031] The same elements have been designated by the same reference numerals in the different figures. In particular, structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0032] For the sake of clarity, only the steps and elements useful for understanding the implementation methods described have been represented and are detailed.

[0033] Unless otherwise specified, when referring to two connected elements, this means directly connected without any intermediate elements other than conductors, and when referring to two coupled elements, this means that these two elements can be connected or linked through one or more other elements. B23499 PCT – UTET1

[0034] In the description that follows, when referring to absolute positional qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative positional qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientational qualifiers, such as the terms "horizontal", "vertical", etc., unless otherwise specified, it refers to the orientation of the figures.

[0035] Unless otherwise specified, the expressions "approximately", "roughly", "about", and "on the order of" mean to within 10% or 10°, preferably to within 5% or 5°.

[0036] An embodiment of a remote charging system for an energy storage element of a self-contained device and / or a data exchange system with the self-contained device will now be described in an application where the self-contained device is an implantable medical device, also referred to hereafter as an implant. However, the charging and / or data exchange system can be used for charging the energy storage element of any type of self-contained device and / or for exchanging data with any type of self-contained device, for example, a sensor that is not directly accessible and is placed in a medium that allows the propagation of ultrasonic waves.

[0037] Figure 1 shows, in a partial and schematic manner, one embodiment of a charging system 10 for an implant 20. The implant 20 is located in the body of a person 11 at a location that depends on the functions performed by the implant 20. The charging system 10 comprises a mobile charging device 40 and a fixed charging station 70. The charging station 70 includes an electrical socket 67 for connection to a power supply, not shown, for example the B23499 PCT – UTET1 electrical network, and a connection terminal 68 intended to be connected to a data exchange network, not shown, for example the Internet. In operation, the charging station 70 is not intended to be moved and is, for example, placed on a piece of furniture 12.

[0038] The mobile charging unit 40 is used to remotely power the implant 20. During a charging operation of the implant 20 by the mobile charging unit 40, the mobile charging unit 40 can be held in position on the person 11 by a strap 13. Thus, it is not necessary for the person 11 to remain still during a charging operation of the implant 20 by the mobile charging unit 40. The charging station 70 is used to remotely power the mobile charging unit 40. During a charging operation of the mobile charging unit 40 by the charging station 70, the mobile charging unit 40 can be placed on the charging station 70 without establishing an electrical connection between the mobile charging unit 40 and the charging station 70.According to one embodiment, the mobile charging device 40 is further used to acquire data emitted by the implant 20 or to transmit data to the implant 20. The data exchanged depends in particular on the function performed by the implant 20.

[0039] As an alternative, charging station 70 is not shown. The mobile charging device 40 can then be recharged by being connected to an external power source, not shown, such as the mains electricity supply.

[0040] Figure 2 shows an electrical diagram of one embodiment of the implant 20 of the system 10 of Figure 1. The implant 20 comprises: - an electrical energy storage element 21, for example B23499 PCT – UTET1 an electrical accumulator battery and / or a supercapacitor; - an electro-acoustic transducer 22 configured for the emission and reception of ultrasonic waves; - an energy conversion circuit 23 configured to transmit the energy supplied by the electro-acoustic transducer 22 to the electrical energy storage element 21; - a sensor and / or an actuator 24 powered by the electrical energy storage element 21; - a circuit 26 for supplying an analog control signal C to the electro-acoustic transducer 22 for an operation of detecting the position of the implant 20, described in more detail later;- an amplification and demodulation circuit 27 configured to receive an analog signal Rx supplied by the electro-acoustic transducer 22 and to provide a digital signal Data_Rx obtained by demodulating the analog signal Rx, the amplification and demodulation circuit 27 being further configured to emit a wake-up signal W; - a modulation circuit 28 receiving a digital signal Data_Tx to be transmitted and providing a modulation signal MOD;- an oscillating circuit 29 providing, to the electro-acoustic transducer 22, an analog control signal Tx corresponding to a periodic oscillating signal at a center frequency fixed by a set signal and whose amplitude, frequency and / or phase can be modulated by the MOD signal - a processing circuit 25 configured to provide the Data_Tx signal and the set signal and to receive the Data_Rx signal and the wake-up signal W, the processing circuit 25 being further connected to the sensor / actuator 24 and being powered by; B23499 PCT – UTET1 the electrical energy storage element 21; and - a selection circuit 30, controlled by the processing circuit 25, and configured to selectively connect the electro-acoustic transducer 22 to the energy conversion circuit 23 and the amplification and demodulation circuit 27, to the analog signal supply circuit 26 C, or to the oscillating circuit 29.

[0041] The power conversion circuit 23, the analog signal supply circuit 26 C, the amplification and demodulation circuit 27, the oscillator circuit 29, and the selection circuit 30 can correspond to one or more application-specific integrated circuits (or ASICs).

[0042] The electro-acoustic transducer 22 may comprise a single ultrasonic wave generation / reception element, also referred to hereafter as the electro-acoustic element, two ultrasonic acoustic wave generation / reception elements, or more than two ultrasonic acoustic wave generation / reception elements. In the embodiment illustrated in Figure 2, the electro-acoustic transducer 22 comprises a single ultrasonic acoustic wave generation / reception element, the first electrode of which is connected to a source with a low reference potential, for example, the ground of the implant 20, and the second electrode of which is connected, preferably, to the selection circuit 30.Each ultrasonic acoustic wave generation / reception element can be connected to a dedicated channel of one of the circuits among the energy conversion circuit 23, the analog signal supply circuit 26, the amplification and demodulation circuit 27, and the oscillating circuit 29. According to one embodiment, the electro-acoustic transducer 22 comprises a single wave generation / reception element. B23499 PCT – UTET1 ultrasonic acoustics also designated by reference 22 hereafter.

[0043] By default, the processing circuit 25 is in the sleep phase with respect to the electro-acoustic transducer 22. In the sleep phase, the selection circuit 30 connects the electro-acoustic transducer 22 to the amplification and demodulation circuit 27 and to the energy conversion circuit 23. When the electro-acoustic transducer 22 receives ultrasonic waves while the processing circuit 25 is in the sleep phase, the amplification and demodulation circuit 27 detects the reception of the ultrasonic waves and provides the wake-up signal W to the processing circuit 25. The processing circuit 25 then exits the sleep phase and can perform a data exchange operation as described in more detail later.

[0044] Figure 3 and Figure 4 are respectively a partial and schematic perspective view and top view of an embodiment of the mobile charging device 40 of system 10 of Figure 1.

[0045] The mobile charging device 40 comprises a housing 41, for example cylindrical, in particular cylindrical with a circular base, having two opposite end faces 42 and 43. In one embodiment, the faces 42 and 43 are substantially flat and disc-shaped. Alternatively, the housing 41 may have a prismatic shape, for example with a square or rectangular base. In one embodiment, the height of the housing 41, i.e., the distance between the faces 42 and 43, is between 10 mm and 40 mm. In one embodiment, the maximum lateral dimension of the housing 41, measured parallel to the faces 42 and 43, is between 20 mm and 50 mm. The mobile charging device 40 comprises an electro- transducer B23499 PCT – UTET1 acoustic 44 configured to emit and receive ultrasonic waves, which may be partially exposed on face 42.

[0046] Figure 5 shows an electrical diagram of an embodiment of the mobile charging device 40 of the system 10 of Figure 1. The mobile charging device 40 comprises: - a battery of electrical accumulators 46 - the electro-acoustic transducer 44; - a control circuit 48 connected to the electro-acoustic transducer 44 and powered by the battery 46.

[0047] The control circuit 48 can correspond to one or more application-specific integrated circuits (or ASICs).

[0048] According to one embodiment, the electro-acoustic transducer 44 comprises N electro-acoustic elements E i, where N is an integer ranging from 3 to 100, and i is an integer ranging from 1 to N. According to one embodiment, each electro-acoustic element E i has a first electrode connected, preferably connected, to a source with a low reference potential, for example the ground of the mobile charging device 40. As an example, in Figure 3, the electro-acoustic transducer 44 is shown with five electro-acoustic elements E1 to E5 and, in Figure 4, the electro-acoustic transducer 44 is shown with forty-one electro-acoustic elements E1 to E 41 For example, in Figures 3 and 4, the electro-acoustic element E1 has the shape of a disc and the other electro-acoustic elements E i, i varying from 2 to N, each have the shape of an annular sector and are arranged in a ring in Figure 3 and three concentric rings in Figure 4 surrounding the central electro-acoustic element E1. However, the arrangement of the electro-acoustic elements E i may differ from the one illustrated, the electro-acoustic elements E i which could, for example, be B23499 PCT – UTET1 arranged in rows and columns or, for example, randomly distributed. According to one embodiment, each electro-acoustic element E i the electro-acoustic transducer 44 can be controlled independently by the control circuit 48.

[0049] Each electro-acoustic element 22, E1 to E N is adapted to convert an electrical signal (current, voltage, electric charge) into ultrasonic waves. Each electro-acoustic element 22, E1 to E NFor example, it consists of a plate of single-crystal or polycrystalline piezoelectric material, such as PZT (Lead-Zirconia Titanate), whose thickness varies when a voltage is applied between two faces of the plate. Each electro-acoustic element 22, E1 to E NFor example, a microelectromechanical system (MEMS) is a microelectromechanical system that uses microelectronic production technologies. This microelectromechanical system may consist of a deformable membrane suspended above a cavity. The deformable membrane is driven by a capacitive effect using an electrode attached to the membrane and another electrode separated by the cavity. This type of transducer is known as a CMUT (Capacitive Micromachined Ultrasonic Transducer). Alternatively, the deformable membrane may be driven by a piezoelectric effect using a layer of piezoelectric material with two electrodes attached to the membrane. This type of transducer is known as a PMUT (Piezoelectric Micromachined Ultrasonic Transducer). Each electroacoustic element 22, E1 to E Nis, for example, a magnetostrictive transducer made of a material that changes slightly in size when exposed to a magnetic field. Depending on the type of electro-acoustic element 22, E1 to E N , the control signal of the electro-acoustic element 22, E1 to E N may correspond to a voltage, a current, or B23499 PCT – UTET1 an electrical charge. Conversely, each electro-acoustic element 22, E1 to E N is adapted to convert an ultrasonic wave into an electrical signal (current, voltage, electrical charges).

[0050] According to one embodiment, the frequency of the ultrasonic waves emitted by each electro-acoustic element 22, E1 to E N is between 20 kHz and 100 GHz.

[0051] According to one embodiment, each electro-acoustic element 22, E1 to E NThe device is controlled to emit a continuous ultrasonic wave, meaning one lasting longer than a few milliseconds, or to emit one or more bursts of ultrasonic waves. The duration of each burst / continuous wave can range from 1 ns to 100 ms. Within each burst, the wavelength of the ultrasonic waves can be approximately constant or variable.

[0052] According to one embodiment, each electro-acoustic element 22, E1 to E Nis adapted to provide ultrasonic waves in different frequency bands. In one embodiment, the frequencies of the ultrasonic waves in a first burst of ultrasonic waves can be in a first frequency band, and the frequencies of the ultrasonic waves in a second burst of ultrasonic waves can be in a second frequency band different from the first frequency band. In one embodiment, each electro-acoustic element 22, E1 to E N is adapted to simultaneously provide in the same burst ultrasonic waves in a first frequency band and in a second frequency band different from the first frequency band.

[0053] According to one embodiment, a burst of ultrasonic waves can be composed of multiple frequencies that evolve continuously or discontinuously, regularly or B23499 PCT – UTET1 irregular during the time of an excitation burst. According to one embodiment, a burst of ultrasonic waves corresponding to a pseudo-periodic signal modulated in frequency around a carrier frequency and also modulated in amplitude by an envelope whose variations are slow compared to the oscillations of the phase, such a signal being also called Chirp.

[0054] According to one embodiment, the control signal of each electro-acoustic element 22, E1 to E N corresponds to a periodic waveform, for example a sinusoidal signal, an oscillating signal of increasing or decreasing frequency, a multi-frequency signal, etc.

[0055] According to one embodiment, the control circuit 48 comprises: - a circuit 62 for supplying an analog signal S for controlling the electro-acoustic elements E1 to E Nof the electro-acoustic transducer 44; - a multiplexer 51 with three terminals B1, B2, and B3, controlled by a MUX control signal, the multiplexer 51 being configured to connect terminal B1 to terminal B3 or to connect terminal B1 to terminal B2 depending on the MUX control signal, the circuit 62 being configured to supply the control signal S to terminal B3; - a circuit 52 for supplying the MUX control signal to the multiplexer 51; - for each electro-acoustic element E i , i varying from 1 to N, a delay circuit D i connected a second electrode of the electro-acoustic element E i , the delay circuit D i being configured to receive as input the control signal S supplied at terminal B1 and a delay signal PH i and to provide the electro-acoustic element E i a control signal S' i corresponding to the control signal S delayed by a delay Δφ i which depends on the PH delay signali received ; B23499 PCT – UTET1 - for each electro-acoustic element E i , i varying from 1 to N, a switch SW i connecting terminal B1 directly to the second electrode of the electro-acoustic element E i This allows the transmission of an individual MS measurement signal to terminal B1. i supplied by the electro-acoustic element E i , or connecting terminal B1 to a terminal of the delay circuit D i - a control circuit 54 for each SW switch i - a delay control circuit 56 providing the PH delay signal i at each delay circuit D i - a detection circuit 57 receiving a global measurement signal GMS from terminal B2 and configured to determine a reference signal REF among the individual measurement signals MS i provided by the electro-acoustic elements E i- a circuit 58 for determining a shift map connected to the shift detection circuit 57; and - a time inversion circuit 59 connected to the circuit 58 and adapted to transmit COM_PH control signals to the circuit 56; - an amplification and demodulation circuit 60 connected to terminal B2 and configured to receive an analog GMS signal and to provide a digital Data_Rx' signal obtained by demodulating the analog GMS signal; - a modulation circuit 61 receiving a digital Data_Tx' signal to be transmitted and providing a MOD' modulation signal; - an oscillating circuit 62 providing, at terminal B3, an analog control signal S corresponding to a periodic oscillating signal at a center frequency fixed by a set' signal and whose amplitude, frequency and / or phase can be modulated by the MOD' signal; - a processing circuit 63 configured to provide the Data_Tx' signal and the set' signal and to receive the Data_Rx' signal. B23499 PCT – UTET1

[0056] It is desirable that the ultrasonic waves emitted by the mobile charging device 40 be focused towards the implant 20 so that the maximum energy supplied by the mobile charging device 40 is received by the implant 20 and not lost. However, the exact position of the implant 20 in the person's body 11 is generally not known precisely.

[0057] According to one embodiment, the mobile charging device 40 implements a method for detecting the position of the implant 20 before carrying out a charging and / or data transfer operation so that the ultrasonic waves emitted by the mobile charging device 40 during this charging and / or data transfer operation are focused towards the implant 20.

[0058] This advantageously reduces the energy of the ultrasonic waves emitted by the mobile charging device 40 while ensuring that these ultrasonic waves are received by the implant 20. This reduces the power consumption of the mobile charging device 40 and therefore the capacity, and thus the size, of the battery 46. Furthermore, data exchange is carried out using a single amplification and demodulation circuit 60, a single modulation circuit 61, a single oscillator circuit 62, and a single processing circuit 63 for all electroacoustic elements E1 to E N The electronics of the Mobile Charging Device 40 can therefore be designed simply, with a reduced number of electronic components. The Mobile Charging Device 40 can thus be advantageously compact.

[0059] Figure 6 is a block diagram illustrating one embodiment of an operating method for the control circuit 48 of the mobile charging device 40 of the figure B23499 PCT – UTET1 5. In one embodiment, the control circuit 48 operates as a finite state machine. In Figure 6, each state of the finite state machine is represented by an ellipse. The possible transitions from one state to another (or from one state to the same state) are represented by arrows. In one embodiment, the finite state machine comprises five states called S1, S2, S3, S4, and S5. At the beginning of the process, the starting state is S1, which is illustrated in Figure 6 by the arrow INIT.

[0060] State S1 corresponds to a resting state of the mobile charging device 40, during which the components of the mobile charging device 40 operate at low power consumption. In one embodiment, in state S1, the multiplexer 51 connects terminal B1 to terminal B2. Monitoring of the electro-acoustic transducer 44 can then be implemented. From state S1, there is a transition T1_2 to state S2. The T1_2 transition is triggered when the mobile charging device 40 is activated, for example, by a user or upon the reception of an ultrasonic wave by the transducer 44.

[0061] State S2 corresponds to the implementation of a wake-up process for the mobile charging device 40. In one embodiment, at state S2, the multiplexer 51 connects terminal B1 to terminal B3. The processing circuit 63 can control the emission of ultrasonic waves by the electro-acoustic transducer 44 to wake up the implant 20. The multiplexer 51 can then connect terminal B1 to terminal B2, and the processing circuit 63 can wait for the electro-acoustic transducer 44 to receive an ultrasonic signal emitted by the implant 20, corresponding to a message confirming that the awakening of the implant 20 was successful. From state S2, there is a transition T2_1 to state S1, a transition T2_2 to state S2, and a B23499 PCT – UTET1 transition T2_3 to state S3. Transition T2_2 is triggered when the awakening of the mobile charging device 40 is not yet complete. This can occur when the mobile charging device 40 has not received a confirmation message from the implant 20 after a given time. A new emission of ultrasonic waves by the electro-acoustic transducer 44 to awaken the implant 20 can then be implemented. Transition T2_1 is triggered when the awakening of the mobile charging device 40 has not been successful. This can occur when the mobile charging device 40 has not received a confirmation message from the implant 20 after a given number of attempts. The mobile charging device 40 can then send an alert message to the user. The T2_3 transition is triggered when the wake-up is completed and proceeds correctly.This can occur when the mobile charging device 40 receives the confirmation message from the implant 20.

[0062] State S3 corresponds to the implementation of a method for detecting the position of the implant 20 by the mobile charging device 40, which is described in more detail below. The detection method includes, in particular, the reception by the electro-acoustic transducer 44 of N packets of ultrasonic waves emitted by the implant 20 and the determination of an offset map by the mobile charging device 40. At the end of the detection method, the mobile charging device 40 can emit an ultrasonic signal towards the implant 20 corresponding to a message indicating that the detection method was successful, and the processing circuit 63 can wait for the electro-acoustic transducer 44 to receive an ultrasonic signal emitted by the implant 20 corresponding to an acknowledgment message. B23499 PCT – UTET1

[0063] From state S3, there is a transition T3_4 to state S4, a transition T3_5 to state S5, a transition T3_3 back to state S3, a transition T3_2 back to state S2, and a transition T3_1 back to state S1. Transition T3_4 is triggered when the process of detecting the position of implant 20 by the mobile charging device 40 is completed successfully, and a charging operation for implant 20 is to be performed first. Transition T3_5 is triggered when the process of detecting the position of implant 20 by the mobile charging device 40 is completed successfully, and a data exchange operation with implant 20 is to be performed first. Transition T3_3 is triggered when the process of detecting the position of implant 20 by the mobile charging device 40 has not been completed successfully. A new detection attempt can then be implemented.The T3_2 transition is triggered when the process of detecting the position of implant 20 by the mobile charging device 40 has not been successful after several attempts. The process of waking up the mobile charging device 40 is then implemented, and a new detection attempt can be made. The T3_1 transition is triggered when the process of detecting the position of implant 20 by the mobile charging device 40 has not been successful after several attempts, including the implementation of the process of waking up the mobile charging device 40.

[0064] State S4 corresponds to the implementation of a recharging process for implant 20 by the mobile recharging device 40. State S5 corresponds to the implementation of a data exchange process between the mobile recharging device 40 and implant 20. B23499 PCT – UTET1

[0065] In state S4, the mobile charging device 40 is used to recharge the energy storage element 21 of the implant 20. A charging operation of the implant 20 includes the control of the electro-acoustic transducer 44 of the mobile charging device 40 by the control circuit 48 for the emission of ultrasonic waves by the electro-acoustic transducer 44 of the mobile charging device 40, the reception of the ultrasonic waves by the electro-acoustic transducer 22 of the implant 20 which converts the received ultrasonic waves into an electrical signal and the charging of the energy storage element 21 from the electrical signal.According to one embodiment, when the implant 20 ceases to receive ultrasonic waves from the electro-acoustic transducer 44 to recharge the energy storage element 21, or when the energy storage element 21 is charged, the implant 20 can emit an ultrasonic signal to the mobile charging device 40 corresponding to a message indicating this situation. The implant 20 can return to sleep mode if it does not receive a response from the mobile charging device 40 after a given period.

[0066] In state S5, the mobile charging device 40 is used to acquire data emitted by the implant 20 or to transmit data to the implant 20. The data exchanged depends, in particular, on the function performed by the implant 20. When the implant includes a sensor 24, the data may correspond to measurements taken by the sensor 24. When the implant includes an actuator 24, the data may correspond to control parameters of the actuator 24 to be used by the control circuit 25 of the implant 20 to control the actuator 24. When the implant 20 ceases to receive ultrasonic waves from the electroacoustic transducer 44, the implant 20 can emit an ultrasonic signal to the mobile charging device. B23499 PCT – UTET1 40 corresponds to a message indicating this situation. The implant 20 can return to sleep mode if it does not receive a response from the mobile charging device 40 after a given period.

[0067] A data transmission operation from the mobile charging device 40 to the implant 20 includes the control of the electro-acoustic transducer 44 of the mobile charging device 40 by the control circuit 48 for the emission of ultrasonic waves by the electro-acoustic transducer 44 of the mobile charging device 40, the reception of the ultrasonic waves by the electro-acoustic transducer 22 of the implant 20 which converts the received ultrasonic waves into an electrical signal and the processing of the electrical signal by the control circuit 25 of the implant 20 to extract the received data.A data transmission operation from the implant 20 to the mobile charging device 40 includes the control of the electro-acoustic transducer 22 of the implant 20 by the control circuit 25 for the emission of ultrasonic waves by the electro-acoustic transducer 22 of the implant 20, the reception of the ultrasonic waves by the electro-acoustic transducer 44 of the mobile charging device 40 which converts the received ultrasonic waves into an electrical signal and the processing of the electrical signal by the control circuit 48 of the mobile charging device 40 to extract the received data.

[0068] From state S4, there is a transition T4_5 to state S5, and a transition T4_3 to state S3. Transition T4_5 is triggered when the process of recharging implant 20 by the mobile recharging device 40 is completed successfully. Transition T4_3 is triggered when the process of recharging implant 20 by the mobile recharging device 40 has not been completed. B23499 PCT – UTET1 correctly. From state S5, there is a T5_1 transition to state S1, and a T5_3 transition to state S3. The T5_1 transition is triggered when the data exchange process between the mobile charging device 40 and the implant 20 is completed successfully. The T5_3 transition is triggered when the data exchange process between the mobile charging device 40 and the implant 20 has not been completed successfully, or when the charging process of the implant 20 is required.

[0069] For an operation to recharge the implant 20 by the mobile charging device 40 or for an operation to exchange data between the implant 20 and the mobile charging device 40, the mobile charging device 40 can be held on the person's body 11 by the strap 13. Once the operations to recharge the implant 20 by the mobile charging device 40 and / or to exchange data between the implant 20 and the mobile charging device 40 are completed, the mobile charging device 40 can be connected to the charging station 70 to perform an operation to recharge the battery 46 of the mobile charging device 40 by the charging station 70 and / or to exchange data between the mobile charging device 40 and the charging station 70.

[0070] One advantage of recharging the battery 21 of the implant 20 by transmitting energy via ultrasonic waves is that the emission of electromagnetic waves by the mobile charging device 40 during a charging operation is reduced. Another advantage of recharging the battery 21 of the implant 20 by transmitting energy via ultrasonic waves is that the propagation of ultrasonic waves in the person's body 11 results in little local heating of the tissues compared to an electromagnetic wave. One advantage of performing a B23499 PCT – UTET1 data exchange between implant 20 and mobile charging device 40 using ultrasonic waves is that the risks of unwanted capture of ultrasonic waves by a malicious person for the determination of the data exchanged are reduced, or even zero.

[0071] Figures 7 and 8 schematically illustrate state S3, and Figures 9 and 10 schematically illustrate states S4 and S5. Figures 7 and 9 depict the electro-acoustic transducer 44 with sixty-four electro-acoustic elements E i , i varying from 1 to 64. As an example, the electro-acoustic element E1 has the shape of a disc and the other electro-acoustic elements E i , i varying from 2 to 64, each have the shape of an annular sector and are distributed according to first, second, and third concentric rings surrounding the electro-acoustic element E1, the first ring being the closest to the electro-acoustic element E1, and the third ring being the furthest from the electro-acoustic element E1, the first ring comprising ten electro-acoustic elements E2 to E 11 , the second ring comprising twenty electro-acoustic elements E 12 to E 32, and the third ring comprising thirty-one electro-acoustic elements E 33 to E 64 .

[0072] In state S3, the mobile charging device 40 is in a phase of detecting ultrasonic waves emitted by the implant 20. The multiplexer 51 then connects terminal B1 to terminal B2. The circuit 26 of the implant 20 is then activated to provide the control signal C to the electroacoustic transducer 22 so that the electroacoustic transducer 22 emits bursts of ultrasonic waves at regular intervals, for example periodically with a period T. The period T is, for example, between 1 µs and 1 s, for example 100 µs. The period T must be at least greater than this. B23499 PCT – UTET1 that the difference between the maximum and minimum times required for the ultrasonic wave to travel the distance between transducer 22 and transducer 44. Figure 7 shows implant 20 and a burst of ultrasonic waves 90 emitted by implant 20. In one embodiment, the bursts of ultrasonic waves 90 emitted by electroacoustic transducer 22 are identical. Each burst of ultrasonic waves 90 is detected by each electroacoustic element E i and is reflected in the supply by each electro-acoustic element E i of an individual MS measurement signal i including a packet of oscillations upon reception of each burst of ultrasonic waves 90. As the distance between the implant 20 and each electro-acoustic element E i varies from an electro-acoustic element E iOn the other hand, the amplitude of the oscillation packet and the start time of the oscillation packet relative to the start time of emission of the ultrasonic wave burst by implant 20 of the individual measurement signal MS i supplied by the electro-acoustic element E i varies from an electro-acoustic element E i to the other.

[0073] Figure 8 shows a timing diagram of the control signal C of the electro-acoustic transducer 22 of the implant 20 supplied by the circuit 26, as an example of the timing diagrams of the individual measurement signals MS9, MS 26 , and MS 59 provided respectively by the electro-acoustic elements E9, E 26 , summer 59and a timing diagram of the overall measurement signal GMS received by circuit 57 obtained with the configuration in Figure 7. In Figure 8, the control signal C is very schematically represented by a periodic rectangular signal with period T. Each pulse of the control signal C corresponds to the emission of a burst of ultrasonic waves 90 by the implant 20. In Figure 8, the ninth, twenty-sixth, and fifty-ninth bursts of ultrasonic waves emitted by the implant 20 are shown. Each individual measurement signal MS9, MS 26 , and MS 59 includes a B23499 PCT – UTET1 oscillation packet respectively P9, P 26 , and P 59 corresponding to the reception of each burst of ultrasonic waves 90 respectively by the electro-acoustic elements E9, E 26 , summer 59 For example, in Figure 7, implant 20 is closer to the electro-acoustic element E 59respectively than the electro-acoustic element E 26 respectively and is closer to the electro-acoustic element E 26 respectively than of the electro-acoustic element E9, respectively, for each emission of a burst of ultrasonic waves by the implant 20, the oscillation peak P 59 occurs first, and the oscillation peak P9 occurs last. In Figure 8, the oscillation peak P 59 is represented with the highest intensity. However, this is not necessarily the peak of oscillation P 59 which occurs first has the highest intensity.

[0074] In state S3, circuit 52 of the mobile charging device 40 commands the multiplexer 51 to put the control circuit 48 into receive mode, i.e., to connect terminal B1 to terminal B2. Circuit 54 of the mobile charging device 40 then commands the successive closing of each switch SW i, i varying from 1 to N, a single SW switch i with both closed, the other SW switches j , j varying from 1 to N and different from i, being held open while the SW switch i is closed. Each SW switch i is closed for a duration T. The offset detection circuit 57 then stores the individual measurement signal MS i supplied by the electro-acoustic element E i connected to terminal B1 via switch SW i in the closed state. The overall measurement signal GMS is thus equal to a succession of duration T segments of the individual measurement signals MS i , i varying from 1 to N.

[0075] In Figure 8, the overall measurement signal GMS is the juxtaposition of the MS signals i captured successively by the B23499 PCT – UTET1 electroacoustic elements. In particular, in the example of Figure 8, the overall measurement signal GMS is equal to the juxtaposition of the individual measurement signal MS9 for the ninth burst of ultrasonic waves emitted by the implant 20, and the individual measurement signal MS 26 for the twenty-sixth burst of ultrasonic waves emitted by implant 20, and of the individual MS measurement signal 59 for the fifty-ninth burst of ultrasonic waves emitted by implant 20.

[0076] The detection circuit 57 then determines, from the overall measurement signal GMS, a reference signal REF among the individual measurement signals MS i provided by the electro-acoustic elements E i According to one embodiment, the circuit 57 determines, within the overall measurement signal GMS, which oscillation packet has the maximum intensity, and the reference signal corresponds to the individual measurement signal MS. iof the electro-acoustic element E i having contributed to the maximum intensity oscillation packet of the overall GMS measurement signal. This advantageously improves the accuracy of the reference signal.

[0077] Circuit 59 then determines an offset map. According to one embodiment, circuit 59 determines for each electro-acoustic element E i , the shift Δϕ i between the oscillation packet of the reference signal REF and the packet P i oscillations of the individual measurement signal MS i supplied by the electro-acoustic element E i According to one embodiment, the circuit 59 determines, for each electro-acoustic element E i , the duration between the maximum of the oscillation packet of the reference signal REF in the overall measurement signal GMS and the maximum of the oscillation packet P i of the electro-acoustic element E iin the overall GMS measurement signal, and determines the offset Δϕ i as being equal to the remainder of the Euclidean division of this duration by the period T. It should be noted that the shift Δϕ i It could be positive. B23499 PCT – UTET1 negative or zero. Indeed, since the overall measurement signal GMS corresponds to only one of the individual measurement signals MS i For each burst of ultrasonic waves, it only includes the single packet of oscillations P i of the electro-acoustic element E i for each burst of ultrasonic waves. In Figure 8, considering as an example that the reference signal is that provided by the electro-acoustic element E 59 , we have indicated the offset Δϕ 26 of the electro-acoustic element E 26 and the shift Δϕ9 of the electro-acoustic element E9.

[0078] An advantage of determining the overall measurement signal GMS equal to a succession of duration T parts of the individual measurement signals MS i , i varying from 1 to N, is that the circuit 57 of the mobile charging device 40 does not have to perform a simultaneous analysis of all the individual measurement signals MS i The structure of the mobile charging device 40 is thus simpler. It was previously described that the set of individual measurement signals MS i were used to determine the shifts Δϕ i for each element E i without this being limiting. It is indeed possible to select only a portion of the individual MS measurement signals i and to deduce, for example by interpolation, the total of the shifts Δϕ i .

[0079] In state S5, a process for recharging the battery 21 of the implant 20 by the mobile charging device 40 is implemented, and in state S4, a process for exchanging data between the mobile charging device 40 and the implant 20 is implemented.

[0080] In state S4 and state S5 in the case of data transmission from the mobile charging device 40 to the implant 20, the circuit 59 determines the delays Δφ i to apply to obtain the control signal S' i for each electro-acoustic element E i , i varying from 1 to N, in such a way B23499 PCT – UTET1 that the interference between the ultrasonic waves emitted by all the electro-acoustic elements E1 to E N form the desired ultrasound wave directed and focused towards implant 20. Each delay Δφ i is determined from the shifts Δϕ1de to Δϕ N determined in state S3.

[0081] According to one embodiment, for each electro-acoustic element E i , i varying from 1 to N, the delay Δφ i to be applied by the delay circuit D i is equal to the difference between Δϕ max and Δϕ i , where Δϕ i is the shift determined at state S3 associated with the electro-acoustic element E i , and Δϕ max is the maximum shift among the shifts Δϕ1 to Δϕ N determined in state S3.

[0082] In the case where each electro-acoustic element E1à i varying from 1 to N emits a continuous sound wave, the delay Δφ i to be applied to the analog control signal S to obtain the control signal S' i can be obtained by applying a phase shift in the expression of the analog control signal S.

[0083] In states S4 and S5, circuit 59 transmits the COM_PH parameterization signals to the delay control circuit 56 so that, when the electro-acoustic elements E1 to E are controlled N , the delay control circuit 56 provides, for each electro-acoustic element E i , i varying from 1 to N, the delay signal PH i to the delay circuit D i associated with the electro-acoustic element E i , so that the delay circuit D i applies a delay Δφ i to the analog control signal S.

[0084] In states S4 and S5, circuit 52 of the mobile charging device 40 commands the multiplexer 51 to put the mobile charging device 40 into transmit mode, that is, to connect terminal B1 to terminal B3. Circuit 54 of the mobile charging device 40 then commands the opening of all switches SW1 to SW1. N Circuit 62 is activated B23499 PCT – UTET1 to output an analog control signal S. Circuit 56 simultaneously controls each delay circuit D i with a PH control signal i corresponding, which may be different from a D delay circuit i to the other. Each delay circuit D i provides a signal S' i which corresponds to the received signal S delayed by a delay that depends on the PH signal i and controls the electro-acoustic element E i with the S' signal i The electro-acoustic elements E i They therefore emit ultrasonic waves that are delayed relative to each other, the desired ultrasonic beam resulting from the superposition of the ultrasonic waves.

[0085] Figure 9 is analogous to Figure 7 and very schematically illustrates ultrasonic waves W9, W 26 , and W 59 emitted respectively by the electro-acoustic elements E9, E 26 , summer 59These ultrasonic waves W9, W 26 , and W 59 combine with the ultrasonic waves of all other electro-acoustic elements E i to form an ultrasonic wave 92 directed and focused towards the implant 20.

[0086] Figure 10 represents chronograms C9, C 26 , etc 59 of the control signal S'9, S' 26 , and S' 59 supplied respectively by the delay circuits D9, D 26 , and D 59 to the electro-acoustic elements E9, E 26 , summer 59 used with the configuration in Figure 9. Considering that the electro-acoustic element closest to implant 20 corresponds to electro-acoustic element E 59 , the delay circuit D 59 applies the maximum delay Δφ max to the control signal S, the delay circuit D 26 applies a delay Δφ 26to the control signal S, and the delay circuit D6 applies a delay Δφ6 to the control signal S.

[0087] One advantage of applying delays Δφ i The control signal S indicates that the mobile charging device 40 may only include a single circuit 62 for supplying the B23499 PCT – UTET1 control signal S. The structure of the mobile charging device 40 is thus simpler.

[0088] Figure 11 shows an electrical diagram of another embodiment of the mobile charging device 40 of the system in Figure 1. The mobile charging device 40 shown in Figure 11 comprises all the elements of the mobile charging device 40 shown in Figure 5, some of which are present in two or more copies. More precisely, the mobile charging device 40 shown in Figure 11 comprises M sets of N electro-acoustic elements E1 to E N , N switches SW1 to SW N, and N delay circuit D1 to D N , M being equal to 2 and the product of M by N being equal to the total number of elements E i of the mobile charging device 40 as an example in Figure 11. For each set of N electro-acoustic elements E1 to E NThe mobile charging device 40 comprises one instance of circuits 56 and 57 and one instance of the multiplexer 51. For the entire circuit, the mobile charging device 40 includes a single instance of circuits 52, 54, 58, 59, 60, 61, 62, and 63. Circuit 59 is connected to M instances of circuit 56. Circuit 58 is connected to M instances of circuit 57. Circuit 60 is connected to M terminals B2, and circuit 62 is connected to M terminals B3. Therefore, for determining the delay map, the mobile charging device 40 shown in Figure 11 has a partially parallel structure. One advantage is that the processing time for determining the delay map is reduced since the processing of the signals provided by the electro-acoustic elements is partially performed in parallel. As an alternative, the number of electro-acoustic elements in each set of electro-acoustic elements may not be the same. B23499 PCT – UTET1

[0089] Various embodiments and variations have been described. A person skilled in the art will understand that some features of these various embodiments and variations could be combined, and other variations will become apparent to a person skilled in the art.

[0090] Finally, the practical implementation of the described methods and variants is within the reach of the person in the trade, based on the functional indications given above.

Claims

B23499 PCT – UTET1 CLAIMS 1. Device (40) comprising: - a first electro-acoustic transducer (44) comprising N electro-acoustic elements (E i ), where N is an integer greater than or equal to 3, each electro-acoustic element (E i ) being configured to emit and receive first ultrasonic waves (W i ); - a first terminal (B1), a second terminal (B2), and a third terminal (B3); - for each electro-acoustic element (E i ), a phase-shifting circuit (D i ) connected to the electro-acoustic element (E i ) and configured to apply a phase shift to a first analog signal (S) received from the first terminal (B1) for the control of the electro-acoustic element (E i ) ; - for each electro-acoustic element (E i ), a switch (SW i ) connecting the first terminal (B1) to the electro-acoustic element (E i ) or to the phase-shifting circuit (Di ) connected to the electro-acoustic element (E i ) ; and - a multiplexer (51) configured to connect the first terminal (B1) to the second terminal (B2) in a first operating mode or to the third terminal (B3) in a second operating mode.

2. Device according to claim 1, further comprising: - a first electronic circuit (57) configured to receive a second analog signal (GMS) at the second terminal (B2) in the first operating mode; and - a second electronic circuit (62) configured to provide the first analog signal (S) to the third terminal (B3) in the second operating mode.

3. Device according to claim 2, further comprising a third electronic circuit (54) configured, B23499 PCT – UTET1 in the first operating mode, to successively close each switch (SW i), the other switches being open, and, in the second operating mode, to keep all switches open (SW i 4. Device according to any one of claims 1 to 3, further comprising a fourth electronic circuit (56) configured to provide control signals (PH i ), not all identical, simultaneously to all the phase-shift circuits (D i 5. A device according to any one of claims 1 to 4, wherein the first electro-acoustic transducer (44) comprises, in addition to the N electro-acoustic elements (E i ), in addition: - at least three additional electro-acoustic elements (E i ); - a first additional terminal (B1), and a second additional terminal (B2); - for each additional electro-acoustic element (E i ), a phase-shifting circuit (D i ) connected to the additional electro-acoustic element (E i) and configured to apply a phase shift to a first analog signal (S) received from the first additional terminal (B1) for the control of the additional electro-acoustic element (E i ) ; - for each additional electro-acoustic element (E i ), a switch (SW i ) connecting the first additional terminal (B1) to the additional electro-acoustic element (E i ) or to the phase-shifting circuit (D i ) connected to the additional electro-acoustic element (E i ) ; and - an additional multiplexer (51) configured to connect the first additional terminal (B1) to the second additional terminal (B2) in the first operating mode B23499 PCT – UTET1 or at the third terminal (B3) in the second operating mode.

6. Device according to claim 5 in dependence on claim 2, further comprising a first additional electronic circuit (57) configured to receive a second additional analog signal (GMS) at the second additional terminal (B2) in the first operating mode.

7. System (10) comprising the device (40) according to any one of claims 1 to 6 and a self-contained device (20), the self-contained device (20) comprising a second electro-acoustic transducer (22) and an electrical energy storage element (21), the second electro-acoustic transducer (44) being configured to convert the first ultrasonic waves (W i) into a third analog signal for recharging the electrical energy storage element (21).

8. System according to claim 7, wherein the second electro-acoustic transducer (22) is configured to emit periodic bursts of second ultrasonic waves (90).

9. System according to claim 7 or 8, wherein the self-contained device (20) is an implantable medical device comprising a sensor and / or an actuator (24) powered by the electrical energy storage element (21).

10. Method of operating the system (10) according to any one of claims 7 to 9, comprising, in the first mode of operation, the provision of bursts of third ultrasonic waves (90) by the second electro-acoustic transducer (22), the provision by B23499 PCT – UTET1 each electro-acoustic element (E i ) of a fourth analog signal (MS i ) comprising a packet of oscillations (P9, P 26 , P59 ) upon receipt of each burst of third ultrasonic waves (90), the memorization of the second analog signal (GMS) obtained by successively closing each of part or all of the switches (SW i ), with the other switches open, the determination from the second analog signal (GMS) of the electro-acoustic element, called the reference electro-acoustic element, among the N electro-acoustic elements (E i providing the maximum intensity oscillation packets and the determination, for each electro-acoustic element (E i ) other than the reference electro-acoustic element, by a shift (Δϕ i ) between the packet of oscillations provided by said electro-acoustic element (E i) upon receipt of one of the bursts of third ultrasonic waves (90) and the oscillation packet of the reference electro-acoustic element upon receipt of said burst of third ultrasonic waves (90).

11. Method according to claim 10, comprising determining, for each electro-acoustic element (E i ) of a delay (Δφ i ) to be applied by the phase-shifting circuit (D i ) connected to said electro-acoustic element (E i ) from the offset (Δϕ i ) associated with the electro-acoustic element (E i ) and the maximum offset among the N electro-acoustic elements (E i ), and, in the second operating mode, the supply of the first analog signal (S) to the first terminal (B1) and the application of the delay by the phase-shifting circuit (D i ) said second signal to control said electro-acoustic element (E i).

12. Method according to claim 10 or 11, wherein the bursts of third ultrasonic waves (90) are emitted periodically. B23499 PCT – UTET1 13. A method according to any one of claims 10 to 12, wherein the second analog signal (GMS) is obtained by successively closing each of a portion of the switches (SW i ), the other switches being open, and in which the shifts (Δϕ i ) for electro-acoustic elements (E i ) associated with switches that have not been closed to obtain the second analog signal (GMS) are determined by interpolation.

14. A method according to any one of claims 10 to 12, wherein the device (40) is according to claim 6, wherein the second additional analog signal (GMS) and the second additional analog signal (GMS) are provided at least partially simultaneously.

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