Method and device for processing an electrical signal for an ultrasonic emitting device

Abstract

Method and device for processing an electrical signal for an ultrasonic emitting device The present disclosure relates to a device (10) and a method for processing an electrical signal (SG1) for an ultrasonic emitting device (20). The method comprises: generating an electrical signal (SG1) defining ultrasonic waves (W), the periodicity of the electrical signal (SG1) being modified by a modulation (ML1) of the phase of the signal (PH1); and providing the electrical signal (SG1) to the ultrasonic emitting device (20) to cause the emission of the ultrasonic waves (W). Figure for abstract: Figure 3

Description

Title of the invention: Method and device for processing an electrical signal for an ultrasonic emitting device Prior art

[0001] An ultrasonic transmitting device (or ultrasonic transmitting device) typically comprises a plurality of transducer elements configured to transmit ultrasonic waves, for various purposes, for example to perform ultrasound imaging.

[0002] For this purpose, the ultrasonic emitting device can be controlled by means of electrical signals, the latter being able to be emitted by means, for example, of one or more pulsers or linear amplifiers. These electrical signals define waves transmitted to the transducer elements of the emitting device, thus causing the emission of ultrasonic waves in a given medium. Electrical signals can optionally be produced in return by these same transducer elements (or other transducer elements), these signals representing a response (or echo) of the medium to the wave stresses.

[0003] In general, during operation, such an ultrasonic emitting device emits electromagnetic (EM) waves. As such, the ultrasonic emitting device also constitutes an electromagnetic wave emitting device (also called an EM emitting device). However, strong radiation of electromagnetic waves is not always desirable.

[0004] There are thus different standards which impose authorized limit levels of electromagnetic emissions from electrical, scientific and medical devices, such as for example the standards IEC 60601-1-2, NF EN 55011 / CISPR 11 and IEC 61000-4-3.

[0005] In particular, the CISPR 11 standard (see for example edition 6.2 2019-01) defines the permissible limits (i.e. the "quasi-peak" / "quasi-peak" values ​​of the electromagnetic emission) for different frequency ranges used. Accordingly, the energy of an electric field emitted by a device must not exceed these limits in order to be declared as a device compliant with said standard. For example, Table 6 of the CISPR 11 standard concerns the electromagnetic radiation disturbance limits for Class A Group 1 devices, measured at a test site. In addition, Table 2 of the CISPR 11 standard concerns the disturbance voltage limits for Class A Group 1 devices, measured at a test site. A medical device, such as for example a system comprising an ultrasound probe, is typically Class A, as long as it is a non-domestic device.

[0006] In addition, the IEC 61000-4-3 / EN 61000-4-3 standard defines an electromagnetic compatibility (EMC) standard. Its parts 4-3 in particular concern the testing and measurement techniques used, as well as the immunity test to electromagnetic fields radiated at radio frequencies.

[0007] Since ultrasonic devices emit electromagnetic waves by construction, they must remain compatible with said standards, while allowing optimal use, i.e. with the emission of waves useful for the study of the region of interest concerned. Disclosure Statement

[0008] As indicated above, conventional ultrasonic emitting devices pose a problem in particular in that they can be a source of electromagnetic emissions which it may be desirable to limit, for example in their radiation, their directions and / or their intensities.

[0009] One of the objects of the present disclosure is to solve at least one of the problems or deficiencies described above.

[0010] In particular, an object of the present disclosure is to limit the electromagnetic emissions of an ultrasonic emitting device while ensuring the latter has satisfactory performance, for example in terms of spectral response and / or delivered acoustic energy (or power).

[0011] In particular, an object of the present disclosure is to design a high-performance ultrasonic emitting device, generating a minimum of electromagnetic emission in operation while presenting limited design, manufacturing and use complexity.

[0012] To this end, according to a first aspect, the present disclosure relates to a method for processing an electrical signal for an ultrasonic emitting device, said method comprising: - generating an electrical signal defining ultrasonic waves, the periodicity of the electrical signal being modified by a modulation of the phase of the signal; and - supplying the electrical signal to the ultrasonic emitting device to cause the emission of the ultrasonic waves.

[0013] By implementing such a method, it advantageously becomes possible to limit the electromagnetic radiation emitted by an ultrasonic emitting device while ensuring satisfactory performance for the latter, for example in terms of spectral response and / or delivered acoustic energy (or power). It is thus advantageous to limit the level of electromagnetic emissions with minimal impact (ideally no impact) on the desired operating performance of the ultrasonic emitting device.

[0014] To do this, the electrical signal supplied to the ultrasonic emitting device is adapted or modified by modulating the phase of the signal. By disturbing the phase of the electrical signal, it is advantageous to reduce the harmonics contained in this signal and thus minimize electromagnetic (EM) radiation. This modulation can be advantageously implemented in an existing emitting system or device, without requiring additional devices and / or structural modifications to the existing system or device. The complexity and cost of implementing the method can therefore be limited.

[0015] The limitation of electromagnetic emissions can be achieved in the various operating modes of the ultrasound emitting device. Examples of different operating modes of a emitting device in the form of an ultrasound probe can include a B-mode (i.e., a brightness / luminosity mode), a Doppler mode, or a ShearWave(r) mode (i.e., a shear wave elastography mode). In other words, it is not necessary to change or modify the specific operating mode of an ultrasound emitting device to achieve the electromagnetic emission reductions according to the concept of the present disclosure. Such electromagnetic emission reductions can thus be achieved independently of the selected operating mode, i.e., regardless of the operating mode implemented by the device.

[0016] The method according to the disclosure may include other features which may be taken separately or in combination, in particular among the following embodiments which are presented for illustration purposes only and may be combined or associated unless otherwise stipulated.

[0017] According to one example, the modulation of the phase of the signal is configured to cause a broadening of the frequency spectrum of the electrical signal.

[0018] According to one example, the modulation of the phase of the electrical signal is deterministic over time.

[0019] According to one example, the modulation of the phase of the electrical signal is random over time.

[0020] According to one example, the modulation of the phase of the electrical signal comprises: - introduction, into the electrical signal, of at least one delay corresponding to a period during which the voltage of the electrical signal is maintained at a constant value.

[0021] According to one example, said at least one delay is less than the period of the electrical signal.

[0022] According to one example, the modulation of the phase of the electrical signal comprises: - an angular shift of the phase of the electrical signal in at least one cycle of the electrical signal.

[0023] According to one example, the angular shift is configured to cause an inversion of the phase of the electrical signal.

[0024] According to one example, the modulation of the phase of the electrical signal comprises a variation of the period of the cycles of the electrical signal over time.

[0025] According to one example, the phase modulation is configured so that the electrical signal delivers electrical energy at least equal to a theoretical energy that would be delivered by the electrical signal if its phase were not disturbed by said phase modulation.

[0026] According to one example, the phase modulation is carried out while maintaining the same frequency on each cycle of the electrical signal.

[0027] According to one example, the ultrasonic waves are compression waves generating shear waves in a medium.

[0028] According to one example, said method is applied to ultrasound medical imaging.

[0029] According to another aspect, the present disclosure may involve a computer program comprising instructions which, when the program is executed by a computer, cause the implementation of the method according to the first aspect. In particular, the different steps of the method according to the first aspect may be defined by computer program instructions.

[0030] Such a computer program may use any programming language or equivalent, and may be in the form of source code, object code, or intermediate code between source code and object code, such as in a partially compiled form, or in any other desirable form.

[0031] According to another aspect, the present disclosure relates to a recording medium (or information medium), readable by a computer (or a processor), on which a computer program is recorded according to this same aspect of the present disclosure.

[0032] On the one hand, the recording medium may be any entity or device capable of storing the program, such as at least one volatile and / or non-volatile memory. For example, the medium may comprise a storage means, such as a rewritable non-volatile memory, a ROM memory, a CD-ROM or a ROM memory of the microelectronic circuit type, or even a magnetic recording means or a hard disk. This memory may for example comprise a graphics card (or video card) memory, this type of memory being in particular capable of processing image data (or video data).

[0033] On the other hand, this recording medium may also be a transmissible medium such as an electrical or optical signal, such a signal being able to be conveyed via an electrical or optical cable, by conventional or terrestrial radio or by beam. self-directed laser or by other means. The computer program according to the present disclosure can in particular be downloaded via a wired or non-wired network, of local or non-local type (Bluetooth® for example, Wi-Fi, Ethernet, Internet, 4G, 5G or others).

[0034] Alternatively, the recording medium may be an integrated circuit in which the computer program is incorporated, the integrated circuit being adapted to perform or to be used in performing the method in question.

[0035] According to another aspect, the present disclosure relates to a device for processing (or controlling device) an electrical signal for an ultrasonic emitting device, this device being configured to implement the method of the first aspect of the present disclosure.

[0036] According to one example, the processing device comprises a memory associated with a processor, this memory comprising a computer program according to the present disclosure.

[0037] According to one example, the present disclosure relates to a device for processing an electrical signal for an ultrasonic emitting device, said processing device comprising: - a generation module configured to generate an electrical signal defining ultrasonic waves, the periodicity of the electrical signal being modified by a modulation of the phase of the signal; and - a supply module configured to supply the electrical signal to the ultrasonic emitting device to cause the emission of the ultrasonic waves.

[0038] The processing device may have functionalities that correspond to the steps (or operations) of the method according to the present disclosure. In particular, the different embodiments mentioned in the present disclosure in relation to the method of the present disclosure as well as the associated advantages may apply analogously to the processing device (and vice versa).

[0039] The characteristics and advantages of the disclosure will appear more precisely on reading the description which follows, given solely as a non-limiting example, and made with reference to the appended figures. In particular, the examples illustrated in the figures can be combined with each other, except in the case of obvious inconsistency. Brief description of the figures

[0040] Other characteristics and advantages of the present disclosure will emerge from the description of the non-limiting exemplary embodiments of the present disclosure set out below, with reference to the appended figures 1 to 14, in which:

[0041] [Fig.l] schematically represents an electrical signal, of the prior art, without phase modulation, for controlling an ultrasonic emitting device according to an example;

[0042] [Fig.2] schematically represents the frequency spectrum of the electrical signal of [Fig.l] without phase modulation according to an example;

[0043] [Fig.3] schematically represents an ultrasound system, comprising a processing device and an ultrasound transmitting device, according to exemplary embodiments of the present disclosure;

[0044] [Fig.4] schematically represents the ultrasonic system of [Fig.3], according to exemplary embodiments of the present disclosure;

[0045] [Fig.5] schematically represents the processing device of [Fig.3], according to exemplary embodiments of the present disclosure;

[0046] [Fig.6] schematically represents in the form of a diagram the steps of a processing method implemented by a processing device, according to exemplary embodiments of the present disclosure;

[0047] [Fig.7] schematically represents the modulation of an electrical signal during the processing method of [Fig.6], according to exemplary embodiments of the present disclosure;

[0048] [Fig.8] schematically represents the frequency spectrum of the electrical signal of [Fig.7], according to exemplary embodiments of the present disclosure;

[0049] [Fig.9] schematically represents the modulation of an electrical signal during the processing method of [Fig.6], according to exemplary embodiments of the present disclosure;

[0050] [Fig. 10] schematically represents the frequency spectrum of the electrical signal of [Fig.9], according to exemplary embodiments of the present disclosure;

[0051] [Fig. 11] schematically represents the modulation of an electrical signal during the processing method of [Fig.6], according to exemplary embodiments of the present disclosure;

[0052] [Fig. 12] schematically represents the frequency spectrum of the electrical signal of [Fig.l 1], according to exemplary embodiments of the present disclosure;

[0053] [Fig. 13] schematically represents the modulation of an electrical signal during the processing method of [Fig.6], according to exemplary embodiments of the present disclosure; and

[0054] [Fig. 14] schematically represents the frequency spectrum of the electrical signal of [Fig. 13], according to exemplary embodiments of the present disclosure. Description of the embodiments

[0055] The present disclosure relates to methods and devices for processing (or controlling) an electrical signal for an ultrasonic emitting device.

[0056] As illustrated in [Fig.l] in one example, an ultrasonic emitting device 2 is configured to emit ultrasonic waves W in response to one or more signals electrical 1. To do this, a control system (not shown) can be configured to provide these electrical signals 1 to the ultrasonic emitting device 2. This control system can in particular comprise one or more electronic pulsers (more simply called “pulsers”) or linear amplifiers, configured to generate the electrical signal(s) 1 intended to control the ultrasonic emitting device 2.

[0057] The ultrasonic emitting device 2 may comprise one or more ultrasonic transducers, each of them being controlled by an electrical signal 1 delivered by the control system. The transmission of these electrical signals 1 may be ensured by a transmission chain from the pulsers to the transducers of the emitting device 1.

[0058] It has been found that the generation of ultrasonic waves W by such an ultrasonic emitting device 2 generates electromagnetic (EM) emissions 3 which it may be desirable to minimize, for example in their radiation, their directions, their intensities. In certain cases, it is desirable to limit the EM radiation 3 of such an emitting device while ensuring that it has good performance, for example in terms of spectral response and / or delivered acoustic energy (or power). In particular, it may be desirable to limit the level of EM emissions 3 with minimal impact on the desired operating performance of the ultrasonic emitting device 2.

[0059] As illustrated in [Fig.2], the frequency spectrum 4 of the electrical signal 1 supplied to the ultrasonic emitting device 2 generally comprises at least one main peak at a fundamental frequency 5 (delivering a significant amount of electrical energy) and secondary peaks 6 at harmonic frequencies, namely peaks 6a, 6b and 6c in this example. These harmonic frequencies correspond to multiples of the fundamental frequency. The generation of such harmonics results from the periodic nature of the wave electrical signal 1.

[0060] These 6 harmonics are outside the bandwidth of the transducers of the ultrasonic emitting device 2 and are not converted into acoustic energy but dissipated in the form of thermal heat, which limits the energy efficiency of the device. The emission of such harmonics can also lead to excessive electromagnetic radiation, which can pose a problem in particular when a maximum limit of this radiation must be respected (for example in accordance with regulations imposed to obtain certification of the system).

[0061] To limit harmonics and avoid excessive electromagnetic radiation, it is known to use linear pulsers, or amplifiers, capable of generating sinusoidal signals, but this technique is particularly expensive and has less or poorly adapted efficiency, in particular in the medical field, particularly because the waves thus generated are limited in power and produce a lot of heat.

[0062] The constraints and / or problems mentioned above therefore require compromises to be made or certain characteristics of such an ultrasonic emitting device to be limited in order to guarantee good performance and acceptable, or even efficient, aging of the assembly according to market requirements. These constraints and / or problems may also make it difficult to qualify such a wave emitting device according to current standards.

[0063] The present disclosure proposes to address the problems and constraints previously described by processing the electrical signal supplied to an ultrasonic emitting device in order to limit the level of harmonics contained in the electrical signal, while preserving the desired maximum acoustic energy (or signal level) at the fundamental frequency, so as to guarantee good performance of the ultrasonic emitting device.

[0064] Methods and devices for processing (or controlling) an electrical signal for an ultrasonic emitting device will now be described according to particular embodiments of the disclosure with joint reference to Figures 3 to 14. Unless otherwise indicated, elements common or similar to several figures bear the same reference signs and have identical or similar characteristics, so that these common elements are generally not described again, for the sake of brevity.

[0065] The terms "first(s)", "second(s)", etc.) are used in this document by arbitrary convention to enable different elements (such as operations, devices, etc.) implemented in the embodiments described below to be identified and distinguished.

[0066] As previously indicated, the present disclosure relates in particular to a treatment method implemented by an ultrasonic emitting device, as well as such a device. [Fig. 3] schematically represents an ultrasonic system SY1 comprising a treatment device (or control device) 10 and an ultrasonic emitting device 20 (also called an ultrasonic emitting device, or ultrasonic wave emitting device, or ultrasonic transducer device) according to exemplary embodiments of the present disclosure.

[0067] More specifically, the processing device 10 is configured to control (or drive) the ultrasonic emitting device 20. For this purpose, the processing device 10 generates one or more electrical signals SGI which it transmits to the ultrasonic device 20 to cause the emission of ultrasonic waves W1. For the purpose of simplifying the presentation of the present disclosure, it is subsequently considered that the processing device 10 generates and transmits an electrical signal SGI to the ultrasonic device. 20, it being understood that this electrical signal SGI may comprise a plurality of electrical signals. The electrical signal SGI thus emitted makes it possible to control the ultrasonic waves W1 emitted by the emitting device 20.

[0068] The ultrasonic emitting device 20, also referred to hereinafter as the ultrasonic device, is configured to emit, and possibly also receive, waves W2. This ultrasonic device 20 may for example take the form of an ultrasound probe (for example an ultrasound probe). The nature of these ultrasonic waves W depends on the configuration of the ultrasonic device 20, in particular in view of the use made of it.

[0069] According to one example, the treatment device 10 and the ultrasound device 20 are separate devices. According to variants, all or part of the treatment device 10 may be implemented in the ultrasound device 20.

[0070] Generally speaking, the ultrasound system SY1, and more precisely the treatment device 10 and the ultrasound emitting device 20, can be stationary or mobile.

[0071] According to one example, the treatment device 10 and the ultrasound device 20 form a single device, stationary or mobile as the case may be.

[0072] For example, the ultrasound device 20 may be connected to the treatment device 10 by a cable or may communicate wirelessly with it. In the latter case, the ultrasound device 20 may, for example, comprise a battery and receive communication signals from the treatment device 10, these signals representing the electrical signal SGI (for example, the driving frequencies and / or any information included in the electrical signal). The ultrasound device 20 may then reproduce the electrical signal SGI internally from the received communication signals.

[0073] The ultrasonic device 20 may for example be a conventional ultrasonic wave emitting device, this device being controlled by means of the treatment device 10 according to a treatment method in accordance with the present disclosure.

[0074] As illustrated in [Fig.3], the processing device 10 comprises in this example a processor 12 and a memory 14. The processing device 10 is configured to control the ultrasonic device 20 by generating and sending an electrical signal SGI. Once generated, this electrical signal SGI is thus transmitted to the ultrasonic device 20 to cause the emission, by said ultrasonic device 20, of ultrasonic waves W1 in the direction of and / or in a medium M. The electrical signal SGI thus generated is representative of (or defines) the ultrasonic waves W1 projected into the medium M. To this end, the processing unit 10 may for example be or comprise at least one electronic pulser, also called a “pulser” capable of generating the electrical signal.

[0075] The electrical signal SGI is a wave (or alternating) signal which is processed by the processing device 10 to control the ultrasonic device 20 so as to obtain good performance of the ultrasonic device 20 while minimizing its EM emissions. As described below, the processing device 10 is configured to modify the periodicity of the electrical signal SGI by an ML1 modulation of the phase PHI ([Fig.3]) of the electrical signal SGI. The processing device 10 can further perform various processing operations during the generation of the electrical signal SGI (amplification, filtration, digitization, signal conditioning, etc.).

[0076] In examples, the processor 12 and the memory 13 may be incorporated into the processing device 10 illustrated in [Fig. 3] or may be incorporated into a computer or computing device communicatively linked thereto.

[0077] The memory 14 can store in the form of a computer program PG1 instructions defining the steps of the methods described in the present disclosure. In this respect, the memory 14 constitutes a recording medium (or information medium) conforming to particular embodiments, readable by the processing device 10, and on which is recorded a computer program PG1 conforming to particular embodiments. This computer program PG1 comprises instructions for executing the steps of a processing method, particular embodiments of which are described in the present disclosure. The processor 12 is thus configured to execute the instructions of the computer program PG1 in order to carry out steps of the processing method.

[0078] Depending on the configuration and the type of computing device considered, the memory 14 may be volatile (such as RAM), non-volatile (such as ROM, flash, EEPROM, etc. or any other storage device and / or computer-readable medium as described below) or a combination of both. The memory 14 may, for example, be managed in DMA mode (for "Direct Memory Access" in English). The memory 14 used by the processing unit 10 may, for example, comprise all or part of a graphics card (or video card) memory, this type of memory being in particular capable of processing and / or sending image data that can be used to display one or more images on a display screen (or unit).

[0079] The processing device 10 may take the form of various suitable computer means (such as, for example, workstation, computer, server, etc.) comprising all or part of the elements described above as well as possibly other elements not mentioned.

[0080] As illustrated in [Fig.3], the ultrasonic device 20 may comprise for example one or more transducers (also called transducer elements) denoted 22, each being configured to convert an electrical signal SGI provided by the treatment device 10 into ultrasonic waves W (and possibly also vice versa). The transducers 22 may thus be configured to emit waves (or ultrasonic pulses, or ultrasonic beams) W1 into the medium M, which corresponds to a transmitting operation. These transducer elements may be arranged in any manner, for example in a line of transducers, a matrix, or in a network of transducers or any other suitable configuration.

[0081] Note that the transducers 22 may optionally also be configured to receive ultrasonic signals W2 from the medium M in a reception operation, for example in response to the transmitted waves W1, although variants according to which the ultrasonic device 20 operates only in transmission are also possible.

[0082] The ultrasound system S Y1 ([Fig.3]) may be an ultrasound imaging system, for example in the medical field. The ultrasound images generated by the system may either be analyzed in real time, for example by a user or an algorithm, and / or an artificial intelligence module, or analyzed later and / or in a location other than that in which the system SY1 is located.

[0083] The system SY1 may be a medical ultrasound system. Similarly, the transmitter device 20 may be a medical ultrasound probe.

[0084] For example, the system SY 1 can be associated with an ultrasound probe 20, in order to study a medium M ([Fig.3]), in particular to collect ultrasound data from such a medium M. The medium M thus observed can be of various natures depending on the case. It can be for example metals, tissues of living beings, in particular human tissues or animal tissues. The observation of a medium M comprising one or more mineral structures for example is also possible (gravel, volcano, mapping of a soil, for example of seabeds, etc.).

[0085] The SY 1 ultrasound system can be configured for various applications, in particular in the fields of acoustics, materials studies, medical imaging and / or biomedicine.

[0086] [Fig.4] schematically represents a non-limiting example of an embodiment of the SY 1 system as previously described with reference to [Fig. 3], namely in this case an ultrasound imaging system. In this example, the processing unit 10 is included in the body of a control station, the latter being further provided with a control interface and a display device. The ultrasound device 20 takes the form of an ultrasound probe, connected in this example in a communicative manner with the processing device 10 via a connection cable 26.

[0087] The ultrasound system SY 1 can be configured to produce an ultrasound image of various types, for example a B-mode image of the medium M (B-mode image displayed in grayscale), a so-called Doppler image illustrating the movements of fluids in the observed medium, and / or an image showing a mechanical characteristic of the medium (for example elastography image data obtained using shear waves (“ShearWave™ Elastography”)). According to one example, the electrical signal SGI transmitted by the treatment device 10 thus causes the emission by the ultrasonic device 20 of ultrasonic compression waves generating shear waves in a medium M.

[0088] As shown in [Fig.5] according to one embodiment, the processor 12 of the processing device 10, controlled by the computer program PG1 ([Fig.3]), can implement a generation module MD2 and a supply module MD4.

[0089] More specifically, the generation module MD2 can be configured to generate an electrical signal SGI defining ultrasonic waves W, the periodicity of the electrical signal SGI being modified (or adapted) by a modulation ML1 of the phase PHI of the signal SGI.

[0090] The supply module (or transmission module) MD4 can be configured to supply the electrical signal SGI to the ultrasonic emitting device 20 to cause the emission of the ultrasonic waves W.

[0091] The configuration and operation of the MD2-MD4 modules of the processing device 10 will appear more precisely in the exemplary embodiments described below with reference to the figures. The MD2-MD4 modules as shown in [Fig.5] represent only one non-limiting example of implementation of the invention.

[0092] Generally, for each step of the processing method of the present disclosure, the disclosure processing device may comprise a corresponding module configured to carry out said step (and vice versa).

[0093] Embodiments of the processing method of the disclosure are now described with reference to Figures 6 to 14. In these examples, the processing method is implemented by the ultrasound system SY1 (Figures 3, 4 and 5), and more precisely by the processing device 10. To do this, the processing device 10, cooperating with the ultrasound device 20, can execute the computer program PG1.

[0094] During a processing step E2 ([Fig.6]), the processing device 10 generates an electrical signal SGI defining ultrasonic waves W, the periodicity of the electrical signal SGI being modified, adapted, or controlled by a modulation ML1 of the phase PHI of the signal SGI.

[0095] The electrical signal SGI is a wave (or alternating) signal intended to control the ultrasonic device 20. By carrying out the ML1 modulation, the PHI phase (or the periodicity) of the SGI signal is disturbed. This PHI modulation may have the effect that the electrical signal SGI is not totally periodic or has a modified periodicity compared to a theoretical case where such ML1 modulation would not be applied to the SGI signal.

[0096] According to one example, the phase PHI is the instantaneous phase. As understood by those skilled in the art, the instantaneous phase of the electrical signal SGI differs from the phase at the origin. For example, for a sinusoidal SGI signal, this signal can be defined as follows:

[0097] [Math. 1] SG1= sin(2 • • / 0 ■ f + (p) where q> is the phase at the origin and where (2*Jt*fO*t + q>) is the instantaneous phase at time t.

[0098] The modulation ML1, achievable in various ways as described below in examples, can in particular be configured to cause a broadening of the frequency spectrum of the electrical signal SGI (and therefore of the ultrasonic waves W emitted at the output). This broadening makes it possible to reduce the frequency harmonics contained in the electrical signal SGI and thus to reduce the EM emissions of the ultrasonic device 20, or more generally of the ultrasonic system SY1.

[0099] During a supply or transmission step E4 ([Fig.6]), the processing device 10 supplies the electrical signal SGI to the ultrasonic device 20 to cause the emission of the ultrasonic waves Wl.

[0100] The electrical signal SGI may comprise periodic cycles. The waveform of the signal may vary depending on the case. The number of cycles during which the electrical signal SGI is transmitted may also be adapted depending on the case.

[0101] According to one example, the electrical signal SGI is transmitted for at least several tens of signal cycles, so as to cause a continuous emission of ultrasonic waves Wl towards a medium M (for example during an emission or “push” lasting approximately 100 ps). The ultrasonic waves Wl thus emitted are, for example, compression waves generating shear waves in the medium M considered (according to a shear wave elastography mode). By nature, the continuous emission of this type of waves tends to generate significant EM radiation, which it may be desirable to avoid.

[0102] According to one example, the modulation ML1 of the PHI phase of the electrical signal SGI is deterministic over time. In other words, the PHI modulation is implemented according to a predefined configuration. In particular, the selection of the cycle(s) of the SGI signal in which the PHI phase is modulated can be carried out in a deterministic or predefined manner.

[0103] According to one example, the modulation ML1 of the phase PHI of the electrical signal SGI is random over time. In particular, the selection of the cycle(s) of the signal SGI in which the phase PHI is modulated can be carried out randomly.

[0104] The present disclosure advantageously makes it possible to limit the EM radiation emitted by the ultrasonic emitting device 20 while ensuring satisfactory performance for the latter, for example in terms of spectral response and / or delivered acoustic energy (or power). It is thus advantageous to limit the level of EM emissions with minimal impact (or even no impact) on the desired operating performance of the ultrasonic emitting device 20.

[0105] To do this, the electrical signal supplied to the ultrasonic emitting device 20 is adapted (or processed) by modulating the phase PHI of the signal SGI. By disturbing the phase PHI of the electrical signal SGI, it is possible to advantageously reduce the harmonics contained in this signal and thus minimize the EM radiation. This modulation can advantageously be implemented in an existing emitting system or device, without requiring additional devices and / or structural modifications to the existing system or device. The complexity and costs of implementing the method are therefore limited.

[0106] In particular, it is advantageous to design an ultrasonic emitting device allowing optimal uses, efficient, while generating a minimum of electromagnetic emission in operation and presenting a limited complexity of design, manufacture and implementation and use.

[0107] The limitation of electromagnetic emissions may be achieved in various operating modes of the ultrasound emitting device. Examples of different operating modes of a emitting device in the form of an ultrasound probe may include a B-mode (i.e., a brightness mode), a Doppler mode, or a ShearWave(r) mode (i.e., a shear wave elastography mode). In other words, it is not necessary to change or modify the specific operating mode of an ultrasound emitting device to achieve the EM emission reductions, which may be achieved independently of the selection of the operating mode of the device.

[0108] For reference, Figures 1 and 2 represent a reference electrical signal 1 without modulation ML1, equivalent to the electrical signal SGI which would theoretically be generated in the examples of the present disclosure if no phase shift ML1 were applied in accordance with the present disclosure.

[0109] Examples of implementation of the modulation ML1 of the electrical signal SGI implemented by the processing device 10 during the step E2 of generation of the processing method are now described with reference to FIGS. 7 to 14.

[0110] According to a first embodiment illustrated in figures 7 and 8, the modulation ML1 of the phase PHI of the electrical signal SGI, noted in this case SG la, is carried out (step E2, [Fig.6]) by introducing (or adding), in the electrical signal SGla, at least one delay (or waiting period) 30, corresponding to a period during which the voltage of the electrical signal SGla is maintained at a constant value. As an example, this constant value is set to zero (0 Volts), although different values ​​are possible.

[0111] [Fig.7] represents in this example the modulated electrical signal SG 1a, where the time is represented along the abscissa axis (in number of clock cycles) and the signal voltage is represented along the ordinate axis. As illustrated, only one delay 30 is introduced into the electrical signal SGI in this example, although it is possible to introduce a plurality of them.

[0112] The introduction of one or more time delays 30 results in a division into N ultrasonic sub-emissions, shorter than if no time delay were applied, N being an integer at least equal to 1. It is thus possible to obtain a discontinuous periodic electrical signal SG la. In other words, the addition of the delay(s) 30 disrupts the periodicity of the electrical signal SG la.

[0113] According to one example, N is equal to 2 or more, which corresponds to the introduction of a plurality of delays 30 in the electrical signal SG la. The addition of a delay 30 between the ultrasonic sub-emissions advantageously makes it possible to minimize the harmonics contained in the electrical signal SG la (and therefore in the ultrasonic waves W at the output) and thus to limit the EM radiation caused by these harmonics.

[0114] More specifically, as illustrated in [Fig.8], the frequency spectrum 34 of the electrical signal SG 1a comprises for example a main peak 35 at a fundamental frequency and secondary peaks 36a, 36b and 36c (collectively denoted 36) at respective harmonic frequencies. The modulation ML1 by adding a delay 30 in this example makes it possible to significantly reduce the harmonics 36, in particular the harmonic 36c (multiple of 7 of the fundamental frequency), while maintaining the peak 35 at the fundamental frequency at a high level. In particular, the reduction in the harmonics 36 results from a spectral broadening caused by the time delay 30 which disrupts the periodicity of the signal SG 1a.

[0115] According to one example, the delay(s) 30 are configured to be less than the period of the electrical signal SGla, i.e. less than the duration of a periodic cycle of the signal SGla. In this way, it is advantageous to maintain the electrical energy density delivered by the signal SGI despite the application of the modulation ML1.

[0116] By way of example, the electrical signal SGla thus modulated produces a continuous ultrasonic emission (or “push”) of approximately 100 ps with a period of 0.5 ps. The delay(s) 30 are for example of the order of approximately 0.2 ps.

[0117] According to a second embodiment illustrated in figures 9 and 10, the modulation ML1 of the phase PHI of the electrical signal SGI, noted in this case SGlb, is carried out (step E2, [Fig.6]) by applying (or introducing) an angular shift of the phase PHI of the electrical signal SGlb in at least one cycle of said signal. This angular shift 40 corresponds to a phase shift of the signal SGI according to a given angular value. The angular value of this shift can be adapted according to the case. For example, This angular value can be set to 30° or 40°, although other values ​​are possible.

[0118] According to one example, an angular shift 40 is applied to a single cycle of electrical signal SG1a. According to another example, such an angular shift 40 is applied to a plurality of cycles of the electrical signal SG1b. The shift 40 may have the same value or a different value from one phase-shifted cycle to another.

[0119] [Fig.9] represents in this example the modulated electrical signal SGlb, where the time is plotted along the abscissa axis (in number of clock cycles) and the signal voltage is plotted along the ordinate axis. As illustrated in this example, an angular shift 40 of a value of 180° is applied to the SGI electrical signal in some cycles compared to other cycles where the signal is not phase shifted.

[0120] The application of one or more angular shifts 40 causes a phase shift between the cycles of the electrical signal SGlb, such that at least one cycle of the signal is out of phase with respect to at least one other cycle of the signal. In this case, it is thus possible to obtain a continuous periodic signal whose periodicity is disturbed or modified by the angular shift(s) 40.

[0121] In the example shown in [Fig.9], the angular shift of the PHI phase is set to a value of 180°, causing a sign inversion of the electrical signal in the phase-shifted cycle(s).

[0122] The application of one or more angular offsets advantageously makes it possible to minimize the harmonics contained in the electrical signal SGlb (and therefore in the ultrasonic waves W at the output) and thus to limit the EM radiation caused by these harmonics.

[0123] More specifically, as illustrated in [Fig.10], the frequency spectrum 44 of the electrical signal SGlb comprises for example a main peak 45 at a fundamental frequency and secondary peaks 46a, 46b and 46c (collectively denoted 46) at respective harmonic frequencies. The modulation ML1 by angular shift in this example makes it possible to significantly reduce the harmonics 46, in particular the harmonic 46c (multiple of 7 of the fundamental frequency), while maintaining the peak 45 at the fundamental frequency at a high level.

[0124] In particular, the reduction of the 46 harmonics results from a spectral broadening caused by the angular shift of the phase which disturbs the periodicity of the SGlb signal. As illustrated, we obtain in fact a multiplication of the frequency peaks contained in the SGlb signal compared to if no ML1 modulation were applied, which results in a redistribution of the electrical energy in the frequency spectrum of the SGlb signal.

[0125] According to one example, an angular shift 40 of 180° is randomly applied to the electrical signal SGlb to cause an inversion of the signal SGlb in at least one randomly chosen cycle. Such a random angular shift can also be applied for a non-zero value other than 180°.

[0126] According to one example, an angular shift 40 of 180° is deterministically applied to the electrical signal SGlb to cause an inversion of the signal SGlb in at least one predefined cycle. Such a deterministic angular shift may also be applied for a non-zero value other than 180°.

[0127] According to one example, angular offsets 40 of different values ​​are respectively applied to a plurality of cycles of the electrical signal SGlb.

[0128] Figures 11 and 12 represent an example similar to that of Figures 9-10, in which the modulation ML1 of the phase PHI of the electrical signal SGI, noted in this case SGlc, is carried out (step E2, [Fig.6]) by applying angular shifts of 18°, 35° and 53° of the phase PHI of the electrical signal SGI. This is equivalent to applying phase shifts to the signal SGlc according to these angular values.

[0129] More specifically, as illustrated in [Fig.12], the frequency spectrum 54 of the electrical signal SGlc comprises for example a main peak 55 at a fundamental frequency and secondary peaks 56a, 56b and 56c (collectively denoted 56) at respective harmonic frequencies. The modulation ML1 by angular shift in this example makes it possible to significantly reduce the harmonics 56, in particular the harmonic 56c (multiple of 7 of the fundamental frequency), while maintaining the peak 55 at the fundamental frequency at a high level.

[0130] The decrease in the 56 harmonics results from a spectral broadening caused by the angular shift of the phase which disturbs the periodicity of the SGlc signal. As illustrated, a multiplication of the frequency peaks contained in the SGlc signal is obtained compared to the case where no ML1 modulation is applied, which results in a redistribution of the electrical energy in the frequency spectrum of the SGlc signal.

[0131] According to a fourth embodiment illustrated in figures 13 and 14, the modulation ML1 of the phase PHI of the electrical signal SGI, noted in this case SGld, is carried out (step E2, [Fig.6]) by a variation 60 over time of the period of the cycles of the electrical signal SGld.

[0132] This variation 60 of the period can thus comprise for example an increase and / or a decrease in the period of the electrical signal SGlc over time. The manner in which the period of the signal SGld varies over time can be adapted according to the case.

[0133] According to one example, a variation 60 of the period is applied continuously over a plurality of consecutive cycles of the electrical signal SGld. This variation may for example be linear, or non-linear, over time.

[0134] [Fig. 13] represents in this example the modulated electrical signal SGld, where the time is represented along the abscissa axis (in number of clock cycles) and the signal voltage is represented along the ordinate axis. As illustrated in this example, the period of the electrical signal SGld is gradually increased over time over a plurality of cycles.

[0135] The application of such a period variation 60 advantageously makes it possible to minimize the harmonics contained in the electrical signal SGld (and therefore in the ultrasonic waves W at the output) and thus to limit the EM radiation caused by these harmonics.

[0136] More specifically, as illustrated in [Fig.14], the frequency spectrum 64 of the electrical signal SGld comprises for example a main peak 65 at a fundamental frequency and secondary peaks 66a, 66b, 66c and 66d (collectively denoted 66) at respective harmonic frequencies. The modulation ML1 by variation of the period in this example makes it possible to significantly reduce the harmonics 66, in particular the harmonic 66b (multiple of 7 of the fundamental frequency), while maintaining the peak 65 at the fundamental frequency at a high level.

[0137] In particular, the reduction of the harmonics 66 results from a spectral broadening caused by the variation 40 of the period which disturbs the periodicity of the signal SGld. As illustrated, we obtain in fact a multiplication of the frequency peaks contained in the signal SGld compared to the case where no ML1 modulation is applied, which results in a redistribution of the electrical energy in the frequency spectrum of the signal SGlb.

[0138] Thus, the ML1 modulation applied during step E2 ([Fig.6]) can therefore be carried out in various ways, the above embodiments being described only by way of example.

[0139] According to an example, the modulation ML1 (step E2, [Fig.6]) of the phase PHI is configured so that the electrical signal SGI delivers an electrical energy E2 at least equal to a theoretical energy El which would be delivered by the electrical signal SGI if its phase PHI were not disturbed by said phase modulation ML1 (E2 > El). By respecting this principle of conservation of the electrical energy, it is advantageous to obtain satisfactory performances, in particular in terms of acoustic energy (or power) delivered at the output of the ultrasonic device 20. It is thus advantageous to limit the level of electromagnetic emissions with a minimum impact (or even no impact) on the desired operating performances of the ultrasonic device 20.

[0140] According to one example, the modulation ML1 (step E2, [Fig.6]) of the phase is carried out while maintaining the same frequency f on each cycle of the electrical signal SGI.

[0141] As understood by a person skilled in the art, all the embodiments and variants described above, some of which have been deliberately simplified to facilitate explanations, constitute only non-limiting examples of implementation of the present disclosure. In particular, a person skilled in the art may envisage any adaptation or combination of the embodiments and variants described above, in order to meet a particular need.

[0142] The present disclosure is therefore not limited to the embodiments described above but extends in particular to a treatment method which would include secondary steps without thereby departing from the scope of the present disclosure. The same would apply to a treatment system for implementing such a method.

Claims

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8. Claims A method of processing an electrical signal (SGI) for an ultrasonic emitting device (20), said method comprising: - generation (E2) of an electrical signal (SGI) defining ultrasonic waves (W), the periodicity of the electrical signal being modified by a modulation (ML1) of the phase (PHI) of the signal; and - supplying (E4) the electrical signal (SGI) to the ultrasonic emitting device (20) to cause the emission of the ultrasonic waves (W), said ultrasonic waves (W) being compression waves generating shear waves in a medium (M), in which the modulation (ML1) of the phase (PHI) of the electrical signal comprises at least one of: - introduction, into the electrical signal (SGla), of at least one delay (30) corresponding to a period during which the voltage of the electrical signal is maintained at a constant value; and - an angular shift (40) of the phase of the electrical signal (SGlb) in at least one cycle of the electrical signal. The method of claim 1, wherein the modulation of the phase of the signal is configured to cause a broadening of the frequency spectrum of the electrical signal. The method of claim 1 or 2, wherein the modulation of the phase of the electrical signal is deterministic over time. The method of claim 1 or 2, wherein the modulation of the phase of the electrical signal is random over time. A method according to any preceding claim, wherein said at least one delay (30) is less than the period of the electrical signal. Method according to any one of the preceding claims, wherein the angular shift (40) is configured to cause an inversion of the phase (PHI) of the electrical signal (SGlb). Method according to any one of the preceding claims, in which the modulation (ML1) of the phase (PHI) of the electrical signal comprises a variation (60) of the period of the cycles of the electrical signal (SGld) over time. Method according to any one of the preceding claims, in which the modulation (ML1) of the phase is configured so that the electrical signal (SGI) delivers electrical energy at least equal to a theoretical energy which would be delivered by the electrical signal if its phase were not disturbed by said phase modulation.

9. Method according to any one of the preceding claims, in which the modulation (ML1) of the phase (PHI) is carried out while maintaining the same frequency on each cycle of the electrical signal (SGI).

10. A method according to any preceding claim, wherein said method is applied to ultrasound medical imaging.

11. Computer program (PG1) comprising instructions for carrying out the steps of a method according to any one of the preceding claims when said program is executed by a computer (10).

12. Device (10) for processing an electrical signal (SGI) for an ultrasonic emitting device (20), said processing device comprising: - a generation module (MD2) configured to generate an electrical signal (SGI) defining ultrasonic waves (W), the periodicity of the electrical signal being modified by a modulation (ML1) of the phase (PHI) of the signal;and - a supply module (MD4) configured to supply the electrical signal to the ultrasonic emitting device (20) to cause the emission of the ultrasonic waves (W), said ultrasonic waves (W) being compression waves generating shear waves in a medium (M), in which the generation module is configured to carry out the modulation (ML1) of the phase (PHI) of the electrical signal by at least one of: - introduction, in the electrical signal (SGla), of at least one delay (30) corresponding to a period during which the voltage of the electrical signal is maintained at a constant value; and - an angular shift (40) of the phase of the electrical signal (SGlb) in at least one cycle of the electrical signal.;

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