Method and device for processing electrical signal for ultrasound transmitting device

Abstract

The invention relates to a device (10) and a method for processing an electrical signal (SG1) for an ultrasound transmitting device (20). The method comprises: generating an electrical signal (SG1) defining an ultrasonic wave (W), the periodicity of the electrical signal (SG1) being varied by modulating (ML1) the phase (PH1) of the signal; and providing the electrical signal (SG1) to the ultrasound transmitting device (20) such that the ultrasound waves (W) are transmitted.

Description

Background Art

[0001] An ultrasound transmitting device (or ultrasound transmitting device) generally includes a plurality of transducer elements configured to transmit ultrasound waves for various purposes, such as for ultrasound imaging.

[0002] To achieve this effect, the ultrasonic transmitting device can be controlled by electrical signals, which can be transmitted by one or more pulse generators or linear amplifiers. These electrical signals define waves that are transmitted to the transducer elements of the transmitting device, which causes ultrasonic waves to be emitted into a given medium. These same transducer elements (or other transducer elements) can responsively generate electrical signals that represent the response (or echo) of the medium to the wave excitation.

[0003] Generally speaking, during operation, such ultrasound transmitting devices transmit electromagnetic waves (EM). In this respect, the ultrasound transmitting device also constitutes an electromagnetic wave transmitting device (also referred to as an EM transmitting device). However, high levels of electromagnetic radiation are not always desired.

[0004] Thus, there exist various standards to specify the permissible limit levels of electromagnetic emissions from electrical, scientific and medical equipment, such as IEC 60601-1-2, NF EN 55011 / CISPR 11 and IEC 61000-4-3.

[0005] In particular, the CISPR 11 standard (see, for example, version 6.2 of January 2019) defines the permissible limits (i.e. the "quasi-peak" values ​​of electromagnetic emissions) using different frequency ranges. Thus, in order for a device to be declared compliant with said standard, the energy of the electric field emitted by the device must not exceed these limits. For example, Table 6 of the CISPR 11 standard relates to the electromagnetic radiation disturbance limits for Class A Group 1 devices measured at a test site. Furthermore, Table 2 of the CISPR 11 standard relates to the disturbance voltage limits for Class A Group 1 devices measured at a test site. Medical devices, such as systems including ultrasound probes, are usually Class A as long as they are not household appliances.

[0006] In addition, the IEC 61000-4-3 / EN 61000-4-3 standard defines the electromagnetic compatibility (EMC) standard. Part 4-3 specifically covers the test and measurement techniques used, as well as immunity testing to radio frequency radiated electromagnetic fields.

[0007] Since ultrasound devices are designed to emit electromagnetic waves, they must remain compatible with the standards while allowing for optimal use, ie, emitting waves useful for the study of the area of ​​interest involved. Summary of the invention

[0008] As discussed above, electromagnetic emissions may need to be limited in terms of, for example, radiation, direction, and / or intensity, and conventional ultrasound transmitting devices are particularly problematic as they may be a source of such electromagnetic emissions.

[0009] One of the objects of the present invention is to solve at least one of the above problems or disadvantages.

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

[0011] In particular, it is an object of the present invention to develop an efficient ultrasound transmitting device which generates minimal electromagnetic emissions during operation and which has limited complexity in design, manufacture and use.

[0012] To this end, according to a first aspect, the invention relates to a method for processing an electrical signal for an ultrasound transmitting device, the method comprising:

[0013] - generating an electrical signal defining an ultrasonic wave, changing the periodicity of the electrical signal by modulating the phase of the signal; and

[0014] -Provide the electrical signal to the ultrasound transmitting device so that ultrasound waves are emitted.

[0015] Implementation of the method advantageously enables limiting the electromagnetic radiation emitted by the ultrasound transmitting device while ensuring that its performance, for example in terms of spectral response and / or acoustic energy (or power) provided, is satisfactory. It is thereby advantageously possible to limit the level of electromagnetic emissions while having minimal (ideally no) impact on the desired operating performance of the ultrasound transmitting device.

[0016] To this end, the electrical signal supplied to the ultrasound transmitting device is adjusted or altered by modulating the phase of the signal. By interfering with the phase of the electrical signal, it is advantageously possible to reduce the harmonics contained in the signal, thereby minimizing electromagnetic (EM) radiation. The modulation can advantageously be implemented in existing transmitting systems or devices without requiring additional equipment and / or structural changes to existing systems or devices. The complexity and costs involved in implementing the method can therefore be limited.

[0017] Electromagnetic emissions may be limited in various operating modes of the ultrasound transmitting device. Examples of different operating modes of a transmitting device in the form of an ultrasound probe may include B-mode (i.e., brightness mode), Doppler mode, or shear wave mode (i.e., shear wave elastography mode). In other words, in order to obtain a reduction in electromagnetic emissions according to the concepts of the present invention, it is not necessary to change or modify the specific operating mode of the ultrasound transmitting device. Thus, the electromagnetic emission reduction can be achieved independently of the selected operating mode, i.e., regardless of the operating mode of the device.

[0018] The method according to the invention may comprise further features which may be employed alone or in combination, in particular in the following embodiments which are presented purely as examples and which may be combined or linked unless otherwise indicated.

[0019] According to an example, the modulation of the phase of the signal is arranged to broaden the frequency spectrum of the electrical signal.

[0020] According to an example, the modulation of the phase of the electrical signal is deterministic over time.

[0021] According to an example, the modulation of the phase of the electrical signal is random over time.

[0022] According to one example, the modulation of the phase of the electrical signal includes:

[0023] - introducing at least one delay in the electrical signal, the delay corresponding to the period during which the voltage of the electrical signal remains at a constant value.

[0024] According to an example, the at least one delay is strictly smaller than a half period of the electrical signal.

[0025] According to an example, at least 4 delays are introduced into the electrical signal.

[0026] According to one example, the electrical signal comprises a plurality of consecutive sequences, each sequence comprising at least one wave period of the electrical signal, each pair of consecutive sequences being separated by a delay, the electrical signals generated during said sequences being in phase.

[0027] According to one example, the modulation of the phase of the electrical signal includes:

[0028] - An angular phase shift of the electrical signal in at least one period of the electrical signal.

[0029] According to one example, the angular offset is configured to cause a phase reversal of the electrical signal.

[0030] According to one example, an angular offset is introduced in each half cycle of the electrical signal.

[0031] According to one example, the angular offset introduced into the electrical signal gradually increases or decreases over time. According to one example, the electrical signal includes at least one first period (or first stage) and at least one second period (or second stage), the angular offset introduced into the electrical signal during the first period gradually increases, and the angular offset introduced into the electrical signal during the second period gradually decreases.

[0032] According to a specific example, the electrical signal modified by the modulation includes at least one of the following:

[0033] - at least one first phase during which the angular offset introduced into the electrical signal gradually increases; and

[0034] - at least one second phase, during which the angular offset introduced into the electrical signal gradually decreases.

[0035] According to one example, the modulation of the phase of the electrical signal includes a variation in the duration of a period of the electrical signal over time.

[0036] According to an example, the modulation of the phase is arranged such that the electrical signal provides an electrical energy at least equal to the theoretical energy that the electrical signal would provide if its phase was not disturbed by said phase modulation.

[0037] According to one example, the phase is modulated while maintaining the same frequency over each cycle of the electrical signal.

[0038] According to one example, ultrasonic waves are compression waves that generate shear waves in a medium.

[0039] According to one example, the method is applied to medical ultrasound imaging.

[0040] According to another aspect, the present invention may relate to a computer program comprising instructions which implement the method according to the first aspect when the program is executed by a computer. In particular, the individual steps of the method according to the first aspect may be defined by the computer program instructions.

[0041] The computer program may use any programming language or equivalent, and its form may be source code, object code, or a code intermediate between source code and object code, such as in a partially compiled form, or any other desirable form.

[0042] According to another aspect, the present invention relates to a computer (or processor) readable recording medium (or storage medium) having stored thereon a computer program according to the same aspect of the present invention.

[0043] In one aspect, the recording medium may be any entity or device capable of storing a program, such as at least one volatile and / or non-volatile memory. For example, the medium may include a storage medium, such as a rewritable non-volatile memory, a ROM, a CD-ROM, or a microelectronic circuit type ROM, or a magnetic recording medium or a hard disk. The memory may, for example, include a graphics card (or video card) memory, which type of memory is particularly configured to process image data (or video data).

[0044] On the other hand, the recording medium may also be a transmissible medium, such as an electrical or optical signal, which can be transmitted via an electrical or optical cable, by conventional or Hertzian radio or by a self-guided laser beam or in other ways. The computer program according to the invention may in particular be transmitted using a local or non-local wired or wireless network (e.g. Wi-Fi, Ethernet, Internet, 4G, 5G or other) to download.

[0045] Alternatively, the recording medium may be an integrated circuit in which the computer program is integrated, the integrated circuit being capable of executing the method or being used in the execution of the method.

[0046] According to another aspect, the present invention relates to a device for processing (or for controlling) an electrical signal for an ultrasound transmitting device, the device being configured to perform the method of the first aspect of the present invention.

[0047] According to an example, the processing device comprises a memory associated with a processor, the memory comprising the computer program according to the invention.

[0048] According to one example, the invention relates to a device for processing an electrical signal for an ultrasound transmitting device, the processing device comprising:

[0049] - a generation module configured to generate an electrical signal defining an ultrasonic wave, the periodicity of which is modified by modulating the phase of the signal; and

[0050] - providing a module configured to provide an electrical signal to the ultrasound transmitting device so as to cause the emission of ultrasound waves.

[0051] The processing device may have functions corresponding to the steps (or operations) of the method according to the present invention. In particular, the various embodiments and related advantages mentioned in the present invention with respect to the method of the present invention may be similarly applicable to the processing device (and vice versa).

[0052] The characteristics and advantages of the invention will appear more clearly on reading the following description, which is provided purely as a non-limiting example and with reference to the accompanying drawings. In particular, the examples shown in the accompanying drawings can be combined with each other, unless there are obvious inconsistencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Attached by the following reference Figures 1 to 14 Other features and advantages of the invention will become apparent from the description of a non-limiting exemplary embodiment of the invention, in which:

[0054] [ Figure 1 ] schematically shows an electrical signal of the prior art for controlling an ultrasound transmitting device according to an example, which has no phase modulation;

[0055] [ Figure 2 ] schematically illustrates a phase modulation without phase modulation according to an example Figure 1 The frequency spectrum of the electrical signal shown;

[0056] [ Figure 3] schematically illustrates an ultrasound system comprising a processing device and an ultrasound transmitting device according to an exemplary embodiment of the present invention;

[0057] [ Figure 4 ] schematically illustrates an exemplary embodiment of the present invention. Figure 3 The ultrasound system shown;

[0058] [ Figure 5 ] schematically illustrates an exemplary embodiment of the present invention. Figure 3 The processing equipment shown;

[0059] [ Figure 6 ] schematically illustrates in the form of a flow chart the steps of a processing method implemented by a processing device according to an exemplary embodiment of the present invention;

[0060] [ Figure 7 ] schematically illustrates an exemplary embodiment of the present invention. Figure 6 Modulation of the electrical signal during the processing method shown;

[0061] [ Figure 8 ] schematically illustrates an exemplary embodiment of the present invention. Figure 7 The frequency spectrum of the electrical signal shown;

[0062] [ Fig. 9 ] schematically illustrates an exemplary embodiment of the present invention. Figure 6 Modulation of the electrical signal during the processing method shown;

[0063] [ Fig.10 ] schematically illustrates an exemplary embodiment of the present invention. Fig. 9 The frequency spectrum of the electrical signal shown;

[0064] [ Fig.11 ] schematically illustrates an exemplary embodiment of the present invention. Figure 6 Modulation of the electrical signal during the processing method shown;

[0065] [ Fig.12 ] schematically illustrates an exemplary embodiment of the present invention. Fig.11 The frequency spectrum of the electrical signal shown;

[0066] [ Fig.13 ] schematically illustrates an exemplary embodiment of the present invention. Figure 6 Modulation of the electrical signal during the processing method shown; and

[0067] [ Fig.14 ] schematically illustrates an exemplary embodiment of the present invention. Fig.13 The frequency spectrum of the electrical signal is shown. DETAILED DESCRIPTION

[0068] The present invention relates to a method and a device for processing (or controlling) electrical signals for an ultrasound transmitting device.

[0069] like Figure 1 As shown in one example, the ultrasound transmitting device 2 is configured to transmit ultrasound waves W in response to one or more electrical signals 1. To this end, a control system (not shown) may be configured to provide these electrical signals 1 to the ultrasound transmitting device 2. The control system may include, in particular, one or more electronic pulse generators (also simply referred to as pulse generators) or linear amplifiers configured to generate one or more electrical signals 1 intended to control the ultrasound transmitting device 2.

[0070] The ultrasound transmitting device 2 may comprise one or more ultrasound transducers, each transducer being controlled by electrical signals 1 provided by a control system. These electrical signals 1 may be transmitted from a pulse generator to the transducers of the transmitting device 2 via a transmission chain.

[0071] It has been noted that the generation of ultrasound waves W by such an ultrasound transmitting device 2 generates electromagnetic (EM) emissions 3, which may need to be minimized, for example, in terms of its radiation, direction and intensity. In some cases, it is desirable to limit the EM radiation of such a transmitting device while ensuring that it performs well, for example in terms of spectral response and / or provided acoustic energy (or power). In particular, it may be desirable to limit the level of EM emissions 3 while minimizing the impact on the desired operating performance of the ultrasound transmitting device 2.

[0072] like Figure 2 As shown, the spectrum 4 of the electrical signal 1 provided to the ultrasonic transmitting device 2 generally includes at least one main peak at the fundamental frequency 5 (providing a large 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 originates from the periodicity of the electrical signal 1.

[0073] These harmonics 6 are outside the bandwidth of the transducer of the ultrasound transmitting device 2 and are not converted into acoustic energy, but are dissipated in the form of heat, which limits the energy efficiency of the device. The emission of such harmonics may also result in excessive electromagnetic radiation, which is particularly problematic when maximum limits on this radiation must be observed (e.g., to comply with mandatory regulations to obtain system certification).

[0074] In order to limit harmonics and prevent excessive electromagnetic radiation, it is known to use linear pulse generators or amplifiers capable of generating sinusoidal signals, but this technology is particularly expensive and not very effective, especially in the medical field, especially because the waves thus generated are limited in power and generate a lot of heat.

[0075] The above-mentioned constraints and / or problems therefore require a compromise, or limit certain characteristics of such ultrasonic emitting devices, in order to guarantee good performance and acceptable, or even optimized aging, according to the market requirements for the overall system. These constraints and / or problems may also make it difficult for such wave emitting devices to be certified according to current standards.

[0076] The present invention aims to solve the above-mentioned problems and limitations by processing the electrical signal provided to the ultrasonic transmitting device to limit the level of harmonics contained in the electrical signal while retaining the desired maximum acoustic energy (or signal level) at the fundamental frequency in order to ensure good performance of the ultrasonic transmitting device.

[0077] Now, according to the specific embodiment of the present invention, and with reference to Figures 3 to 14 , to describe a method and apparatus for processing (or controlling) an electrical signal for an ultrasound transmitting device. Unless otherwise specified, the same or similar elements in multiple figures have the same reference numerals and have the same or similar features, so for the sake of brevity, these common elements are generally not described repeatedly.

[0078] The term “first” (or “first, second”, etc.) is used herein as a random convention to allow identification or distinction of different elements (eg, operations, devices, etc.) performed or used in the following embodiments.

[0079] As mentioned above, the present invention particularly relates to a treatment method performed by an ultrasound transmitting device and the device. Figure 3 An ultrasound system SY1 is schematically shown, which includes a processing device (or control device) 10 and an ultrasound transmitting device 20 (also called an ultrasound transmission device, or a device for transmitting ultrasonic waves, or an ultrasound transducer device) according to an exemplary embodiment of the present invention.

[0080] More specifically, the processing device 10 is configured to control the ultrasonic transmitting device 20. To this end, the processing device 10 generates one or more electrical signals SG1 and transmits them to the ultrasonic device 20 so that the ultrasonic wave W1 is emitted. For the purpose of simplifying the description of the present invention, it will be considered below that the processing device 10 generates the electrical signal SG1 and transmits it to the ultrasonic device 20, but it should be understood that the electrical signal SG1 may include multiple electrical signals. The electrical signal SG1 emitted thereby controls the ultrasonic wave W1 emitted by the transmitting device 20.

[0081] The ultrasound transmitting device 20 (hereinafter also referred to as ultrasound device) is configured to transmit and possibly also receive waves W2. The ultrasound device 20 may, for example, take the form of an ultrasound probe (e.g., an echographic probe). The nature of these ultrasound waves W depends on the configuration of the ultrasound device 20, in particular in view of how it is used.

[0082] According to one example, the processing device 10 and the ultrasound device 20 are separate devices. Alternatively, all or part of the processing device 10 may be implemented in the ultrasound device 20.

[0083] In general, the ultrasound system SY1, and more specifically the processing device 10 and the ultrasound transmitting device 20, may be stationary or movable.

[0084] According to one example, the processing device 10 and the ultrasound device 20 form a single device, which is stationary or movable as the case may be.

[0085] For example, the ultrasound device 20 may be connected to the processing device 10 via a cable, or may communicate wirelessly therewith. In the latter case, the ultrasound device 20 may, for example, include a battery and receive communication signals from the processing device 10, which are representative of the electrical signal SG1 (e.g., any information and / or control frequency included in the electrical signal). The ultrasound device 20 may then internally reproduce the electrical signal SG1 based on the received communication signal.

[0086] The ultrasound device 20 may be, for example, a conventional ultrasound transmitting device which is controlled by the treatment device 10 according to the treatment method according to the invention.

[0087] like Figure 3 As shown, in this example, the processing device 10 includes 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 SG1. Once generated, the electrical signal SG1 is thereby sent to the ultrasonic device 20 so that the ultrasonic device 20 emits an ultrasonic wave W1 in the direction of the medium M and / or emits the ultrasonic wave W1 into the medium M. The electrical signal SG1 generated in this way represents (or defines) the ultrasonic wave W1 projected into the medium M. To this end, the processing unit 10 may, for example, be or include at least one electronic pulse generator (also referred to as a "pulser") capable of generating an electrical signal.

[0088] The electrical signal SG1 is such a wave (or alternating) signal that is processed by the processing device 10 to control the ultrasound device 20 to obtain good performance of the ultrasound device 20 while minimizing its EM emission. As described below, the processing device 10 is configured to control the ultrasound device 20 by controlling the phase PH1 ( Figure 3 ) to change the periodicity of the electrical signal SG1. When generating the electrical signal SG1, the processing device 10 may also perform various processing operations (amplification, filtering, digitization, regulation, etc. of the signal).

[0089] In some examples, processor 12 and memory 13 may be combined in Figure 3 The processing device 10 is shown, or may be incorporated in a computer or computing device communicatively coupled thereto.

[0090] The memory 14 can store instructions that define the steps of the method described in the present invention, in the form of a computer program PG1. In this respect, according to a specific embodiment, the memory 14 constitutes such a recording medium (or storage medium) that can be read by the processing device 10 and on which the computer program PG1 according to a specific embodiment is stored. The computer program PG1 includes instructions for executing the steps of the processing method whose specific embodiment is described in the present invention. The processor 12 is thus configured to execute the instructions of the computer program PG1 to execute the steps of the processing method.

[0091] Depending on the configuration and type of computing device under consideration, the memory 14 may be volatile (e.g., RAM), non-volatile (e.g., ROM, flash memory, EEPROM, etc., or any other storage device and / or computer-readable medium as described below), or a combination of both. The memory 14 may be managed, for example, in DMA (direct memory access) mode. The memory 14 used by the processing unit 10 may, for example, include all or part of a graphics card (or video card) memory, a type of memory that is configured, in particular, to process and / or transmit image data that may be used to display one or more images on a display screen (or unit).

[0092] The processing device 10 may take the form of various suitable computing devices (eg, workstations, computers, servers, etc.) including all or part of the above-mentioned elements and possibly other elements not mentioned.

[0093] like Figure 3 As shown, the ultrasound device 20 may include, for example, one or more transducers (also referred to as transducer elements) 22, each of which is configured to convert the electrical signal SG1 provided by the processing device 10 into an ultrasonic wave W (and possibly convert the ultrasonic wave W into an electrical signal SG1). The transducer 22 may thus be configured to transmit a wave (or ultrasonic pulse, or ultrasonic beam) W1 into the medium M, which corresponds to a transmitting operation. These transducer elements may be arranged in any manner, such as in a transducer arrangement, a matrix, a transducer array, or any other suitable configuration.

[0094] It is noted that, possibly, the transducer 22 may also be configured to receive in receiving operation an ultrasound signal W2 from the medium M, for example in response to the transmitted wave W1 , but variants are also possible in which the ultrasound device 20 operates only in transmitting mode.

[0095] Ultrasonic system SY1( Figure 3 ) may be, for example, an ultrasound imaging system in the medical field. The ultrasound images generated by the system may be analyzed in real time, for example by a computer or an algorithm and / or an artificial intelligence module, or analyzed afterwards and / or at a location other than where the system SY1 is located.

[0096] The system SY1 may be a medical ultrasound system. Similarly, the transmitting device 20 may be a medical ultrasound probe.

[0097] For example, the system SY1 can be associated with an ultrasound probe 20 to study the medium M ( Figure 3 ), in particular collecting ultrasound data from the medium M. The medium M thus observed may have various forms depending on the situation. It may be, for example, metal or living tissue, in particular human or animal tissue. It is also possible to observe a medium M comprising one or more inorganic structures, such as gravel, volcanoes, soil mapping, for example the seabed, etc.

[0098] The ultrasound system SY1 may be designed for a variety of applications, in particular in the fields of acoustics, material research, medical imaging and / or biomedicine.

[0099] Figure 4 Schematically showing the above reference Figure 3 A non-limiting exemplary embodiment of the system SY1 described, in this case an ultrasound imaging system. In this example, the processing unit 10 is included in the body of a control station, which is also equipped with a control interface and a display device. The ultrasound device 20 takes the form of an ultrasound probe, which in this example is communicatively connected to the processing device 10 via a connecting cable 26.

[0100] The ultrasound system SY1 can be configured to generate various types of ultrasound images, such as a B-mode image of the medium M (B-mode grayscale image), a so-called Doppler image showing fluid motion in the observed medium, and / or an image showing mechanical properties of the medium (e.g. ShearWave TM Elastography image data). According to one example, the electrical signal SG1 emitted by the processing device 10 thereby causes the ultrasound device 20 to emit an ultrasound compression wave that generates a shear wave in the medium M.

[0101] like Figure 5 According to one embodiment, a computer program PG1 ( Figure 3 ) The processor 12 of the processing device 10 controlled by the processor 12 can use the generation module MD2 and the provision module MD4.

[0102] More specifically, the generation module MD2 may be configured to generate an electrical signal SG1 defining the ultrasonic wave W, and to change (or adjust) the periodicity of the electrical signal SG1 by modulating ML1 the phase PH1 of the signal SG1 .

[0103] The providing module (or transmitting module) MD4 may be configured to provide the electrical signal SG1 to the ultrasound transmitting device 20 so that the ultrasound wave W is transmitted.

[0104] The configuration and operation of the modules MD2 to MD4 of the processing device 10 will become more apparent in the exemplary embodiments described below with reference to the accompanying drawings. Figure 5 The modules MD2 to MD4 shown represent only one non-limiting exemplary embodiment of the present invention.

[0105] Generally speaking, for each step in the processing method of the present invention, the processing device of the present invention may include a corresponding module configured to perform the step (or vice versa).

[0106] Now refer to Figures 6 to 14 Embodiments of the processing method of the present invention are described. In these examples, the ultrasonic system SY1 ( Figure 3 , Figure 4 and Figure 5 ), more specifically, the processing method is performed by the processing device 10. To this end, the processing device 10 in cooperation with the ultrasound device 20 may run a computer program PG1.

[0107] In processing step E2( Figure 6 ), the processing device 10 generates an electrical signal SG1 defining an ultrasonic wave W, the periodicity of which is changed, adjusted or controlled by modulating ML1 the phase PH1 of the signal SG1.

[0108] The electrical signal SG1 is a wave (or alternating) signal intended to control the ultrasound device 20. The phase PH1 (or periodicity) of the signal SG1 is disturbed by the modulation ML1. The effect of this modulation ML1 may be that the electrical signal SG1 is not completely periodic or has a modified periodicity compared to the theoretical case where no modulation ML1 is applied to the signal SG1.

[0109] According to one example, the phase PH1 is an instantaneous phase. As is understood by those skilled in the art, the instantaneous phase of the electrical signal SG1 is different from the original phase. For example, for a sinusoidal signal SG1, the signal may be defined as follows:

[0110]

[0111] in, is the original phase, and where, is the instantaneous phase at point t.

[0112] Modulation ML1 can be implemented in various ways as described below in the examples, and in particular can be configured to broaden the spectrum of the electrical signal SG1 (and the ultrasonic waves W emitted thereby). This broadening can reduce the frequency harmonics contained in the electrical signal SG1, thereby reducing the EM emission of the ultrasonic device 20, or more generally the ultrasonic system SY1.

[0113] In providing or transmitting step E4 ( Figure 6 ), the processing device 10 provides the electrical signal SG1 to the ultrasonic device 20, so that the ultrasonic wave W1 is emitted.

[0114] The electrical signal SG1 may include periodic cycles. The waveform of the signal may vary according to different situations. The number of cycles of transmitting the electrical signal SG1 may also be adjusted as needed.

[0115] According to one example, the electrical signal SG1 is transmitted during at least several tens of signal cycles so that the ultrasonic wave W1 is continuously emitted to the medium M (e.g. during a "push" or emission lasting about 100 μs). The ultrasonic wave W1 emitted in this way is, for example, a compression wave that generates a shear wave in the medium M under consideration (in shear wave elastography mode). Due to its own nature, the continuous emission of such waves tends to generate significant EM radiation, which may need to be prevented.

[0116] According to an example, the modulation ML1 of the phase PH1 of the electrical signal SG1 is deterministic over time. In other words, the modulation ML1 is performed according to a predetermined configuration. In particular, one or more periods of the signal SG1 in which the phase PH1 is modulated may be selected in a deterministic or predetermined manner.

[0117] According to an example, the modulation ML1 of the phase PH1 of the electric signal SG1 is random over time. In particular, one or more periods of the signal SG1 in which the phase PH1 is modulated may be randomly selected.

[0118] The present invention advantageously enables limiting the EM radiation emitted by the ultrasound transmitting device 20 while ensuring good performance, for example in terms of spectral response and / or acoustic energy (or power) provided. It is thereby advantageously possible to limit the EM emission level while minimizing the impact on the desired operating performance of the ultrasound transmitting device 20 (ideally having no impact).

[0119] To this end, the electrical signal provided to the ultrasound transmitting device 20 is adjusted (or processed) by modulating the phase PH1 of the signal SG1. By interfering with the phase PH1 of the electrical signal SG1, it is advantageously possible to reduce the harmonics contained in the signal, thereby minimizing EM radiation. The modulation can advantageously be performed in an existing transmitting system or device without requiring additional equipment and / or structural changes to the existing system or device. The complexity and costs involved in performing the method are thus limited.

[0120] In particular, it would be advantageous to be able to develop efficient ultrasound emitting devices which allow for optimized use while generating minimal electromagnetic emissions during operation and which have limited complexity in design, manufacture and use.

[0121] Electromagnetic emissions may be limited in various operating modes of the ultrasound transmitting device. Examples of different operating modes of a transmitting device in the form of an ultrasound probe may include B-mode (i.e., brightness mode), Doppler mode, or shear wave mode (i.e., shear wave elastography mode). In other words, a reduction in EM emissions may be obtained without changing or modifying the specific operating mode of the ultrasound transmitting device, which can be independent of the selection of the operating mode of the device.

[0122] As a reference, Figure 1 and Figure 2 A reference electrical signal 1 without modulation ML1 is shown, which is equivalent to the electrical signal SG1 which would theoretically be generated in the example of the invention if the phase shift ML1 were not applied according to the invention.

[0123] Now refer to Figures 7 to 14 An exemplary embodiment of a modulation ML1 of the electric signal SG1 performed by the processing device 10 during the generation step E2 of the processing method is described.

[0124] It is noted that the electrical signal SG1 can be modulated according to various embodiments, for example, as described below, which modulation ML1 can be combined with the electrical signal SG1 described below, especially with reference to Figures 7 to 14 At least two of the described embodiments may be applied in any manner. In other words, a plurality of the modulation techniques described below in the examples may be applied cumulatively.

[0125] according to Figure 7 and Figure 8 In the first embodiment shown, ML1 is modulated (step E2, Figure 6 ) The phase PH1 of the electrical signal SG1 (SG1a in this example) is performed by introducing (or adding) at least one delay (or waiting period) 30 in the electrical signal SG1a, which corresponds to a period for maintaining the voltage of the electrical signal SG1a at a constant value. As an example, the constant value is fixed to zero (0 volts), but other values ​​are also feasible.

[0126] In this example, Figure 7 A modulated electrical signal SG1a is shown, with time (in number of clock cycles) shown along the x-axis and the voltage of the signal shown along the y-axis. As shown, a single delay 30 is introduced into the electrical signal SG1 in this example, but multiple delays may be introduced.

[0127] Introducing one or more time delays 30 will result in N ultrasound sub-emissions being split into shorter ones than if no time delays were applied, N being an integer at least equal to 1. This produces a discontinuous periodic electrical signal SG1a. In other words, adding one or more delays 30 disturbs the periodicity of the electrical signal SG1a.

[0128] According to one example, N is equal to 2 or more, which corresponds to introducing a plurality of delays 30 into the electrical signal SG1a. Adding delays 30 between ultrasound sub-transmissions can advantageously minimize the harmonics contained in the electrical signal SG1a (and thus in the output ultrasound waves W), thereby limiting the EM radiation caused by these harmonics.

[0129] According to one example, the modulation ML1 is implemented such that N is at least equal to 4 (N≥4). It is thereby possible to introduce delays 30 between the ultrasound sub-emissions that together form the electrical signal SG1a. The repetition of these delays 30 advantageously enables the generation of the electrical signal SG1a and thus of the ultrasound waves W over a relatively long period of time, while effectively minimizing the electromagnetic radiation. In particular, the repetition of the delays 30 over time (e.g. 10, 20, 30 or 40 delays 30) enables the broadening of the spectrum of the signal, thus causing a redistribution of the electrical energy, which results in a reduction in the peak spectral density of the electromagnetic emission.

[0130] Exemplarily, compression waves may advantageously be generated in the form of continuous ultrasound transmissions referred to as “push”, i.e., periods of such electrical signal SG1 interspersed with delays 30 (e.g., 4 or more delays) that allow shear waves to be generated in the medium of interest while limiting the electromagnetic radiation likely to be emitted by the probe 20.

[0131] According to one example, the length of one or more delays 30 introduced into the electrical signal SG1 is strictly less than a half period (or one third or one quarter of a period) of the electrical signal SG1, which makes it possible to minimize the waiting time during the delay 30, thereby speeding up the generation of the ultrasonic wave W while limiting the electromagnetic radiation by effectively interrupting the periodicity of the signal. This embodiment is particularly configured to generate shear waves, which requires the generation of a relatively long "push" of the electrical signal SG1. Therefore, it becomes crucial to limit the length of the delay 30 as much as possible so that the method can be performed within a limited time.

[0132] According to a specific example, in E2( Figure 6) comprises a plurality of successive sequences, each sequence comprising at least one wave period (or at least one period) of the electric signal SG1 according to a given frequency, a delay 30 being applied between each pair of successive sequences (or separating them). According to an example, the electric signal SG1 generated during all these sequences over time is in phase (or is identical), which advantageously enables limiting interference or interference that may be caused between different sequences of the electric signal SG1. According to an example, the frequency of the electric signal SG1 is the same in each sequence (in other words, the frequency is constant outside the delay period), which advantageously enables, in particular, the use of a transducer with a very narrow frequency bandwidth, or the use of a waveform offset that repeats the same waveform in time to reduce the memory space required to store the emitted waveform.

[0133] More specifically, if Figure 8 As shown, the spectrum 34 of the electrical signal SG1a includes, for example, a main peak 35 at the fundamental frequency and secondary peaks 36a, 36b and 36c (collectively denoted as 36) at various harmonic frequencies. In this example, the modulation ML1 by adding the delay 30 enables the harmonics 36, in particular the harmonic 36c (7 times the fundamental frequency), to be significantly reduced while maintaining the peak 35 at the fundamental frequency at a high level. In particular, the reduction of the harmonics 36 originates from the spectrum broadening caused by the periodic time delay 30 that corrupts the signal SG1a.

[0134] According to an example, the one or more delays 30 are configured to be smaller than the period of the electrical signal SG1a, ie, smaller than the length of one periodic period of the signal SG1a. Thus, despite the application of the modulation ML1, the electrical energy density provided by the signal SG1 is advantageously maintained.

[0135] Exemplarily, the electrical signal SG1a modulated in this way generates a continuous ultrasound emission (or "push") of approximately 100 μs, with a period of 0.5 μs. The one or more delays 30 are, for example, approximately 0.2 μs.

[0136] according to Fig. 9 and Fig.10 In the second embodiment shown, ML1 is modulated (step E2, Figure 6 ) The phase PH1 of the electrical signal SG1 (SG1b in this example) is performed by applying (or introducing) an angular shift of the phase PH1 of the signal in at least one cycle of the electrical signal SG1b. The angular shift 40 corresponds to a phase shift of the signal SG1 by a given angular value. If necessary, the angular value of the phase shift can be adjusted. Exemplarily, the angular value can be fixed to 30° or 40°, but other values ​​are also feasible.

[0137] According to one example, the angular offset 40 is applied to a single period of the electrical signal SG1a. According to another example, the angular offset 40 is applied to a plurality of periods of the electrical signal SG1b. The offset 40 may have the same value or different values ​​between different periods that are phase-shifted.

[0138] In this example, Fig. 9 The modulated electrical signal SG1b is shown, wherein time (in clock cycles) is shown along the x-axis and the voltage of the signal is shown along the y-axis. As shown in this example, an angle shift 40 of 180° is applied to the signal in some cycles relative to other cycles where the electrical signal SG1 is not phase shifted.

[0139] Applying one or more angular offsets 40 causes a phase shift between periods of the electrical signal SG1b, so that at least one period of the signal is phase shifted relative to at least one other period of the signal. In this example, this results in a continuous periodic signal whose periodicity is disturbed or changed by one or more angular offsets 40.

[0140] exist Fig. 9 In the example shown, the angular shift of the phase PH1 is fixed to a value of 180°, which results in a sign reversal of the electrical signal in one or more periods of the phase shift.

[0141] Applying one or more angular offsets may advantageously minimize the harmonics contained in the electrical signal SG1b (and thus in the output ultrasonic wave W), thereby limiting the EM radiation caused by these harmonics.

[0142] More specifically, if Fig.10 As shown, the spectrum 44 of the electric signal SG1b includes, for example, a main peak 45 at the fundamental frequency and sub-peaks 46a, 46b and 46c (collectively labeled 46) at the respective harmonic frequencies. In this example, the modulation ML1 by the angle shift makes it possible to significantly reduce the harmonics 46, especially the harmonic 46c (7 times the fundamental frequency), while maintaining the peak 45 of the fundamental frequency at a high level.

[0143] In particular, the reduction of harmonics 46 results from the spectral broadening caused by the phase angle shift that corrupts the periodicity of signal SG1b. As shown, this doubles the frequency peaks contained in signal SG1b compared to if modulation ML1 is not applied, thus causing a redistribution of the power in the spectrum of signal SG1b.

[0144] According to an example, an angular offset 40 of 180° is randomly applied to the electrical signal SG1b so that the signal SG1b is inverted in at least one randomly selected period. The random angular offset may also be applied with a non-zero value different from 180°.

[0145] According to one example, an angular offset 40 of 180° is deterministically applied to the electrical signal SG1b so that the signal SG1b is inverted in at least one cycle selected in a predetermined manner. The deterministic angular offset can also be applied with a non-zero value different from 180°.

[0146] According to an example, the angle offset 40 having different values ​​is applied to a plurality of periods of the electrical signal SG1 b .

[0147] Fig.11 and Fig.12 Shown with Figures 9 and 10 An example similar to the example shown, in which ML1 is modulated (step E2, Figure 6 ) The phase PH1 of the electrical signal SG1 (SG1c in this example) is obtained by applying a voltage 50 ( Fig.11 ) is performed by applying an angular shift of 18°, 35° and 53° to the signal SG1c. This is equivalent to applying a phase shift to the signal SG1c according to these angular values.

[0148] More specifically, if Fig.12 As shown, the spectrum 54 of the electric signal SG1c includes, for example, a main peak 56 at the fundamental frequency and sub-peaks 56a, 56b and 56c (collectively labeled 56) at the respective harmonic frequencies. In this example, the modulation ML1 by the angle shift makes it possible to significantly reduce the harmonics 56, especially the harmonic 56c (7 times the fundamental frequency), while maintaining the peak 55 of the fundamental frequency at a high level.

[0149] The reduction of harmonics 56 results from the spectral broadening caused by the phase angle shift that destroys the periodicity of signal SG1. As shown, this doubles the frequency peaks contained in signal SG1c compared to if modulation ML1 is not applied, thus causing a redistribution of the power in the spectrum of signal SG1c.

[0150] According to one example, ML1 is modulated by applying (or introducing) an angle shift 50 to each half-period of the signal SG1 (step E2, Figure 6 ) The phase PH1 of the electrical signal SG1. The angular offset 50 can have the same value for each half cycle or can be varied as required. By applying two angular offsets 50 per cycle in the electrical signal SG1c, the spectrum of the signal can be effectively widened, thereby minimizing the peak of the electromagnetic emission while maintaining the high power level provided by the electrical signal SG1.

[0151] According to one example, the angular offset 50 introduced into the signal SG1 gradually increases or decreases over time. Exemplarily, the angular offset introduced in each half cycle of the signal SG1 gradually increases or decreases over time. It is thereby possible to form waves that, for example, get closer together or farther apart over time, which advantageously enables efficient distribution of the electrical energy of the electrical signal SG1 (spectral broadening), thereby minimizing electromagnetic emissions. It is also feasible to combine increasing and decreasing angular phase offsets. Thus, according to one example, the electrical signal SG1 includes at least one first period (or first stage) during which the angular offset introduced into the electrical signal gradually increases and at least one second period (or second stage) during which the angular offset introduced into the electrical signal gradually decreases. The electrical signal SG1 may in particular include alternating first and second stages, in which these angular offsets increase and decrease over time, respectively.

[0152] according to Fig.13 and Fig.14 In the fourth embodiment shown, ML1 is modulated (step E2, Figure 6 ) The phase PH1 of the electric signal SG1 (SG1d in this example) is achieved by varying the duration of the cycle of the electric signal SG1d by 60° over time.

[0153] The variation 60 of the period may thus for example comprise an increase and / or decrease in the period of the electrical signal SG1d over time. The manner in which the period of the signal SG1d varies over time may be adjusted as required.

[0154] According to an example, the periodic variation 60 is continuously applied to a plurality of consecutive periods of the electrical signal SG1d. The variation may be, for example, linear over time, or non-linear.

[0155] In this example, Fig.13 The modulated electrical signal SG1d is shown, where time (in the number of clock cycles) is shown along the x-axis and the voltage of the signal is shown along the y-axis. As shown in this example, over a plurality of cycles, the cycle of the electrical signal SG1d gradually lengthens with time.

[0156] Applying this variation 60 may advantageously minimize the harmonics contained in the electrical signal SG1d (and therefore in the output ultrasonic wave W) and thereby limit the EM radiation caused by these harmonics.

[0157] More specifically, if Fig.14 As shown, the spectrum 64 of the electric signal SG1d includes, for example, a main peak 65 at the fundamental frequency and sub-peaks 66a, 66b, 66c and 66d (collectively labeled 66) at respective harmonic frequencies. In this example, the modulation ML1 of varying period makes it possible to significantly reduce the harmonics 66, especially the harmonic 66b (7 times the fundamental frequency), while maintaining the peak 65 of the fundamental frequency at a high level.

[0158] Specifically, the reduction of harmonics 66 results from the spectral broadening caused by the periodic variation 40 that corrupts the periodicity of signal SG1d. As shown, this doubles the frequency peaks contained in signal SG1d compared to if no modulation ML1 was applied, thereby causing a redistribution of the power in the spectrum of signal SG1d.

[0159] Therefore, in step E2 ( Figure 6 ) can therefore be implemented in various ways, the above embodiments being described only as examples.

[0160] According to one example, the modulation ML1 of the phase PH1 (step E2, Figure 6 ) is configured such that the electrical energy E2 provided by the electrical signal SG1 is at least equal to the theoretical energy E1 that the electrical signal SG1 would provide if the phase PH1 was not disturbed by the phase modulation ML1 (E2 ≥ E1). By adhering to this principle of maintaining electrical energy, it is advantageously possible to obtain satisfactory performance, in particular in terms of the acoustic energy (or power) provided at the output of the ultrasound device 20. It is thereby advantageously possible to minimize the impact on the desired operating performance of the ultrasound device 20 (ideally without any impact) while limiting the level of electromagnetic emissions.

[0161] According to one example, the phase of ML1 is modulated while maintaining the same frequency f for each cycle of the electrical signal SG1 (step E2, Figure 6 ).

[0162] As will be appreciated by those skilled in the art, all of the above embodiments and variations (some of which have been deliberately simplified to make them easier to explain) constitute only non-limiting exemplary embodiments of the present invention. In particular, those skilled in the art may conceive to adjust or combine the above embodiments and variations to address specific needs.

[0163] Therefore, the present invention is not limited to the exemplary embodiments described above, but extends in particular to a processing method comprising secondary steps without departing from the scope of the present invention. The same applies to a processing system for carrying out the method.

Claims

1. A method for processing an electrical signal (SG1) for an ultrasonic transmitting device (20), the method comprising: - generating (E2) an electrical signal (SG1) defining an ultrasonic wave (W), the periodicity of said electrical signal being varied by modulating (ML1) the phase (PH1) of said signal; as well as - providing (E4) the electrical signal (SG1) to the ultrasound transmitting device (20) so as to cause the ultrasound wave (W) to be emitted.

2. The method of claim 1, wherein: The modulation (ML1) of the phase (PH1) of the electrical signal comprises: - introducing at least one delay (30) in said electrical signal (SG1a), said delay corresponding to a period during which the voltage of said electrical signal is maintained at a constant value.

3. The method of claim 2, wherein: The at least one delay (30) is strictly smaller than a half period of the electrical signal.

4. The method according to claim 2 or 3, wherein: At least four delays (30) are introduced into the electrical signal.

5. The method according to any one of claims 2 to 4, wherein: The electrical signal comprises a plurality of successive sequences, each sequence comprising at least one wave period of the electrical signal, each pair of successive sequences being separated by a delay, and the electrical signals generated during the sequences being in phase.

6. A method as claimed in any one of the preceding claims, wherein: The modulation (ML1) of the phase (PH1) of the electrical signal comprises: - an angular phase shift (40; 50) of the electrical signals (SG1b, SG1c) in at least one period of the electrical signals.

7. The method of claim 6, wherein: The angle shift (40) is configured to invert the phase (PH1) of the electrical signal (SG1b).

8. The method according to claim 6 or 7, wherein: An angular offset (50) is introduced in each half cycle of the electrical signal (SG1c).

9. The method of claim 8, wherein: The electrical signal changed by the modulation includes at least one of the following: - at least one first phase during which said angular offset introduced into said electrical signal gradually increases; and - at least one second phase during which said angular offset introduced into said electrical signal is gradually reduced.

10. A method as claimed in any one of the preceding claims, wherein: The modulation (ML1) of the phase (PH1) of the electrical signal comprises a time-varying (60) of the duration of a period of the electrical signal (SG1d).

11. A method as claimed in any one of the preceding claims, wherein: The modulation (ML1) of the phase is configured so that the electrical signal (SG1) provides an electrical energy E2 at least equal to the theoretical energy that the electrical signal would provide if its phase PH1 was not disturbed by the phase modulation.

12. A method as claimed in any one of the preceding claims, wherein: The phase (PH1) is modulated (ML1) while maintaining the same frequency for each cycle of the electrical signal (SG1).

13. A method as claimed in any one of the preceding claims, wherein: The ultrasonic wave (W) is a compression wave that generates a shear wave in a medium (M).

14. A method as claimed in any one of the preceding claims, wherein: The method is applied to medical ultrasound imaging.

15. A computer program (PG1) comprising instructions for executing the steps of the method as claimed in any one of the preceding claims when the program is run by a computer (10).

16. A device (10) for processing an electrical signal (SG1) for an ultrasonic transmitting device (20), the processing device comprising: - a generation module (MD2) configured to generate an electrical signal (SG1) defining an ultrasonic wave (W), the periodicity of said electrical signal being varied by modulating (ML1) the phase (PH1) of said signal; and - a providing module (MD4) configured to provide the electrical signal to the ultrasound transmitting device (20) so as to cause the ultrasound wave (W) to be emitted.

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