Device for detecting magnetic signal generated by beating heart

Abstract

The invention relates to a device (2) for detecting a magnetic signal generated by a beating heart (M), comprising: at least one nitrogen-vacancy-center, NV, magnetometer unit (4), which is designed to detect a magnetic field intensity and / or field direction; at least one further sensor (5); a signal processing unit (170, 11), to which the at least one NV magnetometer unit (4) and the at least one further sensor (5) are connected, wherein the device is designed to determine at least one effective magnetic field intensity and / or at least one effective field direction from the signals of the at least one NV magnetometer unit (4) and the at least one further sensor (5) by means of the signal processing unit (170, 11).

Description

[0001] The present invention relates to a device for detecting magnetic signals generated by a beating heart. Background Art

[0002] In order to measure very small magnetic field strengths, quantum sensors that are optically pumped or based on NV centers in diamond are particularly suitable as sensors. DE 102022204526.2 describes a magnetometer that uses optically pumped and optically detected magnetic resonance (optically detected magnetic resonance, ODMR). What is used here is the energy level splitting of a specific spin state of unpaired electrons under the influence of an external magnetic field, the so-called Zeeman effect. By splitting the energy levels, when relaxing from the excited state, a change transition is generated, which can then be measured, for example, by optical excitation and frequency-dependent detection of the generated fluorescent radiation or by observing optical properties such as absorption of light. Then, the magnetic field strength can be inferred from the measured optical parameters. Summary of the invention

[0003] According to the invention, a device for detecting magnetic signals generated by a beating heart is provided having the features of claim 1. Advantageous embodiments are the subject matter of the dependent claims and the following description.

[0004] The magnetocardiogram (MKG for short) is the recording and graphic representation of the magnetic field of the heart, which is generated by the electrophysiological activity of the myocardial cells. Within the scope of the present invention, a contactless, passive approach to long-term monitoring of the human heart with high resolution is presented. This is achieved by at least one nitrogen-vacancy magnetometer unit (so-called NV magnetometer unit).

[0005] In detail, a device for detecting magnetic signals generated by a beating heart is now described, the device having: at least one NV-magnetometer unit, which is configured to: detect magnetic field strength and / or field direction; at least one further sensor; and a signal processing unit, the at least one NV-magnetometer unit and the at least one further sensor being connected to the signal processing unit, wherein the device is configured to: determine at least one effective magnetic field strength and / or at least one effective field direction from the signals of the at least one NV-magnetometer unit and the at least one further sensor by means of the signal processing unit. Both a wireless connection and a wired connection are provided between the sensor device and the signal processing unit. Such a device can also be referred to as a magnetocardiograph.

[0006] The present invention studies a signal processing for a magnetocardiograph that is particularly, but not exclusively, related to applications in a home environment. The signal processing used for this situation has in particular the task of being independent of external magnetic field interference quantities. In all places where electric charges move or magnetic or magnetizable materials move, the environmental magnetic field changes. This must be separated from the signal by corresponding signal processing in order to enable the signal to be measured. In addition, particularly good signal processing can achieve improvements in signal resolution, and thereby achieve detection of rare and difficult-to-detect artifacts in the time variation curve of cardiac signals or other biomedical signals and detection of symptoms associated therewith. In the present disclosure, the advantages brought about by coupling with other sensors and technologies are particularly discussed. The at least one other sensor can be advantageously used for signal processing, in particular the triggering of notifications, reference algorithms and comparison algorithms.

[0007] A particular advantage of NV-sensing devices is their size, in particular the size of the sensor medium. For the described application, the active measurement space should be small relative to the object to be measured (the heart), because otherwise the signal would be integrated over a large part of the surface coverage and the signal could disappear because the integral is zero. The smaller the active measurement space is compared to the heart, the better the signal detection. NV-sensing devices have a very small active sensor space. In addition, this miniaturization and manufacturability allows the sensors to be used in geometric arrangements. In particular, arrangements with very high resolution through a very small active sensor space are possible. This also allows easy integration into building parts (walls, ceilings, etc.) or facility items (furniture, etc.), textiles (clothing, quilts, etc.) or other everyday items, with a large number of options being envisaged.

[0008] Diamond NV magnetometers are based on the readout of the magnetic resonance of specific vacancy centers in diamond, in particular nitrogen vacancies (NV), which occur as impurities in the carbon lattice of diamond and can also be introduced in a targeted manner. If the NV center in the ground state is optically excited, for example by irradiating a pump laser beam with a suitable wavelength (in this case in the green wavelength range, for example at 532 nm for off-resonance excitation), the electrons are raised from the triple ground state to the excited triple state and relax at 650-800 nm (637 nm = zero phonon line) while emitting fluorescence in the red wavelength range. Since the NV center with m s = ±1 spin quantum number, the possibility of non-spin-maintaining transition is relatively high, so continuous excitation pumping makes the majority of NV-centers in spin state m s=0 is hyperpolarized.

[0009] In the basic state m s =0 and m s = ±1, there is an energy difference between the spin states, which in this case is approximately 2.87 GHz. Therefore, if microwave radiation is radiated into the diamond in addition to the optical excitation, then in this case a red fluorescence interference occurs at this resonance frequency of 2.87 GHz, because the spin-polarized electrons are driven from the m by the microwave field. s =0 basic status increased to m s = ±1 basis state, and from there it is pumped to m s = ±1 excited state. However, from there, firstly non-radiative transitions and weak infrared fluorescence transitions occur via the singlet state, while the fluorescence in the red range is cancelled.

[0010] If an external magnetic field is present, the so-called Zeeman effect occurs: the energy m s = ±1 triplet-levels are split into Zeeman levels that are equidistant in energy. Then, when the fluorescence close to the spectrum of microwave excitation is marked, two dips are shown in the fluorescence spectrum, the frequency spacing of which is proportional to the magnetic field strength of the external magnetic field. The magnetic field sensitivity is first defined by the minimum resolvable frequency shift and can reach 1pT / √Hz or less. Since the NV-centers in single-crystal diamond have four possible arrangements in the lattice, the following situation occurs when there is an oriented magnetic field, namely: the NV-centers present in the crystal react to the external magnetic field to different degrees depending on their position in the crystal. As a result, in an ideal case, four pairs of fluorescence minima may appear in the spectrum, and from the shape and relative position of the four pairs of fluorescence minima, it is possible to clearly determine not only the magnetic field strength of the external magnetic field as a numerical value but also the direction of the external magnetic field.

[0011] In order to be able to carry out vectorial magnetic field measurement, the device has in one embodiment a means for generating a substantially uniform bias magnetic field in the region of the magnetometer unit or its sensor medium, wherein the bias magnetic fields of different NV magnetometer units are preferably different. This can involve a Helmholtz coil arrangement, wherein at least the sensor medium is arranged inside the Helmholtz coil arrangement (each magnetometer unit preferably has its own bias field, which improves the field determination). Other means can also be involved, such as, for example, simple coils, elongated coils, permanent magnet solutions such as, for example, in a Halbach array, etc.

[0012] The heart signal has a magnetic signature with an amplitude of (still only) picoTesla (pT) at a distance of a few centimeters, compared to the Earth's magnetic field in Central Europe, for example, which is about 50 μT (microTesla), thus 10 times stronger. 6 However, even such low field strengths can be resolved with great precision over a long period of time using the proposed technology. For example, magnetic shielding or gradiometer wiring can be used for this purpose.

[0013] By means of high-resolution detection of precise cardiac signals, a large number of diseases can be detected, such as, for example, persistent atrial fibrillation and paroxysmal ("burst") atrial fibrillation. As a result, myocardial infarctions and therefore strokes (especially after unrecognized myocardial infarctions) can be prevented. In addition, the present invention is suitable for the early identification of ST-elevation myocardial infarctions, other types of elevation myocardial infarctions, pulmonary embolism, AV-node-reentry-tachycardia, ventricular extrasystoles, but also very rare etiological diseases such as, for example, right ventricular tachyarrhythmias, which otherwise can only be identified by gene sequencing, can be identified at an early stage.

[0014] Only an accurate resolution of the cardiac signal makes this detection of symptoms possible. That is, if the signal is heavily contaminated by noise or poorly resolved, the offsets of the different PQRST complexes of the heart relative to each other or over time, fluctuations in their amplitude, deformations or small disturbances cannot be detected. However, this resolution of the standards is an important factor, because the above-mentioned problems can lead to confusion of the complexes (e.g., elevated and offset T waves are interpreted as R waves, which often occur in "healthy" hearts) and to false alarms.

[0015] If the gradient measuring instrument wiring of at least two NV-magnetometer units is used, and the geometric arrangement of at least two NV-magnetometer units is used, then one magnetometer unit always has a larger spacing than the other magnetometer unit relative to the heart (as a relatively weak magnetic field source). Through the gradient measuring instrument wiring, that is, the basic (vector) subtraction of the measured parameters, the magnetic field gradient almost corresponds to the field emitted by the weak source, and the much stronger background field (which is basically the same in the two magnetometer units) is eliminated. Thus, the necessity of magnetic shielding is cancelled, making it possible to measure the magnetic field in the daily environment. The present invention is accordingly particularly suitable for measuring weak magnetic fields without shielding. The technical details of the gradient measuring instrument solution that can also be used within the scope of the present invention are disclosed in DE 102022201690.4 and should be included here together.

[0016] In one embodiment, the device is designed to detect the magnetic field strength and field direction by means of the at least one NV magnetometer unit. Another advantage of NV sensor systems is the direction or vector information. Compared to other technologies, this technology is inherently generated for NV sensor systems. Therefore, it is not necessary to introduce interferences by modulation technology or to use more unfavorable projections, nor is it necessary to use multiple individual sensors. As a result, one has vector and gradient measurement information (diamond size, i.e. single-digit mm) at exactly the same position. ∧ 3 and below), and not separated by a few centimeters to more centimeters as in other technologies. With NV magnetometer units that can determine not only the field strength of the magnetic field but also the direction of the magnetic field, an improved suppression of the background field can be achieved, and thus a better detection of signals that are strongly superimposed by interfering signals can be achieved.

[0017] In one embodiment, the device is configured to determine a repeated reference point in the signal of the at least one NV-magnetometer unit by means of the at least one other sensor, divide the signal of the at least one NV-magnetometer unit into individual signal segments according to the reference point, and determine the valid signal segment from the signal segment. As a result, it is possible to average in particular over the range of multiple heartbeats. In order to be able to distinguish cardiac signals with high accuracy, it is possible to average over the range of multiple heartbeats in order to reduce noise. Because typical heartbeats are slightly irregular, it is recommended to trigger by another sensor, such as a pressure sensor or a pulse oximeter. Here, short average values ​​(such as 5-10 cycles) and long average values ​​(such as 100-200 cycles) are possible in order to obtain different information.

[0018] In particular, the joint observation of the original signal of the at least one NV-magnetometer unit, the at least one other sensor and / or the effective signal segment can also be used for analysis. The at least one other sensor can also provide a comparison signal or an additional signal to directly distinguish artifacts. In addition, the at least one other sensor can also be used to identify additional peaks, for example, to distinguish the increased T-wave from the R-peak. Here, in particular, the NV-magnetometer unit can accurately distinguish the signal variation curve, so that each wave can be clearly identified, and the at least one other sensor, for example, detects strong deviations. If there is an additional "strong deviation", the reference sensor will simply guess a slightly higher pulse, which is not noticeable. By comparing the signals of the NV-magnetometer unit and the additional sensor, for example, the increased T wave (an indicator of myocardial infarction) can be clearly identified. Furthermore, the signal appears in the magnetic signature in some cases, in particular in different measuring channels (vector measurement), differently from the otherwise detected peaks. Here, too, additional features can be very easily identified by a corresponding comparison. Furthermore, if averaging is performed for an external trigger, in which no additional peaks are detected, then additional peaks are also detected as a distinct signal increase of a specific wave over long averaging times, since the peak occurs in only one of the signals.

[0019] For devices with a system consisting of at least two NV-magnetometer units, in practice, typically one NV-magnetometer unit or a (gradiometer) system consisting of two NV-magnetometer units is always particularly close to the heart. Its signal can be advantageously used, in particular, because it should be considered that this signal best reflects the magnetic signal of the heart. This signal can be calculated with other signals, for example, in order to form a derivative of a vector (tension measurement). It can also be determined from this, which other NV-magnetometer units are far away from the heart and are therefore better used for determining the background. In this case, the position of the user, in particular also the position that changes over time, can be determined by the at least one other sensor, such as a pressure or force sensor (or by the magnetic signal itself), so as to adapt the signal processing to the changing position in time.

[0020] Detecting breathing (and similar signals) by means of the at least one further sensor (such as a microphone or a pressure sensor) also allows interference terms to be corrected, since breathing means movement, which corresponds to a movement of the body relative to the NV magnetometer unit. Additional information such as, for example, the course of breathing can also be determined in this way in order to draw conclusions about sleep apnea or, in general, about the health status.

[0021] In particular, a calculation rule can be determined by means of the at least one further sensor, according to which the at least one effective magnetic field strength and / or at least one effective field direction is then determined from the signal of the at least one NV-magnetometer unit. Such a calculation rule can indicate in particular which NV-magnetometer unit signals enter the result at what level. For example, the position of the user (as described above), for example the temperature of the individual NV-magnetometer units, the strength or change of the background field or interference field, etc. can be decisive here.

[0022] The resulting “temporally variable” signal processing is useful for evaluating the data and for identifying which data should be evaluated and which data are evaluated as “defective”, for example because the user moved too frequently and / or too quickly, etc.

[0023] Furthermore, temperature monitoring can also contribute to increasing safety, for example in order to initiate an emergency shutdown.

[0024] Further external influences, such as temperature, pressure, heat, etc., for example, of other persons in bed, can also be detected by the at least one further sensor and thereby corrected or additionally utilized.

[0025] Recommendations such as "Please lower your cushion" or "Another pillow would be healthier for you" can also be derived from the acquired data and output via an interface, such as in an app. In particular, coupling to other technologies such as, for example, a smartwatch and the sensors integrated therein as the at least one further sensor is also possible.

[0026] The at least one further sensor can be selected from the group consisting of a pressure sensor, a force sensor, a temperature sensor, an acceleration sensor, an inertial sensor (IMU), a gyroscope, a pulse and blood oxygen content meter, a microphone, a nitrogen-free vacancy-centered magnetometer unit.

[0027] For the application described, a sampling rate higher than the heart signal, in particular greater than 50 Hz, is required in order to resolve the heart signal. Here, a range of 200 Hz to 400 Hz is considered to be particularly advantageous. A higher range is always better for resolution, but increases the requirements on sensitivity.

[0028] Further advantages and embodiments of the invention are apparent from the description and the drawings.

[0029] The invention is schematically illustrated in the drawings on the basis of exemplary embodiments and is described below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The main components of an NV center magnetometer as can be used within the scope of the present invention are shown in a schematic block diagram.

[0031] Figure 2 In the various illustrations a) to c), a possible arrangement of an NV magnetometer unit of a device for detecting magnetic signals according to one embodiment is shown in each case in the form of a schematic block diagram.

[0032] Figure 3 A user and a device according to one embodiment of the invention are shown schematically in a side view.

[0033] Figure 4 Possible configurations of an arrangement with one or more NV magnetometer units according to embodiments of the present invention are schematically shown in three top views a) to c).

[0034] Figure 5 Two side views a) and b) schematically show possible configurations of a device according to one embodiment of the invention, which has a plurality of systems, which in turn have an NV magnetometer unit and a signal processing unit. DETAILED DESCRIPTION

[0035] Figure 1 The main components of the NV center magnetometer are schematically shown. Here, as the sensor medium, there is first a diamond 110 with nitrogen vacancies (NV). The optical excitation of the NV center can be achieved by a suitable light source 120, such as an LED or a pump laser. Here, for example, a frequency-doubled Nd:YAG laser or a semiconductor laser in the green range of, for example, 510-532 nm, such as 532 nm, is suitable for off-resonance excitation. As an alternative, an LED in a suitable wavelength range can also be used. Depending on the layout, the light of the light source 120 can be radiated into the diamond 110 through suitable optical elements 122, such as, for example, reflectors, beam splitters, focusing mirrors, such as lenses, and if necessary, through fiber-optic elements. In addition, the excitation light can be radiated continuously or pulsed by a laser, so as to, for example, retain a time window for interference-free fluorescence measurement.

[0036] In addition, the magnetometer can include a microwave source 150, which can generate an electromagnetic field in the sensor medium, that is, in the region of the NV center of the diamond 110, within the bandwidth covering the desired resonance frequency. A microwave resonator structure can be used to uniformly distribute the generated microwaves in the space of the measurement range in the diamond. The resonator structure or microwave source 150 is preferably matched to the frequency of the electron spin resonance. In order to achieve vector magnetometry, an additional static bias magnetic field 140 is generated. As a result, the measurement becomes intrinsic vector. For this purpose, different spatial directions in the crystal structure are used. For example, Helmholtz coils are suitable for generating such a magnetic field 140, for which a substantially uniform magnetic field in a restricted range can be generated by means of a coil pair.

[0037] The generated fluorescence 112 from the diamond 110 can be guided to the first photodetector 130 by suitable optical elements 134, such as optical filters, beam splitters, lenses and / or fiber optic elements, which are sensitive at least in the range of the fluorescence wavelength. The first photodetector 130 can also be arranged directly on the diamond 110. The second photodetector 132 is arranged so that it can detect at least a part of the excitation light of the light source 120, which can be coupled out by beam splitters, filters or partially transparent elements. This detector signal 132 of the excitation light can be used as a reference signal, so as to eliminate background signals and highlight the resonance signal of interest, for example, by means of a phase-locked amplifier through modulation of the excitation light. As a supplement or alternative, this reference signal can be used to take into account the fluctuations of the excitation light. Corresponding circuits 160, such as preamplifiers, logarithmic amplifiers, phase-locked amplifiers, signal filters or other circuits are thus provided for obtaining the signals of the first and second photodetectors and preprocessing the signals in a suitable manner for further evaluation. Finally, the preprocessed fluorescence signal can be evaluated by a signal processing unit 170 , for example using a suitable microcontroller or processor, in order to derive from the signal desired parameters of the detected magnetic field, in particular the magnetic field strength and direction of the magnetic field.

[0038] It goes without saying that such a device can also have further units (not shown), such as a communication unit or an interface for outputting measurement results. Such a device can also be advantageously integrated into an ASIC or FPGA.

[0039] In order to be able to use in everyday environments, magnetic fields that do not originate from the expected weak sources, especially those at 10 -5 The Earth's magnetic field in the range of a few microteslas is eliminated as much as possible from the measurement. In contrast, the heart's magnetic field is in the range of 10-12 Fluctuates within the range of Tesla (picotesla).

[0040] The elimination of the background magnetic field can be achieved during the measurement of the magnetic field according to exemplary embodiments by shielding or by a gradiometer system. In principle, a gradiometer is a sensor unit that can detect both the field strength and the gradient of the field.

[0041] For this purpose, at least two individual magnetometer units can be used, which are arranged at different locations in space. Figure 2 A sensor unit is described which uses two or more NV-center-magnetometers in a gradiometer system.

[0042] Figure 2 In different illustrations a) to c), possible geometric arrangements of NV magnetometer units of a device for detecting magnetic signals according to a design are shown. FIG. a) shows in a side view the arrangement of NV magnetometer units S1, S2, ..., Sn in an arbitrary arrangement relative to one another in one plane (the plane is perpendicular to the illustrated plane, that is, only the first row can be seen). FIG. b) shows in a side view two NV magnetometer units S1, S2, whose sensor media are segments of the same diamond crystal 110. FIG. c) shows in a side view a certain number (n times m) of NV magnetometer units S11, S21, ..., Sn1, S12, S22, ..., Sn2, S1m, ..., Snm in an arbitrary three-dimensional arrangement. Here, further layers are connected behind the illustrated plane, so that a cubic grid is formed as a whole. Here, at least one NV magnetometer unit (not shown), for example located in one of the later layers, is not arranged in the following level (illustrated level): the level in which other NV magnetometer units S11, S21, ..., Sn1, S12, S22, ..., Sn2, S1m, ..., Snm are arranged.

[0043] Furthermore, M denotes a signal source, here the heart, and O denotes an optional surface, in particular the body skin, which limits the accessibility or reachability of the magnetic field source M.

[0044] In a design of the invention, more than two (but at least two) NV magnetometer units can be combined to form a gradiometer. With each additional NV magnetometer unit, the background field can be better determined and the position and intensity of the actuator can be better separated from the background.

[0045] In other embodiments of the invention, always two NV-magnetometer units can also form a gradiometer, wherein a plurality of gradiometers are then formed overall according to the number of NV-magnetometer units and detect the signal of interest. A valid measurement signal can then be formed therefrom, in particular by a signal processing unit, for example by averaging, summing, etc.

[0046] The distance d between two NV magnetometer units S1, S2, ... or more precisely their sensor media corresponds to the distance between the following positions at which the magnetic field measurement is carried out simultaneously. If the distance between the measurement positions is relatively small, it can be assumed that the additional background magnetic field B env The intensity of is roughly the same at the two positions. In contrast, the weak magnetic field B of interest decreases significantly as the distance from the magnetic field source M increases.

[0047] Therefore, by arranging two NV-magnetometer units at different spacings and angles from the source or heart, the background field can be eliminated or determined by vector arithmetic, and the small magnetic field of interest can be determined and its source can be characterized (position and orientation). This can be further improved by a distant magnetometer that is so far away that the weak magnetic field of interest falls below the detection threshold. With such a configuration, local changes in the background field can be compensated by the at least two nearby magnetometers. For this purpose, two NV-magnetometer units can be arranged up and down in an axial gradiometer configuration, for example, so that an NV-magnetometer unit of the first layer forms a gradiometer with an NV-magnetometer unit of the second layer below it, respectively.

[0048] exist Figures 3 to 5 A possible embodiment of the invention is schematically shown in FIG. 1 and is generally described below. Identical elements are provided with the same reference numerals and are not described multiple times.

[0049] Here, a device 2 for detecting magnetic signals is shown, which in the example shown has a body, a base substrate 1, such as, for example, with a support surface 1a, and at least one system 3 consisting of at least one NV magnetometer unit 4, wherein the at least one system 3 is embedded in the body. The device 2 is used to detect magnetic signals generated by a beating heart (M), but in principle can detect all magnetic signals, in particular biosignals, that is, such biosignals emitted by a living being.

[0050] For the purpose of illustration, the figures each have a coordinate system at the upper left, in which the illustration plane represents the xz plane and the y-axis runs into the interior of the illustration plane.

[0051] The body is here a cushion body 1 which is designed to accommodate a user 20 sitting up or lying flat on a support surface. However, it can also be a building part, a facility item or a textile or the like. Figure 3 , a cushion is shown as a base cushion body 1 , as it can also be used, in particular, for long-term monitoring of cardiac magnetic signals.

[0052] The device has one system or more than one system. The system can also be arranged in a specific geometrical arrangement, for example in one of a line (1D), a plane (2D) or a distribution in space (3D). As explained, two NV-magnetometer units can always form a gradiometer, wherein then a plurality of gradiometers are formed overall depending on the number of NV-magnetometer units, and these plurality of gradiometers detect the signal of interest. Then, an effective measurement signal can be formed therefrom, in particular by a signal processing unit, for example by averaging, summing, etc.

[0053] Figure 4 In schematic top views, in different views a) to c), variants 3.a) to 3.c) of a system 3 are shown, each with one or more NV-magnetometer units 4, each with one or more further sensors 5. The sensors 5 can be, in particular, pressure sensors, pulse oximeters, temperature sensors, electrodes, etc. The NV-magnetometer units 4 and / or sensors 5 of the system 3 can be arranged in a specific geometrical arrangement, for example in one of a line (1D), a plane (2D) or a distribution in space (3D), as has also been described in connection with the present invention. Figure 2 Or as explained in 5.

[0054] exist Figure 5 In the figure, two side views a) and b) show different variants 2.d, 2.d' of the device 2, the device having two systems 3 in the area of ​​the upper side of the base pad body 1 and one system 3 in the area of ​​the lower side of the base pad body 1. In addition, the system has a signal processing unit 11, and the NV-magnetometer unit of the system 3 is connected to the signal processing unit to determine one or more effective magnetic field strengths and / or field directions. In addition, a communication unit 12 can be provided to connect the device 2 with other devices, such as a PC, a tablet PC, and a smart phone, so as to perform input and output and operation. The communication unit 12 can, for example, have a wired and / or wireless interface. Here, in variant 2.d, the signal processing unit 11 and the communication unit 12 are also integrated in the base pad body, and are arranged outside the base pad body in variant 2.d'.

[0055] Preferably, the communication unit 12 has an interface in order to transmit the results, for example, to a cardiologist or a family member or a user.

[0056] The interface can include, for example, a WiFi interface or a mobile radio interface, in order to establish access to the Internet, for example. The Internet access preferably complies with current security standards regarding encryption, authentication, access restrictions, etc. In this case, it is conceivable to couple to the terminal device, for example via Bluetooth, for example in conjunction with an applet, in order to establish access to the Internet, for example indirectly.

[0057] In one embodiment, it is also possible to upgrade (software update) and / or upgrade (software expansion) via the interface. For this purpose, software for downloading can be provided, for example. The device then has a hard disk storage and corresponding software accordingly, so that software modules can be upgraded or supplemented. Software models for special diseases or software modules for special functions are advantageously provided. The software modules can be classified individually as medical products, as long as this is necessary.

[0058] In one exemplary embodiment, the interface can include an interface for (periodic) querying of licensing data, such as the mentioned software model, and an interface for deactivating the license after expiration.

[0059] In one embodiment, the interface can also be used to output an emergency call, ie, is or represents or includes an emergency call interface. In severe cases, automatic output of the emergency call is envisaged. In addition to the emergency call interface, the interface can also include a backup emergency call interface.

[0060] In one embodiment, the interface can include a direct interface to a communication center, for example directly to a physician / MFA (cardiologist: medical professional staff (Medizinische Fachangestellte / r)), in order to transmit interesting data records. In particular, for remote diagnosis, it is important to transmit specific data records to the cardiologist via a reliable interface for examination.

[0061] In one embodiment, the interface can include an interface to the cloud. In order to process the data records or also learn from the data records (machine learning on the collected data records), a cloud access should be integrated. In this case, it may be important to move forward anonymization steps of the data. A security concept is also advantageous here.

[0062] In one embodiment, the signal processing unit can include an analysis unit. In the usual use of the device, for example as a long-term MKG, a very large amount of data can be generated, which can hardly be filtered manually. It is therefore advantageous to transmit interesting data (i.e. data with specific characteristics) selected by pre-analysis. Of course, such an analysis unit can also be arranged externally at the recipient, i.e. all data are first transmitted and then only interesting data are selected at the recipient.

[0063] In one embodiment, the interface can be an interface to a mobile platform, such as, for example, an application applet (application applet of a user, application applet of multiple users, such as family members). In particular, the user, but also family members can then use the mobile platform to access selected data, selected prompts and selected user interfaces. This is also important for family members or, for example, nursing staff for monitoring purposes. The application applet can also be ordered as a plug-in for technology. Here, security concepts and Internet interfaces are also advantageous. Thus, a licensing option can also be provided, which allows the Abo model to be checked.

Claims

1. A device (2) for detecting magnetic signals generated by a beating heart (M), comprising: at least one nitrogen-vacancy-center-, NV, magnetometer unit (4), which is configured to: detect a magnetic field strength and / or a field direction; at least one further sensor (5); a signal processing unit (170, 11), to which the at least one NV magnetometer unit (4) and the at least one further sensor (5) are connected, The device is designed to determine at least one effective magnetic field strength and / or at least one effective field direction from signals of the at least one NV magnetometer unit (4) and of the at least one further sensor (5) by means of the signal processing unit (170, 11).

2. The device according to claim 1 is configured to: determine repeated reference points in the signal of the at least one NV-magnetometer unit (4) with the aid of the at least one additional sensor (5), divide the signal of the at least one NV-magnetometer unit (4) into individual signal segments according to the reference points, and determine valid signal segments from the signal segments.

3. The device according to claim 1 or 2 is configured to determine the position of the user by means of the at least one further sensor (5) and to determine one of the at least one NV-magnetometer units (4) as being close to the heart or far from the heart based on the position.

4. The device according to any of the preceding claims is configured to: determine a calculation rule with the aid of the at least one further sensor (5), and determine the at least one effective magnetic field strength and / or at least one effective field direction from the signal of the at least one NV magnetometer unit (4) according to the calculation rule.

5. A device according to any of the preceding claims, wherein the at least one additional sensor (5) is configured to detect at least one measurement variable selected from the group consisting of heart beat, electric field, oxygen saturation in the blood, pressure, force, sound, temperature, acceleration, magnetic field strength, and magnetic field direction.

6. The device according to any of the preceding claims, wherein the at least one further sensor (5) is a magnetometer cell free of nitrogen-vacancy centers.

7. A device according to any of the preceding claims, wherein the at least one NV magnetometer unit (4) has a diamond crystal or a segment of a diamond crystal with nitrogen-vacancy centers as a sensor medium (110), wherein the device is configured to detect the magnetic field strength and / or field direction by reading out a spin resonance in the sensor medium (110) that is dependent on the magnetic field strength.

8. The device according to claim 7 also has at least one excitation light source (120) for radiating light (124) into the sensor medium (110), at least one microwave source (150) for generating a resonance field in the sensor medium, and at least one photodetector (130) for detecting resonance-dependent fluorescence (112) from the sensor medium (110).

9. The device according to claim 8, wherein at least two NV magnetometer units (4) are assigned one and the same excitation light source (120) and / or one and the same microwave source (150). 10 . The device according to claim 7 , wherein the sensor medium of at least two NV magnetometer units ( 4 ) each comprises a section of the same diamond crystal ( 110 ).

11. The device according to any of claims 7 to 10, wherein the spacing (d) between the sensor media (110) of at least two NV-magnetometer units (4) is between 1 and 30 mm, preferably between 5 and 20 mm.

12. The device according to any of the preceding claims, further comprising a data interface.

13. The device according to claim 12, wherein the data interface comprises at least one interface selected from the group consisting of a WiFi interface, a mobile radio interface, an Internet interface, a direct interface to a communication center, an interface for querying license data, an interface to the cloud, and an interface to a movable platform. 14 . The device according to claim 12 , which is designed to enable a software upgrade and / or a software update and / or to output an emergency call via the data interface.

15. The device according to claim 1, further comprising an analysis unit for selecting data having specific properties from the magnetic signal.

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