ARRANGEMENT FOR A CAPACITIVE SENSOR DEVICE

Description

[0001] The present invention relates to an arrangement for a capacitive sensor device of a vehicle. Furthermore, the invention relates to an exterior door handle and a method for operating a capacitive sensor device of a vehicle.

[0002] It is known from the prior art that a capacitive sensor device with a sensor element can be used on a vehicle to detect changes in the environment of the sensor element, such as movement or the approach of a person. To evaluate the sensor element, it can be repeatedly charged and discharged, which is accompanied by the output and reception of electrical signals within the sensor device. For this purpose, rectangular signals are usually used, which can arise due to the recharging and / or switching between a discharging and a charging current path.

[0003] US 2017 / 3 736 86 A1 discloses a capacitive sensor device with at least one sensor electrode for detecting a change in the environment of the capacitive sensor. It is provided that a sinusoidal signal is generated at the sensor electrode directly by a voltage source.

[0004] The document "Capacitive Sensors: Design and application" by Larry K. Baxter from January 1, 1997, discusses the generation of a sine wave.

[0005] The document "How to Low-Pass Filter a Square Wave" by Robert Keim from March 7, 2018, discusses low-pass filtering of a sine wave.

[0006] For evaluating the sensor element, recharging methods are known, for example, as disclosed in DE 10 2012 102 422 A1, DE 10 2012 105 266 A1, DE 10 2013 112 909 A1 or DE 10 2013 112 910 A1.

[0007] A common problem is that such a signal for evaluation, and especially a square wave, can have a spectrum with unfavorable frequencies. It is conceivable, for example, that interfering radiation may occur during the charge transfer using the signal at the sensor element. Accordingly, reducing the interference caused by the sensor device on the environment is often a technical challenge and requires complex measures. For example, problems can arise due to interactions with radio signals in the range from 510 kHz to 1.71 MHz. Such radio signals are emitted in particular by external medium wave radio transmitters (in the AM band) or similar. The measures to reduce and / or compensate for these interactions are often technically complex and costly.

[0008] It is therefore an object of the present invention to at least partially remedy the disadvantages described above. In particular, it is an object of the present invention to enable improved operation of a capacitive sensor device of a vehicle.

[0009] The above object is achieved by an arrangement having the features of the independent device claim, an exterior door handle having the features of the further, subordinate device claim, and by a method having the features of the independent method claim. Further features and details of the invention emerge from the respective subclaims, the description, and the drawings. Features and details described in connection with the arrangement according to the invention naturally also apply in connection with the exterior door handle according to the invention and the method according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0010] The object is achieved in particular by an arrangement according to claim 1 for detecting an activation action in the vehicle, e.g. in the front and / or side and / or rear area of ​​the vehicle. The activation action can be carried out, for example, by a person in the vicinity of the vehicle. For example, the person may wish to open the tailgate of the vehicle by making a gesture in the rear area. This gesture is, for example, a movement of a body part below a bumper, which can be detected by the sensor device. If necessary, a gesture in the vicinity of a door handle of the vehicle can also be provided as an activation action, for example to unlock and / or open a vehicle door.

[0011] According to the invention, the arrangement comprises the following components: at least one sensor electrode for detecting a change in an environment of the vehicle, in particular in an environment of the sensor element, preferably in an area outside the vehicle and / or below a bumper and / or in the area of ​​a door handle, preferably for detecting the gesture and / or the activation action, a transmission arrangement for providing an output signal by a frequency-dependent change in an electrical input signal of the transmission arrangement, wherein preferably the input signal is provided at an input of the transmission arrangement, an output of the transmission arrangement which is electrically connected to the sensor electrode in order to operate the sensor electrode with the output signal, preferably by transmitting the output signal to the sensor electrode.

[0012] According to the invention, the transmission arrangement has at least one filter component in order to carry out the frequency-dependent change.

[0013] This has the advantage that the spectrum of the input signal can be adapted by the transmission arrangement, i.e., for example, (unwanted) interfering frequencies of the input signal can be filtered out and / or their radiation can be avoided when operating with the output signal, in particular when outputting the output signal at the sensor electrode. The solution according to the invention is based in particular on the consideration that the use of a square wave signal as an output signal for the sensor electrode is particularly problematic with regard to possible interfering frequencies. Under certain circumstances, it may not be possible without further measures to sufficiently ensure that the transmission of the output signal and / or the output at the sensor electrode does not have any interfering effects on the output signal and / or electromagnetic radiation at the sensor electrode.This can be avoided by using at least one filter component to shape the output signal depending on the input signal. The input signal, for example, specifies an evaluation sequence as a rectangular signal, i.e., a clock pulse and / or a temporal sequence of switching operations for at least one switching element. The at least one filter component then effects a shaping, i.e., an adaptation with regard to the frequency components of the input signal, e.g., harmonic suppression. In particular, the transmission arrangement can be adapted, e.g., by appropriately adapting the filter components, so that a sinusoidal signal is output as the output signal. This has particularly advantageous properties with regard to the frequency spectrum.

[0014] Advantageously, the arrangement according to the invention can provide only a single (structurally designed) sensor electrode for forming a (variable) sensor capacitance, wherein the counter electrode for forming the sensor capacitance is preferably formed by a mass of the vehicle and is thus not considered a separate (dedicated) component. Parasitic capacitances of the sensor device are preferably neglected in this consideration. This enables a particularly simple structural design.

[0015] The sensor element, in particular the sensor electrode, can be a sensor element made of an electrically conductive material. For example, the sensor electrode is designed as an elongated (longitudinally stretched) electrical conductor, e.g., an electrical cable, and is optionally connected to the vehicle electronics via a single direct electrical connection.

[0016] An electrical connection can be understood as both a direct and an indirect connection, i.e., also via other electrical components, but preferably only if the connection is made exclusively electrically. For example, the electric field between the sensor electrode and the vehicle ground cannot be considered a direct electrical connection, so the sensor electrode preferably has only a single direct electrical connection to the vehicle electronics. Where appropriate, the vehicle electronics can also be understood as at least the sensor device and / or the control device and / or the transmission arrangement.

[0017] The vehicle is preferably designed as a motor vehicle, preferably a passenger car, and / or as an electric vehicle and / or as a hybrid vehicle and / or as an autonomous vehicle.

[0018] It is furthermore conceivable that the at least one sensor element, preferably the at least one sensor electrode, is arranged in a front and / or side and / or rear area of ​​the vehicle in order to detect in particular the change in the environment and / or the activation action accordingly in the said environment area, i.e. front and / or side and / or rear area of ​​the vehicle. In this way, the activation action in this environment area can be reliably detected by the sensor device. For example, elements and / or functions of the vehicle in this environment area can be moved or activated intuitively based on the detection. Such functions are, for example, lighting of the vehicle and / or unlocking a locking device of the vehicle and / or the like. The elements can, for example,as a tailgate and / or side door and / or sliding door and / or bonnet, which are moved and / or opened and / or closed based on the detection. It is also optionally possible for the sensor element to be arranged on and / or within or in the area of ​​a door sill in order to open, for example, a side door or sliding door of the vehicle based on the detection. So that a movement and / or a movement pattern can be reliably recorded based on the detection, at least two sensor elements, preferably sensor electrodes, can be provided as an alternative or in addition to the aforementioned features. These are, for example, arranged together in at least one of the aforementioned environmental areas, e.g. together in a bumper or door sill or door handle or the like.

[0019] The capacitive sensor device can preferably have the sensor element (or the sensor electrode) and / or the transmission arrangement and / or a control device. Control of the capacitive sensor device can be seen in that the transmission arrangement emits the output signal, which is transmitted to the sensor element for charging. Evaluation can be seen in that a holding arrangement of the control device receives charges from the sensor element via a received signal, which can be evaluated, for example, to detect the activation action. Thus, a holding arrangement of the control device can advantageously be provided for evaluating the sensor element (i.e. in particular the sensor electrode), which holding arrangement is optionally evaluated by a control device to enable reliable detection.

[0020] Furthermore, the arrangement according to the invention can be provided for the at least one filter component to influence both the output of the output signal (at the output or on a transmit path) and the reception of charges from the sensor electrode to a holding arrangement (on a receive path) by means of a receive signal, preferably through the frequency-dependent change. This can be achieved, for example, by electrically connecting the holding arrangement to the transmission arrangement.

[0021] It can further be advantageous for the transmission arrangement to be designed as an active electronic filter, preferably a Sallen-Key filter, by means of the at least one filter component. This has the advantage that the output signal, particularly as a guided signal, retains the frequency characteristics produced by the at least one filter component particularly reliably.

[0022] Preferably, it can be provided that the transmission arrangement forms an all-pass filter or a low-pass filter by means of the at least one filter component in order to preferably filter the input signal in such a way that radiation in an interfering frequency range, preferably from a second harmonic of the input signal, is at least reduced during operation of the sensor electrode. In other words, it can be provided that the transmission arrangement is designed to suppress harmonics of the input signal in order to suppress harmonics when the output signal is output to the sensor electrode. This has the advantage that the transmission arrangement can form a harmonic filter in order to at least reduce interference caused by the output signal. The interfering frequency range is in particular a predefined frequency range and is, for example,depending on regionally used transmitters and radio frequencies, or the like. The harmonic preferably indicates an oscillation with a frequency that corresponds to an integer multiple of the fundamental frequency of the input signal. The fundamental frequency is, for example, an operating frequency of essentially 333 kHz. A harmonic above the fundamental frequency is also called a harmonic or overtone.

[0023] Particularly advantageously, the arrangement according to the invention can provide that the at least one filter component is designed to form an electronic filter, preferably a low-pass and / or bandpass filter, in order to preferably implement the frequency-dependent modification of the input signal. Particularly preferably, the at least one filter component is connected to a source device as a further filter component, so that an active filter, particularly preferably a Sallen-Key filter, is formed. The source device is, for example, a controlled source device, in particular a voltage source device. It can be understood as a real electrical component or as an electrical circuit that approximately has the function of an ideal controlled source (also known as a "dependent source"), in particular a voltage source.Thus, the source device can be considered a real controlled source, in particular a real voltage source (CVS). An example of such a source device is an operational amplifier (OP), in particular a controlled, preferably voltage-controlled, operational amplifier. It is particularly advantageous if the source device is designed as a (real) low-impedance controlled (voltage) source. This has the advantage that the output signal, as a guided output signal, maintains its signal shaping particularly reliably.

[0024] According to a further possibility, the at least one filter component can comprise a first filter component, in particular for forming an RC low-pass filter, and a second filter component, in particular for forming a Sallen-Key filter, wherein the filter components are interconnected to jointly implement the frequency-dependent modification of the input signal. Preferably, the second filter component can also comprise an operational amplifier. This can filter the interfering frequencies particularly reliably, since a sinusoidal signal can be provided.

[0025] Advantageously, within the scope of the invention, it can be provided that the output signal can be provided as a function of the frequency-dependent change in the input signal by connecting the at least one filter component between the output and an input of the transmission arrangement. In particular, the output signal is provided in such a way that the input signal changed by the filter component is applied to a control input of a source device in order to control the source device with regard to the output of the output signal, and an output of the source device is connected to the output of the transmission arrangement or corresponds thereto. Furthermore, feedback can also be provided in the source device in order to use an operational amplifier as the source device, for example. The operational amplifier can, if necessary, have an amplification with a gain factor of 1 between a (e.g.non-inverting) input and output of the operational amplifier.

[0026] According to the invention, an input signal source is connected to an input of the transmission arrangement in order to provide the input signal as a signal based on a square wave signal at the input, which signal is actively modified by signal shaping, by smoothing the edges of the square wave signal and by a time-varying amplitude, in particular in the case of pulses of the square wave signal within the pulse duration, in order to support the frequency-dependent modification, preferably harmonic suppression, of the transmission arrangement. It is advantageous here if the input signal source, preferably a control device and / or a control arrangement, already provides a first signal shaping. This can support the further shaping by the at least one filter component. For this purpose, a square wave signal (i.e. an at least rectangular signal, possibly with interruptions), e.g.pre-filtered by the input signal source, so that an initial attenuation of harmonics occurs, which is further amplified by the transmission arrangement.

[0027] It is also optionally conceivable for a control device to be provided as part of an input signal source in order to generate the input signal, preferably via a digital-to-analog converter. The digital-to-analog converter is, for example, part of the control device and / or designed separately. Even during this generation, a signal that differs from a square-wave signal can be provided, which, for example, has the edges smoothed. The generation of the input signal is predetermined, for example, by an adaptation means.

[0028] Furthermore, it is conceivable that a control arrangement is provided as part of an input signal source for signal shaping of the input signal, which control arrangement is preferably connected between an input of the transmission arrangement and a control device, in order to preferably modify an input signal generated by the control device through signal shaping and apply it to the input of the transmission arrangement. Thus, the control arrangement, e.g., as a resistor network or the like, can already serve to shape and / or prefilter the input signal.

[0029] Advantageously, the invention can provide for a control device as part of an input signal source to be designed to control a control arrangement such that the input signal corresponds to a rectangular signal that alternates back and forth between first and second values, wherein the first and second values ​​preferably change in an ascending and descending manner over time. In other words, pulses of the signal output sequentially can have different (maximum) amplitudes. This can cause a staircase shape in the input signal, which can particularly effectively support the signal shaping and / or frequency-dependent modification by the at least one filter component.

[0030] A further advantage can be achieved within the scope of the invention if a switch element is connected between the output of the transmission arrangement and the sensor electrode in order to connect a receive path and a transmit path alternately to the sensor electrode in a controlled, preferably repeated and / or clocked manner (preferably by a control device), wherein the output is preferably connected (in particular directly) to the transmit path, and / or a holding arrangement for evaluation at the sensor device is connected (in particular directly) to the receive path. This enables, for example, the implementation of a charge reversal method for evaluating a variable capacitance (sensor capacitance) provided by the sensor electrode. The switch element is designed, for example, as an electronic switch that can be electrically switched by the control device.

[0031] Furthermore, in the arrangement according to the invention, it is conceivable that the output of the transmission arrangement is connected to the sensor electrode via at least one switch element, wherein the switch element is preferably connected to a control device in order to repeatedly output the output signal, preferably in a clocked manner, to the sensor electrode. For this purpose, the control device can be connected, for example, to a control input of the switch element for switching. Alternatively or additionally, it is conceivable that a holding arrangement is connected to the sensor electrode via the at least one switch element, wherein the switch element is connected to the control device in order to repeatedly connect the holding arrangement, preferably in a clocked manner, to the sensor electrode, preferably alternating with the output of the output signal at the sensor electrode. This enables, in particular, the implementation of a charge reversal process.

[0032] Optionally, it can be provided that a holding arrangement for evaluation is integrated in a receive path in the sensor device in order to receive a receive signal depending on the charge stored in the sensor electrode and / or depending on a variable sensor capacitance of the sensor device, preferably after the sensor electrode has been charged by the output signal, wherein the sensor electrode is designed to provide the sensor capacitance.

[0033] This makes it easy to detect an activation action in the environment when the sensor capacity changes significantly.

[0034] Furthermore, within the scope of the invention, it can be provided that the sensor electrode is designed to be arranged in electrically operative connection with the surroundings of the vehicle, preferably in a bumper or in a door handle of the vehicle, so that during operation of the sensor electrode, an electric field is created in the surroundings to provide a variable sensor capacitance depending on the surroundings. Designing the sensor element as a sensor electrode also has particular advantages for such an arrangement in the door handle or bumper, since the sensor electrode can be flexible, bendable, elastic, or designed to be particularly space-saving.

[0035] Furthermore, it can be advantageous within the scope of the invention to provide a holding arrangement for evaluating a variable sensor capacitance, preferably to detect the change in the vehicle's surroundings based on this evaluation, wherein the holding arrangement is preferably designed as an integrator, in particular to carry out charge accumulation based on a charge stored in the sensor electrode. In other words, the holding arrangement can use a holding capacitance to temporarily store a quantity of charge (optionally also via a current mirror), which is received by the sensor electrode via a received signal. Furthermore, the holding arrangement can also have a circuit with at least one operational amplifier, which is designed with frequency-dependent negative feedback, preferably by means of at least one capacitor, in order to form the integrator (also: integrator). This enables particularly simple and cost-effective evaluation.

[0036] It is further conceivable for the transmission arrangement to be connected to a holding arrangement in order to receive a received signal from the sensor electrode as a function of the frequency-dependent change in the holding arrangement, preferably in order to also provide the frequency-dependent change for the received signal for evaluation in the sensor device, i.e. in particular in order to receive a received signal from the sensor electrode as a function of the frequency-dependent change. For example, by using feedback to evaluate the received signal in the holding arrangement, a signal changed by the at least one filter component can affect the received signal. This changed signal is guided, for example, via an electrical line from the transmission arrangement to the holding arrangement, for example to an integrator input.This means that the advantageous frequency adaptation can be provided by the transmission arrangement both for the output signal, i.e. for the control, and for the received signal, i.e. for the evaluation.

[0037] A further advantage can be achieved within the scope of the invention if an operational amplifier input of the transmission arrangement (preferably an operational amplifier for providing an active filter) is connected to a (first) integrator input of the holding arrangement, preferably to receive a received signal from the sensor electrode as a function of the frequency-dependent change, so that the frequency-dependent change is preferably provided both for the received signal in a receive path and for the output signal in a transmit path. This connection between the transmission arrangement and the holding arrangement preferably also serves to shape the received signal during an evaluation, wherein the receive path is preferably connected to a second integrator input of the holding arrangement.In this way, the frequency-dependent variation can influence the spectral characteristics, particularly harmonic suppression, of both the output signal and the received signal. This can further prevent interference.

[0038] Furthermore, it is conceivable for the transmission arrangement to form a filter with low-pass properties, which has a cutoff frequency in a range from 100 kHz to 800 kHz, preferably 200 kHz to 600 kHz, more preferably 400 kHz to 550 kHz, particularly preferably 470 kHz. This can be achieved in particular by appropriately adapting the components of the transmission arrangement. Alternatively or additionally, the transmission arrangement can be designed to have the filter properties of an active low-pass filter, in particular third-order and / or with an attenuation of -20 dB at 1 MHz and / or a cutoff frequency of 470 kHz. In other words, a harmonic suppression of at least -20 dB can be provided.The filter is particularly suitable for an operating frequency of the sensor device 20 of (essentially) 333 kHz, which can be determined by the frequency of the switching between the charge transfer phases and / or transfer phases. In particular, harmonics starting from the 2nd or 3rd harmonic can be effectively suppressed.

[0039] The invention also relates to an exterior door handle for a vehicle, comprising an arrangement according to the invention, wherein the exterior door handle is designed, for example, for arrangement on a side door or tailgate of the vehicle.

[0040] A sensor device with the arrangement according to the invention is also protected.

[0041] Also protected is a method for operating a capacitive sensor device of a vehicle having the arrangement according to the invention, in particular for controlling and / or evaluating the capacitive sensor device for detecting an activation action in the vehicle, preferably in the side and / or front and / or rear area of ​​the vehicle. It is provided that the sensor device has at least one sensor electrode for providing a sensor capacitance.

[0042] The following steps are carried out in the method according to the invention: a) Switching at least one switch element to connect a transmit path to the sensor electrode, b) Generating an electrical input signal, in particular at an input of a transmission arrangement, preferably by a control device such as a microcontroller, c) Carrying out a frequency-dependent change in the electrical input signal to provide an output signal, preferably at an output of the transmission arrangement, preferably by the transmission arrangement, particularly preferably by at least one filter component, d) Outputting the output signal via the transmit path to the sensor electrode, e) Switching the at least one switch element to connect a receive path to the sensor electrode and preferably to disconnect the connection to the transmit path, f) Transmitting a receive signal from the sensor electrode to a holding arrangement in the receive path in order to evaluate the sensor capacitance.

[0043] The method according to the invention thus brings with it the same advantages as have been described in detail with reference to an arrangement according to the invention.

[0044] According to an advantageous development of the invention, it can be provided that the frequency-dependent change results in harmonic suppression in both the output signal and the received signal. This can preferably be achieved by a connection between the holding arrangement and the transmission arrangement. This makes it possible to continuously avoid interference during operation of the sensor element. Preferably, within the scope of the invention, it can be provided that the generation of the electrical input signal as a periodic signal is repeatedly interrupted to provide an interruption phase in order to pause the output of the output signal and in particular also the transmission of the received signal, preferably in such a way that the output signal is output as a burst signal. In other words, a pause can occur after repeated transmissions of the output signal to the sensor electrode and transmissions of the received signal from the sensor electrode.This pause, or interruption phase, can be performed regularly to reduce energy consumption. To achieve this, the control device outputs a "zero signal" as an input signal, for example, a voltage of 0 V or similar.

[0045] Further advantages, features and details of the invention will become apparent from the following description, in which embodiments of the invention are described in detail with reference to the drawings.

[0046] They show: Fig. 1 a perspective view of the rear of a vehicle with a user, Fig. 2 a schematic circuit diagram of a sensor device, Fig. 3 a schematic representation of an arrangement according to the invention, Fig. 4 a schematic representation of a sensor device, Fig. 5 schematic representations of signal curves, Fig. 6a further schematic representation of an arrangement according to the invention.

[0047] In the following figures, identical reference numerals are used for the same technical features, even in different embodiments.

[0048] Figure 1shows a schematic perspective view of a vehicle 1. A tailgate 2 is shown above a bumper 3 of the vehicle 1, wherein the tailgate 2 can be opened, for example, according to a (first) vehicle function and / or closed again according to a (second) vehicle function. At least one sensor element 20.1, in particular a sensor electrode 20.1, of a capacitive sensor device 20 can be integrated into the bumper 3. Alternatively or additionally, the at least one sensor element 20.1 can also be integrated into an (outside) door handle 4 of the vehicle 1 or another vehicle component. The capacitive sensor device 20 accordingly has a capacitive sensor, which is at least partially formed by the sensor element 20.1. The sensor element 20.1 is preferably cable-shaped and / or designed with an elongated extension in order to provide the longest possible detection range for detecting an activation action. It is also conceivable for the sensor element 20.1 to have an extension deviating from an elongated extension, e.g., substantially circular, rectangular, or point-shaped, or the like. The activation action is, for example, the movement of an activation means 9, such as a body part 9, in particular a foot 9, of a user 8 in an environment outside the vehicle 1 or the sensor element 20.1. To carry out the activation action, one possibility is for the user 8 to move the activation means 9 under the bumper 3. This movement is then detected as a change in a sensor capacitance CS of the capacitive sensor device 20 and can preferably be evaluated and detected by a control device 50 of the sensor device 20.For this purpose, the control device 50 is electrically connected and / or wired to the sensor element 20.1. Accordingly, it may be expedient for the control device 50 to be designed as a control unit of the vehicle 1, preferably as part of - or electrically connected to - the vehicle electronics. In this case, it is conceivable that, in order to reduce the circuit complexity, only a single electrical connection, e.g. a single electrical line such as a cable, leads from the control device 50 to the sensor element 20.1, i.e. the sensor element 20 is only connected via a single electrically conductive connection. The sensor element 20 thus corresponds to a sensor electrode 20.1 for providing the sensor capacitance CS. Furthermore, it is possible for the activation action to be detected by the control device 50, which then activates the vehicle function or at least one of the vehicle functions.

[0049] In Figure 2The detection principle for detecting the activation action and for evaluating the sensor capacitance CS is shown in more detail using a schematic diagram of the capacitive sensor device 20 and an arrangement 10 according to the invention, in particular circuit arrangement 10. Only one or possibly several sensor elements 20.1 can be provided. Examples are shown in Figure 2two sensor elements 20.1 in the form of sensor electrodes 20.1, each of which can provide a sensor capacitance CS. In other words, a sensor element 20.1 or a sensor electrode 20.1 can each provide a capacitive sensor, which can each be understood as a capacitor. With multiple sensor elements 20.1, at least one switching device 60 with at least one selective switch can be provided, which alternately selects the sensor elements 20.1, i.e., establishes an electrical connection thereto. The at least one switching device 60 alternately connects the sensor elements 20.1, for example, to a pre-filter arrangement 80 and / or at least one switch element S. The use of at least two sensor elements 20.1 has the advantage that, for example, movements and / or movement patterns can be detected.

[0050] The respective sensor element 20.1 may comprise an electrically conductive material to form a (single) sensor electrode 20.1. To provide the sensor capacitance CS, it is sufficient if only the respective sensor electrode 20.1 is provided without a counter electrode. In this case, the Figure 2 The counter electrodes shown (opposite the respective sensor elements 20.1) are merely representative for illustrating the principle and are not to be considered as actual components. Alternatively, at least one or an associated counter electrode for each sensor element 20.1 can be structurally provided.

[0051] Each sensor element 20.1 can form the sensor capacitance CS with respect to a ground potential 20.2, in particular the vehicle ground, and the environment of the vehicle 1. The sensor capacitance CS can thus be changed by the environment of the vehicle 1, in particular when an activation agent 9 moves into the surrounding area of ​​the sensor element 20.1. In this way, an activation action can be detected very reliably based on the sensor capacitance CS.

[0052] Various methods can be considered for evaluating the sensor capacitance CS. The methods are based in particular on transferring the charge located in the sensor element 20.1 or stored by means of the sensor capacitance CS to a holding arrangement 50.4 with a holding capacitance CH. This makes use of the fact that the stored charge depends on the variable sensor capacitance CS and thus on the environment of the vehicle 1 (e.g., the activation action). The holding arrangement 50.4 can have a holding capacitor, which serves for charge accumulation and / or intermediate storage and evaluation of the charge by the control device 50. Advantageously, the holding arrangement 50.4 has an operational amplifier OP', which can optionally be connected to at least one further component and / or a feedback loop (e.g.,via a capacitor) forms an integrator (see also . Figure 6 The integrator serves to store a charge quantity specific to the charge quantity received by the sensor element 20.1 during the charge transfer via a received signal. The operational amplifier OP' can be connected via an output O to a control device 50.1, e.g., in the form of a microcontroller, possibly via an analog-to-digital converter 50.2, in order to evaluate the stored charge quantity.

[0053] A repeatedly performed receive phase (also called a recharge phase) can advantageously be used for recharging. The receive phase can be a specific switching phase, i.e. a switching state of at least one switch element S. For this purpose, for example, the at least one switch element S, in particular at least one changeover switch S, is repeatedly switched, preferably at a frequency of 333 kHz. The receive phase in this case occurs when the switch element S electrically connects a receive path r to the sensor element 20.1. After a further switching of the switch element S to another switching state, however, a transmit phase (possibly also called a charging phase) occurs, in which the switch element S electrically connects a transmit path t to the sensor element 20.1. Both paths r, t can be designed as lines (e.g. on a circuit board), which thus provide an electrically conductive connection.

[0054] The transmission phase can be used to supply charge to sensor element 20.1, i.e., to charge the capacitive sensor. For this purpose, for example, sensor element 20.1 is electrically connected to a transmission arrangement 30 via switch element S and transmit path t during the transmission phase. This causes an output signal A to be transmitted via transmit path t, in particular from transmission arrangement 30 to sensor element 20.1. The reception phase, on the other hand, can be used to receive charge from sensor element 20.1 (stored due to sensor capacitance CS), i.e., to effect charge reversal. For this purpose, for example, sensor element 20.1 is electrically connected to a holding arrangement 50.4 via switch element S and receive path r during the reception phase. This causes the transmission of a receive signal via the receive path r, in particular from the sensor element 20.1 to the holding arrangement 50.4.In addition, the switching device 60 can also be repeatedly switched to alternately connect the different sensor elements 20.1 to the receive and transmit path r,t.

[0055] The following examines the receiving phase in more detail, which can be used for evaluation in the sensor device 20. During the receiving phase, the charge stored by the sensor capacitance CS can be "recharged," i.e., the holding arrangement 50.4 can be charged with the holding capacitance CH (e.g., a holding capacitor) as a function (e.g., proportionally) of the sensor capacitance CS or the charge stored thereby. The charge recharge can, if necessary, be performed via a low-pass filter 50.5 and / or, for example, also via a current mirror not explicitly shown. The charge state of the holding arrangement 50.4 or the holding capacitor, which is then relevant for detecting the activation action, can be determined in particular based on a voltage across or in series with the holding capacitor, optionally via the analog-to-digital converter 50.2. For this purpose, the analog-to-digital converter 50.2 can, on the one hand, be connected to the holding arrangement 50, e.g., via a low-pass filter 50.5.4 and, on the other hand, to the control device 50.1. Furthermore, at least one further control element 50.7 (also called a compensator) can optionally be connected to the receive path r, for example, to compensate for an excess charge during the transfer. For this purpose, the control element 50.7 can comprise, for example, a control circuit. Thus, the control element 50.7 (optionally together with other elements such as the control device 50.1) can be designed to detect an excess charge (i.e., when the transferred charge quantity can no longer be stored by the holding capacitance CH) and / or to perform compensation.

[0056] The control device 50.1 of the control device 50 can be implemented, for example, as a microcontroller or the like, and can optionally also carry out the (in particular repeated and / or clocked) switching of the switching element S. In particular, the control device 50.1 can do this depending on at least one adaptation means 50.3, preferably a computer program, in order to determine and / or vary a phase duration of the reception phase and / or the transmission phase. Furthermore, the control device 50.1 can also interrupt the alternating execution of the reception phase and / or the transmission phase, i.e., introduce a further interruption phase. This serves, for example, to pause the output of an output signal A and / or the transmission of the reception signal, for example to reduce energy consumption.

[0057] The principle circuit diagram according to Figure 2It is clear that, in particular, the described switching of the switch element S, without any further measures, generates a square-wave signal for controlling and / or evaluating the sensor element 20.1. This correspondingly has a very broad frequency spectrum. Such an unfavorable frequency spectrum can, without any further measures, lead to disruptive electromagnetic radiation (emission) from the sensor element 20.1 into the surroundings of the vehicle 1, particularly in frequency ranges that can have disruptive effects on other radio signals or the like.

[0058] Therefore, as a measure within the scope of the invention, it can be provided that a phase-dependent and / or frequency-dependent transmission and / or modification of at least one signal is carried out for control and / or evaluation. For example, for control (i.e., for transmission to the sensor element 20.1 and / or for charging and / or operating the sensor element 20.1), a signal, namely the output signal A, can be output and / or generated directly at an output 30.2 of a transmission arrangement 30, wherein the width of the frequency spectrum of the signal, in particular the harmonics, and thus the interference effect can be reduced via signal shaping and / or filtering. As a further signal for the evaluation, the received signal from the sensor element 20.1 can also be influenced by the phase-dependent and / or frequency-dependent transmission or modification, e.g., by connecting the transmission arrangement 30 to the holding arrangement 50.4 to control the reception of the received signal.

[0059] It is also advantageous if the signal and / or the signal shaping are influenced by the control device 50.1 and / or by a control arrangement 50.6 connected to the control device 50.1 and / or integrated therein. These can be connected to an input 30.1 of the transmission arrangement 30 in order to provide an input signal E (in particular control signal E) for the transmission arrangement 30 at the input 30.1. In this way, the transmission arrangement 30 can be interposed between the control device 50.1 and the sensor element 20.1 in order to carry out the frequency- and / or phase-dependent transmission or modification of the input signal E. This is carried out in particular as an advantageous frequency filtering such that the interfering frequencies in the input signal E are predominantly filtered out. For this purpose, the input signal E, when it is present at the input 30.1 of the transmission arrangement 30, is filtered and output as output signal A at output 30.2. Depending on this transmitted / modified (in particular filtered) input signal E, a guided output signal A can also be output by the transmission arrangement 30. This ensures that the shape of the transmitted, modified, or filtered signal—and thus the filtered frequency spectrum—is also retained at the sensor element 20.1. "Guided" can be understood in particular to mean that the output signal A is actively generated as a function of the transmitted, modified, or filtered input signal E and is applied to the sensor element 20.1, e.g., through the use of an operational amplifier OP.

[0060] How Figure 2 and with further details also Figure 6As can be seen schematically, the transmission arrangement 30 can also be connected to an input of the holding arrangement 50.4. In this case, the holding arrangement 50.4 comprises, for example, an integrator. By way of example, it can therefore be provided that an input of the transmission arrangement 30, in particular a non-inverted input "+" of the operational amplifier OP of the transmission arrangement 30, is connected to an input of the integrator, preferably a (non-inverted) input "+" of a further operational amplifier OP' of the integrator. This connection is preferably designed such that the holding arrangement 50.4 receives the received signal from the sensor element 20.1 via the receive path r depending on the frequency- and / or phase-dependent transmission and / or modification by the transmission arrangement 30. For this purpose, a signal provided by the transmission arrangement 30 (e.g., at the input "+" of the operational amplifier OP in Figure 3 and 6), which exhibits the frequency and / or phase-dependent change due to the filtering, e.g., influence the function of the holding arrangement 50.4 or the integrator. If the connection is made to the input of the integrator, this provided signal can be regarded as a type of reference for the integration (e.g., by connecting to the non-inverted operational amplifier input of the integrator, the provided signal influences the differential voltage of this further operational amplifier OP' of the integrator and, if necessary, via feedback at the operational amplifier OP', thus also the received signal). The interconnection of the Figure 6 The components shown can be the same as those in Figure 2 and 3 correspond, as indicated by dashed connecting lines.

[0061] In Figure 3The transmission arrangement 30 is shown in further detail. The circuit for generating the input signal E, i.e. in particular the control device 50, preferably the control device 50.1 and / or the control arrangement 50.6, is schematically represented by an input signal source 40. This is capable of generating an electrical input signal E, such as at least one input signal E embodied essentially as a square-wave signal or based thereon. The control arrangement 50.6 can also optionally perform further signal shaping of the input signal E, e.g., via connectable resistors, in order to shape the input signal E. For this purpose, the control arrangement 50.6 can also be controlled by the control device 50.1 in order to perform the signal shaping, e.g., in a controlled manner by the adaptation means 50.3. The input 30.1 is electrically connected to at least one first filter component 30.4, in particular an RC element, and / or a second filter component 30.5, in particular further resistors R and / or capacitors C to form a Sallen-Key filter. The first filter component 30.4 comprises, for example, a (possibly single) resistor R and a (possibly single) capacitor C. Preferably, a third-order filter can be provided overall by interconnecting the two filter components 30.4, 30.5 through the transmission arrangement 30. The use of an operational amplifier OP further enables the design as an active filter, preferably a Sallen-Key filter.

[0062] In Figure 2the control device 50.1 is schematically connected to the control arrangement 50.6 via a line. This serves to simplify the representation of the circuit diagram, wherein the line can optionally also be understood as multiple lines which connect respective outputs of the control device 50.1 to respective resistors of the control arrangement 50.6. For example, the control device 50.1 can be connected to the control arrangement 50.6 via at least one or two or three or four separate electrical lines, in particular in order to control at least one resistor of the control arrangement 50.6 via the lines. Furthermore, the lines can, for example, each connect an output of the control device 50.1 to at least one resistor of the control arrangement 50.6, and preferably then electrically connect the respective output to the input 30.1 via the respective resistor(s).The control arrangement 50.6 comprises at least two or three or four resistors, each of which is connected to a first terminal via a respective line with the control device 50.1 and to a second terminal with the input 30.1. Since these are different lines and outputs of the control device 50.1, the resistors can be controlled individually and / or independently of one another in order to provide the input signal E at the input 30.1 in a shaped form. In other words, a programmable voltage divider is formed by the control arrangement 50.6. This enables the input signal E to be shaped as required. Figure 5 is explained in more detail.

[0063] It can be seen that the filter components 30.4, 30.5 can be electrically connected to a source device 30.3, in particular a current and / or voltage source device 30.3. In Figure 3In the example shown, the source device 30.3 is embodied as the operational amplifier OP, which is interconnected with the filter components 30.4, 30.5 in the sense of a Sallen-Key filter configuration. Accordingly, the operational amplifier OP and / or the source device 30.3 can also be understood as a further filter component, if necessary. The source device 30.3 outputs an output signal A at the output 30.2 based on the input signal E filtered by the filter components 30.4, 30.5. To actively guide the output signal A, the source device 30.3 is connected to a supply voltage. Shown here, by way of example, are a first voltage U1 for providing a first supply potential VE and a second voltage U2 for providing a second supply potential VC, wherein the voltages are, for example, of the same magnitude and of different polarities. U1 is, for example, -5 V and U2 is, for example, +5 V.By appropriately designing the components, a transmission arrangement 30 can be provided which has the filter properties of an active low-pass filter, in particular a third-order filter and / or with an attenuation of -20 dB at 1 MHz and / or a cutoff frequency of 470 kHz. In other words, a harmonic suppression of at least -20 dB can be provided. The filter is particularly suitable for an operating frequency of the sensor device 20 of (essentially) 333 kHz, which is determined by the frequency of the switching between the reception phases and / or transmission phases. For example, the operating frequency (or other operating frequencies) is determined by the switching frequency of the switching element S or corresponds to it. In particular, harmonics from the 2nd harmonic or 3rd harmonic can be effectively suppressed.

[0064] Alternatively, the filter components 30.4, 30.5 may be omitted, so that, for example, the transmission arrangement 30 only comprises the controlled source device 30 to transmit the input signal E essentially unchanged and then output it as output signal A (e.g., as a square-wave signal) without filtering. Furthermore, the transmission arrangement 30 may also have the filter properties of an all-pass filter or the like.

[0065] A further alternative and / or addition to the arrangement 10 according to the invention is shown in Figure 3shown in dashed lines. A connection to a further source device 30.3' can be provided at the output 30.2, preferably at the operational amplifier OP and / or the source device 30.3 and / or the at least one filter component 30.4, 30.5, in order to provide an alternative output 30.2'. This configuration is only optional, for example, to use a current source and / or a converter as the further source device 30.3' in order to output a guided output signal A' in an alternative manner. This configuration with the further source device 30.3' can be used in addition to the shown configuration with the operational amplifier OP, or it can also replace the source device 30.3. In the latter case, the filter formed by the filter components 30.4, 30.5 can also be designed as a passive filter and / or the further source device 30.3' can also form a filter component to form an active filter.In principle, the output signal A or A' can therefore be a forcibly guided sensor voltage or a forcibly guided sensor current.

[0066] In Figure 4the transmission path of a signal S' between the switch element S and the at least one sensor element 20.1 is shown. Within this transmission path along a transmission path u, further electronic elements can be arranged, which is indicated by a dashed line of the transmission path u. These further elements can, for example, effect further filtering of the signal S'. Depending on the switch position (switching state), the switch element S connects this transmission path to the receive path r for evaluation or the transmit path t for control. In a first switch position of the switch element S, the signal S' can thus correspond to the output signal A, which is transmitted from the output 30.2 of the transmission arrangement 30 to the sensor element 20.1. In a second switch position of the switch element S, however, the signal S' can correspond to a receive signal and be transmitted to the holding arrangement 50.4 via the receive path r.In the latter case, the signal S is specific for the detection and can be evaluated, for example, by the control device 50 to detect an activation action.

[0067] How to continue in Figure 4As shown, a pre-filter arrangement 80, in particular a preselector 80, preferably in the form of an absorption circuit and / or a bandpass filter or a bandstop filter (bandstop filter), can be used. This allows interfering frequencies of the signal S' to be filtered out, which may enter through the sensor element 20.1 (in the sense of radiation or immission). This makes it clear that the sensor element 20.1 can also be regarded as a type of antenna, via which emissions (from the sensor device 20 into the environment of the vehicle 1) exit and immissions (from the environment into the sensor device 20) can enter. The terms emissions and immissions are used here in the sense of interfering radio signals and electromagnetic radiation, respectively. The pre-filter arrangement 80 can be designed, for example, as an LC resonant circuit and / or absorption circuit, e.g., with a capacitor C and coil L connected in parallel.The pre-filter arrangement 80 is connected, for example, to a first and second terminal 80.1, 80.2. Advantageously, the first terminal 80.1 can connect the pre-filter arrangement 80 to a supply potential, and / or the second terminal 80.2 can connect the pre-filter arrangement 80 to a ground potential. This has the advantage that signal components of the signal S' in the undesired frequency range can be conducted, i.e., discharged, via at least one of these terminals. For this purpose, the pre-filter arrangement 80 becomes low-impedance for this potentially undesired frequency range. For the desired frequency, however, the pre-filter arrangement 80 can become high-impedance, so that the signal S' for this frequency is not passed through the pre-filter arrangement 80 (the pre-filter arrangement 80 therefore acts as a bandpass filter for the desired frequency such that the pre-filter arrangement 80 does not discharge the desired frequency).In the ideal case, i.e. operation exclusively with a signal S' of the desired frequency, no loss occurs due to this filtering. The power loss can accordingly be significantly reduced by this design. Furthermore, it may be possible for a resistor and / or a resistor arrangement for the pre-filter arrangement 80 to be integrated into the receive path r and the transmit path t, wherein the resistors and / or the resistor arrangements are preferably (substantially) identical (with the same resistance value and / or the same size and / or the same impedance). The resistors and / or the resistor arrangements can be designed to adapt a transfer function of the pre-filter arrangement 80.

[0068] Figure 5shows various options II. to V. for signal shaping the input signal E (solid line) and the resulting output signal A (dashed line). For clarification, illustration I. is shown, in which no frequency- and / or phase-dependent change and / or only a frequency- and / or phase-dependent transmission of the input signal E takes place through the transmission arrangement 30. In illustration II., on the other hand, the input signal E is filtered by the transmission arrangement 30, i.e. in particular via the filter components. The filter components preferably provide an analog low-pass filter, which changes the rectangular shape of the input signal E. In this way, a sinusoidal output signal A can be provided. Illustration III.shows an example of advanced signal shaping, in which, in addition to filtering by the filter components of the transmission arrangement 30, modulation (particularly as "smoothing") is also effected by the control device 50.1 and / or the control arrangement 50.6. The input signal E deviates from the original rectangular shape and, due to the modulation, exhibits a temporally increasing and decreasing amplitude of individual pulses. This advanced signal shaping can, for example, be effected directly during the generation of the input signal E by the control device 50.1. A further development is shown in illustration IV., in which, in addition to the modulation according to III., a further modulation is used. The input signal E has a stepped shape, which can promote filtering by the transmission arrangement 30. In other words, according to illustration III., the control arrangement 50.6 and / or a control device 50.1 may be designed to shape the input signal E by generating a rectangular signal with temporally successive pulses, wherein the pulse amplitudes of different pulses vary over time, preferably with an amplitude that increases and decreases over time (in particular within a burst), wherein the pulse amplitude of individual pulses preferably remains (essentially) constant over the pulse width. In contrast, in illustration IV., the pulse amplitude of individual pulses can also change over time within the pulse width, preferably having a stepped shape. In this way, a sinusoidal output signal A can be generated particularly reliably. A particularly advantageous example of an input signal E is shown in illustration V. This signal can be obtained, for example, by signal shaping which is carried out by the control device 50.1 and / or the control arrangement 50.6 is provided. For this purpose, the control arrangement 50.6 is designed, for example, as a programmable voltage divider. The illustrated form has several temporally successive rectangular pulses which differ from one another in terms of their pulse amplitude. For this purpose, a control signal can be output by the control device 50.1 for the control arrangement 50.6 via the various lines, each of which is connected to at least one resistor of the control arrangement 50.6. This signal is designed, for example, in the form of pulse width modulation or the like, and differs for different lines. The resistances of the different lines are, for example, of different sizes. In this way, the input signal E can be generated very precisely with the desired shape.The symmetry of the shape, in particular the similar ascending and descending pulse sequence and / or the constant absolute value of the amplitude difference for different pulses, allows a particularly advantageous spectrum to be generated. In particular, this allows the third harmonic in the spectrum of the input signal E to be eliminated (if necessary, completely).

[0069] The above explanation of the embodiments describes the present invention exclusively by way of examples. Reference sign list

[0070] 1Vehicle 2Tailgate 3Bumper 4Door handle 8User 9Body part, activation device 10Arrangement, circuit arrangement 20Sensor device 20.1Sensor electrode, sensor element 20.2Ground potential 30Transmission arrangement 30.1Input 30.2Output 30.3Source device, voltage source device 30.4First filter component, RC element for 1st order low-pass filter 30.5Second filter component, further arrangement for 2nd order low-pass filter 40Input signal source, digital signal generation 50Control device 50.1Control device, microcontroller 50.2Analog-to-digital converter 50.3Adaptation means, software 50.4Holding arrangement 50.5Low-pass filter 50.6Control arrangement 50.7Further control element 60Switching device 80Preselector, prefilter 80.1First connection, supply connection 80.2Second connection, ground connection rReceive path tTransmit path AOutput signal CCapacitor CHHolding capacitance CSSensor capacitance EInput signal OPOperational amplifier RResistor SSwitch element U1First voltage U2Second voltage VCSupply voltage, second potential VESupply voltage, first potential

Claims

1. Arrangement (10) for a capacitive sensor device (20) of a vehicle (1), in particular for actuation and / or evaluation in the capacitive sensor device (20) for detecting an activation action in the vehicle (1): - at least one sensor electrode (20.1) for detecting a change in an environment of the vehicle (1), - a transmission arrangement (30) for providing an output signal (A) by means of a frequency-dependent change in an electrical input signal (E) of the transmission arrangement (30), - an output (30.2) of the transmission arrangement (30), which is electrically connected to the sensor electrode (20.1) in order to operate the sensor electrode (20.1) with the output signal (A), wherein the transmission arrangement (30) has at least one filter component (30.4, 30.5) to perform the frequency-dependent change, wherein an input signal source (40) is connected to an input (30.1) of the transmission arrangement (30) in order to provide the input signal (E) as a signal based on a square-wave signal at the input (30.1), which is actively modified by signal shaping by grinding the edges of the square-wave signal and by a time-varying amplitude in order to support the frequency-dependent modification, preferably a harmonic suppression, of the transmission arrangement (30).

2. Arrangement (10) according to claim 1, characterized in that the transmission arrangement (30) is designed by the at least one filter component (30.4, 30.5) as an active electronic filter, preferably as a Sallen-Key filter, and / or in that the transmission arrangement (30) forms a low-pass filter by means of the at least one filter component (30.4, 30.5) in order to filter the input signal (E) in such a way that, during operation of the sensor electrode (20.1), radiation in an interfering frequency range, preferably from a second harmonic of the input signal (E), is at least reduced.

3. Arrangement (10) according to one of the preceding claims, characterized in that the at least one filter component (30.4, 30.5) comprises a first filter component (30.4), in particular for forming an RC low-pass filter, and a second filter component (30.5), in particular for forming a Sallen-Key filter, the filter components (30.4, 30.5) being interconnected in order to jointly perform the frequency-dependent change in the input signal (E).

4. Arrangement (10) according to one of the preceding claims, characterized in that the output signal (A) can be provided as a function of the frequency-dependent change in the input signal (E) in that the at least one filter component (30.4, 30.5) is connected between the output (30.2) and an input (30.1) of the transmission arrangement (30).

5. Arrangement (10) according to one of the preceding claims, characterized in that a control device (50.1) is provided as part of an input signal source (40) in order to generate the input signal (E), preferably via a digital-to-analog converter.

6. Arrangement (10) according to one of the preceding claims, characterized in that for signal shaping of the input signal (E), a control arrangement (50.6) is provided as part of an input signal source (40), which is connected between an input (30.1) of the transmission arrangement (30) and a control device (50.1) in order to change an input signal (E) generated by the control device (50.1) by means of the signal shaping and to apply it to the input (30.1) of the transmission arrangement (30), and / or in that a control device (50.1) as part of an input signal source (40) is designed to control a control arrangement (50.6) in such a way that the input signal (E) corresponds to a rectangular signal which alternates between first and second values, the first and second values changing in increasing and decreasing order over time.

7. Arrangement (10) according to one of the preceding claims, characterized in that a switch element (S) is connected between the output (30.2) of the transmission arrangement (30) and the sensor electrode (20.1) in order to connect a receive path (r) and a transmit path (t) alternately to the sensor electrode (20.1), wherein the output (30.2) is connected to the transmit path (t), and a holding arrangement (50.4) for evaluation at the sensor device (20) is connected to the receive path (r).

8. Arrangement (10) according to one of the preceding claims, characterized in that a holding arrangement (50.4) for evaluation is integrated in the sensor device (20) in a receive path (r) in order to receive a receive signal as a function of the charge stored in the sensor electrode (20.1) and / or as a function of a variable sensor capacitance (CS) of the sensor device (20) after the sensor electrode (20.1) has been charged by the output signal (A), the sensor electrode (20.1) being designed to provide the sensor capacitance (CS), and / or in that a holding arrangement (50.4) is provided for evaluating a variable sensor capacitance (CS) in order to detect the change in the environment of the vehicle (1) on the basis of this evaluation, the holding arrangement (50.4) being designed as an integrator in order to carry out a charge accumulation on the basis of a charge stored in the sensor electrode (20.1).

9. Arrangement (10) according to one of the preceding claims, characterized in that the sensor electrode (20.1) is designed to be arranged in electrical operative connection with the environment of the vehicle (1), preferably in a bumper (3) or in a door handle (4) of the vehicle (1), so that during operation of the sensor electrode (20.1) an electric field is generated in the environment in order to provide a variable sensor capacitance (CS) as a function of the environment.

10. Arrangement (10) according to one of the preceding claims, characterized in that the transmission arrangement (30) is connected to a holding arrangement (50.4) in order to receive a reception signal from the sensor electrode (20.1) as a function of the frequency-dependent change at the holding arrangement (50.4), preferably in order to also provide the frequency-dependent change for the reception signal for evaluation at the sensor device (20), and / or in that the transmission arrangement (30) forms a filter with a low-pass characteristic which has a cut-off frequency in a range from 100 kHz to 800 kHz, preferably 200 kHz to 600 kHz, preferably 400 kHz to 550 kHz, particularly preferably 470 kHz.

11. Arrangement (10) according to one of the preceding claims, characterized in that an operational amplifier input of the transmission arrangement (30) is connected to an integrator input of the holding arrangement (50.4) in order to receive a receive signal from the sensor electrode (20.1) as a function of the frequency-dependent change, so that the frequency-dependent change is provided both for the receive signal in a receive path (r) and for the output signal (A) in a transmit path (t).

12. Exterior door handle (4) for a vehicle (1) with an arrangement (10) according to one of the preceding claims.

13. Method (10) for operating a capacitive sensor device (20) of a vehicle (1), in particular for activation and / or evaluation in the capacitive sensor device (20) for detecting an activation action in the vehicle (1), wherein the sensor device (20) has at least one sensor electrode (20.1) for providing a sensor capacitance (CS), wherein the following steps are carried out: a) Switching at least one switch element (S) to connect a transmit path (t) to the sensor electrode (20.1), b) Generating an electrical input signal (E), c) Performing a frequency-dependent change of the electrical input signal (E) to provide an output signal (A), d) Output of the output signal (A) via the transmit path (t) at the sensor electrode (20.1), e) Switching the at least one switch element (S) to connect a receive path (r) to the sensor electrode (20.1) and to disconnect the transmit path (t), f) Transmitting a receive signal from the sensor electrode (20.1) to a holding arrangement (50.4) in the receive path (r) in order to evaluate the sensor capacitance (CS), wherein the capacitive sensor device (20) comprises an arrangement (10) according to one of the previous claims relating to an arrangement (10).

14. Method according to one of the preceding method claims, characterized in that the frequency-dependent change results in harmonic suppression for both the output signal (A) and the received signal, and / or that the generation of the electrical input signal (E) as a periodic signal is repeatedly interrupted to provide an interruption phase in order to pause the output of the output signal (A) and in particular also the transmission of the received signal, preferably in such a way that the output signal (A) is output as a burst signal.