Device and method for monitoring a signal path and signal processing system

Abstract

A device (100) for monitoring a signal path (150), the signal path (150) comprising a first processing unit (151) that generates a first signal (104) based on an input signal (101) of the signal path (150), and a second processing unit (152) that generates an output signal (102) of the signal path (150), wherein the output signal (102) depends on the first signal (104), comprising: an output estimation module (110) configured to determine an estimated output signal (102') of the second processing unit (152) based on the input signal (101); and a comparison module (120) configured to determine a state of the signal path (150) based on a deviation of the output signal (102) from the estimated output signal.

Description

AREA

[0001] Examples include a device and a method for monitoring a signal path, and a signal processing system comprising a signal path and a device for monitoring a signal path. BACKGROUND

[0002] Document DE 600 35 062 T2 proposes an arrangement for monitoring and / or controlling the bit rate of data pulses.

[0003] Publication EP 2 947 872 A2 proposes a matrix circuit for high-frequency signals.

[0004] Document DE 10 2010 007 349 A1 proposes an anomaly monitoring device.

[0005] Monitoring signal processing within signal paths is often desirable to verify the correct operation of the signal path. Monitoring the signal path can allow for the determination of its state. This can be of interest when a system relies on sensor data processed by a signal path to trigger safety measures. In automobiles, for example, a steering wheel angle sensor provides information about the steering angle of the vehicle's steering wheel, which is used by an electronic control unit (ECU) to control a driver for the steering system's mechanics. In the event of a malfunction due to deterioration of functionality within the signal path, incorrect information can be transmitted, potentially endangering the safety of the vehicle's occupants. Therefore, safety-relevant applications or systems in an automobile (e.g.,Electronic power steering systems must achieve Automotive Safety Integrity Level D (ASILD). This means that a single-point fault metric above 99% and a latent fault metric above 90% must be achieved. Therefore, there may be a need to monitor a signal path to be aware of its condition. SUMMARY

[0006] An example relates to a device for monitoring a signal path. The signal path comprises a first processing unit that generates a first signal based on an input signal of the signal path, and a second processing unit that generates an output signal of the signal path, the output signal being dependent on the first signal. The device includes an output estimator module configured to determine an estimated output signal of the second processing unit based on the input signal. Furthermore, the device includes a comparator module configured to determine a state of the signal path based on a deviation of the output signal from the estimated output signal. Determining a deviation of the signal path's output signal from an estimated output signal of the signal path can allow for determining whether the signal path is operating correctly.A device according to the example can thus allow the state of the monitored signal path to be determined. That is, the device can indicate whether the monitored signal path is operating as desired and whether the output signal of the signal path is reliable.

[0007] Another example relates to a signal processing system comprising a signal path and a device for monitoring a signal path. The signal path includes a first processing unit and a second processing unit, wherein the first processing unit is configured to generate a first signal based on an input signal of the signal path, and wherein the second processing unit is configured to generate an output signal of the signal path that depends on the first signal. A signal processing system according to the example can allow the determination of whether the output signal provided by the signal path within the signal processing system is reliable.

[0008] Another example relates to a method for monitoring a signal path. The signal path comprises a first processing unit that generates a first signal based on an input signal of the signal path, and a second processing unit that generates an output signal of the signal path, the output signal depending on the first signal. The method involves determining an estimated output signal of the second processing unit based on the input signal and determining a state of the signal path based on a deviation of the output signal from the estimated output signal. Determining a deviation of the signal path's output signal from an estimated output signal allows one to determine whether the signal path is functioning correctly. Thus, a state of the monitored signal path can be determined.The procedure can indicate whether the monitored signal path is working as desired and whether the output signal of the signal path is reliable.

[0009] Another example relates to a computer program with program code to perform the above procedure when the computer program is run on a computer or processor. BRIEF DESCRIPTION OF THE FIGURES

[0010] Some exemplary embodiments of devices and / or methods are described below solely by way of example and with reference to the accompanying figures, in which: Fig. 1 represents an example of a device for monitoring a signal path; Fig. 2 represents an example of a signal processing system; Fig. Figure 3 represents an exemplary implementation of the device for monitoring a signal path, as shown in Fig. 2; Fig. 4 represents another example of a signal processing system; and Fig. Figure 5 is an example of a method for monitoring a signal path. DETAILED DESCRIPTION

[0011] Several examples will now be described in more detail with reference to the accompanying drawings, which illustrate some of these examples. The thickness of lines, layers, and / or areas in the figures may be exaggerated for clarity.

[0012] While other examples of various modifications and alternative forms are appropriate, some examples are shown in the figures and described in detail here. It is understood, however, that the intention is not to limit examples to the specific forms revealed. Further examples may encompass all modifications, correspondences, and alternatives falling within the scope of revelation. Throughout the description of the figures, identical reference signs refer to identical or similar elements that may be implemented identically or in a modified form compared to one another, while providing the same or similar functionality.

[0013] It is understood that when an element is described as "connected" or "coupled" to another element, the elements may be connected or coupled directly or via one or more intermediate elements. Conversely, when an element is described as "directly" "connected" or "coupled" to another element, no intermediate elements are involved. Other expressions used to describe the relationship between elements should be interpreted similarly (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," to name just a few).

[0014] The terminology used herein is intended to describe specific examples and is not meant to be limiting to further examples. Whenever a singular form, e.g., "a" and "the," "a," or "a," is used, or the use of only a single element is neither explicitly nor implicitly defined as mandatory, further examples may also use plural elements to implement the same functionality. If functionality is subsequently described as being implemented using multiple elements, further examples may implement the same functionality using a single element or a single processing entity.It is further understood that the terms “include”, “comprehensive”, “exhibit” and / or “exhibit” when used indicate the presence of the specified features, integers, steps, operations, processes, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, processes, elements, components and / or groups thereof.

[0015] Fig. Figure 1 schematically depicts a device 100 for monitoring a signal path 150. For illustrative purposes only, Fig. Figure 1 further presents an example of the signal path 150. The signal path 150 comprises a first processing unit 151, which generates a first signal 104 based on an input signal 101 of the signal path 150. The signal path 150 further comprises a second processing unit 152, which generates an output signal 102 of the signal path 150. The output signal 102 depends on the first signal 104. The first processing unit and / or the second processing unit 152 can include one or more microprocessors or one or more microcontrollers for a memory for storing dedicated software.

[0016] It is noted that data processing in signal path 150 can be expressed as a data flow or stream along signal path 150. The data processing of signal path 150 can be expressed functionally and is usually known for a given application. Individual data processing steps can be implemented with functional units that realize an individual data processing step performed along signal path 150. Without limitation, some or all of these individual units can also be implemented as a piece of software or code that performs the individual data processing step.

[0017] As indicated by signal path 150, the first processing unit 151 corresponds to the beginning of signal path 150, while the second processing unit 152 corresponds to the end of signal 150. Signal path 150 can include any number of additional signal processing components, which are connected in any way between the first processing unit 151 and the second processing unit 152 to further process the first signal 104. Individual signal processing components can be, for example, amplifiers, comparators, filters, analog-to-digital or digital-to-analog converters, or a more complex digital circuit arrangement. However, in some examples, the first processing unit 151 and the second processing unit 152 can be directly coupled, i.e., no additional signal processing components are connected between the first processing unit 151 and the second processing unit 152.

[0018] The input signal 101 of signal path 150 can be an analog signal or a digital signal (e.g., using a Short PWM Code, SPC, or Peripheral Sensor Interface 5, PSI5, protocol). Depending on the specific implementation, the output signal 102 of signal path 150 can be an analog signal or a digital signal. Similarly, the first signal 104 can be an analog signal or a digital signal.

[0019] The device 100 comprises an output estimator 110 configured to estimate an output signal 102' of the second processing unit 102 based on the input signal 101. In some examples, the estimated output signal 102' can be determined by processing the input signal 101 using the signal path 150 processing algorithm, or essentially the signal path 150 processing algorithm. For example, identical operations with reduced accuracy or resolution can be performed by the estimator 110. In some examples, the estimated output signal 102' can be determined using a lookup table. The lookup table can include information about a plurality of estimated output signals assigned to different input signals.The lookup table can include information about a first estimated output signal associated with a first input signal, and information about a different second estimated output signal associated with a second input signal, the second input signal being different from the first input signal. That is, the estimated output signal 102' can be determined by real-time calculation or by reference to predetermined information about estimated output signals (i.e., using a priori knowledge of the behavior of the components within the monitored signal path 150, assuming they operate without errors). It is obvious to a person skilled in the art that the determination of the estimated output signal 102' can be based on additional or different criteria.

[0020] Furthermore, the device 100 comprises a comparison module 120 configured to determine a state 103 of the signal path 150 based on a deviation of the output signal 102 from the estimated output signal 102'. A variety of criteria can be used to determine the deviation of the output signal 102 from the estimated output signal 102'. For example, waveforms, edges, pulse widths, or amplitudes of the output signal 102 and the estimated output signal 102' can be compared. In some examples, two or more criteria can be considered for determining the deviation of the signals. An absolute or relative degree of deviation of the output signal 102 from the estimated output signal 102' can be determined. For example, an absolute or relative deviation of a pulse width of the output signal 102 and the estimated output signal 102' can be determined.Based on the deviation of the output signal 102 from the estimated output signal 102', the state of the signal path 150 is determined. That is, different states of the signal path 150 can be assigned to different degrees of deviation. For example, a first state can be assigned to a first deviation range, a second state can be assigned to a different second deviation range, a third state can be assigned to a different third deviation range, and so on. Accordingly, the device 100 can indicate whether the monitored signal path 150 is operating as desired (as required). That is, the device 100 can indicate whether the output signal 102 of the signal path 150 is reliable. By selecting the granularity of states for the monitored signal path 150, the functionality (operational capability) of the signal path 150 can be determined with the required accuracy.

[0021] In some examples, the comparator module 120 can be configured to determine a first state of the signal path 150 if the deviation of the output signal 102 from the estimated output signal 102' is below a first threshold. Furthermore, the comparator module 120 can be configured to determine a second state of the signal path 150 if the deviation of the output signal 102 from the estimated output signal 102' is below a different second threshold. That is, the comparator module 120 determines the second state if the deviation of the output signal 102 from the estimated output signal 102' is between the first and second thresholds. Finally, the comparator module 120 can be configured to determine a third state of the signal path 150 if the deviation of the output signal 102 from the estimated output signal 102' is greater than the second threshold.Accordingly, the functionality of signal path 150 can be classified into three states. This allows for a more detailed description of the functionality of signal path 150 compared to conventional two-state descriptions (e.g., functional / non-functional).

[0022] For example, the first state can indicate normal operation of signal path 150, i.e., the first state can indicate that signal path 150 is operating without errors. The second state can indicate a deterioration in the functionality of signal path 150, i.e., the second state can indicate that the functionality of signal path 150 is limited but still acceptable. The remaining third state can indicate a failure of signal path 150, i.e., the second state can indicate that the functionality of signal path 150 is unacceptably limited or that a malfunction of signal path 150 has occurred. Based on the detailed information about the state of signal path 150, the operation of a component that receives the output signal 102 of signal path 150 can be set. For example,The output signal 102 can normally be used for the first state, can still be used for the second state, and cannot be used for the third state. However, the second state can, for example, trigger the component to perform additional reliability, consistency, or plausibility checks. Accordingly, signal path 150 can still be used in an application if its functionality is not critically restricted.

[0023] In other words, Fig. Figure 1 describes a signal processing system 199 comprising a signal path 150 and a device 100 for monitoring a signal path. The monitored signal path 150 includes a first processing unit 151 and a second processing unit 152, wherein the first processing unit 151 is configured to generate a first signal 104 based on an input signal 101 of the signal path 150, and wherein the second processing unit 152 is configured to generate an output signal 102 of the signal path 150 that depends on the first signal 104. The signal processing system 199 can thus allow the determination of whether the output signal 102 provided by the signal path 150 within the signal processing system 199 is reliable. That is, the determined state of the signal path 150 can indicate a degree of functionality of the signal path 150.

[0024] In some examples, the signal processing system 199 may include a component coupled to the signal path to provide the input signal 101. The component can generally be any component capable of providing an input signal to the signal path 150. For example, the component may be another signal processing component or a sensor element.

[0025] An example of a signal processing system, which further includes a component for providing the input signal, is in Fig. 2 shown. The signal processing system that is in Fig. Figure 2 shows a signal processing system in an automotive vehicle. The component for providing the input signal includes a sensor element 230 configured to provide a sensor signal 201 that indicates a physical quantity as the input signal of the signal path 250.

[0026] The first processing unit of signal path 250 is an automotive ECU 251, which generates an initial signal 204 based on the input sensor signal 201. The ECU 251 may have one or more microprocessors or microcontrollers for processing the sensor signals 201 according to instructions from a computer program stored in the ECU 251. For example, the ECU 251 may digitize, filter, or amplify the sensor signal 201. Furthermore, the ECU 251 may perform safety checks to verify the correct operation of the sensor element 230. In some examples, the ECU 251 may also combine the sensor signal 201 with one or more other signals. As a result of the processing, the initial signal 204 is output by the ECU 251.

[0027] The second processing unit of signal path 250 is a driver 252 of an actuator 240 of the automotive vehicle. The driver 252 receives the first signal 204 from the ECU 251 as an input signal. The driver 252 generates a control signal for the actuator 240 as an output signal 202 of signal path 250. The output signal 202 depends on the first signal 204, i.e., it depends on the sensor signal 201. The output signal 202 contains information for setting the actuator 240. The output signal 202 can be a digital signal or an analog signal. For example, the output signal 202 can be a pulse-width modulated (PWM) signal.

[0028] Signal path 250 is monitored by a signal path monitoring device (comparator circuit) 200. The device 200 receives the sensor signal 201 and the output signal 202. An output estimator module (not shown) of the device 200 determines an estimated output signal of the driver 252 based on the received sensor signal 201. For example, the output estimator module can use a lookup table to determine the estimated output signal. In some examples, the output estimator module can calculate the estimated output signal based on the input signal (e.g., using a linear equation). A comparator module (not shown) of the device 200 determines a state 203 of the signal path 250 based on a deviation of the output signal 202 from the estimated output signal. Accordingly, the device 200 can indicate whether the monitored signal path 250 is operating as desired., the device 200 can indicate whether the output signal 202 of the signal path 250 is reliable.

[0029] For example, the device 200 can display three different states of the signal path 250: normal operation (mode) of the signal path 250, deterioration of the functionality of the signal path 250 and failure of the signal path 250.

[0030] With regard to the specific example of an electronic power steering system in the automobile, the sensor element 230 can be configured to detect a magnetic field. Detecting a magnetic field can, for example, allow the measurement of steering wheel torque or steering wheel angle (e.g., using the Hall effect). Accordingly, the detected sensor signal 201 can indicate steering wheel torque or steering wheel angle. The sensor signal 201 is processed by the ECU 251 and the driver 252 of signal path 250 to provide a control signal for the actuator 240 of the electronic power steering system as an output signal 202 of signal path 250. For example, the actuator 240 can be an electric motor of the electronic power steering system. The electric motor can, for example, be coupled to a steering gear of the automobile.Accordingly, an assistive torque can be applied to the steering gear of the vehicle to support the driver in steering. The assistive torque is based on the measured steering wheel torque and / or steering wheel angle. The output signal 202 can, for example, be a PWM signal supplied to an H-bridge of the electric motor. By adjusting the pulse width of the PWM signal, the rotational speed of the rotor in the electric motor can be set. Consequently, the assistive torque provided by the electric motor can be adjusted. In some examples, the output signal 202 can be a PWM signal for controlling a three-phase electric motor.

[0031] In the example of the electronic power steering system, the sensor signal 201 can, for example, indicate steering wheel torque. Accordingly, a lookup table used by the estimation module of the device 200 can contain information about expected output signals from the driver 252 for specific values ​​of steering wheel torque (assuming that the signal path 250 is operating correctly). If the sensor signal 201 indicates a steering wheel angle, the lookup table can contain information about expected output signals from the driver 252 for specific values ​​of the steering wheel angle (assuming that the signal path 250 is operating correctly). For example, the lookup table can contain information about the specific shape or pulse width of a PWM signal provided by the driver 252 as an output signal for a specific value of the steering wheel angle or a specific value of the steering wheel torque.Accordingly, the output estimation module of the device 200 can determine the estimated output signal based on this information.

[0032] In the state of "normal operation," the difference (deviation) between the output signal 202 and the estimated output signal is below a defined first threshold (e.g., 1%, 2%, 3%, 4%, or 5%). Accordingly, a deviation of the actual behavior of actuator 240 from its intended behavior is below a first threshold level. The first threshold level can be selected, for example, such that a driver cannot detect the deviation. With regard to the electronic power steering system, the first threshold level (i.e., the first threshold for signal deviation) can be selected such that the deviation in the motor's behavior (i.e., the deviation in the provided assist torque) is not detectable by the driver within the steering play.

[0033] In the "functional deterioration" state, the difference (deviation) between the output signal 202 and the estimated output signal is below a defined second threshold (e.g., 8%, 9%, 10%, 11%, or 12%) but above the first threshold. This means that the deviation of the actual behavior of actuator 240 from its intended behavior exceeds the first threshold level. Accordingly, a driver can detect this difference in actuator 240's behavior. For example, with regard to the electronic power steering system, a driver might require more steering effort. Furthermore, the electronic power steering system can signal the "functional deterioration" state to the driver (e.g., through a warning light on the dashboard, an audible signal, or haptic feedback).

[0034] In the "failure" state, the difference (deviation) between output signal 202 and the estimated output signal exceeds the second threshold. This means the difference (deviation) between output signal 202 and the estimated output signal is so large that the functionality of the system, which includes or is based on signal path 250, can no longer be guaranteed and must be deactivated. With regard to the electronic power steering system, the system can be switched off, and a fault can be indicated to the driver (e.g., warning light on the instrument panel, acoustic signal, or haptic feedback).

[0035] Accordingly, greater diagnostic coverage of signal path 250 and thus of the electronic power steering system with regard to failures can be provided by the device 200 for monitoring a signal path.

[0036] An exemplary implementation of the device 200 for monitoring a signal path is shown in Fig. Figure 3 shows the device 200 receiving the input signal 202 and the output signal 202. The output estimator 210 of the device 200 receives the input signal 201 and determines the estimated output signal 202' of the driver 252 (as an example of a second processing unit) based on the input signal 201. The device 200 also includes the comparator 220. The comparator 220 receives the estimated output signal 202' and the output signal 202.

[0037] Optionally, the device 200 can include a conversion module 211 configured to generate a converted output signal 202'' based on the output signal 202. The information represented by the converter output signal 202'' corresponds to the information represented by the output signal 202. For example, the conversion module 211 can digitize the output signal 202. That is, in some examples, the converted output signal 202'' can be the digital replica of the analog output signal 202. In some examples, the conversion module 211 can modify the format of the output signal 202 as required for comparison with the estimated output signal 202'. As shown in Fig. As shown in Figure 3, when the device 200 includes the conversion module 211, the comparator module 220 receives the estimated output signal 202' and the converted output signal 202'' (which is equivalent to the output signal 202).

[0038] The comparator module 220 comprises a first comparator 221. The first comparator 221 receives the estimated output signal 202' and the output signal 202. If the device 200 includes the conversion module 211, the first comparator 221 receives the converted output signal 202'' instead of the output signal 202. Furthermore, the first comparator 221 receives a signal 224 indicating the first threshold (e.g., representing the boundary between normal operation and deterioration of functionality). The first comparator 221 is configured to compare the estimated output signal 202' and the output signal 202, or alternatively, the estimated output signal 202' and the converted output signal 202''. That is, the first comparator 221 is configured to determine whether the deviation of the output signal 202 from the estimated output signal 202' is above or below the first threshold.Since the converted output signal 202'' is equivalent to the output signal 202, comparing the estimated output signal 202' and the converted output signal 202'' also allows us to determine whether the deviation of the output signal 202 from the estimated output signal 202' is above or below the first threshold.

[0039] Furthermore, the comparator module 220 includes a second comparator 222, which receives the estimated output signal 202' and the output signal 202. If the device 200 has the conversion module 211, the second comparator 222 receives the converted output signal 202'' instead of the output signal 202. The second comparator 222 also receives a signal 225 indicating the second threshold (e.g., representing the boundary between deterioration of functionality and failure). The second comparator 222 is configured to compare the estimated output signal 202' and the output signal 202, or alternatively, the estimated output signal 202' and the converted output signal 202''. That is, the second comparator 222 is configured to determine whether the deviation of the output signal 202 from the estimated output signal 202' is above or below the second threshold.Since the converted output signal 202'' is equivalent to the output signal 202, comparing the estimated output signal 202' and the converted output signal 202'' also allows us to determine whether the deviation of the output signal 202 from the estimated output signal 202' is above or below the second threshold.

[0040] For example, the first comparator 221 can provide a binary determination result, where 0 indicates that the deviation is below the first threshold, and 1 indicates that the deviation is above the first threshold, or vice versa. Alternatively, the first comparator 221 can provide a true / false determination result, where "true" indicates that the deviation is below the first threshold, and "false" indicates that the deviation is above the first threshold, or vice versa. Similarly, the second comparator 222 can provide its determination result.

[0041] The determination results are supplied (provided) to a decision logic 223 of the comparison module 220. The decision logic 223 is configured to determine the state of the signal path based on the determination results of the first comparator 221 and the second comparator 222. For example, the decision logic 223 determines that the signal path is in a first state 203-1, which indicates normal operation of the signal path, if the determination result of the first comparator 221 shows that the signal deviation is below the first threshold, and the determination result of the second comparator 222 shows that the signal deviation is below the second threshold.Decision logic 223 determines that the signal path is in a second state 203-2, indicating a deterioration of the signal path's functionality, if the determination result of the first comparator 221 indicates that the signal deviation is above the first threshold, and the determination result of the second comparator 222 indicates that the signal deviation is below the second threshold. For example, decision logic 223 determines that the signal path is in a third state 203-3, indicating the signal path's failure, if the determination result of the first comparator 221 indicates that the signal deviation is above the first threshold, and the determination result of the second comparator 222 indicates that the signal deviation is above the second threshold. If the determination results of the first comparator 221 and the second comparator 222 are contradictory (i.e., inconsistent), decision logic 223 may, for example,The decision logic 223 can determine that the signal path is in the third state 203-3 or indicate a failure of the device 200. For example, if the determination result of the first comparator 221 indicates that the signal deviation is below the first threshold, and the determination result of the second comparator 222 indicates that the signal deviation is above the second threshold, the decision logic 223 can determine that the signal path is in the third state 203-3 or indicate a failure of the device 200.

[0042] ZB, the device 200 can be implemented by an 8-bit microcontroller, a 16-bit microcontroller, or any dedicated equivalent hardware component (e.g., an application-specific integrated circuit, ASIC; Application Specific Integrated Circuit).

[0043] The exemplary device 200, which is in Fig. As shown in Figure 3, this can allow for high diagnostic coverage of a monitored signal path. Furthermore, the device 200 can provide self-diagnostic functionality.

[0044] In Fig. Figure 4 shows another example of a signal processing system. The signal processing system of Fig. 4 is similar to the one in Fig. Figure 2 illustrates this. However, in addition to sensor signal 201, which indicates a physical quantity, sensor element 430 provides a second sensor signal 401 indicating the identical physical quantity. That is, ECU 251, as an example of the first processing unit in a signal path, receives the input signal and the second input signal, both of which provide information about the same quantity. ECU 251 can therefore generate the first signal 204 based on sensor signal 201 and the second sensor signal 401.

[0045] Accordingly, the output estimation module of device 200 can be further configured to monitor a signal path and determine the estimated output signal based on the second input signal 401. That is, input signal 201 and the second input signal 401 can be used to determine the estimated output signal. The redundancy of the input signals can be used to test the consistency of both signals. For example, if input signal 201 and the second input signal 401 display different values, the ECU 251 or device 200 can indicate a failure of the sensor element or the sensor path that couples sensor element 430 and the ECU 251. Thus, higher diagnostic coverage of sensor element 430 and signal path 250 can be provided.

[0046] Alternatively, the output estimator module of the device 200 for monitoring a signal path can further be configured to determine a second estimated output signal of the driver 252 (which is an example of a second processing unit of a signal path) based on the second input signal 401. That is, the output estimator module can determine the estimated input signal based on the input signal 201 and a second estimated input signal based on the second input signal 401. Accordingly, the comparator module of the device 200 can further be configured to determine the state of the signal path based on a deviation of the output signal from the second estimated output signal. For example, the comparator module can use one of the concepts described above to determine the deviation of the output signal from the second estimated output signal.Based on the deviation results for the first and second estimated output signals, the state of the signal path can be determined. For example, if a first state for the signal path is determined for the deviation of the first estimated output signal, and a different second state for the signal path is determined for the deviation of the second estimated output signal, a failure of the signal path can be indicated by the comparator module. This allows for higher diagnostic coverage of sensor element 430 and signal path 250.

[0047] An example of a Method 500 for monitoring a signal path is in Fig. Figure 5 illustrates the signal path. The signal path comprises a first processing unit that generates a first signal based on an input signal of the signal path, and a second processing unit that generates an output signal of the signal path, the output signal depending on the first signal. Method 500 comprises determining 502 an estimated output signal of the second processing unit based on the input signal. Furthermore, Method 500 comprises determining 504 a state of the signal path based on a deviation of the output signal from the estimated output signal. Determining a deviation of the output signal of the signal path from an estimated output signal of the signal path can allow one to determine whether the signal path is operating correctly. Thus, a state of the monitored signal path can be determined., the procedure 500 can indicate whether the monitored signal path is working as desired and whether the output signal of the signal path is reliable.

[0048] Further details and aspects of the procedure will be mentioned in connection with the proposed concept or one or more of the examples described above (e.g. Fig. 1-4). The procedure may include one or more additional optional features that correspond to one or more aspects of the proposed concept or to one or more of the examples described above.

[0049] The aspects and features mentioned and described in conjunction with one or more of the previously detailed examples and figures can further be combined with one or more of the other examples to replace a similar feature of the other example or to additionally introduce the feature into the other example.

[0050] Examples can further include a computer program with program code for performing any of the above procedures when the computer program is executed on a computer or processor. Steps, operations, or processes of various procedures described above can be performed by programmed computers. Examples can also include program storage devices, such as digital data storage media, that are machine-, processor-, or computer-readable and encode machine-, processor-, or computer-executable programs of instructions. The instructions perform or cause some or all of the steps of the procedures described above to be performed. The program storage devices can be, for example, digital storage devices, magnetic storage media such as magnetic disks and magnetic tapes, hard disk drives, or optically readable digital data storage media.Further examples should also cover computers, processors or control units programmed to perform the steps of the procedures described above, or (field) programmable logic arrays ((F)PLA = (Field) Programmable Logic Arrays) or (field) programmable gate arrays ((F)PGA = (Field) Programmable Gate Arrays) programmed to perform the steps of the procedures described above.

[0051] The description and drawings only illustrate the principles of disclosure. It is therefore understood that the person skilled in the art may derive various arrangements which, although not expressly described or illustrated here, embody the principles of disclosure and are contained within their essence and scope. Furthermore, all examples listed here are expressly intended for teaching purposes only, to assist the reader in understanding the principles of disclosure and the concepts contributed by the inventor(s) to the advancement of technology, and are to be understood as serving without limitation to such specifically listed examples and conditions. Furthermore, all statements made here concerning principles, aspects, and examples of disclosure, as well as specific examples thereof, are intended to encompass their equivalents.

[0052] The functions of various elements depicted in the figures, including each functional block designated as "means," "means of providing a sensor signal," "means of generating a transmit signal," etc., can be provided by dedicated hardware such as "a signal provider," "a signal processing unit," "a processor," "a controller," etc., as well as by hardware capable of executing software in conjunction with associated software. When provided by a processor, the functions can be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared.Furthermore, the explicit use of the terms "processor" or "controller" should not be interpreted as referring exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), read-only memory (ROMs) for storing software, random-access memory (RAMs), and non-volatile storage devices. Other hardware, both conventional and / or custom-designed, may also be included.

[0053] A block diagram can, for example, represent a detailed circuit diagram that implements the principles of the disclosure. Similarly, a flowchart, process diagram, state transition diagram, pseudocode, and the like can represent various processes that are essentially represented in a computer-readable medium and can thus be executed by a computer or processor, irrespective of whether such a computer or processor is explicitly shown. Methods disclosed in the description or in the claims can be implemented by an apparatus that includes means for performing each of the corresponding steps of those methods.

[0054] Furthermore, it is understood that the disclosure of multiple steps, processes, operations, sequences, or functions revealed in the description or claims should not be interpreted as being in a specific order, unless explicitly or implicitly stated otherwise, e.g., for technical reasons. The disclosure of multiple steps or functions therefore does not restrict them to a specific order, unless these steps or functions are not interchangeable for technical reasons. Furthermore, in some examples, a single step, function, process, or sequence may include or be broken down into multiple sub-steps, functions, processes, or sequences. Such sub-steps may be included and form part of the disclosure of that single step unless they are expressly excluded.

[0055] Furthermore, the following claims are hereby included in the detailed description, where each claim can stand alone as a separate example. While each claim can stand alone as a separate example, it should be noted that—although a dependent claim may refer to a specific combination with one or more other claims—other examples may also include a combination of the dependent claim with the subject matter of any other dependent or independent claim. These combinations are explicitly suggested here unless it is stated that a particular combination is not intended. Furthermore, features of a claim are also intended to be included for any other independent claim, even if that claim is not directly dependent on the independent claim.

Claims

[1] A device (100) for monitoring a signal path (150), the signal path (150) comprising a first processing unit (151) that generates a first signal (104) based on an input signal (101) of the signal path (150), and a second processing unit (152) that generates an output signal (102) of the signal path (150), wherein the output signal (102) depends on the first signal (104), comprising: an output estimation module (110) configured to determine an estimated output signal (102') of the second processing unit (152) based on the input signal (101); and a comparison module (120) configured to determine a state of the signal path (150) based on a deviation of the output signal (102) from the estimated output signal. [2] The device according to claim 1, wherein the comparator module (120) is configured to determine a first state of the signal path (150) when the deviation of the output signal (102) from the estimated output signal (102') is below a first threshold, to determine a second state of the signal path (150) when the deviation of the output signal (102) from the estimated output signal (102') is below a different second threshold, and to determine a third state of the signal path (150) when the deviation of the output signal (102) from the estimated output signal (102') is greater than the second threshold. [3] The device according to claim 2, wherein the first state indicates normal operation of the signal path (150), wherein the second state indicates a deterioration of the functionality of the signal path (150) and wherein the third state indicates a failure of the signal path (150). [4] The device according to claim 2 or 3, the comparison module (120) comprising a first comparator (221) configured to determine whether the deviation of the output signal (102) from the estimated output signal (102') is above or below the first threshold, a second comparator (222) configured to determine whether the deviation of the output signal (102) from the estimated output signal (102') is above or below the second threshold, and a decision logic (223) configured to determine the state of the signal path based on the determination results of the first comparator and the second comparator. [5] The device according to one of claims 1-4, wherein the output estimation module (110) is configured to determine the estimated output signal (102') using a lookup table, wherein the lookup table has information about a first estimated output signal associated with a first input signal and information about a different second estimated output signal associated with a second input signal, wherein the second input signal is different from the first input signal. [6] The device according to one of the preceding claims, wherein the first processing unit (151) further receives a second input signal (401), wherein the input signal (101) and the second input signal (401) comprise information about an identical quantity and wherein the output estimation module is further configured to determine the estimated output signal (102') based on the second input signal (401). [7] The device according to any one of claims 1-5, wherein the first processing unit (151) further receives a second input signal (401), wherein the input signal (101) and the second input signal (401) contain information about an identical quantity, wherein the output estimation module is further configured to determine a second estimated output signal of the second processing unit (152) based on the second input signal (401), and wherein the comparison module is further configured to determine the state of the signal path (150) based on a deviation of the output signal (102) from the second estimated output signal. [8] A signal processing system (200), comprising: a signal path (150) comprising a first processing unit (151) and a second processing unit (152), wherein the first processing unit (151) is configured to generate a first signal (104) based on an input signal (101) of the signal path (150), and wherein the second processing unit (152) is configured to generate an output signal (102) of the signal path (150) that depends on the first signal (104); and a device (100) for monitoring a signal path according to any one of claims 1-7. [9] The signal processing system according to claim 8, further comprising a component coupled to the signal path (150) to provide the input signal (101). [10] The signal processing system according to claim 9, wherein the component comprises a sensor element configured to provide a sensor signal indicating a physical quantity as the input signal (101). [11] The signal processing system according to claim 10, wherein the sensor element is configured to detect a magnetic field. [12] The signal processing system according to claim 10 or 11, wherein the sensor signal indicates a steering wheel torque. [13] The signal processing system according to one of claims 8-12, wherein the output signal is a pulse width modulated signal. [14] The signal processing system according to one of the preceding claims, wherein the first processing unit is an electronic control unit of an automotive vehicle, and wherein the second processing unit is a driver for an actuator of the automotive vehicle. [15] The signal processing system according to claim 14, wherein the actuator is an electric motor of an electronic power steering system of the automotive vehicle. [16] A method (500) for monitoring a signal path, the signal path comprising a first processing unit that generates a first signal based on an input signal of the signal path, and a second processing unit that generates an output signal of the signal path, wherein the output signal depends on the first signal, comprising: Determine (502) an estimated output signal of the second processing unit based on the input signal; and Determining (504) a state of the signal path based on a deviation of the output signal from the estimated output signal. [17] The method according to claim 16, wherein a first state of the signal path is determined when the deviation of the output signal from the estimated output signal is below a first threshold, a second state of the signal path is determined when the deviation of the output signal from the estimated output signal is below a different second threshold, and a third state of the signal path is determined when the deviation of the output signal from the estimated output signal is greater than the second threshold. [18] The method according to claim 17, wherein the first state indicates normal operation of the signal path, wherein the second state indicates deterioration of the functionality of the signal path, and wherein the third state indicates a failure of the signal path. [19] The method according to one of the preceding claims, wherein the first processing unit further receives a second input signal, wherein the input signal and the second input signal comprise information about an identical quantity and wherein the determination (502) of the estimated output signal is further based on the second input signal. [20] The method according to one of claims 16-18, wherein the first processing unit further receives a second input signal, wherein the input signal and the second input signal contain information about an identical quantity, wherein the method further comprises determining a second estimated output signal of the second processing unit based on the second input signal, and wherein determining the state of the signal path is further based on a deviation of the output signal from the second estimated output signal.

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