Gyroscope shock and disturbance measurement circuit

Abstract

Gyro measurement circuit (600) based on a differential demodulation concept, comprising: a first demodulation unit (602A) coupled to receive a gyro output signal from a gyroscope (202), wherein the first demodulation unit (602A) derives the gyro output signal using a first reference signal (f R1 ) to a first demodulated gyro output, wherein the gyro output signal comprises a pulse signal and a plurality of gyro measurement signals relating to a rotational speed of interest; a second demodulation unit (602B), coupled to receive the gyro output signal, wherein the second demodulation unit (602B) derives the gyro output signal using a second reference signal (f R2 ) to a second demodulated gyro output, where the first and second reference signals (f R1 , f R2) are symmetrical with respect to a characteristic frequency (f0) of the gyroscope (202); a subtractor (604) coupled to the first and second demodulation units (602A, 602B), wherein the subtractor (604) differentially combines the first and second demodulated gyro outputs to isolate the impulse signal, which is asymmetric with respect to the reference frequency (f0); and a peak detector (606) coupled with the subtractor (604), wherein the peak detector (606) determines whether the combined gyro output exceeds a threshold level (VTH) and generates a shock indicator to warn a main system if an anomalous shock or disturbance situation occurs.

Description

Cross-reference to related registration

[0001] This application claims priority under 35 USC §119(e) over preliminary application No. 61 / 816,419 entitled “Gyroscope Shock and Disturbance Measurement Circuit”, filed on April 26, 2013, the subject matter of which is incorporated herein in its entirety for reference. Background A. Technical field

[0002] The present invention relates to integrated circuits, and more precisely to systems, devices, and methods for detecting a shock or disturbance suffered by a gyroscope and for distinguishing rotation-based measurement signals from interference signals introduced by the shock or disturbance. DE 10 2004 061 804 A1 discloses, for example, a micromechanical gyroscope with seismic mass, drive means, and measuring elements for detecting deflections due to Coriolis force and interference. To compensate for the interference deflection, an interference deflection signal is demodulated from the deflection signal, and a compensation signal is generated from this, which is then fed to compensation means. B. Background of the invention

[0003] Microelectromechanical systems (MEMS) are widely used as sensors for measuring acceleration, rotation, pressure, and many other physical parameters. Typically fabricated on a silicon substrate using a micromachining process, MEMS devices have characteristic feature sizes of a few micrometers and convert mechanical motion into electrical signals that can indicate the level of a parameter of interest. In particular, MEMS-based gyroscope devices have been developed and applied to monitor the rotational speeds of devices about specific axes, and a variety of consumer and automotive applications have successfully employed such MEMS-based gyroscope devices.For example, many automotive applications incorporate gyroscope devices for stability control, navigation support, load balancing / suspension control, collision avoidance and rollover detection.

[0004] Conventional MEMS-based gyroscope devices use mechanical vibration elements (test masses) to detect rotational speed. Fig. Figure 1A represents a mechanical element 100 arranged in a rotating reference frame. The mechanical element 100 is driven to oscillate along a first orthogonal axis (x-axis), and as the frame rotates with respect to a second orthogonal axis (y-axis), oscillatory motion is induced along the third orthogonal axis (z-axis) due to Coriolis acceleration. A corresponding inertial Coriolis force F C can be represented as: Fc=−2Ωmv where Ω is the rotational speed, m is the mass of the mechanical element 100 and v is the oscillation speed along the first orthogonal axis.

[0005] Fig. Figure 1B represents an exemplary vibration gyroscope device 150, which is based on electrostatic actuation and capacitive sensing for detecting the Coriolis force. A test mass 152 is driven to oscillate along an x-axis by comb drives 154 arranged on two opposite sides. A capacitor is formed between the substrate and the test mass 152. In response to rotation about a y-axis, the test mass 152 oscillates toward and away from the substrate on which the gyroscope device 150 is located, and therefore the gap between the capacitor and the substrate changes, resulting in a capacitive change associated with the Coriolis force. An interface reading circuit is typically incorporated into the gyroscope device 150 to convert this capacitive change into a gyroscope measurement signal that is related to the magnitude of the Coriolis force and therefore to the corresponding rotational speed.

[0006] Although the gyroscope measurement signal contains valuable information about rotational speed, it is also subject to interference from various shock and disturbance sources, which can significantly degrade the accuracy of the rotation measurement. Shock resistance is particularly critical in automotive applications, where stringent safety requirements necessitate a fail-safe and robust system. In such a context, the occurrence of a shock or disturbance must be indicated and used to signal that an unreliable and unpredictable rotational speed signal is being output if the level of the shock or disturbance exceeds a threshold tolerable by a suitable rotation measurement system. Many existing gyroscope devices on the market employ sensor or housing solutions to enhance the shock resistance of the devices themselves.However, none of them indicates the occurrence of a shock or disturbance with respect to a certain tolerance and warns a main system to take appropriate countermeasures. Summary of the invention

[0007] Various embodiments of the invention relate to integrated circuits and, more precisely, systems, devices, and methods for incorporating a gyro measurement circuit into a gyroscope to detect a shock or disturbance experienced by the gyroscope device and to accurately distinguish rotation-based gyro measurement signals from disturbance signals introduced by the shock or disturbance. The gyro measurement circuit specifically utilizes the symmetry of these signals with respect to a characteristic frequency of the gyroscope.

[0008] According to one embodiment of the invention, a gyro measurement circuit is implemented based on a differential demodulation concept. Two demodulation units are used to demodulate a gyro output signal comprising a pulse signal and a plurality of gyro measurement signals. Two reference signals, symmetrical with respect to the reference frequency, are used for demodulation, and the resulting demodulated outputs are differentially combined in a subtractor to isolate the pulse signal, which is asymmetrical with respect to the reference frequency. A peak detector further determines whether the combined gyro output exceeds a threshold level and generates a pulse indicator to warn a main system of an anomalous pulse or disturbance situation.

[0009] According to a further embodiment of the invention, a gyro measurement circuit is implemented based on a non-differential demodulation concept. The gyro measurement circuit comprises a demodulation unit and a peak detector. The demodulation unit is first coupled to receive a gyro output signal, which includes a gyro measurement signal and at least one of a shock signal and a plurality of gyro noise signals from a gyroscope. Such a gyro output signal is demodulated using a reference signal such that the at least one of the shock signal and the plurality of gyro noise signals is retained, while the gyro measurement signal relating to a rotational speed of interest is suppressed. The peak detector determines whether the demodulated gyro output exceeds a threshold level and generates a shock indicator to warn a main system of an anomalous shock or disturbance situation.

[0010] Certain features and advantages of the present invention have been described in general terms herein; however, additional features, advantages, and embodiments presented here will be obvious to a person skilled in the art from the drawings, the description, and the claims therein. Accordingly, it should be understood that the scope of the invention is not limited by the particular embodiments disclosed in this summary section. Brief description of the drawings

[0011] Reference is now made to embodiments of the invention, examples of which may be shown in the accompanying figures. It is intended that these figures are for illustrative purposes only and not to be limiting. Although the invention is generally described in the context of these embodiments, it is understood that the scope of the invention is not intended to be limited to these specific embodiments. Fig. 1A represents a mechanical element arranged in a rotating reference frame. Fig. 1B represents an exemplary vibration gyroscope device based on electrostatic actuation and capacitive sensing to detect a Coriolis force. Fig. Figure 2 represents an exemplary rotation measurement system according to various embodiments in the invention. Fig. Figure 3 represents an exemplary block diagram of a gyro measurement circuit based on a non-differential demodulation concept according to various embodiments of the invention. Fig. Figure 4A represents a first exemplary spectral diagram of inputs coupled into a rotation measurement system according to various embodiments in the invention. Fig. Figure 4B presents a first exemplary spectral diagram of signal components in a gyro output signal and of a reference signal used in a gyro measurement circuit according to various embodiments in the invention. Fig. Figure 4C presents a first exemplary spectral diagram illustrating a mechanism for separating a shock signal from two gyro measurement signals into a gyro output signal according to various embodiments in the invention. Fig. Figure 5A represents a second exemplary spectral diagram of inputs coupled into a rotation measurement system according to various embodiments in the invention. Fig. Figure 5B presents a second exemplary spectral diagram of signal components in a gyro output signal and of a reference signal used in a gyro measurement circuit according to various embodiments in the invention. Fig. Figure 5C presents an exemplary spectral diagram illustrating a mechanism for separating one of two gyro interference signals from the two gyro measurement signals in a gyro output signal according to various embodiments in the invention. Fig. Figure 6 shows an exemplary block diagram of a gyro measurement circuit based on a differential demodulation concept according to various embodiments in the invention. Fig. Figure 7A represents a third exemplary spectral diagram of inputs coupled into a rotation measurement system according to various embodiments in the invention. Fig. Figure 7B shows an exemplary spectral diagram of signal components in a gyro output signal and of two reference signals used in a gyro measurement circuit according to different embodiments in the invention. Fig. Figure 7C presents an exemplary spectral diagram illustrating a differential demodulation mechanism for separating a shock signal from gyro measurement and interference signals in a gyro output signal according to various embodiments in the invention. Fig. Figure 8 represents another exemplary block diagram of a gyro measurement circuit based on a differential demodulation concept according to various embodiments in the invention. Fig. Figure 9A presents an exemplary flowchart of a method for indicating a disturbance or shock that a rotation measuring system according to various embodiments in the invention experiences. Fig. Figure 9B presents another exemplary flowchart of a method for indicating an impact suffered by a rotation measuring system according to various embodiments in the invention. Detailed description of the preferred embodiments

[0012] The following description sets out particular details for illustrative purposes, to facilitate understanding of the invention. However, it will be obvious to a person skilled in the art that the invention can be implemented without these details. A person skilled in the art will recognize that embodiments of the present invention described below can be carried out in a variety of ways and using a variety of means. They will also recognize that additional modifications, applications, and embodiments are within its scope, as are additional areas in which the invention can be beneficial. Accordingly, the embodiments described below are illustrative of certain embodiments of the invention and are intended to avoid obfuscation of the invention.

[0013] Reference in the description to "an embodiment" means that a specific feature, structure, property, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearance of the phrase "in an embodiment" or similar expressions at different points in the description does not necessarily always refer to the same embodiment.

[0014] Furthermore, connections between components or between process steps in the figures are not limited to connections that are directly affected. Instead, connections between components or process steps shown in the figures can be modified or otherwise altered by adding intermediate components or process steps without deviating from the teachings of the present invention.

[0015] Various embodiments of the invention relate to integrated circuits and, more precisely, systems, devices, and methods for incorporating a gyro measurement circuit into a gyroscope to detect a shock or disturbance experienced by the gyroscope device and to accurately distinguish rotation-based gyro measurement signals from disturbance signals introduced by the shock or disturbance. In addition to the rotation-based gyro measurement signals, gyro disturbance signals or a shock signal may be present in a gyro output signal supplied by the gyroscope device to the gyro measurement circuit, but these signals have different magnitudes and characteristics. If the shock signal exceeds a threshold level, the gyro output signal is faulty, and a rotational speed derived from the gyro output signal is no longer reliable. Sometimes, the gyro output signal is also considered faulty if any of the gyro disturbance signals exceeds the threshold level.

[0016] According to the invention, the gyro measurement circuit is configured according to a differential or non-differential demodulation concept and applies at least one reference signal to demodulate the gyro output signal. The reference frequency of the at least one reference signal is selected according to the frequencies of the pulse signal or gyro interference signals such that the pulse or gyro interference signals can be separated from the rotation-based gyro measurement signals in the gyro output signal. The pulse or interference signals are continuously monitored, and any anomalous situation is indicated to a main system that relies on the gyroscope for rotation detection. Upon detection of such conditions, the main system can take appropriate countermeasures, such as ignoring the erroneous gyro output signal, to ensure the accuracy of the rotation detection.

[0017] Fig. Figure 2 represents an exemplary rotation measurement system 200 according to various embodiments of the invention. The rotation measurement system 200 comprises a gyroscope device 202 and a gyro interface circuit 204, which further includes a control circuit 206 and a gyro measurement circuit 208. According to various embodiments of the invention, the gyroscope device 202 is a MEMS device manufactured using a microfabrication process. The control circuit 206 provides a control signal to electrostatically control a test mass contained in the gyroscope device 202, and the test mass is thus driven to oscillate along a first orthogonal direction in a rotating reference frame. The control signal preferably has a control frequency that is consistent with a characteristic frequency f0 of the gyroscope device 202.In response to rotation about a second orthogonal direction, the test mass monitors a physical displacement along a third orthogonal direction and a corresponding capacitive change. The gyro measuring circuit 208 is coupled to detect the capacitive change associated with a corresponding Coriolis force along the third orthogonal direction.

[0018] The gyroscope 202 provides a gyro output signal for the gyro measurement circuit 204, and this gyro output signal contains gyro measurement signals resulting from a rotational speed of interest of the gyroscope 202. In a preferred embodiment, the gyro output signal is associated only with a capacitive change caused by the Coriolis force and contains only the gyro measurement signals. However, in many cases, a shock or disturbance may be present and inevitably affect the gyro output signal. Therefore, the gyro output signal often contains a shock signal or gyro disturbance signals introduced by the shock or disturbance.

[0019] According to the present invention, the gyro measuring circuit 208 detects and indicates an unwanted shock or disturbance in addition to the rotation measurement when a specific shock or disturbance signal contained in the gyro output signal exceeds a threshold level. Under such circumstances, useful information regarding a rotational speed associated with the gyro output signal is rendered erroneous and inaccurate by the excessively high shock or disturbance signal. Accordingly, a main application system employing the rotation measurement system 200 can rely on a shock indicator generated by the gyro measuring circuit 208 to determine whether the gyro output signal should be ignored and removed from the rotational speed of interest.

[0020] The mechanical structure of the gyroscope device 202 can be abstractly represented in theory as a combination of a mixer 202A and a low-pass filter 202B. The mixer 202A mixes the control signal and the rotational speed and generates an intermediate gyro output signal associated with the corresponding Coriolis force. The intermediate gyro output signal is further filtered to generate the gyro output signal. The low-pass filter 202B is equipped with a transfer function H p(s) associated, which has a resonance peak at a peak frequency f1. The corner frequency of the low-pass filter 202B is essentially consistent with the peak frequency f1. The characteristic frequency f0 of the gyroscope device 202 is lower than the peak frequency f1, and thus the gyro output signal can retain precisely the information of interest regarding the rotational speed. In a particular embodiment, the characteristic frequency f0 and the peak frequency f1 are 20 kHz and 21 kHz, respectively.

[0021] An analog filter 210 can be connected to an input of the gyro measurement circuit 208. The analog filter 210 is a low-pass filter used to filter, scale, or amplify the gyro output signal before further processing. The analog filter 210 serves anti-aliasing purposes and does not affect the rotation-related spectral content of the gyro output signal. Therefore, the cutoff frequency of the analog filter 210 is chosen to be higher than both the characteristic frequency f0 and the peak frequency f1. For example, the cutoff frequency of the analog filter 210 can be set to 100 kHz if the characteristic frequency f0 and the peak frequency f1 of the gyroscope 202 are 20 kHz and 21 kHz, respectively.

[0022] In some embodiments, the gyro output signal provided by the gyroscope 202 is an analog signal. After filtering and scaling / amplifying in the analog filter 210, the gyro output signal is converted into a digital signal, which can be further processed in a digital domain to obtain the rotational speed and generate the indicator output.

[0023] In certain embodiments, the gyroscope device 202 and the gyro interface circuit 204 are fabricated on two separate substrates and assembled to form the rotation measurement system 200 in a hybrid format. In some other embodiments, the gyroscope device 202 and the gyro interface circuit 204 are fabricated on a single substrate using a microfabrication process involving multiple material layers. Although they may occupy different chip areas that are physically separated on the substrate, the gyroscope device 202 can also be integrated on top of the gyro interface circuit 204 to save chip area. For such vertical integration, the fabrication process, material layers, and configuration of both the gyroscope device 202 and the interface circuit 204 must be correctly executed.

[0024] Fig. Figure 3 shows an exemplary block diagram 300 of a gyro measurement circuit based on a non-differential demodulation concept according to various embodiments of the invention. The gyro measurement circuit 300 generates a shock indicator that indicates whether a shock or interference signal exceeds a threshold level V. TH exceeds the limit, and therefore the application's main system can rely on the shock indicator to determine whether the gyro output signal is faulty and needs to be ignored.

[0025] The gyro measurement circuit 300 comprises a demodulation unit 302 and a peak detector 304. The demodulation unit 302 demodulates a gyro output signal using a reference signal such that any impulse or noise signal is retained, while the gyro measurement signals are suppressed in the demodulated gyro output signal. This effectively separates the impulse or noise signal from the gyro measurement signals. The peak detector 304 further measures whether the magnitude of the demodulated gyro output signal exceeds a threshold level V. TH exceeds the threshold and generates the corresponding shock indicator to warn the main system if an anomalous shock or disturbance situation is occurring.

[0026] The demodulation unit 302 further comprises an electronic mixer 306 and a low-pass filter 308. The electronic mixer 306 combines the reference signal and the gyro output signal and modifies the spectral content of the gyro output signal with respect to a reference frequency f. R of the reference signal. The low-pass filter 308 has a gain G LP and a corner frequency f LP on, which are designed to process the shock or noise signal and the gyro measurement signals differently in the gyro output signal, and in particular to maintain or amplify the level of the shock or noise signal while suppressing that of the gyro measurement signals. A selection procedure is applied to determine the reference frequency f R , the corner frequency f LP and the profit G LP to determine, and a corresponding justification for such a selection procedure is set out below in Fig. 4A to 4C and Fig. 5A to 5C are given exactly.

[0027] The peak detector 304 comprises a sampling circuit 310 and a comparator 312. The sampling circuit 310 samples the demodulated gyro output signal received by the demodulation unit 302. The comparator 312 compares the sampled signal with the threshold level V. TH and generates the shock indicator based on a comparison result.

[0028] Fig. Figure 4A presents a first exemplary spectral diagram 420 of inputs coupled into a rotation measurement system according to various embodiments of the invention. Rotation of the gyroscope device 202 is incorporated via the capacitive change associated with the Coriolis force and typically exhibits a relatively low rotation frequency Ω. Such rotation is directly associated with vehicle motion when the main system is a vehicle and represents a useful signal of interest to the supplier or user of a main system. The rotational speed is typically located at the lower end of the frequency spectrum. In some embodiments, the rotation frequency Ω may be limited to below 300 Hz.

[0029] A mechanical shock is normally introduced into the rotation measurement system 200 by acceleration stimuli or general vibrations to which the main system is subjected. The shock is directly incorporated into the gyro output signal without mechanical modulation by the gyroscope device 202. Therefore, a shock frequency f is used. SK The frequency associated with the impact is not limited by the low-pass filter 202B and, in certain embodiments, can be higher than the characteristic frequency f0 or the peak frequency f1 of the gyroscope 202. In one embodiment, the impact frequency f extends SK approximately up to 30 kHz, if the characteristic frequency f0 and the peak frequency f1 of the gyroscope 202 are 20 kHz and 21 kHz respectively.

[0030] Fig. Figure 4B presents a first exemplary spectral diagram 440 of signal components in a gyro output signal and a reference signal used in a gyro measurement circuit according to various embodiments of the invention. Based on equation (1), the rotation of the gyroscope 202 is modulated into two gyro measurement signals that are symmetrical about the characteristic frequency f0. Two measurement frequencies from these two gyro measurement signals are f0-Ω and f0+Ω, respectively, and in certain embodiments, the measurement frequencies can be in the range of DC voltage up to 15 kHz. On the other hand, the impulse signal is not modulated by the gyroscope 202 and is directly included in the gyro output signal. The first gyro measurement signal, the second gyro measurement signal, and the impulse signal form the signal components of the gyro output signal received by the gyroscope 202.

[0031] With regard to the signal components, the reference frequency f Rthe reference signal is specifically chosen to be closer to the impulse frequency f SK than at one of the two gyro measurement frequencies f0-Ω and f0+Ω. On the one hand, the reference frequency f R also lie sufficiently far away from the peak frequency f1 of the gyroscope 202. This is particularly true because the peak frequency f1 is associated with a natural oscillation mode of the gyroscope 202, and an undesirable, erroneous amplified response can be generated around this peak frequency f1. On the other hand, the reference frequency f R not so far away from the shock frequency that a response from the shock signal could be equally impaired.

[0032] In certain embodiments, the impulse signal is not limited to a single frequency, and the impulse frequency f SK is with a bandwidth BW SK associated. The reference frequency f Ris still determined similarly to above, but in particular chosen so that it is close to or within the frequency range of the impact frequency f. SK lies.

[0033] Fig. Figure 4C presents a first exemplary spectral diagram 460, which indicates a mechanism for separating the impulse signal from the two gyro measurement signals according to various embodiments of the invention. The impulse signal and the two gyro measurement signals are converted in the electronic mixer 306 with respect to the reference signal and change to different frequencies compared to their original frequencies. The characteristic frequency f0 becomes a demodulated characteristic frequency |f R -f0| converted. Similarly, the modulated frequencies of the impulse signal and the two gyro measurement signals |f R -f SK |, |f R -(f0-Ω)| or |f R -(f0+Ω)|. The absolute values ​​are used because in some embodiments the reference frequency f Ris lower than the impact frequency f SK or the gyro measurement frequency f0-Ω.

[0034] In this embodiment, the reference frequency f R both higher than the impact frequency f SK as well as the gyro measurement frequencies f0-Ω and f0+Ω. The modulated frequencies of the impulse signal and the two gyro measurement signals can be simply referred to as f R -f SK , f R -(f0-Ω) and f R -(f0+Ω) can be represented.

[0035] The corner frequency f LP of the low-pass filter 308 is between the modulated impulse frequency |f R -f SK | and the modulated gyro measurement frequencies, i.e. |f R -(f0-Ω)| and |f R -(f0+Ω)|, controlled. The level of the impulse signal is maintained or adjusted by the gain G. LPThe impulse signal is amplified. In contrast, the first and second gyro measurement signals are attenuated. After such modulations based on mixing and low-pass filters, the impulse signal is separated in the gyro output signal, and the peak detector 304 can further determine whether the impulse signal exceeds the threshold level V. TH exceeds.

[0036] A person skilled in the art knows that the gyro measurement circuit 300 is preferably used when the impulse signal is not modulated by the gyroscope device 202 and lies relatively far away from the gyro measurement signals in the frequency spectrum. The difference between the impulse frequency f SK and the measurement frequencies f0±Ω must be sufficiently large so that the corner frequency f LP It can be controlled to an amount between them.

[0037] The modulation method based on a single demodulation unit 302 is not applicable if the impulse frequency f SKsignificantly close to one of the two measurement frequencies f0-Ω and f0+Ω in Fig. 4C is located. The significant proximity of the impact frequency to another frequency is determined based on whether the corner frequency f LP The low-pass filter 308 can be set up to distinguish the corresponding modulated frequencies. More precisely, in an embodiment that is equipped with Fig. 4C is associated with a problem for the gyro measurement circuit 300 based on a single modulation unit 302, when the modulated impulse frequency f R -f SK and the modulated gyro measurement frequency f R -f0-Ω are so close that the low-pass filter 308 cannot easily be set up to distinguish them.

[0038] However, in some embodiments, the gyroscope 202 can further couple a rotational disturbance in addition to the rotation of interest of the main system. If the main system is a vehicle, such a rotational disturbance can result from internal vibrations of the vehicle or parasitic vibrations of a gyroscope housing. In particular, the rotational disturbance is modulated by the gyroscope 202, so that gyro disturbance signals are generated which have symmetrical disturbance frequencies with respect to the characteristic frequency f0.

[0039] Fig. Figure 5A presents a second exemplary spectral diagram 520 of inputs coupled into a rotation measurement system according to various embodiments of the invention. In addition to the rotation of interest, a rotation disturbance at the gyroscope device 202 is also included, caused by the capacitive change associated with the Coriolis force. Such a rotation disturbance has a disturbance frequency f. RDon, which is normally in a medium frequency range, e.g. 1–5 kHz. In many embodiments, the interference frequency f RD lower than the characteristic frequency f0 of the gyroscope 202.

[0040] Fig. Figure 5B presents a second exemplary spectral diagram 540 of signal components in a gyro output signal and a reference signal used in a gyro measurement circuit according to various embodiments of the invention. Similarly, the rotational disturbance of the gyroscope 202 is modulated to two gyro disturbance signals that are symmetrical with respect to the characteristic frequency f0. Two gyro disturbance frequencies of these two gyro disturbance signals are f0-f DR or f0+f DRThese two gyro interference signals and the two gyro measurement signals form the signal components in the gyro output signal received by gyroscope 202. The gyro interference signals are further away from the reference frequency f0 compared to the gyro measurement signals because the rotational disturbance typically has a higher frequency than the rotation of interest itself.

[0041] With regard to these signal components, the reference frequency f R the reference signal is specifically chosen to be closer to one of the two gyro interference frequencies f0-f DR and f0+f DR than is the case for both gyro measurement frequencies f0-Ω and f0+Ω. More precisely, the reference frequency f R should be chosen so that it is lower than the characteristic frequency f0 and therefore closer to the gyro disturbance frequency f0-f DR than at the gyro measurement frequency f0-Ω. Otherwise, the reference frequency f RIt should be chosen so that it is higher than the characteristic frequency f0 and therefore closer to the gyro disturbance frequency f0+f DR than at the gyro measurement frequency f0+Ω.

[0042] Nevertheless, the reference frequency f must be R sufficiently far from the peak frequency f1 of the gyroscope 202 to avoid unwanted amplification associated with the gyroscope's natural oscillation mode at this peak frequency. On the other hand, this reference frequency f R not so far away from one of the gyro interference frequencies that a response could be affected by the interference signal.

[0043] Fig. Figure 5C presents an exemplary spectral diagram 560, which indicates a mechanism for separating one of the two gyro interference signals from the two gyro measurement signals according to various embodiments in the invention. The two gyro interference signals and the two gyro measurement signals are separated in the electronic mixer 306 with respect to the reference signal f.R They are converted and change to different frequencies compared to their original frequencies. As a result, the modulated frequencies of the two gyro interference signals are |f R -(f0-f RD )| or |f R -(f0+f RD )|, while the modulated frequencies of the two gyro measurement signals |f R -(f0-Ω)| or |f R -(f0+Ω)| are. The absolute values ​​are used because in some embodiments the reference frequency f R is lower than one of the two gyro interference frequencies f0±f RD or one of the two gyro measurement frequencies f0±Ω.

[0044] In this embodiment, the reference frequency f R higher than the gyro interference frequencies f0±f RD and the gyro measurement frequencies f0±Ω. The modulated frequencies of the gyro interference signal and the two gyro measurement signals can be simply expressed as f R -(f0-f RD ) or f R -(f0+f RD ), f R -(f0-Ω) or f R-(f0+Ω) can be represented.

[0045] The corner frequency f LP The low-pass filter 308 is between a lower frequency of the modulated gyro interference frequencies, i.e. |f R -(f0-f RD )| and |f R -(f0+f RD )|, and a lower frequency of the modulated gyro measurement frequencies, i.e. |f R -(f0-Ω)| and |f R -(f0+Ω)|, controlled. The level of a gyro interference signal is maintained or adjusted with the gain G. LP The gyro interference signal is amplified, while the other gyro interference signal and the two gyro measurement signals are attenuated. After such modulation based on mixing and low-pass filters, a gyro interference signal is isolated from the gyro output signal, and the peak detector 304 can further determine whether this isolated gyro interference signal exceeds the threshold level V. TH exceeds.

[0046] A person skilled in the art knows that the gyro measurement circuit 300 is preferably used when the gyro interference signals are relatively far away from the gyro measurement signals in the frequency spectrum. The difference between the interference frequency f RD and the rotation frequency Ω must be sufficiently large so that the corner frequency f LP can be controlled to an amount between them. Therefore, the modulation method based on a single demodulation unit 302 is not applicable if the interference frequency f RD essentially close to the measurement frequency Ω in Fig. 5C lies. The significant proximity of the impact frequency to another frequency is determined based on whether the corner frequency f LP The low-pass filter 308 can be set up to distinguish the corresponding modulated frequencies. More precisely, in an embodiment that is equipped with Fig. 5C is associated with a problem for the gyro measurement circuit 300 based on a single modulation unit 302, when the modulated interference frequency f R -f0-f RD and the modulated gyro measurement frequency f R -f0-Ω are so close that the low-pass filter 308 cannot easily be set up to distinguish them.

[0047] In certain embodiments, the impulse signal may also be present together with gyro interference signals, and a similar modulation method can be applied to isolate only the impulse signal or to isolate both the impulse signal and one of the gyro interference signals.

[0048] However, the modulation method based on a single demodulation unit 302 is also not applicable if the impulse frequency f SK essentially close to one of the gyro interference frequencies f0±f RD in Fig. 5C, and when the shock signal needs to be distinguished from the gyro interference signals. The gyro measurement circuit 300, which is based on a single demodulation unit 302, may not be able to output a correct shock indicator under these circumstances. Although the gyro interference signals are acceptable through the rotation measurement system 200 and the main system, the gyro interference frequency f0+f RD so close to the impact frequency f SK The possibility is that the gyro measuring circuit 300 considers the gyro interference signals as the shock signal and outputs an erroneous shock indicator.

[0049] In various embodiments, which are Fig. 4A to 4C and 5A to 5C, the reference signal can be used at a single reference frequency f RThe signal type may be chosen, yet each of the other signals belonging to the gyro measurement signals, the gyro interference signals, and the shock signal can be associated with a specific frequency bandwidth. Regardless of their bandwidths, the gyro measurement signals and the shock signal are simply plotted around their respective center frequencies. In these figures, the heights of the corresponding arrow lines are not proportional to the actual magnitudes of these signals.

[0050] Fig. Figure 6 shows an exemplary block diagram 600 of a gyro measurement circuit based on a differential demodulation concept according to various embodiments in the invention. The gyro measurement circuit 600 contains two demodulation units 602A and 602B, each of which demodulates the gyro output signals at two reference signals f. R1 and f R2The system demodulates the gyro output signals, compensates for their magnitudes as needed, and band-limits them. In particular, the two reference signals are symmetrical about the characteristic frequency f0 and can thus be expressed as f0-Δf. R or f0+Δf R The gyro output signals are further combined differentially by a subtractor 604. A peak detector 606 then detects whether the magnitude of the combined output signal exceeds a threshold level V. TH exceeds the threshold and generates a corresponding shock indicator to warn the main system if an anomalous shock or disturbance situation is occurring.

[0051] Such a differential demodulation method is used to address the above problems with the non-differential demodulation concept when the collision frequency f SKThe impulse signal lies close to one of the frequencies of the gyro measurement signal or the gyro interference signal. This method exploits the symmetrical nature of both the gyro measurement signals and the gyro interference signals. These symmetrical signals, after being demodulated by symmetrical reference signals, can essentially cancel each other out via differential combination in the subtractor 604. As a result, the impulse signal can be detected with improved insensitivity to vibration measurement or interference signals coupled into the gyro output signal.

[0052] Fig. Figure 7A represents a third exemplary spectral diagram 720 of inputs coupled into a rotation measurement system according to various embodiments of the invention. In addition to the rotation of interest of the gyroscope 202, both a rotation disturbance and a shock can be included in the gyro output signal.

[0053] In various embodiments, the interference frequency f can be RD the rotational disturbance is located in an intermediate frequency range, e.g. 1 - 5 kHz, while the shock frequency f SK The impact may have a higher frequency. The characteristic frequency f0 of the gyroscope 202 can be between the disturbance frequency f RD and the impact frequency f SK lay.

[0054] Fig. Figure 7B shows an exemplary spectral diagram 740 of signal components in a gyro output signal and of two reference signals used in a gyro measurement circuit according to various embodiments of the invention. The rotation of interest of the gyroscope 202 is coupled based on the Coriolis force and modulated into two gyro measurement signals that are symmetrical about the reference frequency f0. Similarly, the rotational disturbance on the gyroscope 202 is also modulated into two gyro disturbance signals that are symmetrical with respect to the reference frequency f0. These two gyro disturbance signals and the two gyro measurement signals form the signal components in the gyro output signal supplied to the rotation measurement system 200. In some embodiments, the gyro disturbance signals can be located further away from the reference frequency f0 compared to the gyro measurement signals.

[0055] In addition to the gyro measurement and interference signals, the gyro output signal also includes a pulse signal with a pulse frequency f. SK The impulse signal is not modulated by the gyroscope 202 and is directly incorporated into the gyro output signal. Therefore, the impulse signal is not symmetrical with respect to the characteristic frequency f0.

[0056] Given these signal components, two reference signals are used to demodulate the gyro output signal in the gyro measurement circuit 600. The first reference signal, used by the first demodulation unit 602A, has a first reference frequency f. R1 on, which around Δf R is higher than the reference frequency f0, and the second reference signal used by the second demodulation unit 602B has a second reference frequency f R2 on, which around Δf Ris lower than the reference frequency f0. As a result, the reference signals, the gyro measurement signals and the gyro disturbance signals are symmetrical with respect to the reference frequency f0, with the exception of the impulse signal.

[0057] The first reference frequency f R1 The first reference signal is chosen so that it is closer to the impulse signal and the gyro disturbance frequency f0+f DR than at the gyro measurement frequency f0+Ω, and the second reference frequency f R2 is therefore closer to the gyro interference frequency f0-f DR than at the gyro measurement frequency f0-Ω. The reference frequencies f R1 and f R2 Due to the undesired natural oscillation mode at the peak frequency f1 of the gyroscope 202, they must be sufficiently far away from this peak frequency, while not being so far away that responses from the shock signal and from the gyro interference signals are affected.

[0058] Fig. Figure 7C represents an exemplary spectral diagram 760, which indicates a differential demodulation mechanism for separating the impulse signal from the gyro measurement and interference signals according to various embodiments in the invention. Due to their symmetry with respect to the characteristic frequency f0, the two gyro measurement signals are converted into two measurement signals at identical frequencies Δf by both the first and the second demodulation units 602A and 602B. R ±Ω is demodulated, except that the positions of the two demodulated measurement signals in the frequency spectrum of the two corresponding demodulations are opposite each other. Likewise, the two gyro interference signals become two interference signals at identical frequencies Δfa±|f RD -f o| demodulated, and the positions of the two demodulated gyro interference signals are also opposite each other in the frequency spectrum 760 of the two corresponding demodulations. In contrast to the gyro measurement and interference signals, the impulse signal is asymmetric with respect to the characteristic frequency f0, and the demodulated impulse signals are each centered at two different frequencies |f0+Δf R -f SK | and |f0+Δf R -f SK | in the frequency spectrum 760 belonging to the two corresponding demodulations.

[0059] Although the respective frequencies of either the demodulated measurement or interference signals match each other, this is not necessarily true for their amplitudes, because the gyroscope 202, which has the characteristic frequency f0 and the peak frequency f1, can exhibit different filtering effects on the signals that are symmetrical with respect to the characteristic frequency f0. According to some embodiments, the demodulated gyro output signals are compensated in the first and second demodulation units 602A and 602B to neutralize the filtering effects of the gyroscope 202. In one embodiment, such compensation is mainly achieved by tailoring the gains G. LP1 and G LP2 for filtering in the first and second demodulation units 602A and 602B. In a further embodiment, the phases φ R1 and φ R2The first and second reference signals are also adjusted to compensate for filtering effects of the gyroscope 202. Based on such compensation, the amplitudes of the demodulated interference signals match and can be canceled out by subtraction; in some embodiments, this also applies to the amplitudes of the demodulated measurement signals.

[0060] The corner frequencies f LP1 and f LP2 are the same, for filtering in the first and second demodulation units 602A and 602B. Due to differential combination in the subtractor 604, the corner frequencies f LP1 and f LP2 relatively easier to control. In certain embodiments, both the demodulated interference signals and the demodulated measurement signals are matched to each other; therefore, the corner frequencies f LP1 and f LP2 only between the different frequencies |f0+Δf R -f SK | and |f0+Δf R -f SKThe two modulated impulse signals are controlled. When the second demodulated gyro output signal is subtracted from the first demodulated gyro output signal, the modulated gyro interference signals and the modulated gyro measurement signals cancel each other out.

[0061] In one embodiment, the amplitudes of the demodulated interference signals are matched to each other, but those of the demodulated measurement signals are not. The corner frequencies f LP1 and f LP2 They need to be controlled better below the frequencies of the demodulated measurement signals, so that the uncompensated measurement signals can be suppressed by filtering. However, it is easier to set the corner frequencies f LP1 and f LP2 to control in such a way as to control them between the impulse signal and the demodulated interference signals.

[0062] Based on two differential demodulations, an impulse signal in the gyro output signal is isolated, and the peak detector 304 can further determine whether this isolated impulse signal exceeds the threshold level V. TH exceeds. An expert knows that the Gyro measurement circuit 600 is effective in addressing the problems when the frequency of the impulse signal is close to that of a Gyro interference signal and / or that of a Gyro measurement signal.

[0063] In various embodiments, which are Fig. 7A to 7C, the reference signals can be used at two specific reference frequencies f R1 and f R2 The frequency bandwidth may be chosen, yet each of the other signals relating to the gyro measurement signals and the shock signal can be associated with a specific frequency bandwidth. Regardless of their bandwidths, the gyro measurement signals and the shock signal are simply represented around their respective center frequencies. As shown in Fig. 4A to 4C and 5A to 5C are heights of corresponding arrow lines in Fig. 7A to 7C are not represented in a proportional format to the actual values ​​of these signals.

[0064] Fig. Figure 8 presents another exemplary block diagram 800 of a gyro measurement circuit based on a differential demodulation concept according to various embodiments in the invention. In one embodiment of the gyro measurement circuit 600, each of the demodulation units 602A or 602B comprises an electronic mixer and a low-pass filter coupled together. The electronic mixers 802A and 802B in the demodulation units 602A or 602B mix the gyro output signal with two reference signals, which have two different reference frequencies (f0+Δf). R or f0-Δf R ) and two different phases (φ R1 or φ R2). The corresponding low-pass filters 804A and 804B filter the respective mixed gyro output signals based on two different gains G. LP1 and G LP2 , but two matching corner frequencies f LP1 and f LP2 The two matching corner frequencies f LP1 and f LP2 are equal to a single frequency f LP In various embodiments of the invention, the phases φ R1 and φ R2 the reference signals and / or the gains G LP1 and G LP2 the filter was custom-designed to compensate for the potentially different filtering effects that the gyroscope 202 might have on the gyro measurement and interference signals with frequencies higher or lower than the characteristic frequency f0.

[0065] The two demodulated gyro output signals are differentially combined in the subtractor 604 such that the second demodulated gyro output signal is subtracted from the first demodulated gyro output signal to generate a combined gyro output signal. Due to compensation, the two demodulated gyro interference signals cancel each other out in the two demodulated gyro output signals, and in some embodiments, the two demodulated gyro measurement signals also cancel each other out. The demodulated impulse signal is contained in the combined gyro output signal and effectively isolated from the gyro measurement or interference signals.

[0066] The following peak detector 606 comprises a sampling circuit 806 and a comparator 808. The sampling circuit 806 samples the combined gyro output signal received from the subtractor 604. The comparator 808 compares the sampled signal with the threshold level V. THand generates the shock indicator according to a comparison result.

[0067] Fig. Figure 9A presents an exemplary flowchart 900 of a method for indicating a disturbance or shock suffered by a rotation measuring system according to various embodiments in the invention. Fig. Figure 9B presents a further exemplary flowchart 950 of a method for indicating an impact experienced by a rotation measurement system according to various embodiments of the invention. Methods 900 and 950 are based on a non-differential demodulation concept and a differential demodulation concept, respectively.

[0068] Method 900 for indicating the shock or disturbance begins in step 902 with the reception of a gyro output signal from a gyroscope. In addition to gyro measurement signals related to a rotational speed of interest, the gyro output signal also contains the shock signal and the gyro disturbance signal.

[0069] To separate a pulse signal or a gyro interference signal, such a gyro output signal is demodulated in step 904 using a reference signal that has a reference frequency f R exhibits this. During demodulation, the gyro output signal is mixed with the reference signal and further processed according to a corner frequency f. LP Band-limited. The impulse signal or gyro interference signal contained in the gyro output signal is therefore demodulated together with the gyro measurement signal of interest. In one embodiment, the impulse signal is present, while no gyro interference signals are present; therefore, the corner frequency f LP between the frequencies of the demodulated impulse signal and the demodulated gyro measurement signal. In another embodiment, the gyro interference signals are included in the gyro output signal, while no impulse signal is present; therefore, the corner frequency f is LPbetween the respective lower frequencies of the demodulated gyro measurement and interference signals. In certain embodiments, both the gyro interference signal and the impulse signal are included in the gyro output signal in addition to the gyro measurement signal, and the corner frequency f LP The frequency is set between the frequency of the demodulated pulse signal and the lower frequency of the demodulated gyro interference signals, or between the respective lower frequencies of the demodulated gyro measurement and interference signals. As a result, the demodulated pulse signal or a demodulated gyro interference signal is retained, while the other signal components in the demodulated gyro output signal are attenuated.

[0070] Step 906 determines whether the demodulated gyro output signal exceeds a threshold value V. THexceeds. A shock indicator is output to a main system of the rotation measurement circuit to report the presence of the shock or disturbance and faultiness of the gyro measurement signal in relation to the rotation information of interest.

[0071] Method 950 for indicating the shock or disturbance begins in step 952 with the reception of a gyro output signal from a gyroscope. In addition to gyro measurement signals related to a rotational speed of interest, the gyro output signal contains a shock signal and may also contain gyro disturbance signals. The gyro measurement and disturbance signals are symmetrical with respect to the gyroscope's characteristic frequency f0, while this is not the case for the shock signal.

[0072] In step 954, such a gyro output signal is demodulated using a first reference signal, which has a first reference frequency f. R1exhibits. In step 956, the gyro output signal is also demodulated using a second reference signal, which has a second reference frequency f. R2 exhibits this. During one of the two demodulations, the gyro output signal is mixed with the first or second reference signal and adjusted according to a corner frequency f. LP1 or f LP2 The band is further limited. The first and second reference signals are chosen to be symmetrical with respect to the reference frequency f0. The phases of the first and second reference signals and / or the gains of the band limiting are adjusted to compensate for certain filtering effects that the gyroscope exhibits on specific gyro measurement signals or specific gyro interference signals. After such compensation, the demodulated gyro measurement signals have identical magnitudes, as do the demodulated gyro interference signals, if they were originally present.

[0073] In step 958, the first demodulated gyro output signal from step 954 is differentially combined with the second demodulated gyro output signal from step 956. In some embodiments, the gyro measurement signals, which are symmetrical about the reference frequency f0, are essentially canceled out, as are the gyro interference signals if they were originally included in the gyro output signal. As a result, the combined gyro output signal contains the demodulated impulse signal, which is therefore isolated from the gyro measurement and / or interference signals.

[0074] Step 960 determines whether the combined gyro output signal exceeds a threshold value V. TH exceeds. A shock indicator is output to a main system of the rotation measurement circuit to report the presence of the shock or disturbance and faultiness of the gyro measurement signal in relation to the rotation information of interest.

[0075] Method 900, which is based on non-differential demodulation, comprises a single demodulation step but is difficult to apply when an impulse signal is close to a gyro measurement signal or a gyro interference signal. In contrast, Method 950 comprises two complementary demodulation steps and can be applied in the problem situation described above, where Method 900 has difficulty handling it.

[0076] While the invention is open to various modifications and alternative forms, particular examples of which have been shown in the drawing and are described in more detail here. It is understood, however, that the invention is not intended to be limited to the particular forms disclosed, but rather, on the contrary, that the invention is intended to cover all modifications, equivalents, and alternatives that fall within the scope of the appended claims.

Claims

[1] Gyro measurement circuit (600) based on a differential demodulation concept, comprising: a first demodulation unit (602A) coupled to receive a gyro output signal from a gyroscope (202), wherein the first demodulation unit (602A) derives the gyro output signal using a first reference signal (f R1 ) to a first demodulated gyro output, wherein the gyro output signal comprises a pulse signal and a plurality of gyro measurement signals relating to a rotational speed of interest; a second demodulation unit (602B), coupled to receive the gyro output signal, wherein the second demodulation unit (602B) derives the gyro output signal using a second reference signal (f R2 ) to a second demodulated gyro output, where the first and second reference signals (f R1 , f R2) are symmetrical with respect to a characteristic frequency (f0) of the gyroscope (202); a subtractor (604) coupled to the first and second demodulation units (602A, 602B), wherein the subtractor (604) differentially combines the first and second demodulated gyro outputs to isolate the impulse signal, which is asymmetric with respect to the reference frequency (f0); and a peak detector (606) coupled with the subtractor (604), wherein the peak detector (606) determines whether the combined gyro output exceeds a threshold level (VTH) and generates a shock indicator to warn a main system if an anomalous shock or disturbance situation occurs. [2] Gyro measuring circuit (600) according to claim 1, wherein the plurality of gyro measuring signals are symmetrical with respect to the characteristic frequency (f0) and are suppressed by the differential combination method in the subtractor (604). [3] Gyro measuring circuit (600) according to claim 1, wherein the gyro output signal further comprises a plurality of gyro interference signals relating to a disturbance in the mechanical behavior of the gyroscope (202) and thus being symmetrical with respect to the characteristic frequency (f0), wherein the plurality of gyro interference signals is also suppressed by the differential combination method in the subtractor (604). [4] Gyro measurement circuit (600) according to claim 3, wherein the impulse signal is substantially in the frequency spectrum close to at least one signal among the plurality of gyro disturbance signals and the plurality of gyro measurement signals. [5] Gyro measuring circuit (600) according to claim 3, wherein at least one signal from the impulse signal, the plurality of gyro measuring signals and the plurality of gyro interference signals has a frequency bandwidth (BW) SK is associated. [6] Gyro measuring circuit (600) according to claim 1, wherein the first and the second reference signal (fR1 , f R2 ) with a first phase (φ R1 ) or a second phase (φ R2 ) are associated and the first and second phases (φ R1 , φ R2 ) are configured to neutralize certain filtering effects that the gyroscope (202) exerts on signals that are symmetrical with respect to the reference frequency (f0). [7] Gyro measuring circuit (600) according to claim 1, wherein a frequency of at least one of the first and the second reference signal (f R1 , f R2 ) is chosen such that it is closer to the frequency (f SK ) of the shock signal as being at a respective frequency that each of the multitude of gyro measurement signals exhibits. [8] Gyro measuring circuit (600) according to claim 1, wherein the first demodulation unit (602A) further comprises: a first electronic mixer (802A) that provides the first reference signal (f R1) and the gyro output signal combined and the spectral content of the gyro output signal with respect to a first reference frequency (f R1 ) of the first reference signal is changed; and a first low-pass filter (804A), coupled with the first electronic mixer (802A), wherein the first low-pass filter (804A) provides a first filter gain (G LP1 ) and a first corner frequency (f LP1 ) which are configured to allow the first low-pass filter (804A) to process the multitude of gyro measurement signals and the shock signal differently. [9] Gyro measuring circuit (600) according to claim 8, wherein the second demodulation unit (602B) further comprises: a second electronic mixer (802B) that provides the second reference signal (f R2 ) and the gyro output signal combined and the spectral content of the gyro output signal with respect to a second reference frequency (f R2 ) of the second reference signal is changed; and a second low-pass filter (804B), coupled with the second electronic mixer (802B), wherein the second low-pass filter (804B) provides a second filter gain (G LP2 ) and a second corner frequency (f LP2 ) which are configured to allow the second low-pass filter (804B) to process the multitude of gyro measurement signals and the shock signal differently. [10] Gyro measuring circuit (600) according to claim 9, wherein the first gain (G LP1 ) and the second prize (G LP2 ) are configured to neutralize certain filtering effects that the gyroscope (202) exerts on signals that are symmetrical with respect to the reference frequency (f0). [11] Method for indicating a shock in an output of a gyroscope (202), comprising the steps: Receiving (952) a gyro output signal from the gyroscope (202), wherein the gyro output signal comprises a pulse signal and a multitude of gyro measurement signals relating to a rotational speed of interest; Demodulating (954) the gyro output signal to a first demodulated gyro output using a first reference signal (f R1 ); Demodulating (956) the gyro output signal to a second demodulated gyro output using a second reference signal (f R2 ), where the first and second reference signals (f R1 , f R2 ) are symmetrical with respect to a characteristic frequency (f0) of the gyroscope (202); Differential combination (958) of the first and second demodulated gyro outputs to isolate the impulse signal, which is asymmetric with respect to the reference frequency (f0); and Determine (960) whether the combined gyro output has a threshold level (V TH ) exceeds. [12] Method according to claim 11, wherein the gyro output signal further comprises a plurality of gyro interference signals relating to a disturbance in the mechanical behavior of the gyroscope (202) and thus being symmetrical with respect to the characteristic frequency (f0), wherein the plurality of gyro interference signals is also suppressed by the differential combination method in the subtractor (604). [13] Method according to claim 12, wherein the impulse signal is substantially in the frequency spectrum close to at least one signal among the plurality of gyro disturbance signals and the plurality of gyro measurement signals. [14] Method according to claim 11, wherein the first and the second reference signal (f R1 , f R2 ) with a first phase (φ R1 ) or a second phase (φ R2 ) are associated and the first and second phases (φ R1 , φ R2) are configured to neutralize certain filtering effects that the gyroscope (202) exerts on signals that are symmetrical with respect to the reference frequency (f0). [15] Method according to claim 11, wherein a frequency of at least one of the first and the second reference signals (f R1 , f R2 ) is chosen such that it is closer to the frequency (f SK ) of the shock signal as being at a respective frequency that each of the multitude of gyro measurement signals exhibits. [16] Method according to claim 11, wherein one of the two demodulation steps (954, 956) is a first substep of mixing the gyro output signal with a respective reference signal (f R1 , f R2 ) and a second substep of weighted filtering of the mixed gyro output signal with a respective filter gain (G) LP1 , G LP2 ) includes. [17] Gyro measuring circuit (300), comprising: a demodulation unit (302), coupled to receive a gyro output signal, which is a gyro measurement signal and at least one comprises a pulse signal and a plurality of gyro disturbance signals from a gyroscope (202), wherein the demodulation unit (302) derives the gyro output signal using a reference signal (f R ) demodulated to a demodulated gyro output, such that at least one of the impulse signal and the multitude of gyro noise signals is retained, while the gyro measurement signal relating to a rotational speed of interest is suppressed; and a peak detector (304) coupled to the demodulation unit (302), wherein the peak detector (304) determines whether the demodulated gyro output has a threshold level (V TH ) exceeds, and generates a shock indicator to warn a main system if an anomalous shock or disturbance situation is present. [18] Gyro measuring circuit (300) according to claim 17, wherein the demodulation unit (302) further comprises: an electronic mixer (306) that uses the reference signal (f R ) and the gyro output signal is combined and the spectral content of the gyro output signal with respect to a reference frequency (f R ) of the reference signal (f R ) changed; and a low-pass filter (308) coupled to the electronic mixer (306), wherein the low-pass filter (308) has a filter gain (G LP ) and a corner frequency (f LP ) which are configured to allow the low-pass filter (308) to process the gyro measurement signal and the at least one of the impulse signal and the multitude of gyro interference signals differently. [19] Gyro measuring circuit (300) according to claim 17, wherein the frequency of the gyro measuring signal is associated with a characteristic frequency (f0) of the gyroscope (202) and a frequency (Ω) of a rotational speed for the measurement of which the gyroscope (202) is used. [20] Gyro measuring circuit (300) according to claim 17, wherein the frequency of the reference signal (f R ) is chosen such that it is closer to a first frequency of the at least one from the impulse signal and the multitude of gyro interference signals than to a second frequency of the gyro measurement signal, and must also be sufficiently far away from a peak frequency (f1) of the gyroscope (202).

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