148 results about "Quadrature error" patented technology

The invention relates to a gyroscope with a vibrating structure, produced by micromachining in a thin wafer, which comprises a movable inertial assembly (1) comprising at least one movable mass (50) able to vibrate in the plane of the wafer along a drive axis x and along a sense axis y roughly perpendicular to the x-axis, an interdigital sensor comb (90) and an interdigital drive comb (70). It furthermore comprises at least one additional interdigital comb (10a), called the quadrature-error compensation comb, connected to the mass (50) and which has two asymmetric air gaps e and λe, λ being a positive real number, for subjecting the mass to an adjustable electrostatic stiffness due to coupling between the x-axis and the y-axis by applying a variable DC voltage V to this comb, the adjustable stiffness allowing compensation for the quadrature error of the gyroscope.

The invention relates to a digital signal processing method and a device for a micro-mechanical gyroscope. The device mainly comprises a digital signal processor, a direct digital frequency synthesizer, a digital phase-locked loop and an analog-to-digital converter. The frequency synthesizer is used for outputting a sine drive signal with controllable frequency and amplitude. A drive feedback signal and an angular velocity readout signal are synchronously converted by the analog-to-digital converter; the converted frequency is an integral multiple of the frequency of the drive signal, and thesampling time length is an integral multiple of the period of the drive signal. With the adoption of the digital signal processor, the sampling data is multiplied by the fixed sine and cosine coefficients, and the input angular velocity and the orthotropic error as well as the phase and the amplitude of the drive feedback signal are resolved in an accumulative manner, and the phase parameters areutilized for adjusting the frequency of the drive signal, so that the frequency of the drive signal follows up the resonance frequency of the gyroscope. The amplitude parameters are utilized for adjusting the amplitude of the drive signal, so that the vibration amplitude is constant. The device realizes the drive of the micro-mechanical gyroscope and the digitization of the angular velocity demodulation, has simple structure and high computation precision, and is easy to produce and transplant in batch.

Methods and apparatus are provided for detecting a rate of rotation. In one implementation, the method includes vibrating a proof mass at a pre-determined frequency in a drive axis. In response to a rotation, sensing an amount of deflection of the proof mass in an axis orthogonal to the drive axis, in which the amount of deflection is sensed as a change in charge. The method further includes generating a quadrature error cancellation signal to substantially cancel quadrature error from the sensed change in charge.

The invention discloses a quadrature error closed-loop compensating circuit for a vibrating type silicon micromechanical gyroscope. A gyroscope detection signal enters a synchronous demodulation circuit by diving into two parts after being amplified and filtered: one part of gyroscope detection signal is demodulated through reference signals generated by a phase-locked loop, and after low-pass filtering is performed, an angular velocity signal is obtained; the other part of the gyroscope detection signal is demodulated through the reference signals, which is subjected to phase displacement for 90 degrees, and generated by the phase-locked loop, after low-pass filtering is performed, the voltage amplitude of quadrature error signals in the detection signal is extracted out, and a feedback control voltage is obtained through an integrating circuit; the feedback control voltage passes through a single-double switching circuit and is modulated to the driving frequency through a driving detection capacitance so as to generate a feedback current to compensate quadrature displacement current in the detection shaft direction, and then quadrature error amount in the detection signal is eliminated and finally, the pure angular velocity is obtained. According to the invention, the quadrature error amount in an angular velocity detection loop is eliminated by using the feedback current to compensate the quadrature displacement current in the detection shaft direction of the micromechanical gyroscope, and high-precision closed-loop compensating for the quadrature error of the vibrating type silicon micromechanical gyroscope is achieved.

A vibration gyro having a structure for canceling a quadrature error generated by structural asymmetricity due to production tolerance and a means for correcting a bias value when an angular velocity is zero. In order to apply a counter torque to a sense mass for canceling the quadrature error, left correction comb electrodes are fixed to a substrate adjacent to a left drive mass, and comb electrodes opposed to the correction comb electrodes are arranged on an inner portion of a frame member which constitutes the left drive mass. By applying DC voltage to the correction electrodes, electrostatic force, for canceling the leakage rotational displacement of the sense mass generated when the input angular velocity is zero, is generated.

A microelectromechanical gyroscope, includes: a supporting body; a first movable mass and a second movable mass, which are oscillatable according to a first driving axis and tiltable about respective a first and second sensing axes and are symmetrically arranged with respect to a center of symmetry; first sensing electrodes and a second sensing electrodes associated with the first and second movable masses and arranged on the supporting body symmetrically with respect to the first and second sensing axis, the first and second movable masses being capacitively coupled to the respective first sensing electrode and to the respective second sensing electrode, a bridge element elastically coupled to respective inner ends of the first movable mass and of the second movable mass and coupled to the supporting body so as to be tiltable about an axis transverse to the first driving axis.

Bulk acoustic wave (BAW) gyroscopes purposefully operate using non-degenerate modes, i.e., resonant frequencies of drive and sense modes are controlled so they are not identical. The resonant frequencies differ by a small controlled amount (Δf). The difference (Δf) is selected such that the loss of sensitivity, as a result of using non-degenerate modes, is modest. Non-degenerate operation can yield better bandwidth and improves signal-to-noise ratio (SNR) over comparable degenerate mode operation. Increasing Q of a BAW resonator facilitates trading bandwidth for increased SNR, thereby providing a combination of bandwidth and SNR that is better than that achievable from degenerate mode devices. In addition, a split electrode configuration facilitates minimizing quadrature errors in BAW resonators.

The invention discloses a MEMS (micro-electro-mechanical system) fully decoupled closed-loop gyroscope. The gyroscope comprises a substrate and a sensitive device layer, wherein an insulating layer isarranged between the substrate and the sensitive device layer; the sensitive device layer comprises a first substructure, a second substructure and a coupling connection beam; each of the first substructure and the second substructure comprises a driving frame, driving folding beams, driving decoupling beams, a Coriolis mass block, a detection frame, detection beams, detection decoupling beams, driving fixed comb teeth, driving movable comb teeth, driving detection fixed comb teeth, driving detection movable comb teeth, detection fixed comb teeth, detection movable comb teeth, force feedbackfixed comb teeth, force feedback movable comb teeth and anchor points. Generation of quadrature error signals is suppressed, and the zero bias stability index of the MEMS gyroscope is improved; the gyroscope has compact structure and small chip area, and can prevent a detection-mode sensitive mass from twisting due to larger displacement, thereby having good overall linearity and high measurementaccuracy.

The invention discloses a resonant gyroscope closed-loop control method and system. The method comprises the following steps: vibration displacement signals are acquired and converted in driving and detecting directions in driving and detecting modes; a driving displacement signal generates a control signal through a driving loop and the control signal is input into the driving electrode to excitethe harmonic oscillator to vibrate at a constant amplitude in the driving direction; a detection displacement signal is divided into two paths, and one path is input into the detection electrode through the quadrature error suppression loop and the other path generates a detection signal through a force balance loop and superposes the detection signal with a correction demodulation signal; demodulation and amplitude operation is performed on the signals demodulated by the two loops; amplitude results are summed and PID control operation is performed to obtain a scale compensation signal; andthe amplitude of the signal with the disturbance feedback force is regulated by using the scale compensation signal, and the signal subjected to the amplitude regulation is input into the detection electrode to realize automatic compensation of the scale factor of the gyroscope. According to the method and the system, the complete closed-loop control function of the resonant gyroscope is realized,the problems of poor adaptability, time consumption, labor consumption and the like in the prior art are solved, and the stability of the scale factor of the gyroscope in the running state is improved.

A Quadrature Error Corrected Digital Waveform Synthesizer (QECDWS) employs frequency dependent phase error corrections to, in effect, pre-distort the phase characteristic of the chirp to compensate for the frequency dependent phase nonlinearity of the RF and microwave subsystem. In addition, the QECDWS can employ frequency dependent correction vectors to the quadrature amplitude and phase of the synthesized output. The quadrature corrections cancel the radars' quadrature upconverter (mixer) errors to null the unwanted spectral image. A result is the direct generation of an RF waveform, which has a theoretical chirp bandwidth equal to the QECDWS clock frequency (1 to 1.2 GHz) with the high Spurious Free Dynamic Range (SFDR) necessary for high dynamic range radar systems such as SAR. To correct for the problematic upconverter local oscillator (LO) leakage, precision DC offsets can be applied over the chirped pulse using a pseudo-random noise dither. The present dither technique can effectively produce a quadrature DC bias which has the precision required to adequately suppress the LO leakage. A calibration technique can be employed to calculate both the quadrature correction vectors and the LO-nulling DC offsets using the radar built-in test capability.

Embodiments of the invention are concerned with correction of quadrature errors associated with digital communications systems, and in particular in a wireless transmit chain in which an up-converter and a down-converter both have a direct conversion architecture. One embodiment comprises a correction network for correcting a difference between a transmission characteristic of an in-phase signal path and a transmission characteristic of a quadrature signal path, said quadrature signal path being for the transmission of in-phase and quadrature parts of a signal and the signal comprising frequency components within a base band, wherein the correction network comprises an in-phase input port, a quadrature input port, an in-phase output port and a quadrature output port, wherein each input port is connected to each output port by a digital filter network, the digital filter network comprising a set of filter tap coefficients and configuration means for configuring values of said set of filter tap coefficients. Since each input port is connected to each output port by a digital filter network comprising a set of filter tap coefficients and having configuration means for configuring values of said set of filter tap coefficients, frequency dependent quadrature impairments, for example due to the analogue components of a quadrature up-converter or down-converter, may be corrected by suitable control of the coefficients.

A method compensates for a sensitivity of an inertial sensor having a resonator and an accelerometer. The method includes adding a test signal to a quadrature tuning voltage applied to the resonator of the inertial sensor. The method also includes receiving a quadrature error signal from the accelerometer of the inertial sensor. The method also includes detecting a phase difference between the quadrature error signal and the test signal. The method also includes determining a bandwidth of the accelerometer based on the detected phase difference, the bandwidth indicating the sensitivity of the accelerometer.

An integrated circuit for a wireless communication unit has a transmit power control system employing a quadrature (I/Q) based power detector having at least one reference path and at least one detector path. The integrated circuit includes: a first quadrature error determination module for determining a quadrature error of a transmit signal and a second quadrature error determination module for determining a quadrature error of a detector signal input to the at least one detector path; a first quadrature balancing module arranged to correct for quadrature error of the transmit signal and output a reference signal to the at least one reference path; a second quadrature balancing module arranged to correct for quadrature error of the reference signal input to the at least one reference path, and a third quadrature balancing module arranged to correct for quadrature error of the detector signal input from the at least one detector path.

A demodulator for automatically performing quadrature control in which there is no necessity for the modulator side to perform precision adjustment and deterioration in characteristics e.g., error rate is suppressed for long. The demodulator includes a quadrature controller fed with an in-phase component and a quadrature component output from the quadrature detecting unit to correct quadrature error between phases of in-phase and quadrature signals based on a quadrature error signal, an automatic gain controller AGC outputting in-phase and quadrature components of a demodulated signal corrected for amplitude errors by an amplitude error signal, an error detection unit fed with in-phase and quadrature components of the demodulated signal to output in-phase and quadrature components and polarity signals, an amplitude error detector outputting in-phase and quadrature components of the amplitude error to the AGC based on the in-phase and quadrature components and the respective polarity signals, and a quadrature error detection unit generating a quadrature error signal Qd based on the in-phase and quadrature components and the polarity signals to output the generated quadrature error signal to the quadrature controller.

Methods and systems are described for generating, at a plurality of delay stages of a local oscillator, a plurality of phases of a local oscillator signal, generating a loop error signal based on a comparison of one or more phases of the local oscillator signal to one or more phases of a received reference clock, generating a plurality of phase-specific quadrature error signals, each phase-specific quadrature error signal associated with a respective phase of the plurality of phases of the local oscillator signal, each phase-specific quadrature error signal based on a comparison of the respective phase to two or more other phases of the local oscillator signal, and adjusting each delay stage according to a corresponding phase-specific quadrature error signal of the plurality of phase-specific quadrature error signals and the loop error signal.

The invention belongs to the field of laser interference measurement, and relates to a quadrature error-free double-path polarization interference and double-Wollaston prism light-splitting type homodyne laser vibration meter. An interference part generates double paths of linear polarization reference light and linear polarization measurement light whose polarization directions are orthogonal and light paths are overlapped through a quarter-wave plate and a polarization-eliminating beam splitter NBS, and in a detection part, reference light and measurement light generate four paths of photoelectric signals with a phase difference of 90 degrees through two Wollaston prisms whose spatial rotation angles around light beams form a specific relation, thereby obtaining an outstanding characteristic of inhibiting a nonlinear error from a light path structure and in principle. The quadrature error-free double-path polarization interference and double-Wollaston prism light-splitting type homodyne laser vibration meter provided by the invention adopts less optical elements to realize four-channel homodyne quadrature laser interference measurement, can effectively solve the problems in an existing technical scheme that polarization leakage and polarization aliasing exist in the light paths, a direct current biased error and a non-quadrature error exist in an output signal, and a nonlinear error of a measurement result is obvious, and thus has remarkable technical advantages in the field of ultra-precise vibration measurement.

The invention relates to an automatic testing method of a mode matching voltage of an MEMS gyroscope. The automatic testing method comprises the following steps: step 1, adding a driving closed control loop between a driving electrode of a driving mode of the MEMS gyroscope and a driving detection electrode to ensure that the driving mode of the MEMS gyroscope vibrates at resonant frequency and a specified indicated constant amplitude is maintained, and acquiring a driving displacement voltage signal VDP at the moment; step 2, connecting a sensitive mode detection electrode of the MEMS gyroscope with a preposition read-out circuit, and converting a quadrature error displacement variable quantity generated by the sensitive mode of the gyroscope into a voltage variable quantity through the preposition read-out circuit, so as to obtain a quadrature error voltage signal Vsp of the sensitive mode of the gyroscope; step 3, adjusting the controlled quantity VT inputted to the sensitive mode of the gyroscope, so that the phase difference between the driving displacement voltage signal VDP and the quadrature error voltage signal Vsp is 0, and the controlled quantity VT at the moment is the mode matching voltage. The automatic testing method disclosed by the invention can automatically test the mode matching voltage under different environmental temperatures in real time.

Tuning fork and method in which a pair of elongated tines having front and rear surfaces are disposed symmetrically about an axis, and balancing masses on the front surface of one tine and on the rear surface of the other tine are trimmed to reduce quadrature error and also to maintain mass balance between the tines.

A MEMS gyroscope, wherein a suspended mass is mobile with respect to a supporting structure. The mobile mass is affected by quadrature error caused by a quadrature moment; a driving structure is coupled to the suspended mass for controlling the movement of the mobile mass in a driving direction at a driving frequency. Motion-sensing electrodes, coupled to the mobile mass, detect the movement of the mobile mass in the sensing direction and quadrature-compensation electrodes are coupled to the mobile mass to generate a compensation moment opposite to the quadrature moment. The gyroscope is configured to bias the quadrature-compensation electrodes with a compensation voltage so that the difference between the resonance frequency of the mobile mass and the driving frequency has a preset frequency-mismatch value.