Abstract: Systems and methods for sensing angular motion using a microelectromechanical system (MEMS) gyroscope are described. These systems and methods may be useful for sensing angular motion in the presence of low-frequency noise, which may be noise below 1 KHz. In a system for sensing angular motion, low-frequency noise may give rise to duty cycle jitter, which may affect the demodulation of the sense signal and cause errors in angular motion estimates. The systems and methods described herein address this problem by relying on double-edge phase detection technique that involves sensing when the rising and falling edges of the resonator signal deviate from their expected values in the idealized 50% duty cycle scenario. To prevent the formation of ripples in the double-edge phase detection that may otherwise affect the demodulation of the sense signal, a switch may be used. The switch may be maintained in a non-conductive state when a ripple is received.

Abstract: Circuits and methods for compensating microelectromechanical system (MEMS) gyroscopes for quality factor variations are described. Quality factor variations arise when mechanical losses are introduced in the gyroscope's resonator, for example due to thermoelastic damping or squeeze-film damping, which may hinder the gyroscope's ability to accurately sense angular velocity. Quality factor compensation may be performed by generating a compensation signal having a time decay rate that depends on the quality factor of resonator. In this way, artifacts that may otherwise arise in gyroscope's output are limited. Additionally, or alternatively, quality factor compensation may be performed by controlling the force with which the gyroscope's resonator is driven. This may be achieved, for example, by controlling the average value of the drive signal.

Abstract: Various embodiments provide methods of determining the quality factor of a resonating body in ways that are advantageous over previously known methods. For example, embodiments allow the determination of the quality factors of a resonating body without preventing the simultaneous use of the resonating body. For micromachined (“MEMS”) devices, embodiments allow the determination of the quality factors of a resonating body in a manner that is not dependent on transduction parameters of the MEMS device.

Abstract: Systems and techniques are described for matching the resonance frequencies of multiple resonators. In some embodiments, a resonator generates an output signal reflecting the resonator's response to an input drive signal and an input noise signal. The output signal is then compared to the noise signal to derive a signal representative of the resonance frequency of the resonator. Comparing that signal to the output signal of a second resonator gives an indication of whether there is a difference between the resonance frequencies of the two resonators. If there is, one or both of the resonators may be adjusted. In this manner, the resonance frequencies of resonators may be matched during normal operation of the resonators.

Abstract: A method for detecting frequency mismatch in microelectromechanical systems (MEMS) gyroscopes is described. Detection of the frequency mismatch between a drive signal and a sense signal may be performed by generating an output signal whose spectrum reflects the physical characteristics of the gyroscope, and using the output signal to determine the frequency fC of the sense signal. The output signal may be generated by cross-correlating a random or pseudo-random noise signal with a response signal, where the response signal can be obtained by allowing the noise signal to pass through a system designed to have a noise transfer function that mimics the frequency response of the gyroscope. Since the noise signal is random or pseudo-random, cross-correlating the noise signal with the response signal reveals spectral characteristics of the gyroscope. To improve computational efficiency, the cross-correlation can be performed on demodulated versions of the noise signal and the response signal.

Abstract: A system and method for providing a dynamic region of interest in a lidar system can include scanning a light beam over a field of view to capture a first lidar image, identifying a first object within the captured first lidar image, selecting a first region of interest within the field of view that contains at least a portion of the identified first object, and capturing a second lidar image, where capturing the second lidar image includes scanning the light beam over the first region of interest at a first spatial sampling resolution, and scanning the light beam over the field of view outside of the first region of interest at a second spatial sampling resolution, wherein the second sampling resolution is less than the first spatial sampling resolution.

Abstract: Systems and techniques are described for matching the resonance frequencies of multiple resonators. In some embodiments, a resonator generates an output signal reflecting the resonator's response to an input drive signal and an input noise signal. The output signal is then compared to the noise signal to derive a signal representative of the resonance frequency of the resonator. Comparing that signal to the output signal of a second resonator gives an indication of whether there is a difference between the resonance frequencies of the two resonators. If there is, one or both of the resonators may be adjusted. In this manner, the resonance frequencies of resonators may be matched during normal operation of the resonators.

Abstract: A regulated supply voltage can be established using switching cycles defined at least in part according to a switching clock period. Imaging information can be acquired from an imaging sensor and a discrete-time representation of the imaging information can be received. Noise, such as corresponding to the switching cycles, can be reduced or suppressed. In an example, a discrete-valued noise template can be stored in a memory, wherein a count of values in the noise template is less than a count of an entirety of a physical row of pixels from the imaging sensor. The discrete-valued noise template can be aligned with a portion of the discrete-time representation of the imaging information. The noise in the discrete-time representation can be at least partially canceled using the aligned discrete-valued noise template. The template can be constructed such as by aggregating imaging information obtained from an optically-black portion of the imaging sensor.

Abstract: A slew rate booster, switchably enabled selector, or other arrangement may be included in a cascode amplifier to keep the current buffer/common gate transistor and the input/common source transistor saturated as the voltage at the source of the current buffer transistor drops during a transient input voltage spike at the gate of the input transistor. In some instances a higher potential may be supplied to a gate of the current buffer transistor during an initial phase of the settling period than during a second phase of the settling period when a lower potential may be applied. Other techniques may be used in different embodiments. Devices and methods are provided.

Abstract: Embodiments of the present invention may provide accuracy enhancement techniques to improve ADC SNRs. For example, regular bit trials from a most significant bit (MSB) to predetermined less significant bit of a digital word and extra bit trials may be performed. The results of the regular and extra bit trials may be combined to generate a digital output signal. A residue error may be measured, and the digital output signal may be adjusted based on the measured residue error.

Abstract: Embodiments of the present invention may provide accuracy enhancement techniques to improve ADC SNRs. For example, regular bit trials from a most significant bit (MSB) to predetermined less significant bit of a digital word and extra bit trials may be performed. The results of the regular and extra bit trials may be combined to generate a digital output signal. A residue error may be measured, and the digital output signal may be adjusted based on the measured residue error.

Abstract: Embodiments of the present invention may provide an analog-to-digital converter (ADC) system. The ADC system may include an analog circuit to receive an input signal and a reference voltage, and to convert the input signal into a raw digital output. The analog circuit may include at least one sampling element to sample the input signal during a sampling phase and reused to connect to the reference voltage during a conversion phase, and an ADC output to output the raw digital output. The ADC system may also include a digital processor to receive the raw digital output and for each clock cycle, to digitally correct reference voltage errors in the analog-to-digital conversion.

Abstract: An apparatus for limiting the bandwidth of an amplifier provides for the design of an input impedance, a feedback impedance, and a load impedance such that the load impedance is proportional to the sum of the input impedance and feedback impedance. A sampling circuit has a load impedance including a resistor and capacitor in series to reduce the effective amplifier transconductance, which decreases bandwidth without increasing noise density or making this circuit more difficult to drive than a conventional circuit.

Abstract: Embodiments of the present invention may provide an analog-to-digital converter (ADC) system. The ADC system may include an analog circuit to receive an input signal and a reference voltage, and to convert the input signal into a raw digital output. The analog circuit may include at least one sampling element to sample the input signal during a sampling phase and reused to connect to the reference voltage during a conversion phase, and an ADC output to output the raw digital output. The ADC system may also include a digital processor to receive the raw digital output and for each clock cycle, to digitally correct reference voltage errors in the analog-to-digital conversion.

Abstract: An apparatus for limiting the bandwidth of an amplifier provides for the design of an input impedance, a feedback impedance, and a load impedance such that the load impedance is proportional to the sum of the input impedance and feedback impedance. A sampling circuit has a load impedance including a resistor and capacitor in series to reduce the effective amplifier transconductance, which decreases bandwidth without increasing noise density or making this circuit more difficult to drive than a conventional circuit.

Abstract: A system and method for implementing a differential signaling driver with a common-mode voltage not equal to one half the power supply voltage using voltage-mode techniques. Embodiments of the present invention maintain balanced impedance at the signal output. In an embodiment, a driver may have multiple operating modes for each potential supply voltage or common-mode voltage. In an embodiment, each potential mode may involve configuring the driver by activating or deactivating switches or resistors in the driver and each potential mode may have different resistor values.

Abstract: Embodiments of the present disclosure may provide a charge redistribution DAC with two sets of capacitors that provides a DAC output by sharing charges between a plurality of pairs of capacitors in lieu of charging the capacitors using traditional external reference voltages. The charge redistribution DAC may comprise a plurality of pairs of first and second capacitors that each has a first side and a second side, and a group of first switches and a group of second switches. Each first or second switch selectively controls connection of the first side of a respective first or second capacitor to one of a pair of output signal lines according to a DAC input word. The charge redistribution DAC further may comprise a group of bridging switches each connected between second sides of paired first and second capacitors.

Abstract: An uncalibrated converter element in an analog-digital converter may be replaced with two or more smaller elements having an effective total net value that is equal to that of the uncalibrated converter element. In an exemplary case where the element is capacitor, one or more of these smaller capacitors may be independently calibrated by switching the smaller capacitor between two voltages, such as a reference voltage and ground, and then calculating a difference of corresponding digital output codes generated by the backend ADC with previously calibrated capacitors associated with lesser significant bits. The total capacitance of the uncalibrated capacitor may be apportioned between the smaller capacitors so that the individual maximum charge contribution of each smaller capacitor to the converter output together with any expected manufacturing variance does not exceed the aggregated contribution of the previously calibrated capacitors.

Abstract: An architecture of an integrated circuit allows for the canceling of noise sampled on a capacitor in the integrated circuit, after an input signal has already been sampled. Thermal noise correlated with an arbitrary input signal may be canceled after selectively controlling a plurality of switching devices during a sequence of clock phases. An auxiliary capacitor may be used to store a voltage equal to the thermal noise and enable the cancellation of the thermal noise from the sampled signal in conjunction with a noise cancellation unit.

Abstract: An adaptive delay device that provides a delay to a signal based on circuit conditions such as temperature, supply voltage values and/or fabrication processes. The adaptive delay device may respond to circuit conditions by charging a capacitive device to a threshold voltage. A comparator may incorporate the adaptive delay device to provide adaptive timing for the comparator functions thereby attaining improved noise performance and/or reduce power consumption.