Abstract: A method includes determining a droop component of a measured parameter of a device under test (DUT). The measured parameter is responsive to an excitation signal having a frequency component, and the droop component is determined responsive to a first value of the parameter at a first time and a second value of the parameter at a second time. The parameter at the first time has a first phase value, and the parameter at the second time has a second phase value. The first phase value is equal to the second phase value. The method also includes correcting a frequency domain representation of the parameter by applying the droop component at a frequency of the representation of the parameter corresponding to the frequency component of the excitation signal.

Abstract: From a current measurement circuit, digital samples are received of a current signal that flows through a battery cell within a measurement period. From a voltage measurement circuit, digital samples are received of a voltage signal across the battery cell within the measurement period. First voltage spectral components are generated based on performing a first transform operation on the digital samples of the voltage signal. A current spectrum is generated based on performing a second transform operation on the digital samples of the current signal. Second voltage spectral components are generated based on a first condition of the battery cell before the measurement period and a second condition of the battery cell after the measurement period. A voltage spectrum is including the first voltage spectrum and the second voltage spectrum is generated. An impedance spectrum of the battery cell is generated based on the voltage spectrum and the current spectrum.

Abstract: From a current measurement circuit, digital samples are received of a current signal that flows through a battery cell within a measurement period. From a voltage measurement circuit, digital samples are received of a voltage signal across the battery cell within the measurement period. First voltage spectral components are generated based on performing a first transform operation on the digital samples of the voltage signal. A current spectrum is generated based on performing a second transform operation on the digital samples of the current signal. Second voltage spectral components are generated based on a first condition of the battery cell before the measurement period and a second condition of the battery cell after the measurement period. A voltage spectrum is including the first voltage spectrum and the second voltage spectrum is generated. An impedance spectrum of the battery cell is generated based on the voltage spectrum and the current spectrum.

Abstract: A circuit configured to: generate a reference clock signal; generate an excitation signal at a target frequency having a period that is a first integer number of cycles of the reference clock signal; update a driver circuit at an update frequency having a period that is a second integer number of cycles of the reference clock signal; digitize sense signals resulting from the excitation signal at a frequency having a period that is a third integer number of cycles of the reference clock signal; identify a fourth integer number of sense signal samples; optionally utilize an excitation control signal having a period that is a fifth integer number of cycles of the reference clock signal; and minimize harmonics at the target frequency of the excitation signal based on the first integer number, the second integer number, the third integer number, the fourth integer number, and possibly the fifth integer number.

Abstract: A method includes determining a droop component of a measured parameter of a device under test (DUT). The measured parameter is responsive to an excitation signal having a frequency component, and the droop component is determined responsive to a first value of the parameter at a first time and a second value of the parameter at a second time. The parameter at the first time has a first phase value, and the parameter at the second time has a second phase value. The first phase value is equal to the second phase value. The method also includes correcting a frequency domain representation of the parameter by applying the droop component at a frequency of the representation of the parameter corresponding to the frequency component of the excitation signal.

Abstract: From a current measurement circuit, digital samples are received of a current signal that flows through a battery cell within a measurement period. From a voltage measurement circuit, digital samples are received of a voltage signal across the battery cell within the measurement period. First voltage spectral components are generated based on performing a first transform operation on the digital samples of the voltage signal. A current spectrum is generated based on performing a second transform operation on the digital samples of the current signal. Second voltage spectral components are generated based on a first condition of the battery cell before the measurement period and a second condition of the battery cell after the measurement period. A voltage spectrum is including the first voltage spectrum and the second voltage spectrum is generated. An impedance spectrum of the battery cell is generated based on the voltage spectrum and the current spectrum.

Abstract: A circuit for determining device under test (DUT) model parameters is described. The circuit includes a parameter estimator circuit configured to: obtain initial values for DUT model parameters based on sense signal samples; execute a parameter convergence model having a regularization parameter and a cost function that accounts for error residuals; and obtain final values for the DUT model parameters by adjusting the regularization parameter in iterations of the parameter convergence model as a function of cost function improvement until the parameter convergence model converges to within a target tolerance.

Abstract: A method includes selecting a frame of an audio signal. The method further includes determining a first power spectral density (PSD) distribution of the frame. The method further includes generating a first reference PSD distribution indicating an estimate of background noise in the frame based on a non-linear weight, a second reference PSD distribution of a previous frame of the audio signal, and a second PSD distribution of the previous frame. The method further includes determining whether voice activity is detected in the frame based on the first PSD distribution of the frame and the first reference PSD distribution.

Abstract: One example includes an ultrasonic ranging system. The system includes an ultrasonic transducer configured to transmit an ultrasonic signal and to receive reflected ultrasonic signal paths having been reflected from a plurality of target objects during a ranging operation. The system also includes a ranging processor configured to detect a location associated with the plurality of target objects based on monitoring phase information associated with the reflected ultrasonic signal paths.

Abstract: A method includes selecting a frame of an audio signal. The method further includes determining a first power spectral density (PSD) distribution of the frame. The method further includes generating a first reference PSD distribution indicating an estimate of background noise in the frame based on a non-linear weight, a second reference PSD distribution of a previous frame of the audio signal, and a second PSD distribution of the previous frame. The method further includes determining whether voice activity is detected in the frame based on the first PSD distribution of the frame and the first reference PSD distribution.

Abstract: Techniques for target input detection, including receiving input data, dividing the input data into data blocks, determining a detection feature value for a first data block, determining a detection threshold based on a set of detection feature statistics determined for a background sampling time period, and determining a target signal has been received based on a comparison between the detection feature value for the first data block to the detection threshold.

Abstract: One example includes an ultrasonic ranging system. The system includes an ultrasonic transducer configured to transmit an ultrasonic signal and to receive reflected ultrasonic signal paths having been reflected from a plurality of target objects during a ranging operation. The system also includes a ranging processor configured to detect a location associated with the plurality of target objects based on monitoring phase information associated with the reflected ultrasonic signal paths.

Abstract: A circuit for measuring an impedance of a device under test (DUT). The circuit includes: (i) circuitry for generating a stimulus wave at a stimulus frequency; (ii) an amplifier circuit coupled to the DUT to present a response signal from the DUT in response to the stimulus wave; (iii) switching circuitry for selectively coupling, between the stimulus wave and an input to the amplifier, either the DUT, a first calibration impedance, or a second calibration impedance. With the switching functionality, calibrations are performed so to provide a measure of impedance of the DUT in response to the plural calibrations.

Abstract: A system includes a controller to provide at least one control output to an automated system in response to a control command received at a control input of the controller. The control output controls the operation of the automated system based on the control command. A signature analyzer generates the control command to the controller and receives an impedance signature related to a property of a material or object encountered by the automated system. The signature analyzer compares the impedance signature to at least one comparison signature to determine the property of the material or object. The signature analyzer adjusts the control command to the controller to control the operation of the automated system based on the determined property.

Abstract: A microcontroller-based system for identifying a paper type of a sample of paper from a measurement of its electrical impedance. An interdigital dielectric sensor (55) is deployed in the paper path of a printer (PTR), and the electrical impedance at the sensor, as affected by a sheet of paper (P) near the sensor, is measured over a plurality of frequencies of a stimulus signal. The stimulus signal may be sinusoidal or a square wave. The impedance characteristic, in magnitude or phase, or both, is compared against a plurality of reference impedance characteristics, each associated with a paper type, to identify the closest match and thus the type of paper of the sample sheet.

Abstract: A microcontroller-based system for measuring the impedance of a device under test (DUT), responsive to a square wave stimulus, includes parallel stimulus signal paths, selectable by a switch, that can correspond to different stimulus frequency ranges. At least one of the paths includes an off-chip PLL and integer divider circuit to modify the frequency of the stimulus. A discrete Fourier transform executed by a processor is used to determine the impedance of the DUT at the stimulus frequency. Multiple frequencies can be analyzed at the same time by using a summation circuit and/or by analyzing odd harmonics of the stimulus frequency.

Abstract: A microcontroller-based system for measuring the impedance of a device under test (DUT) (35) responsive to a square wave stimulus. A clock generator circuit (26) in the microcontroller (20) generates a clock signal at a base clock frequency. A first timer (25) divides down the base clock frequency by a first frequency divisor integer to set the stimulus frequency of a square wave generated by a general purpose input/output (GPIO) function (24), and a second timer (28) divides down the base clock frequency by a second frequency divisor integer to set the sampling frequency of an analog-to-digital converter (ADC) (30). A discrete Fourier transform executed by a processor (22) is used to determine the impedance of the DUT at the stimulus frequency. The first and second integers are selected so that aliased harmonics fall in different DFT bins from the fundamental tone.

Abstract: A system includes a controller to provide at least one control output to an automated system in response to a control command received at a control input of the controller. The control output controls the operation of the automated system based on the control command. A signature analyzer generates the control command to the controller and receives an impedance signature related to a property of a material or object encountered by the automated system. The signature analyzer compares the impedance signature to at least one comparison signature to determine the property of the material or object. The signature analyzer adjusts the control command to the controller to control the operation of the automated system based on the determined property.

Abstract: One example includes an ultrasonic ranging system. The system includes an ultrasonic transducer configured to transmit an ultrasonic signal and to receive reflected ultrasonic signal paths having been reflected from a plurality of target objects during a ranging operation. The system also includes a ranging processor configured to detect a location associated with the plurality of target objects based on monitoring phase information associated with the reflected ultrasonic signal paths.

Abstract: A microcontroller-based system for measuring the impedance of a device under test (DUT), responsive to a square wave stimulus, includes parallel stimulus signal paths, selectable by a switch, that can correspond to different stimulus frequency ranges. At least one of the paths includes an off-chip PLL and integer divider circuit to modify the frequency of the stimulus. A discrete Fourier transform executed by a processor is used to determine the impedance of the DUT at the stimulus frequency. Multiple frequencies can be analyzed at the same time by using a summation circuit and/or by analyzing odd harmonics of the stimulus frequency.