A sinusoidal-amplitude-to-digital-output circuit includes a comparator with an input terminal, a reference terminal and an output terminal. A digital bus is connected to the output terminal. A reference voltage source is connected to the reference terminal. A feedback resistor is connected in parallel with the comparator between the output terminal and the input terminal to provide hysteresis for noise rejection such that circuit converts voltage received at the input terminal into a digital pulse-width modulated waveform that varies non-linearly with amplitude of the voltage received at the input terminal.

A semiconductor device according to one embodiment selects one of the first and second resolver/digital converters and interrupts a supply of a power supply voltage to the other one of the first and second resolver/digital converters, and when an error is detected in the selected one of the first and second resolver/digital converters, the semiconductor device starts the supply of the voltage to the other one of the first and second resolver/digital converters, and switches the one of the first and second resolver/digital converters to the other one of the first and second resolver/digital converters.

A resolver-to-digital converter, comprising: a feedback (FB) filter chain loop having a state observer configured to estimate a rotation speed and a rotation angle of an object, based on a pair of input sine and cosine signals that are amplitude-modulated (AM) to correspond with the rotation angle of the object; and a feedforward (FF) filter chain path configured to estimate the rotation speed of the object based on the pair of input sine and cosine signals, wherein the state observer of the FB filter chain loop is further configured to offset the estimated rotation speed of the FB filter chain loop with the estimated rotation speed of the FF filter chain path to decrease a settling time of the estimated rotation angle.

An n-th-harmonic error estimation unit that estimates the error component of an n-th harmonic included in a resolver angle and a subtraction unit that subtracts an n-th-harmonic estimated angle error from to output the corrected angle are included. The n-th-harmonic error estimation unit includes an n-th-harmonic error phase detection unit that obtains a phase difference u such that the integral, for a 1/n period of an electrical angle of the rotor, of the output obtained by synchronously detecting by using a rectangular wave obtained by comparison from a COS wave expressed as cos(n+u) becomes zero and generates a SIN wave expressed as sin(n+u); a synchronous detector that synchronously detects by using a rectangular wave obtained by comparison from the SIN wave; an integrator that integrates the detected output for a 1/n period of the electrical angle; an actual angle integral calculation unit; an amplitude setter that sets an error amplitude from the value obtained by subtracting the integral of the actual angle integral calculation unit from the integral of the integrator; and a multiplier that generates the n-th-harmonic estimated angle error by multiplying the SIN wave by the error amplitude.

For an easily implementable method for position determination using an inductive position sensor with increased precision of the position information, the position sensor generates a measurement signal from which a frequency functional dependent on the excitation frequency is formed, which represents a measure of the noise signal and the excitation frequency of the excitation signal is changed so that the frequency functional is minimized or maximized and the excitation frequency that minimizes or maximizes the frequency functional is used for the excitation signal.

Various embodiments provide a filter for propagation delay compensation and interpolation in encoder digital signal processing. The filter can include a first low pass filter configured to reduce noise of a digital input comprising a measured angular position; a first differentiator configured to receive a filtered digital input and to calculate a speed from a difference in time of the measured angular position and a previous angular position; a second low pass filter configured to reduce noise from the speed; a second differentiator configured to receive a filtered speed and to calculate acceleration using a difference in time of the filtered speed and a previous speed; a third low pass filter configured to reduce noise of the acceleration; and a delay compensator configured to receive the filtered digit input, the filtered speed, and a filtered acceleration, and to calculate a propagation delay compensated digital output.

Measurement systems, methods for operating an angular sensor interface, and angular sensor interfaces. The measurement system includes a position sensor, a signal processor, and a propagation delay compensation filter. The position sensor is configured to generate analog signals. The signal processor is configured to generate position signals from the analog signals. The propagation delay compensation filter is configured to generate low-pass filtered position signals from the position signals, and calculate speed signals from the low-pass filtered position signals. The propagation delay compensation filter is further configured to generate low-pass filtered speed signals from the speed signals, and calculate acceleration signals from the low-pass filtered speed signals. The propagation delay compensation filter is further configured to generate low-pass filtered acceleration signals from the acceleration signals. The propagation delay compensation filter is also configured to produce compensated angular position signals from the low-pass filtered speed and acceleration signals.