A counter is started on the falling edge of a tach pulse. This counter counts to the rising edge of a second tach pulse, such as the next tach pulse. During the duration of the tach pulse the FPGA calculates the RPM of a motor. In this way, during each commutation period, a RPM is calculated. The present system performs a RPM calculation during each commutation period and/or tach pulse duration.

A harmonic distortion separation method, nonlinear character determination method, apparatus and system where a phase difference between an inherent harmonic and a generated harmonic is determined by using multiple groups of input power, output power and fundamental magnitudes of a memoryless nonlinear transfer function of a nonlinear model of a system to be measured, and power of a harmonic generated by the system to be measured is separated by using the phase difference. In an embodiment, the phase difference between the inherent harmonic and the generated harmonic is first determined by using an assumption that a model coefficient is a constant according to the set nonlinear model, then the harmonic separation is performed by using the phase difference, and the power of the harmonic generated by the system to be measured is calculated.

The present disclosure relates to a motor control system including: a motor control device, including a semiconductor integrated circuit having a memory and forming a control loop for a motor so as to control a drive of the motor; and an external debug device, externally connected to the motor control device and accessible to the memory in the motor control device. The external debug device includes a disturbance signal superimposer and a frequency characteristics deriver. The interference signal superimposer generates a disturbance signal for the control loop and superimposes the disturbance signal on a signal generated in the control loop. The frequency characteristics deriver derives frequency characteristics of the control loop based on the signal generated in the control loop by superimposition.

A method of detecting whether a receiver coil is near a transmit coil in a wireless power transfer system (WPTS), the method involving: applying a pseudo-random signal to the transmit coil; while the pseudo-random signal is being applied to the transmit coil, recording one or more signals produced within the WPTS in response to the applied pseudo-random signal; by using the one or more recorded signals, generating a dynamic system model for some aspect of the WPTS; and using the generated dynamic system model in combination with stored training data to determine whether an object having characteristics distinguishing the object as a receiver coil is near the transmit coil.

A method of detecting whether a receiver coil is near a transmit coil in a wireless power transfer system (WPTS), the method involving: applying a pseudo-random signal to the transmit coil; while the pseudo-random signal is being applied to the transmit coil, recording one or more signals produced within the WPTS in response to the applied pseudo-random signal; by using the one or more recorded signals, generating a dynamic system model for some aspect of the WPTS; and using the generated dynamic system model in combination with stored training data to determine whether an object having characteristics distinguishing the object as a receiver coil is near the transmit coil.

Systems and methods are provided for testing remote frequency identification (RFID) straps. A testing system includes an amplifier electrically coupled to an inductor or inductive component. The system further includes a pair of contact points to be placed in contact with a pair of contact pads of an RFID strap. Connecting the contact points and the contact pads places the RFID strap in parallel with the inductor to define a resonant circuit. The characteristics of the resonant circuit as an oscillator depend at least in part on the capacitance and the resistance of the RFID strap. As such, the characteristics of the resonant circuit as an oscillator may be monitored to determine the capacitance and/or the resistance of the RFID strap. One or more characteristics of the RFID strap may be compared to one or more threshold values to determine whether the RFID strap is acceptable or defective.

An apparatus for determining a measure of the frequency of an electrical signal is provided. The apparatus is configured to, based on a plurality of samples of the electrical signal, determine a Hilbert transformation to obtain a value for each of the samples of the electrical signal for use as an imaginary representation of each of the samples of the electrical signal and combine each said imaginary representation with a corresponding real representation of the samples of the electrical signal to form a complex representation of the electrical signal; perform a Fourier transform on each said complex representation of the samples of the electrical signal and determine a phase angle therefrom; and determine a measure of the frequency of the electrical signal based on a derivative of the phase angle with respect to time.

An apparatus for determining a measure of the frequency of an electrical signal is provided. The apparatus is configured to, based on a plurality of samples of the electrical signal, determine a Hilbert transformation to obtain a value for each of the samples of the electrical signal for use as an imaginary representation of each of the samples of the electrical signal and combine each said imaginary representation with a corresponding real representation of the samples of the electrical signal to form a complex representation of the electrical signal; perform a Fourier transform on each said complex representation of the samples of the electrical signal and determine a phase angle therefrom; and determine a measure of the frequency of the electrical signal based on a derivative of the phase angle with respect to time.

A frequency estimator for estimating a frequency, including a counter configured to count an integer number of full clock cycles during a measurement time window; a Time-to-Digital Converter (TDC) configured to measure a fraction of a clock cycle during the measurement time window; and a processor configured to determine the estimated frequency based on the counted number of full clock cycles and the measured fraction of the clock cycle.

A frequency estimator for estimating a frequency, including a counter configured to count an integer number of full clock cycles during a measurement time window; a Time-to-Digital Converter (TDC) configured to measure a fraction of a clock cycle during the measurement time window; and a processor configured to determine the estimated frequency based on the counted number of full clock cycles and the measured fraction of the clock cycle.