Dual mode filters having two reconfigurable multi-stage filters. In a dual band mode, each reconfigurable filter filters an input signal in a different band using every filter stage. In a single band mode, both reconfigurable filters are effectively divided into two sub-chains that include either the odd-numbered filter stages or the even-numbered filter stages. Together, the four sub-chains in the single band mode filter an input signal in a single band with a higher parallelization than each reconfigurable filter in the dual band mode. In some embodiments, the dual mode filter is a decimation filter. In other embodiments, the dual mode filter is a resampling filter. In still other embodiments, the dual mode filter is an interpolation filter.

An inverter system for mitigating oscillation of an electric motor that drives a load comprises a torque command generation module for receiving a commanded torque from an operator of a vehicle. A torque damping module is configured to receive the commanded torque and generating a commanded compensating torque to dampen any mechanical oscillation or resonance of the electric motor based on the observed rotational speed of the motor. The torque damping module further comprises a digital filter of order greater than one, a gain adjuster and a limiter.

Techniques and apparatus presented herein are directed toward monitoring an electric power delivery system to detect and locate a power generation event. A power generation event may include a tripped generator, a loss of a transmission line, or other loss of power generation. To detect the event, an analysis engine may receive and monitor input data. A detection signal may be generated based on the input data. Upon detecting the event, the analysis engine may determine a source and propagation of the event through the delivery system. Based on the source and propagation of the event, the analysis engine may determine the location of the event. The analysis engine may generate an overlay with the input data to provide the location and other information about the event to a user such that remedial action can be taken to resolve the event and restore the lost power generation.

Systems and methods for digital signal processing using a sliding windowed infinite Fourier transform (“SWIFT”) algorithm are described. A discrete-time Fourier transform (“DTFT”) of an input signal is computed over an infinite-length temporal window that is slid from one sample in the input signal to the next. The DTFT with the temporal window at a given sample point is effectively calculated by phase shifting and decaying the DTFT calculated when the temporal window was positioned at the previous sample point and adding the current sample to the result.

Examples provide a method and apparatus for an analog bi-quad infinite impulse response (IIR) filter. An amplifier generates a positive output signal corresponding to a received RF signal and a negative output signal. A set of selectively switchable time-delay circuits associated with a positive arm of the filter causes a predetermined delay corresponding to a desired sample frequency. A first set of configurable variable gain amplifiers amplify the positive output signal to establish a set of positive coefficients. A set of selectively switchable time-delay circuits associated with a negative arm of the filter causes a predetermined delay. A delayed negative output signal is generated which is amplified by a second set of configurable variable gain amplifiers to establish a set of negative coefficients. A set of power combiners function as sum junctions to combine the delayed positive output signals and the delayed negative output signals into a single output signal.

Methods and devices are described for reducing the audible effect of pre-responses in an audio signal. The pre-responses are effectively delayed by employing a digital non-minimum-phase filter, which includes a zero lying outside the unit circle in its z-transform response. This zero is not paired with another zero at a reciprocal position inside the unit circle, as this would linearise the phase modification. The filtering can introduce a greater group delay at the pre-response frequency than at a low frequency, such as 500 Hz or even 0 Hz. The technique can be used to reduce pre-responses in an existing audio signal and also to pre-empt pre-responses that would be introduced to the audio signal by subsequent processing.

Method for carrying out a morphing process, wherein an output parameter relating to the output of an audio signal outputted into an interior via an audio output device is changed.

Dual mode filters having two reconfigurable multi-stage filters. In a dual band mode, each reconfigurable filter filters an input signal in a different band using every filter stage. In a single band mode, both reconfigurable filters are effectively divided into two sub-chains that include either the odd-numbered filter stages or the even-numbered filter stages. Together, the four sub-chains in the single band mode filter an input signal in a single band with a higher parallelization than each reconfigurable filter in the dual band mode. In some embodiments, the dual mode filter is a decimation filter. In other embodiments, the dual mode filter is a resampling filter. In still other embodiments, the dual mode filter is an interpolation filter.

A novel and useful discrete time IIR bandpass filter is disclosed that takes advantage of clock phase reuse thereby leading to significant improvements in filtering, especially stop band rejection in comparison to prior art filters. The bandpass filter of the present invention achieves improved filtering performance without adding any additional clock phases to the circuit. In particular, reuse of the already existing clock phases increases the order and performance of the filter. The invention exploits reuse of the clock phases to provide higher order filtering along with a discrete time IIR filter design which is capable of operating at high frequency. Consequently, much better filtering is achieved and the quality factor of the filter is improved leading to sharper transition bands especially for close-in band blockers in modern 4G/5G receivers.

A filter assembly, for example for a control loop for controlling the position of at least one element, comprises first and second filters. The first filter suppresses an undesired component in a signal to be filtered. The first filter produces a first signal delay in a first frequency range. The second filter produces a second signal delay in the first frequency range. The second signal delay at least partly compensates the first signal delay.