A signal density modulation (SDM) encoder includes a first subtractor, a sigma circuit and a multi-bit quantizer. The first subtractor is used for receiving an input signal. The sigma circuit is coupled to the first subtractor. The multi-bit quantizer, coupled to the first subtractor and the sigma circuit, is configured to generate an output signal. The sigma circuit or the multi-bit quantizer produces a first feedback signal to the first subtractor. The first subtractor performs a subtraction operation according to the first feedback signal and the input signal, and generates a delta signal. The sigma circuit performs an operation on the delta signal, such that the SDM encoder has a noise transfer function having a high pass filtering effect. The noise transfer function is a ratio of a quantization error brought by the multi-bit quantizer with respect to the input signal. The output signal has more than two levels.

A filter is disclosed. The filter includes at least one first multiplication approximation unit, for approximating at least one first multiplication operation corresponding to at least one first coefficient with at least one first bit-wise shift operation; and at least one second multiplication approximation unit, for approximating at least one second multiplication operation corresponding to at least one second coefficient with a plurality of second bit-wise shift operations and at least one addition operation.

The invention provides a system improving signal handling, e.g., transmission and/or processing. In an embodiment, the system may include a filter circuit, a magnitude bit truncation circuit and a utility circuit. The filter circuit may be coupled to a target signal which contains one or more desired signals at one or more interested bands, for attenuating each said interested band to form a filtered signal. The magnitude bit truncation circuit may be coupled to the filter circuit, for truncating one or more bits of each sample of the filtered signal to form a truncated signal. The utility circuit may be coupled to the magnitude bit truncation circuit, for handling the truncated signal to implement handling of the target signal, so as to reduce resource requirement and enhance error tolerance comparing with directly handling the target signal.

Prism signal processing is a new FIR filtering technique that can offer a fully recursive calculation and elegant filter design. Its low design and computational cost may be particularly suited to the autonomous signal processing requirements for the Internet of Things. Arbitrarily narrow band-pass filters may be designed and implemented using a chain of Prisms and a simple yet powerful procedure. Using the described method and system, an ultra-narrowband filter can be evaluated in fractions of a microsecond per sample on a desktop computer. To achieve this update rate using a conventional non-recursive FIR calculation would require supercomputer resources. FPGA embodiments of the system demonstrate computation efficiency and broad applications of the technique.

Prism signal processing is a new FIR filtering technique that can offer a fully recursive calculation and elegant filter design. Its low design and computational cost may be particularly suited to the autonomous signal processing requirements for the Internet of Things. Arbitrarily narrow band-pass filters may be designed and implemented using a chain of Prisms and a simple yet powerful procedure. Using the described method and system, an ultra-narrowband filter can be evaluated in fractions of a microsecond per sample on a desktop computer. To achieve this update rate using a conventional non-recursive FIR calculation would require supercomputer resources. FPGA embodiments of the system demonstrate computation efficiency and broad applications of the technique.

Systems and methods for multi-thread power limiting via a shared limit estimates power consumed in a processing core on a thread-by-thread basis by counting how many power events occur in each thread. Power consumed by each thread is approximated based on the number of power events that have occurred. Power consumed by individual threads is compared to a shared power limit derived from a sum of the power consumed by all threads. Threads that are above the shared power limit are stalled while threads below the shared power limit are allowed to continue without throttling. In this fashion, the most power intensive threads are throttled to stay below the shared power limit while still maintaining performance.

Systems and methods for multi-thread power limiting via a shared limit estimates power consumed in a processing core on a thread-by-thread basis by counting how many power events occur in each thread. Power consumed by each thread is approximated based on the number of power events that have occurred. Power consumed by individual threads is compared to a shared power limit derived from a sum of the power consumed by all threads. Threads that are above the shared power limit are stalled while threads below the shared power limit are allowed to continue without throttling. In this fashion, the most power intensive threads are throttled to stay below the shared power limit while still maintaining performance.

In some examples, to perform motion detection of a moveable platform, variance values based on acceleration data from an accelerometer on the moveable platform are computed. Using the computed variance values, it is determined whether the moveable platform is in motion.

A digital filter, an audio signal processing system, and a method of designing a digital filter are provided, where the digital filter reduces a DC component of a signal which corresponds to an input data sequence, and has a transfer function H(s) represented as

[00001]$H\left(s\right)=\frac{s^2+\frac{{\omega }_0}{Q}s}{s^2+\frac{{\omega }_0}{Q}s+{\omega }_0^2}$

where a cutoff frequency F.sub.0 is ω.sub.0/2π and a Q factor is Q.

A filter circuit includes a first stage comprising a first infinite impulse response (IIR) filter; a third stage comprising a third IIR filter; and a second stage interposed between the first stage and the third stage, the second stage comprising a second IIR filter, where an output terminal of the first IIR filter is coupled to an input terminal of the second IIR filter, and an output terminal of the second IIR filter is coupled to an input terminal of the third IIR filter, where the second stage of the filter circuit is configured to operate in an acquisition mode when a transient is detected in an input signal to the first IIR filter, where during the acquisition mode, the second stage of the filter circuit is bypassed.