A sensor circuit is provided with a chopper-stabilized amplifier circuit configured to receive a signal from at least one magnetic sensing element, a sigma-delta modulator (SDM) configured to receive a signal from the chopper-stabilized amplifier circuit, and a feedback circuit configured to reduce ripple in a signal generated by the chopper-stabilized amplifier circuit. The feedback circuit includes a demodulator to demodulate a signal from the SDM in a digital domain by inverting a bit stream of the signal from the SDM according to a frequency chopping rate, a digital integrator configured to integrate an output signal of the demodulator to form an integrated signal, and a digital-to-analog converter (DAC) configured to convert the integrated signal to an analog signal and provide the analog signal to the chopper-stabilized amplifier circuit.

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.

A high order filter circuit is integrated by a plurality of the low order filter circuits. Before correcting the high order filter circuit, switch units may restore the high order filter circuit to the low order filter circuits for correction, and then combine the corrected low order filter circuits to form the original high order filter circuit.

A low order filter circuit having a frequency correction function, a frequency correction method for a low order filter circuit, and a high order filter circuit are provided. An analog to digital converter (ADC) may detect a peak of a signal processed by a second order filter unit, and after comparison and determination are performed by a digital correction unit, a frequency control signal is outputted as a feedback to a notch filter or a band-pass filter in the second order filter unit where frequency adjustment is performed. The high order filter circuit is integrated by a plurality of the low order filter circuits. Before correcting the high order filter circuit, switch units may restore the high order filter circuit to the low order filter circuits for correction, and then combine the corrected low order filter circuits to form the original high order filter circuit.

Disclosed herein, among other things, are systems and methods for reducing the comb filtering for hearing devices. A method includes determining an effective time delay as a function of frequency between a direct path from a sound source to an eardrum of a wearer of a hearing device and an amplified path from the sound source through the hearing device to the eardrum of the wearer, and calculating a set of cancellation frequencies based at least in part on the determined effective time delay. The method also includes comparing an aided gain response and a real-ear occluded gain response of the hearing device, and determining one or more spectral interaction regions based at least in part on the comparison. A subset of cancellation frequencies is determined by comparing the spectral interaction regions with the set of cancellation frequencies, and a filter is constructed using the subset of cancellation frequencies and a determined attenuation configured to reduce comb filtering.

A notch filter appropriately adjusts the amount of attenuation at a center frequency of its notch band through changing or adjusting a value of an adjustable parameter A, and adaptively controls the amount of signal attenuation of a predetermined frequency component for an input signal that passes the notch filter, so as to partially suppress or partially attenuates the predetermined frequency component without affecting the size of a bandwidth of the notch filter.

The invention relates to a signal processing device, a signal processing method, an information processing program and a recording medium, which removes wide-range frequency noise. In a signal processing device (10), a cycle of acquiring a signal from a sensor is a data acquisition cycle, which is shorter than a cycle of forwarding time sequence data from which noise is removed to a controller, that is, a forwarding cycle.

A digital filter includes integrator circuits configured to operate based on a clock of a sampling frequency f.sub.S that is equal to a sampling frequency of input data and determine a sum of the input data on a sample-by-sample basis, a frequency converter circuit configured to perform decimation on data of the sampling frequency f.sub.S to reduce the sampling frequency f.sub.S to a sampling frequency f.sub.D=f.sub.S/N, one or more differentiator circuits configured to operate based on a clock of the sampling frequency f.sub.D and subtract data of an immediately preceding sample from the input data, a differentiator circuit for removal of 50 Hz configured to operate based on the clock of the sampling frequency f.sub.D and subtract, from the input data, data preceding the input data by a plurality of samples, and a differentiator circuit for removal of 60 Hz configured to operate based on a clock of the sampling frequency f.sub.D and subtract, from the input data, data preceding the input data by a plurality of samples.

An interference removal filter that includes a combination of a first filter and a second filter, where the first filter passes signals over a frequency range of size B with a variation of less than +/3 dB, where the peak value of the impulse response of the second filter is displaced in time from the peak value of the impulse response of the first filter by at least 2/B time units, and where the combination of the first filter and the second filter produces a notch in frequency at a frequency location within the frequency range.

A low order filter circuit having a frequency correction function, a frequency correction method for a low order filter circuit, and a high order filter circuit are provided. An analog to digital converter (ADC) may detect a peak of a signal processed by a second order filter unit, and after comparison and determination are performed by a digital correction unit, a frequency control signal is outputted as a feedback to a notch filter or a band-pass filter in the second order filter unit where frequency adjustment is performed. The high order filter circuit is integrated by a plurality of the low order filter circuits. Before correcting the high order filter circuit, switch units may restore the high order filter circuit to the low order filter circuits for correction, and then combine the corrected low order filter circuits to form the original high order filter circuit.