An automatic filtering method includes: a step of analyzing an input signal so as to obtain a frequency spectrum of the input signal; and a step of selecting, on the basis of the frequency spectrum, at least one filter from among a plurality of preset filters and filtering the input signal. The step of selecting includes determining, on the basis of the frequency spectrum of, a signal type in the input signal; selecting, on a basis of the signal type, a corresponding filter corresponding to the signal type; filtering the input signal with use of a first parameter of the corresponding filter and setting a second parameter for the corresponding filter on a basis of a result of the filtering; and filtering the input signal with use of the second parameter set for the corresponding filter. The method may ensure a filtering effect against noise.

A data storage device is disclosed comprising a head actuated over the disk. A first notch filter is calibrated at a first temperature, and a second notch filter is computed for a second temperature based on the first notch filter and a first delta temperature between the first temperature and the second temperature. The second notch filter is computed by transforming a continuous-time transfer function of the first notch filter adjusted by the first delta temperature into a discrete-time transfer function of the second notch filter.

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.

A radio communication receiver and a method performed by the radio communication receiver for configuring a Notch filter of the radio communication receiver. The method comprises retrieving stored and previously determined filter coefficients from a set of filter coefficients, where the retrieved filter coefficients constitute a fraction of the total number of filter coefficients; and setting the rest of the filter coefficients to one. The method further comprises normalising the retrieved filter coefficients; and transforming the filter coefficients such that the Notch position ends up at the one or more frequencies to be filtered out.

An automatic filtering method and device includes a step of analyzing an input signal so as to obtain its frequency spectrum; and a step of selecting, on the basis of the frequency spectrum, at least one filter from among a plurality of preset filters and filtering the input signal. The method and device automatically use a suitable filter on the basis of the frequency spectrum and repeat simulation of automatic fine adjustment to ensure a filtering effect against noise.

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.

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 method for compensating the bandedge ripple of an analog filter, using a circuit comprising a low pass filter is described. The method comprises receiving, at the analog filter, a plurality of tones of different frequencies from a tone generator, measuring, an amplitude of each tone in the plurality of tones after each tone is processed by the analog filter, storing the measured amplitudes and frequencies in a database, measuring a bandedge ripple by measuring a difference in amplitude between a first tone and a second tone from the plurality of tones, and selecting a low pass filter, from a plurality of low pass filters, based on the measured difference.

To suppress an unstable operation of a device caused by filtering, an output selection unit is configured to acquire an unfiltered value representing an input signal (signal before filtering) stored in an input holding unit, a filtered value representing a signal acquired by filtering the input signal by a filtering unit, and a previous output value representing an output signal output at a previous time, select a middle value out of the filtered value, the unfiltered value, and the previous output value, and set the selected middle value as a current output value of an output signal.

A radio communication receiver and a method performed by the radio communication receiver for configuring a Notch filter of the radio communication receiver. The method comprises retrieving stored and previously determined filter coefficients from a set of filter coefficients, where the retrieved filter coefficients constitute a fraction of the total number of filter coefficients; and setting the rest of the filter coefficients to one. The method further comprises normalising the retrieved filter coefficients; and transforming the filter coefficients such that the Notch position ends up at the one or more frequencies to be filtered out.