An improved sliding discrete Fourier transform (SDFT) algorithm called CIC-SDFT and its apparatus are provided. An input signal is multiplied by a modulated twiddle factor, and is then processed by a modified cascade integrator-comb (CIC) filter. The CIC-SDFT comprises an integrator section and a comb section, with a downsampler disposed between the two sections to enable downsampling of the SDFT computations. Through addition of more integrator stages and comb stages to the CIC-SDFT, the accuracy of spectrum estimation may be improved in a computationally inexpensive manner and with less complexity than applying windowing functions to known SDFTs. Various embodiments provide a partially-nonrecursive method of CIC-SDFT that further decreases computational complexity.

An analog-to-digital converter (ADC) includes a modulator configured to oversample an input signal generated from an output signal of a transducer; and a filter configured to perform a decimation operation on an output from the modulator and a frequency characteristics correction operation according to a filter control signal on the output from the modulator, wherein the frequency characteristics correction operation is performed to complement a frequency characteristics of the output signal of the transducer such that overall frequency characteristics of the transducer and the filter be flat in a signal band.

A cascaded integrator-comb (CIC) decimation filter includes N integrator stages, N1 differentiator stages, and a decimator coupled to receive an integrated signal that is output from the N integrator stage and generate a decimated signal that is input to the N1 differentiator stages. The decimator periodically asserts an integration reset signal. A last integrator stage of the N integrator stages is reset in response to assertion of the integration reset signal.

A power conversion apparatus can include: a power module configured to transfer an analog sensing signal corresponding to a current of an inductor and a voltage applied at both terminals of a capacitor, and to perform power conversion by driving a power semiconductor with a pulse-width modulation signal; and a controller configured to receive the analog sensing signal from the power module, to convert the analog sensing signal to a digital signal, to generate the pulse-width modulation signal, and to transfer the pulse-width modulation signal to the power module.

A digital filtering method includes receiving a digital signal, and passing the digital signal through a Pth order comb cascade. The method includes beginning pre-computing of intermediate integrator states of a Pth order integrator cascade as a function of the digital signal, prior to receiving output from a last comb of the Pth order comb cascade. The outputs from each comb of the Pth order comb cascade are then applied to the pre-computed intermediate integrator states to thereby produce a filtered version of the digital signal. The Pth order comb cascade may operate at a sampling frequency, and the pre-computing of the intermediate integrator states is performed at the sampling frequency, while the application of the outputs from each comb of the Pth order comb cascade to the pre-computed intermediate integrator states is performed at a multiple of the sampling frequency.

Filters are discussed where a first window function and a second window function are applied to a digital input signal, wherein a window length of the first window function is longer than a window length of the second window function. The results of this windowing are integrated.

A method, an apparatus and a device for simultaneously sampling multiples signals and a medium are provided. The method includes: modulating multiple target input signals with CDM, to obtain a single target analog signal; performing ?? modulation on the single target analog signal to obtain a target digital bit stream; demodulating the target digital bit stream to obtain a target demodulated bit stream; and filtering the target demodulated bit stream to obtain multiple target output signals. With the method, the hardware overhead for simultaneous sampling of multiple-channel signals is reduced while ensuring accuracy. Accordingly, the apparatus and the device, and the medium have the above beneficial effects.

A digital frequency measuring apparatus includes a frequency divider dividing an input frequency signal and providing a divided frequency signal; a period counter counting clock cycles in a period of the divided frequency signal using a clock signal and providing a period count value for each period; and a digital filter amplifying the period count value using an accumulated gain, converting an amplified period count value into a frequency, and providing a first digital output value. The digital filter determines the accumulated gain using a predetermined stage number and a predetermined decimator factor.

A communication system using adaptive sample rate reduction (ASRR) is disclosed. The system includes a digital front end (DFE) and a radio frequency (RF) interface. The DFE is configured to receive a baseband signal, identify reduced performance parameters for the baseband signal, reduce a sampling rate for the baseband signal based on the reduced performance parameters and generate a digital interface signal using the reduced sampling rate. The RF interface is configured to generate an analog TX signal from the digital interface signal.

Aspect of the present disclosure provide for a circuit. In an example, the circuit comprises a multiplexer having a first input, a second input, a control input, and an output. The circuit further comprises a first register having an input coupled to the output of the multiplexer and an output. The circuit further comprises a second register having an input coupled to the output of the first register and an output. The circuit further comprises a subtractor having a first input coupled to the output of the multiplexer and a second input coupled to the output of the second register. The circuit further comprises a third register having an input coupled to the output of the subtractor and an output coupled to the first input of the multiplexer.