A tunable dual-band resonator and a tunable dual-band band-pass filter using the tunable dual-band resonator. The dual-band resonator is structured such that a stub is added to each half-wavelength resonator provided with half-wavelength resonator protrusions (capacity-component adjust parts). The dual-band resonator is made up of an odd-number mode resonator in a shape including a ground conductor disposed on the back surface of a dielectric body, and a strip conductor disposed on the top surface thereof, and an even-number mode resonator in such a shape as to be formed when the stub is connected to an end face on the opposite side of the open-end of the strip, characterized in that a dielectric rod having a circular cross section is provided in the space above the respective stubs and another dielectric rod having a circular cross section is provided in the space above the half-wavelength resonator protrusions.

An electronic device capable of bandwidth compensation includes a register unit for storing a calibration code determined by performing an on-die termination (ODT) calibration process and a data receiving circuit, wherein the calibration code is utilized for controlling a termination resistance of an ODT unit. The data receiving circuit comprises a first control circuit coupled to the register unit and the active low-pass filter for generating a first control signal according to the calibration code stored in the register unit, the first control signal being utilized for adjusting a capacitance of a first feedback capacitor unit or a resistance of a first feedback resistor unit of an active low-pass filter.

The present disclosure provides an integrating circuit and a signal processing module. The integrating circuit comprises an operational amplifier; an integrating capacitor, coupled to an output terminal and a first input terminal of the operational amplifier; and an adjustable resistance module, coupled between the first input terminal of the operational amplifier and an integrating input terminal of the integrating circuit. The adjustable resistance module receives a plurality of first control signals, to adjust a resistance value of the adjustable resistance module. The present disclosure may realize the noise brought by sidelobe to enhance the SNR, and reduce the power consumption and complexity of the overall circuit.

A programmable resistor can provide discrete logarithmic (linear-in-dB) gain control. It can include multiple like programmable resistor subnetworks or cells, such as can be connected in parallel, such as according to a decoding scheme. The subnetworks can be configured to cover a subrange such as [0 dB, 6 dB) relative to the maximum resistance value. Coarse increments of 6 dB can be further added to this range by successively doubling the number of subnetworks that are connected in parallel. An additional decoder help ensure a linear control curve, free of dead zones or other nonlinearities. The programmable resistor can be suitable for use in such circuits as programmable-gain amplifiers, filters, or more complex networks, such as where the resistance can be programmed as a function of a digital code. An example including a tuning circuit for a variable gain active filter is described.

A tunable multi-path filter, a method for filtering a radio frequency signal with the tunable multi-path filter, and a communication device including the tunable multi-path filter. In one embodiment, the tunable multi-path filter includes a voltage controlled current source, an oscillator source, and at least two filter paths. The voltage controlled current source for receiving a radio frequency (RF) signal and generating a current signal. The oscillator source for generating a tunable clock signal. Each of the at least two filter paths are coupled to the voltage controlled current source and the oscillator source, and are configured to generate an output voltage signal based at least in part on the current signal and the tunable clock signal. In some embodiments, the tunable multi-path filter further includes a carrier signal rejection component that is configured to reduce the carrier feedthrough in the output voltage signals.

A circuit component that is adjustable at run time and a method of designing the circuit are disclosed. The component contains a hierarchy of recursive levels in which a bottom level is a compound element made from two connected simple elements, and each higher level contains two compound elements connected in the same fashion. The described circuit allows for a large number of available values of the component value to be arranged in a logarithmic fashion rather than a linear one as in the prior art, thus generally reducing errors between any desired value for the component and the available values. In addition, such compound elements reduce the power dissipated by the analog element and the susceptibility to noise as compared to prior art adjustable components without adversely affecting the overall gain of the circuit.

A device includes a controller and an adaptive continuous-time filter that includes a control input and a first array of elements. The controller generates a digital word responsive to a time constant and compares a select bit of the digital word to a corresponding reference word to generate a control bit. The controller includes a duplicate array of elements, and applies the control bit to an adjustable element of the duplicate array of elements to modify the time constant. The controller provides the output word to the control input of the adaptive continuous-time filter to generate a filter response that accounts for effects of semiconductor process variation in the first array of elements.

Certain aspects of the present disclosure provide methods and apparatus for calibrating a tunable active filter. One example apparatus is a filter circuit that generally includes a tunable active filter comprising at least one amplifier and a first feedback path coupled between an input and an output of the at least one amplifier, the first feedback path comprising at least one switch; and an amplitude limiter coupled to the tunable active filter and comprising at least one transistor disposed in a second feedback path coupled between the input and the output of the at least one amplifier.

A circuit and method for lowering noise in an audio rendering system is described. An analysis is made of the spectral content of an audio signal, i.e., the frequencies it contains, over a certain time interval. Cutoff frequencies of high pass and low pass filters that pass the audio signal are then adjusted for each interval by changing the effective values of adjustable impedance elements in the filters, so that the bandwidth of the system is adjusted to be what is sufficient to pass any frequencies in the resulting analog audio signal during any given time interval, rather than requiring the entire 20 kHz audio spectrum to be constantly present.

A circuit component that is adjustable at run time and a method of designing the circuit are disclosed. The component contains a hierarchy of recursive levels in which a bottom level is a compound element made from two connected simple elements, and each higher level contains two compound elements connected in the same fashion. The described circuit allows for a large number of available values of the component value to be arranged in a logarithmic fashion rather than a linear one as in the prior art, thus generally reducing errors between any desired value for the component and the available values. In addition, such compound elements reduce the power dissipated by the analog element and the susceptibility to noise as compared to prior art adjustable components without adversely affecting the overall gain of the circuit.