When a plurality of RF signals having different freque bands are output at the same time by carrier aggregation, a switch element allows parallel connection between two capacitance elements such that a low pass filter has a first cut-off frequency that is lower than the frequency of an intermodulation distortion signal generated by the carrier aggregation. When an RF signal of a frequency band is output, the switch element releases parallel connection between the two capacitance elements such that the low pass filter has a second cut-off frequency that is higher than the first cut-off frequency.

When a plurality of RF signals having different frequency bands are output at the same time by carrier aggregation, a switch element allows parallel connection between two capacitance elements such that a low pass filter has a first cut-off frequency that is lower than the frequency of an intermodulation distortion signal generated by the carrier aggregation. When an RF signal of a frequency band is output, the switch element releases parallel connection between the two capacitance elements such that the low pass filter has a second cut-off frequency that is higher than the first cut-off frequency.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

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.

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 phase shifter for adjusting a phase shift between an input signal and output signal of the phase shifter includes: a first signal path between the input and the output; a second signal path between the input and the output; and a phase-shifter circuit configured to shift a phase of a first signal of the first signal path and a phase of a second signal of the second signal path by a constant phase angle relative to each other. The first and second signal paths each comprise a voltage-divider circuit connected to its respective signal path and configured to adjust an amplitude of a signal of the respective signal path. The output signal is based on a combination of the first signal and the second signal.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

Methods and system for using a multifunctional filter to minimize insertion loss in a multi-mode communications system are described. Specifically described is a multifunctional filter that is configurable to operate in a band-pass mode when a first type of signal is propagated through the multifunctional filter, and to operate in a low-pass mode when a second type of signal is propagated through the multifunctional filter. The multifunctional filter presents a lower insertion loss to the second type of signal when operating in the low-pass mode than in the band-pass mode.

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.

An apparatus and method for a frequency based integrated circuit that selectively filters out unwanted bands or regions of interfering frequencies utilizing one or more tunable notch or bandpass filters or tunable low or high pass filters capable of operating across multiple frequencies and multiple bands in noisy RF environments. The tunable filters are fabricated within the same integrated circuit package as the associated frequency based circuitry, thus minimizing R, L, and C parasitic values, and also allowing residual and other parasitic impedance in the associated circuitry and IC package to be absorbed and compensated.