Various methods and devices that involve tuning filters are disclosed. A disclosed method for tuning a filter comprises trimming a center frequency of the filter. The method also comprises trimming an input signal magnitude of the filter. The method also comprises measuring a performance metric of the filter after trimming the center frequency of the filter and the input signal magnitude of the filter. The method also comprises repeating the trimming steps and the measuring step until the filter is tuned for a first physical test condition. A disclosed device that includes a filter also includes first and second trimming circuits that trim the center frequency and input signal magnitude of the filter. A disclosed system includes a motor to transfer a transmitting device from a first physical test condition to a second physical test condition relative to a proximity coupling device with a filter.

RF communications circuitry includes an RF filter structure, which includes a group of resonators, a group of cross-coupling capacitive structures, and a group of egress/ingress capacitive structures, is disclosed. Each of the group of cross-coupling capacitive structures is coupled between two of the group of resonators. A first portion of the group of egress/ingress capacitive structures is coupled between a first connection node and the group of resonators. A second portion of the group of egress/ingress capacitive structures is coupled between a second connection node and the group of resonators.

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.

An extensible filter structure is disclosed allowing realizable effective filtering over many decades in frequency. Multiple devices operating with mismatched frequency ranges can be multiplexed together with or without switching.

Apparatus and methods for high voltage variable capacitors are provided herein. In certain configurations, an integrated circuit (IC) includes a variable capacitor array and a bias voltage generation circuit that biases the variable capacitor array to control the array's capacitance. The variable capacitor array includes a plurality of variable capacitor cells electrically connected in parallel between a radio frequency (RF) input and an RF output of the IC. Additionally, each of the variable capacitor cells can include a cascade of two or more pairs of anti-series metal oxide semiconductor (MOS) capacitors between the RF input and the RF output. The pairs of anti-series MOS capacitors include a first MOS capacitor and a second MOS capacitor electrically connected in anti-series. The bias voltage generation circuit generates bias voltages for biasing the MOS capacitors of the variable capacitor cells.

A flexible multi-path RF adaptive tuning network switch architecture that counteracts impedance mismatch conditions arising from various combinations of coupled RF band filters, particularly in a Carrier Aggregation-based (CA) radio system. In one version, a digitally-controlled tunable matching network is coupled to a multi-path RF switch in order to provide adaptive impedance matching for various combinations of RF band filters. Optionally, some or all RF band filters include an associated digitally-controlled filter pre-match network to further improve impedance matching. In a second version, some or all RF band filters coupled to a multi-path RF switch include a digitally-controlled phase matching network to provide necessary per-band impedance matching. Optionally, a digitally-controlled tunable matching network may be included on the common port of the multi-path RF switch to provide additional impedance matching capability. In a third version, CA direct mapped adaptive tuning networks include filter tuning blocks for selected lower frequency bands.

An analog to digital conversion circuit of a touch screen computing device includes a plurality of analog to digital converter circuits operable to convert a plurality of analog signals into a plurality of digital signals at an oversampling rate, a digital decimation filtering module operable to convert the plurality of digital signals into a plurality of digital filtered signals at a first output rate, a coefficient processor operable to generate real component coefficients and imaginary component coefficients of a filtering function at a plurality of frequencies, a first bandpass filter circuit operable to produce first affect values at known frequencies of the plurality of frequencies, and a second bandpass filter circuit operable to produce second affect values at selected frequencies of the plurality of frequencies.

A wideband tunable combiner system for a dual frequency diversity transmitter is provided that includes a tunable capacitance network. Incoherent RF signals with the same audio signal may be combined with the system into a combined RF signal for transmission on an antenna. The tunable capacitance network, in conjunction with a combiner and a band pass filter, may optimize the isolation between the incoherent RF signals and reduce intermodulation, while maintaining a wide operating bandwidth. The capacitance value of the tunable capacitance network may be selected based on the frequencies of the incoherent RF signals, RF spectrum information, or antenna loading data. An RF transmitter including the tunable combiner system may have improved spectral efficiency and performance and take advantage of available spectrum.

A phase shifter includes a transformer connected between a first port and a second port and including a first coil and a second coil that is magnetically coupled to the first coil, the transformer including a parasitic inductance component; and an impedance adjustment circuit including a reactance element that suppresses a deviation in impedance due to the parasitic inductance component of the transformer. A coupling coefficient between the first coil and the second coil of the transformer and a value of the reactance element of the impedance adjustment circuit are determined such that a phase-shift amount changes in accordance with a frequency band.

An object is to provide a technique that can reduce the degradation in the characteristics of a transmitting filter by improving heat dissipation characteristics of a composite component having a stack structure. Since a transmitting filter is disposed in or on a first substrate 14, the heat generated in the transmitting filter is efficiently dissipated, for example, to an external module substrate 2 electrically connected to the first substrate 14. It is thus possible to reduce changes in the characteristics of the transmitting filter caused by a temperature rise. Thus, by improving heat dissipation characteristics of a composite component 10 having a stack structure, the degradation in the characteristics of the transmitting filter can be reduced.