A confined data communication system includes a reference generation circuit operable to produce one or more analog reference signals, an analog to digital converter circuit operable to process an analog signal to produce a digital representative signal, a digital filtering circuit operable to filter the digital representative signal to produce an affect value, a data processing module operable to interpret the affect value to produce processed output data, and a processing module operable to set frequency and waveform for each of the one or more analog reference signals, set digital filtering parameters for the digital filtering circuit, set a sampling rate for the analog to digital converter circuit, and set data interpretation parameters for the data processing module.

A method and apparatus for generating an RF signal uses digital signal components to generate a synthesized RF signal having a plurality of frequency components. An analog filter is used to filter the synthesized RF signal. The analog filter is a tunable, active feedback circuit having one or more variable resonators and a variable gain block connected in a signal loop that is defined by a passband. The analog filter is tuned such that the passband of the analog filter overlaps one or more desired frequency components of the plurality of frequency components of the synthesized RF signal, and such that the passband has a relative bandwidth of about 1% or less.

An acoustic wave device includes a piezoelectric substrate made of LiNbO.sub.3, and a dielectric film provided on the piezoelectric substrate to cover first and second IDT electrodes on the piezoelectric substrate. The first and second IDT electrodes include main electrode layers. When wave lengths determined by electrode finger pitches of the first and second IDT electrodes are .sub.1 and .sub.2, respectively, the average value thereof is .sub.0, .sub.1/.sub.0=1+X, and .sub.2/.sub.0=1X, a relationship of 0.05X0.65 is satisfied. The wavelength .sub.1 is the longest, and the wavelength .sub.2 is the shortest. In Euler angles (, , ) of the piezoelectric substrate, is 05, is 010, and satisfies Expression 1, wherein a relationship of B.sub.1<Tr0.10.sub.0 and B.sub.2<Tr0.10.sub.0 are satisfied.

In a multilayer filter, first to fourth resonant circuits are connected to an input/output portion. The input/output portion includes an input/output port group including an unbalanced port and a pair of balanced ports or an input/output port group including two pairs of balanced ports. Each of the first to fourth resonant circuits includes an inductor conductor and first and second capacitor conductors. The inductor conductor includes first and second ends. The first capacitor conductor is connected to the first end. The second capacitor conductor is connected to the second end. The second and third resonant circuits are magnetically coupled to each other. The second and third resonant circuits are arranged between the first resonant circuit and the fourth resonant circuit in a first direction. Each of first and second electrodes of a jump capacitor conductor is connected to the inductor conductors of the first and fourth resonant circuits.

A filter (10) has a first passband and a second passband on a higher frequency side than the first passband and includes a series arm circuit (11) and a parallel arm circuit (12), wherein the parallel arm circuit (12) includes a parallel arm resonator (p1) connected between a node (x1) and ground and having a resonant frequency frp located between a first passband and a second passband, an inductor (L1) connected between the node (x1) and the ground, and an inductor (L2) connected between the node (x1) and the ground and connected in series to the parallel arm resonator (p1), and a circuit in which the parallel arm resonator (p1) and the inductor (L2) are connected in series is connected in parallel to the inductor (L1).

The invention relates to a filter circuit which, on the hardware level, prevents charge transfers caused by one or more currents in a frequency divider (200) from generating an interference signal that can cause a signal distortion at the output of a current-to-voltage converter (300) belonging to a filter circuit. This signal distortion would otherwise have to be removed by means of laborious post-processing of the signal. In this process, the voltage curve at the input of the frequency divider (200) or the current at the second output of the frequency divider (200) are employed so that, by means of a compensation circuit arrangement, it is possible to model a compensation signal that essentially compensates for an interference signal caused by the charge transfers. The invention also relates to an associated method.

A trap filter includes a first inductor, a second inductor, and a capacitor. A first end of the first inductor extends to a first connection portion, a third end of the second inductor is connected to a second end of the first inductor, and a fourth end extends to a second connection portion. The capacitor is connected in parallel with the second inductor. The first inductor and the second inductor are subtractive-polarity coupled. An inductance value of the second inductor is less than an absolute value of mutual inductance generated by coupling of the first inductor and the second inductor.

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.

A tunable passband filter including a signal input port for receiving an input radio frequency (RF) signal, a signal output port for transmitting a filtered output RF signal, a first high-pass section having a first tunable microelectromechanical system (MEMS) switch array to receive the input RF signal from the signal input port, a second high-pass section having a second tunable MEMS switch array to transmit the output RF signal to the signal output port, and a low pass section operatively coupled between the first high-pass section and the second high-pass section, and having each of a first tunable MEMS bridge array, a second tunable MEMS bridge array, and a high impedance line. The tunable passband filter is configured to filter the input RF signal to yield the filtered output RF signal.

A high frequency amplification circuit includes transmission amplification circuits 11 and 12; a transmission filter D-Tx whose pass band is a band D of a first frequency band group; transmission filters E-Tx and G-Tx whose pass bands are respectively bands E and G of a second frequency band group; an output matching circuit 31 configured to match the transmission amplification circuit 11 and the transmission filter D-Tx; and an output matching circuit 32 configured to match the transmission amplification circuit 12 and the transmission filters E-Tx and G-Tx. The band D is positioned at a high frequency-side end portion of the first frequency band group, and the band E is positioned at a low frequency-side end portion of the second frequency band group. The output matching circuit 31 includes a low-pass circuit, and the output matching circuit 32 includes an impedance-variable circuit.