274results about "Single resonant circuit with varying inductance/capacitance only" patented technology

A method and apparatus for use in a digitally tuning a capacitor in an integrated circuit device is described. A Digitally Tuned Capacitor DTC is described which facilitates digitally controlling capacitance applied between a first and second terminal. In some embodiments, the first terminal comprises an FW+ terminal and the second terminal comprises an RF terminal. In accordance with some embodiments, the DTCs comprises a plurality of sub-circuits ordered in significance from least significant bit (LSB) to most significant bit (MSB) sub-circuits, wherein the plurality of significant bit sub-circuits are coupled together in parallel, and wherein each sub-circuit has a first node coupled to the first RF terminal, and a second node coupled to the second FW terminal. The DTCs further include an input means for receiving a digital control word, wherein the digital control word comprises bits that are similarly ordered in significance from an LSB to an MSB.

A tunable duplexer circuit is described, wherein the frequency response as well as bandwidth and transmission loss characteristics can be dynamically altered, providing improved performance for transceiver front-end applications. The rate of roll-off of the frequency response can be adjusted to improve performance when used in duplexer applications. A method is described where the duplexer circuit characteristics are optimized in conjunction with a specific antenna frequency response to provide additional out-of-band rejection in a communication system. Dynamic optimization of both the duplexer circuit and an active antenna system is described to provide improved out-of-band rejection when implemented in RF front-end circuits of communication systems. Other features and embodiments are described in the following detailed descriptions.

Disclosed is a high frequency apparatus which eliminates an influence of interfering signals. An interference-cut filter (24) for eliminating interfering signals is disposed between an input terminal (22) and a mixer (27). The interference-cut filter (24) is so controlled that it effectively demonstrates the function while the interfering signals are transmitted. Control of the interference-cut filter (24) is made by a switch (23), which is controlled by a selector switch controller (39), and the switch controller (39) is controlled responsive to an error correction counter (38) and a radio wave transmitted from a cellular telephone (40). This structure eliminates interference attributable to communication signals transmitted by the cellular telephone (40) and undesirable signals entering from the outside. The invention can thus realize high quality reception.

A tuning circuit for adjusting an oscillation frequency of an oscillator circuit. The tuning circuit comprises a film bulk acoustic wave resonator (FBAR) having a series resonance frequency and a parallel resonance frequency, and an inductor coupled in series or parallel with the film bulk acoustic wave resonator. The series connection of the inductor and FBAR decreases the series resonance frequency. The parallel connection of the inductor and the FBAR increases the parallel resonance frequency. The tuning circuit further comprises a varactor coupled in series or parallel with the inductor and the FBAR combination. The varactor tunes the oscillation frequency over the increased tuning range.

A method and apparatus for dynamically varying the impedance of a tank circuit whereby, over time, the response of the circuit to a received signal is maximized.

An LC tank structure. The structure, including a set of wiring levels on top of a semiconductor substrate, the wiring levels stacked on top of each other from a lowest wiring level nearest the substrate to a highest wiring level furthest from the substrate; an inductor in the highest wiring level, the inductor confined within a perimeter of a region of the highest wiring level; and a varactor formed in the substrate, the varactor aligned completely under the perimeter of the region of the highest wiring level. The structure may additionally include an electric shield in a wiring level of the set of wiring levels between the lowest wiring level and the highest wiring level. Alternatively, the inductor includes a magnetic core and alternating electrically non-magnetic conductive metal coils and magnetic coils around the core.

An integrated variable voltage diode capacitor topology applied to a circuit providing a variable voltage load for controlling variable capacitance. The topology includes a first pair of anti-series varactor diodes, wherein the diode power-law exponent n for the first pair of anti-series varactor diodes in the circuit is equal or greater than 0.5, and the first pair of anti-series varactor diodes have an unequal size ratio that is set to control third-order distortion. The topology also includes a center tap between the first pair anti-series varactor diodes for application of the variable voltage load. In preferred embodiments, a second pair of anti-series varactor diodes is arranged anti-parallel to the first pair of anti-series varactor diodes so the combination of the first pair of anti-series varactor diodes and the second pair of anti-series varactor diodes control second-order distortion as well.

An integrated center frequency selectable resonant coupling network suited for use in an integrated circuit is disclosed. The network includes an integrated coupling transformer having a secondary winding for coupling to a load and a primary winding for coupling to a source; a first integrated capacitive circuit controllably coupled across one of the primary and secondary windings and when so coupled operable to resonate with the integrated coupling transformer at a frequency in a first frequency band; and a second integrated capacitive circuit coupled across a second one of the primary and the secondary windings that is operable to resonate with the integrated coupling transformer at a frequency in a second frequency band. The method is in an IC and includes providing and coupling an input signal within alternatively a first frequency band and a second frequency band to a primary winding of an integrated coupling transformer; controlling an integrated switched capacitor network, coupled to the transformer, to provide a coupling network that is alternatively and respectively resonant at a first and second frequency within the first and second frequency band thus selectively providing an output signal at a secondary winding of the transformer; and down converting the output signal.

An anchor to hold getter materials in place within a micromechanical device package substrate. First and second cavity faces define an anchor cavity and mechanically retain a getter away from a region holding the micromechanical device. The getter anchor may be formed in a substrate comprised of at least three layers. The layers form a cavity in the substrate with a wide bottom portion—formed in the middle layer and a relatively narrower top portion—formed by the top layer. The narrow portion helps to retain the getter in the cavity by creating a mechanical lock on the wide portion of getter in the bottom of the cavity.

A resonant circuit tuning system and a method for tuning are provided. The resonant circuit tuning system may include a resonant circuit having a first capacitive element in series between a transmitter and an antenna coil and a second capacitive element in parallel with the transmitter and the antenna coil. At least one of the first capacitive element and second capacitive element may be configured to be varied. The resonant circuit tuning system also may include a controller for controlling a variable value of at least one of the first and second capacitive elements.

A tuner includes a plurality of paths, and at least one of the paths includes a front-end filter circuit, an amplifier, and a trace filter. The trace filter includes a varactor and an inductor, which are coupled to an output end of the amplifier. Further, the amplifier and the varactor of the tuner are packed in a complementary metal-oxide semiconductor (CMOS) chip.

A digitally adjustable inductive element which can be implemented in an integrated circuit. The digitally adjustable inductive element can include a first inductor, and a digital inductance controller operatively coupled to the first inductor which can be utilized to vary the effective inductance of the first inductor. The digitally adjustable inductive element can include a second inductor operatively coupled to the first inductor, and a digital current controller operatively coupled to the second inductor. The digital current controller can include a number of transistors operatively coupled to the second inductor. The digitally adjustable inductive element can be utilized to create a tunable oscillator. The tunable oscillator can include a first inductor, a digital inductance controller operatively coupled to the first inductor which can be utilized to vary the effective inductance of the first inductor, and an oscillator circuit which generates an oscillating signal utilizing the effective inductance of the first inductor. The tunable oscillator can include a second inductor operatively coupled to the first inductor, and a digital current controller operatively coupled to the second inductor. The digital current controller can include a number of transistors operatively coupled to the second inductor.

A linear voltage controlled capacitance circuit is provided that includes a plurality of MOS varactor pairs. Each MOS varactor pair is operable to receive a first tuning voltage, a second tuning voltage, and a bias voltage unique to the MOS varactor pair. The capacitance circuit is operable to generate a positive tank node signal and a negative tank node signal based on the first and second tuning voltages and the bias voltages. A means to control voltage-to-capacitance gain is also provided to compensate for coarse tuning capacitance change.

Embodiments may be used to control a controllable element that has a nonlinear but monotonic relationship with a control value. In such embodiments, a system may perform control by receiving an error value corresponding to an error of an output signal from the controllable element, and determining the control value within two iterations of a Newton (Secant) algorithm, where the control value enables generation of the output signal within a predetermined tolerance to a nominal value for the control signal.

A tuning apparatus is provided, wherein the on and off resistances of semiconductor switches within an tuning IC are optimized, so as to provide high sensitivity and superior stability, a wide range of tuned frequency variation, compactness and high performance. The tuning apparatus has a tuning circuit, which has N-channel MOS transistors (N transistors) 5a through 5f, serving as a plurality of semiconductor switches, and a counter circuit 6, which controls the opening and closing of the N transistors, a plurality of capacitors 4a through 4f, which are each connected in series with the plurality of N transistors, and a receiving antenna 2 wherein the total electrostatic capacitance of the plurality of capacitors is varied by the opening and closing of the plurality of N transistors, thereby varying the frequency tuned by the plurality of capacitors and the receiving antenna.

A system for processing a signal comprises a Radio Frequency (RF) signal tuner, one or more filters in a signal path of the RF tuner each based on Inductive / Capacitive (LC) circuitry, a variation unit operable to measure a variation of the LC circuitry, and a frequency control unit adapted to adjust the one or more filters based on the LC variation during operation of the tuner.

A passive transponder includes an antenna, an antenna oscillator circuit and a data source. The antenna oscillator circuit is configured to operate at a first resonant frequency or at a second resonant frequency, depending on reception of energy at the transponder or on a data transmission from / to the data source.

A method and apparatus for manufacturing thin RFID tags adapted to be mounted proximate an interfering substance, such as metal or liquid. Each tag comprises: a web substrate having a predetermined thickness; an antenna attached to the substrate; and an RFID integrated circuit connected to the antenna, the RFID integrated circuit comprising a tank circuit adapted to be tuned in response to an RF signal after the tag has been mounted proximate the interfering substance. In one embodiment, the tag is manufactured using roll-to-roll manufacturing technology.

A tunable capacitor device may be provided in accordance with example embodiments of the invention. The tunable capacitor device may include a first capacitor; a second capacitor; a third capacitor, where the first, second, and third capacitors are connected in series, wherein the second capacitor is positioned between the first capacitor and the second capacitor; and at least one switch transistor, where the at least one switch transistor is connected in parallel with the second capacitor.

A method and apparatus for dynamically varying the impedance of a tank circuit whereby, over time, the response of the circuit to a received signal is maximized.

An embodiment of the present invention provides an apparatus, comprising at least one anti-parallel pair VVC network comprised of two parallel VVCs with one biased in the opposite polarity of the other and at least one anti-series VVC network comprised of two VVCs configured in series, one biased in the opposite polarity of the other such that the resulting AC capacitive variations produce a desired capacitance variation.

The present invention provides a semiconductor integrated circuit capable of reducing a chip occupied area and reducing variations in control gain of a digitally controlled oscillator (DCO). The semiconductor integrated circuit is equipped with the digitally controlled oscillator (DCO). The digitally controlled oscillator (DCO) comprises oscillation transistors (NM1, NM2) and a resonant circuit (20). The resonant circuit (20) comprises inductances (L11, L12), a frequency coarse-tuning variable capacitor array (CCT11) and a frequency fine-tuning variable capacitor array (CFT11). The frequency coarse-tuning variable capacitor array (CCT11) comprises a plurality of coarse-tuning capacitor unit cells (CCT0, CCT1...). The frequency fine-tuning variable capacitor array (CFT11) comprises a plurality of fine-tuning capacitor unit cells (CFT0, CFT1...). The capacitance values of the coarse-tuning capacitor unit cells of the frequency coarse-tuning variable capacitor array (CCT11) are set in accordance with a binary weight 2M-1. The capacitance values of the fine-tuning capacitor unit cells of the frequency fine-tuning variable capacitor array (CFT11) are also set in accordance with a binaryweight 2N-1.

A method and apparatus for detecting RF field strength. A field strength reference generator develops a field strength reference current as a function of a field strength of a received RF signal; and a field strength quantizer develops a digital field-strength value indicative of the field strength reference current. In one embodiment, detected field strength is used to dynamically vary the impedance of a tank circuit whereby, over time, induced current is maximized. In another embodiment, using the quantized field strength to sense changes to the environment to which the RFID tag is exposed.

A method and apparatus for detecting RF field strength. A field strength reference generator develops a field strength reference current as a function of a field strength of a received RF signal; and a field strength quantizer develops a digital field-strength value indicative of the field strength reference current. In one embodiment, detected field strength is used to dynamically vary the impedance of a tank circuit whereby, over time, induced current is maximized. In another embodiment, using the quantized field strength to sense changes to the environment to which the RFID tag is exposed.

A broadband tuner includes a tracking filter with calibration to compensate for component errors and drift. The filters use off-die inductors that are preferably within a system-in-package (SIP) with other critical tuner components, which produces a highly integrated tuner front end with high Q filters within a single package. High voltage varactors with a large tuning range can be used for variable capacitors. The integration of the tuner into a SIP allows the tuner design to be optimized for cost and performance while keeping the critical RF layout requirements within the tuner. A configurable tuner front end enables modes for low noise, high linearity, good input return loss (S11) across the entire RF band, and applying a test tone in the calibration mode. The switchable mode enables the tuner to be effective during weak terrestrial reception, strong terrestrial reception, and connection to a cable plant.

A tunable capacitance unit coupled between a pair of circuit nodes. The tunable capacitance unit comprises a tuning input supplying a tuning voltage, and first and second tuning capacitance units. Each of the tuning capacitance units comprises a pair of accumulation-mode MOS varactors with source / drains thereof coupled to the tuning input, a pair of blocking capacitors coupled to a respective gate of the accumulation-mode MOS varactors and to a respective one of the circuit nodes, and a pair of biasing resistors coupled to a respective gate of the accumulation-mode MOS varactors and to a respective bias terminal receiving a respective reference voltage. The reference voltages received by the first and second tuning capacitance units are symmetrical to a predetermined voltage.

A frequency multiplier and amplification circuit are disclosed. One embodiment of the present invention comprises: a multiplier operably coupled to multiply a first sinusoidal waveform having a first frequency with a second sinusoidal waveform having a second frequency to produce a third sinusoidal waveform, having a frequency representative of a difference between the first frequency and the second frequency, and a fourth sinusoidal waveform having a frequency representative of a sum of the first and second frequencies; and a frequency-tuned load operably coupled to substantially attenuate the third sinusoidal waveform and to substantially pass the fourth sinusoidal waveform as an output of the frequency-tuned multiplier circuit. The frequency-tuned multiplier circuit can be a single-ended multiplier circuit or a differential multiplier circuit with corresponding single-ended or differential first and second sinusoidal waveforms.