193results about "Discontinuous tuning for band selection" patented technology

A gain compensator compensates for the gain variation of a varactor-tuned voltage tuned oscillator (VCO) in a phase lock loop (PLL). The VCO includes a parallel LC circuit having multiple fixed capacitors that can be switched-in or switched-out of the LC circuit according to a capacitor control signal to perform band-select tuning of the VCO. The gain compensator compensates for the variable VCO gain by generating a charge pump reference current that is based on the same capacitor control signal that controls the fixed capacitors in the LC circuit. The gain compensator generates the charge pump reference current by replicating a reference scale current using unit current sources. The number of times the reference scale current is replicated is based on the fixed capacitance that is switched-in to the LC circuit and therefore the frequency band of the PLL. The reference scale current is generated based on a PLL control that specifics certain PLL characteristics such as reference frequency, loop bandwidth, and loop damping. Therefore, the reference pump current can be efficiently optimized for changing PLL operating conditions, in addition to compensating for variable VCO gain.

A system incorporating the subject disclosure may include, for example, a method including determining, by a communication device comprising a processor, a usage state of the communication device. The communication device includes selectable antennas, and the usage state includes an orientation of the communication device. The method also includes selecting a set of antennas according to the usage state, and obtaining an antenna gain pattern for an antenna in the selected set of antennas. The method further includes evaluating an expected performance of an antenna configuration corresponding to the selected set of antennas, relative to a performance of an existing antenna configuration. The method also includes initiating usage of the antenna configuration in accordance with improved performance relative to the existing antenna configuration. The antenna configuration comprises a polarization configuration, and the selected set of antennas comprises elements in different planes. Other embodiments are disclosed.

A RF front-end having two antenna switches operatively connected to two separate antennas. The antenna switches can be used to route various transmit and receive paths to the antennas. In particular, one of the antenna switches has three switch position for use in selectively routing the 2 GHz receive paths, and another antenna switch has six switch positions for use in selectively routing the 2 GHz transmit paths and the 1 GHz signal paths. With the disclosed topology, the front-end can be used to support GSM and W-CDMA communications in many regional variants in the world. The supported variants include US1, US2, EU1, EU2 and EU / US modes. The same front-end can also be used in BT / WLAN connectivity. For MIMO purposes, one more antenna switch for the 2 GHz receive paths can be added to the same RF front-end.

A tuner circuit includes a band selection filter coupled to receive an input RF signal and provide a band selected output signal where the band selection filter includes a bank of band pass filters. Each band pass filter includes an inductor and a variable capacitor forming an LC resonator where the inductor is an integrated planar spiral inductor. The tuner circuit further includes a frequency conversion circuit coupled to receive an input signal corresponding to the band selected output signal and provide a frequency converted output signal having a predetermined frequency. The integrated planar spiral inductor can be formed using a single metal spiral or multiple metal spirals. In a multi-spiral structure, a first metal spiral having an inward spiral pattern and a second metal spiral having an outward spiral pattern to form an inductor with large inductance, low series resistance and high Q values, even at low frequency.

A RF front-end having two antenna switches operatively connected to two separate antennas. The antenna switches can be used to route various transmit and receive paths to the antennas. In particular, one of the antenna switches has three switch position for use in selectively routing the 2 GHz receive paths, and another antenna switch has six switch positions for use in selectively routing the 2 GHz transmit paths and the 1 GHz signal paths. With the disclosed topology, the front-end can be used to support GSM and W-CDMA communications in many regional variants in the world. The supported variants include US1, US2, EU1, EU2 and EU / US modes. The same front-end can also be used in BT / WLAN connectivity. For MIMO purposes, one more antenna switch for the 2 GHz receive paths can be added to the same RF front-end.

A wideband RF tracking filter having a set of parallel tuned resonator amplifier stages with a de-Q resistor for each subband is disclosed. The resonant amplifier contains programmable tuned LC tank impedance and an array of parallel voltage to current converters (V2I) for each subband. The de-Q resistor together with the array of V2I converters provides a flat gain over each subband and each of the other subbands covering different frequencies.

A tunable receiver is disclosed including a plurality of select filters to perform an initial band selection, a variable-gain low noise amplifier (LNA) whose gain is controlled to prevent its output power level to exceed a pre-determined power threshold, a plurality of digitally-tunable tracking filters to pass signals within a selected channel and to reject signals in a corresponding image band, a second LNA to further amplify the received RF signal and to generate differential signal outputs, a down converting stage which converts the received RF signal to an IF signal while rejecting signals in the image band, an IF trap to further reject undesired signals present at the output of the down converting stage, an IF amplifier to amplify the IF signal to compensate for losses, an IF filter to provide channel select and reject undesirable signals, and a variable-gain IF amplifier to amplify the IF signal and maintain its power level within specification.

A multiport RF switch assembly with integrated impedance tuning capability is described that provides a single RFIC solution to switch between transmit and receive paths in a communication system. Dynamic tuning is integrated into each switch sub-assembly to provide the capability to impedance match antennas or other components connected to the multiport switch. The tuning function at the switch can be used to shape the antenna response to provide better filtering at the switch / RF front-end (RFFE) interface to allow for reduced filtering requirements in the RFFE. Memory is designed into the multiport switch assembly, allowing for a look-up table or other data to reside with the switch and tuning circuit. The resident memory will result in easier integration of the tunable switch assembly into communication systems.

A tunable receiver is disclosed including a plurality of select filters to perform an initial band selection, a variable-gain low noise amplifier (LNA) whose gain is controlled to prevent its output power level to exceed a pre-determined power threshold, a plurality of digitally-tunable tracking filters to pass signals within a selected channel and to reject signals in a corresponding image band, a second LNA to further amplify the received RF signal and to generate differential signal outputs, a down converting stage which converts the received RF signal to an IF signal while rejecting signals in the image band, an IF trap to further reject undesired signals present at the output of the down converting stage, an IF amplifier to amplify the IF signal to compensate for losses, an IF filter to provide channel select and reject undesirable signals, and a variable-gain IF amplifier to amplify the IF signal and maintain its power level within specification.

A dual band RF tuning circuit (1) has a first impedance element (4) and a second impedance element (5) between an RF input port (2) and an RF output port (3), tuning being provided by the impedance elements (4, 5) to a first RF signal, and a switching transistor (9) connected to the second impedance element (5) to open circuit the second impedance element (5) for tuning to a second RF signal by the first impedance element (4) alone.

The present invention provides a radio frequency identification tag reader system, that comprises a radio frequency identification tag reader that outputs a drive signal at a predetermined frequency at which a radio frequency tag operates, an antenna that receives the drive signal and radiates an electromagnetic field in response to the drive signal, a tuning circuit disposed between the reader and the antenna so that the drive signal passes through the tuning circuit, wherein the tuning circuit has at least one component that defines a selectable, variable electrical characteristic that selects a resonant frequency of the antenna, a sensor circuit in communication with the antenna so that the sensor circuit detects a response by the antenna to the drive signal and outputs a sensor signal that corresponds to power of an electromagnetic field radiated by the antenna in response to the drive signal, and a processor in communication with the tuning circuit so that the processor controls the selectable component, and wherein the processor receives the sensor signal and sets the variable electrical characteristic in response to the sensor signal.

A method that incorporates the subject disclosure may include, for example, obtaining, by a first base station comprising a processor, information regarding a trajectory of a communication device. The method can also include determining a location of the communication device relative to a second base station. The method can also include transmitting a recommendation to the communication device regarding adjusting an antenna configuration of the communication device to facilitate data communication services with the second base while maintaining voice communications services with the first base station. Other embodiments are disclosed.

A system that incorporates the subject disclosure may include, for example, a circuit for receiving a request to initiate a first multiple-input and multiple-output (MIMO) communication session and a second MIMO communication session, and configuring a first antenna configuration and a second antenna configuration to enable the first MIMO communication session and the second MIMO communication session. The first MIMO communication session shares spectrum from the first antenna configuration and the second antenna configuration, and the second MIMO communication session utilizes spectrum from the second antenna configuration that differs from the shared spectrum. Other embodiments are disclosed.

There is provided a television tuner which is small and inexpensive, so that although a television signal and an FM broadcast signal have different electric field strengths in band and signal, one circuit can receive both the television signal and the FM broadcast signal. A television signal is frequency-converted to the intermediate-frequency band of a television. An FM broadcast signal is frequency-converted to a voice intermediate frequency in the intermediate-frequency band. A first parallel tuned circuit and a second parallel tuned circuit are connected in parallel with each other in an intermediate-frequency tuned circuit. When the television signal is received, the television signal is tuned to a broad band by only the first parallel tuned circuit. When the FM broadcast signal is received, the FM broadcast signal is tuned to a narrow band by the first parallel tuned circuit and the second parallel tuned circuit.

A TV signal receiving tuner which is small in size and inexpensive due to a reduced number of local oscillators. In the TV signal receiving tuner, a local oscillation signal output from a local oscillator is directly applied to a first mixer through a first programmable divider to receive a UHF TV signal, the local oscillation signal output from the local oscillator is applied to the first mixer after its frequency is divided to 1 / 3 by the first programmable divider to receive a VHF high-band TV signal, and the local oscillation signal output from the local oscillator is applied to the first mixer after its frequency is divided to 1 / 5 by the first programmable divider to receive a VHF low-band TV signal.

An integrated circuit (IC) structure and method of distributing multiple broadband signal inputs to multiple integrated circuits, where each IC receives at least one original signal and outputs a replica of the original signals to other ICs and receives at least one replica signal output by another IC.

A multiple-mode receiver incorporating direct conversion (processing received signals using intermediate frequencies within the same frequency range as the received signal bandwidth) rather than superheterodyne circuitry, allowing receiver hardware components to be re-used rather than replicated for each band. Various embodiments are disclosed in which low pass filters, mixers, quadrature generators, oscillators, and amplifiers are re-used.

The invention provides a wideband RF front-end. One embodiment of the present invention includes a transceiver for wireless communication. The transceiver includes an antenna, a transmitter, which comprises a tunable matching network and a modulator, and a receiver, which comprises a programmable band-pass filter (BPF) and a demodulator.

An integrated tuner circuit includes a first terminal to which a UHF TV signal is input via a UHF amplifier. The amplifier is switched to an operating state when a UHF TV signal is received. A switching-voltage generation circuit includes a first switching circuit for generating a switching voltage used to switch the operating state of a UHF high-frequency amplifying circuit. The switching voltage of the first switching circuit is output to the first terminal

The present invention provides methods and apparatuses for a shared filter transceiving system. A shared filter transceiving system having a capacitor bank to adjust the time constant of the shared filter comprises a first input configured to receive a first signal. The capacitor bank is coupled to the first input having a plurality of selectable capacitors including a reference capacitor. A second input is coupled to the capacitor bank configured to receive a second signal. A configurable switch is coupled to the capacitor bank configured to couple a first selectable capacitor with the reference capacitor when the first input is active and couple a second selectable capacitor with the second reference capacitor when the second input is active. The second selectable capacitor is a predetermined offset value of the first selectable capacitor.

A VCO include a resonance tank circuit(A) and an amplification circuit(B) which oscillates and is amplified at a resonance frequency of the resonance tank circuit(A). The resonance tank circuit(A) is provided with a capacity band switching circuit(D) for varying an oscillation frequency band, and a current band switching circuit(E) for feeding an appropriate current, corresponding to each oscillation frequency band, to the amplification circuit(B). This allows expansion of the oscillation frequency variable range as well as realization of a favorable phase noise characteristic in a broad band by optimization of a current in each frequency band.

An RF filtering and amplifying apparatus is proposed, comprising: a plurality of RF filters, connected with each other in a manner of cascade, for filtering the received radio signal level by level; a LNA (low noise amplifier), for amplifying the filtered signal to output an amplified and filtered signal. The RF filtering and amplifying apparatus in the present invention can not only meet the requirement for the selectivity of the filters, but also achieve desirable in-band distortion and insertion loss meanwhile.

A gain deviation is leveled in the same band by using a varactor diode having the same characteristics as that used in an input tuning circuit for coupling the input tuning circuit and a high frequency amplifier The input tuning circuit has a tuning varactor diode whose tuning frequency varies with a tuning voltage applied to the cathode of the tuning varactor diode, a high-frequency amplifier is provided in a stage subsequent to the input tuning circuit, and a coupling varactor diode for coupling the input tuning circuit to the high-frequency amplifier, in which the cathode of the coupling varactor diode and that of the tuning varactor diode are connected with each other and a bias voltage higher than the voltage at the anode of the tuning varactor diode and lower than the lowest voltage of the tuning voltage is applied to the anode of the coupling varactor diode.

A method includes receiving a desired channel indication in a radio tuner, determining a band of operation in which the channel is located, and if the channel is within a first band coupling multiple inductors into a resonant tank, and if the desired channel is within a second band coupling a single inductor into the resonant tank.

One embodiment of the present invention includes a transceiver for wireless communication. The transceiver includes an antenna, a transmitter, which comprises a tunable matching network and a modulator, and a receiver, which comprises a programmable band-pass filter (BPF) and a demodulator.

An oscillation frequency changing means is inserted between a tuner and an oscillator of local oscillator (56) of a high frequency receiving device, and the oscillation frequency changing means, in each frequency band received, changes the oscillation frequency characteristic of local oscillator (56) in relation to the tuning voltage supplied from PLL circuit (78), and operates in accordance with the frequency characteristic of tuning filter (52, 54, 62, 64) to obtain an oscillation signal varied just by a predetermined frequency, thereby making it possible to receive broadband channels of continuous VHF broadcast band and UHF broadcast band.

A system includes a filter and a tuner formed on an integrated circuit. The filter receives an input signal comprising a first number of channels and communicates an intermediate output signal comprising a second number of channels less than the first number of channels. The tuner is coupled to the filter and receives the intermediate output signal and communicates an output signal comprising a third number of channels less than the second number of channels.

In accordance with an embodiment, a switchable capacitance circuit includes a plurality of capacitance-switch cells that each has a first semiconductor switching circuit and a capacitance circuit having a first terminal coupled to the first semiconductor switching circuit. A resistance of the first semiconductor switching circuit of a first switch-capacitance cell of the plurality of capacitance-switch cells is within a first tolerance of a resistance of the first semiconductor switching circuit of a second capacitance-switch cell of the plurality of capacitance-switch cells, and a capacitance of the capacitance circuit of the first capacitance-switch cell is within a second tolerance of a capacitance of the capacitance circuit of the second capacitance-switch cell.