Skyworks Solutions, Inc.

Newport Media, Inc.

Ultrawave Labs, Inc.

Aly Mamdouh Ismail

Edward Youssoufian

Geoffrey O Hatcher

Hassan Elwan

Frank Carr

Amr M Fahim

Nabil R Yousef

David L Yates

David Yates

John E Vasa

Sai Kwok

Balasubramanian Ramachandran

Janakan Sivasubramaniam

Francis Carr

Dave Yates

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.

Adaptive continuous-time filter adjustment device

This invention uses one or more cancellation modules to eliminate the transmitter leakage at the output of the receive antenna and prior the receiver circuitry so that the received signals can be analyzed without degradation in quality due to simultaneous operation of the transmitter and receiver. Each cancellation circuit could be limited to only 30-50 dB of rejection due to component mismatches and other circuit non-idealities. To obtain further cancellation, more than one cancellation circuit can be applied after the first low noise amplifier. The output of the low noise amplifier can be repeatedly mixed with additional cancellation signals 'n' number of times such that the 'n' low noise amplifier is mixed with the &#x201c;n&#x201d; cancellation signal. For each additional cancellation signal added a 20-30 dB reduction in noise may be achieved such that cascading three or four cancellation signals from cancellation modules may produce a 150 dB gain.

High dynamic range transceiver

A direct conversion radio-frequency (RF) receiver includes a controller and an adaptive continuous-time filter. The adaptive continuous-time filter receives a multiple-bit control signal generated by the controller to adjust a characteristic of the continuous-time filter. The controller generates the multiple-bit control signal in response to process variation in the semi-conductor material used to implement the controller and the adaptive continuous-time filter. A method for tuning an adaptive continuous-time filter comprises determining a RC time constant, converting the RC time constant to a digital word, comparing a select bit of the digital word to a respective bit of a predetermined reference word to generate a control bit, applying the control bit to an adjustable element to modify the RC time constant, repeating the determining, converting, comparing and applying steps until the control bits generate an output word and providing the output word to the adaptive continuous-time filter.

Phase-locked loop based controller for adjusting an adaptive continuous-time filter

A method of filtering and a RF filtering circuit comprising a LO adapted to generate in-phase and quadrature LO signals; a quadrature passive mixer operatively connected to the LO; a filtering impedance operatively connected to the quadrature passive mixer, wherein the voltage at an input node of the quadrature passive mixer comprises the voltage across the filtering impedance up-converted to a frequency of a LO signal received by the quadrature passive mixer. Preferably, the voltage across the filtering impedance comprises a frequency of an input signal of the quadrature passive mixer down-converted by a frequency of the in-phase and quadrature LO signals and filtered by the filtering impedance.

System and method for performing RF filtering

A direct conversion radio-frequency (RF) receiver includes a controller and an adaptive continuous-time filter. The adaptive continuous-time filter receives a multiple-bit control signal generated by the controller to adjust a characteristic of the continuous-time filter. The controller generates the multiple-bit control signal in response to process variation in the semiconductor material used to implement the controller and the adaptive continuous-time filter. A method for tuning an adaptive continuous-time filter comprises determining a RC time constant, converting the RC time constant to a digital word, comparing a select bit of the digital word to a respective bit of a predetermined reference word to generate a control bit, applying the control bit to an adjustable element to modify the RC time constant, repeating the determining, converting, comparing and applying steps until the control bits generate an output word and providing the output word to the adaptive continuous-time filter.

A system and method for performing stepped automatic gain control (AGC) for orthogonal-frequency-division-multiplexing (OFDM) applications comprises a radio frequency (RF) tuner and an OFDM demodulator operatively connected to the RF tuner, the OFDM demodulator comprising logic circuitry adapted to (i) detect OFDM symbols from a stream of data; (ii) detect boundaries of the OFDM symbols; (iii) detect a cyclic prefix duration of data values associated with the OFDM symbols; and (iv) provide a feedback to the RF tuner of the information pertaining to the boundaries of the OFDM symbols and the cyclic prefix duration.

Stepped automatic gain control for OFDM systems

Digital autonomous AGC for a DVB-H receiver comprises detecting a plurality of RF signals entering a LNA in the DVB-H receiver; detecting a RF transmitter blocker signal occurring at the LNA; and differentiating between a desired RF signal and an undesired RF transmitter blocker signal by varying a differential gain of current through the LNA. A RF servo loop is used for detecting the RF transmitter blocker signal. Logic circuitry of the RF servo loop is integrated with a baseband AGC loop to step control the differential gain of current through the LNA. A RF wideband detector is used for detecting the plurality of RF signals entering the LNA; and sending a voltage output corresponding to voltage levels of the RF signals to a plurality of comparators, wherein each of the plurality of comparators are set at a different programmable voltage threshold level compared with one another.

System and method for digital autonomous automatic gain control (AGC) for DVB-H receivers

A technique for downconverting a RF signal comprises an antenna adapted to receive an RF signal; a transconductance amplifier connected to the antenna and adapted to amplify the RF signal; a passive mixer connected to the transconductance amplifier and adapted for current domain mixing of electrical current transferred from the transconductance amplifier; and a load impedance connected to the passive mixer. The load impedance may comprise a parallel combination of a frequency dependent negative resistance component, a capacitor, and a resistor. The load impedance may comprise a pair of complex poles, a pair of imaginary zeros, and a real pole. Voltages at an input and an output of the passive mixer are related such that the input voltage of the passive mixer is an upconverted version of the output voltage of the passive mixer, wherein the input voltage of the passive mixer is at an output of the transconductance amplifier.

Low power highly linear RF downconverter

A low noise nth order filter, system, and method includes a plurality of nested general immittance converters (GICs) operatively connected to one another in successive GIC stages; and a capacitor operatively connected to each of the GICs, wherein a first successive GIC stage begins at a first node located in between a previous GIC stage and a corresponding capacitor operatively connected to the previous GIC stage. A second successive GIC stage begins at a second node located in between the first node and the first successive GIC stage. The filter may further comprise a resistor operatively connected to at least one successive GIC stage, wherein the resistor is preferably located in between the first node and the first successive GIC stage.

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A mixer is disclosed having an output stage with an amplifier or gain device configured in a feedback loop to maintain a virtual ground at the input to the gain device. The gain device provides significant dynamic range, gain, and the appropriate impedance matching to insure a low noise output signal of a desired magnitude. Use of an amplifying output stage removes the dependence between mixer gain and mixer configuration, such as mixer bias resistor value, while concurrently overcome undesirable flicker noise that results from use of active devices in the mixer bias structure. A stable virtual ground at the mixer output and gain device input provides linearity over frequency. The gain device may comprises an operational amplifier or trans-resistance/trans-conductance device.

High dynamic range compact mixer output stage for a wireless receiver

A DC-offset cancellation system for a wireless receiver is disclosed. The DC-offset cancellation system comprises an amplifier and an impedance inverter configured to transform inductance applied to a received signal to a capacitance.

DC offset cancellation in a wireless receiver

A low noise filter is arranged to receive an input signal from a downconverter. The low noise filter is constructed to block or cancel any DC offset in the input signal, as well as filter selected frequency components from the input signal. The low noise filter uses a shared capacitor both to handle the DC offset and to set filter response characteristics. As the low noise filter is implemented with a Frequency Dependent Negative Resistance (FDNR) device, the shared capacitor may be relatively small. The low noise filter has a load capacitor, with the output of the load capacitor coupled to a bias resistor and voltage. This bias structure cooperates with the load capacitor to set a high cutoff frequency for the low noise filter useful for blocking or canceling the DC offset.

Low noise filter for a wireless receiver

A circuit and method of reducing noise in the circuit comprises a first transistor and an amplifier operatively connected to the first transistor, wherein the amplifier comprises a plurality of transistors and is adapted to amplify an input signal, and wherein the input signal is differentially captured at an output of the first transistor and the amplifier. Preferably, the plurality of transistors comprises a second transistor and a third transistor. Furthermore, a noise level of the first transistor and the third transistor are preferably cancelled. The size of the second transistor may be approximately 1/50&#x3a9;. Preferably, a gain on an amplifier stage formed by the second transistor and the third transistor is adapted to be increased. Moreover, an equivalent transconductance of the amplifier is preferably independent of an impedance matching on the amplifier. Preferably, a noise figure level of the circuit is less than approximately 1 dB.

Wideband ultra low noise amplifier

A dB-linear variable gain amplifier, a method for creation, and a system includes an amplifier; a pair of resistor arrays operatively connected to the amplifier, wherein each resistor array comprises MOS transistor resistive switches; a differential ramp-generator circuit operatively connected to the pair of resistor arrays; and voltage control lines generated by the differential ramp-generator circuit, wherein the voltage control lines are operatively connected to each of the MOS transistor resistive switches in the pair of resistor arrays. The number of the voltage control lines that are operatively connected to the each of the MOS transistor resistive switches is equal to the number of resistors in a particular resistor array. The differential ramp-generator circuit is preferably operable to take an automatic gain control voltage and generate a series of differential ramp voltages and apply the series of differential ramp voltages to one of the MOS transistor resistive switches.

Growing community of inventors

Irvine, CA, United States of America

Aly Mamdouh Ismail