Patent application number | Description | Published |
20080220737 | NOISE SHAPED NTH ORDER FILTER - 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. | 09-11-2008 |
20080242252 | WIDEBAND RESISTIVE IMPUT MIXER WITH NOISE-CANCELLED IMPEDANCE - A radio frequency (RF) mixing circuit including a quadrature mixer that receives non-overlapping in-phase and quadrature local oscillator (LO) signals, and a plurality of low noise amplifiers (LNAs) operatively connected to the quadrature mixer, the plurality of LNAs presenting an input impedance at a baseband. A first voltage at an input node of the quadrature mixer is equal to a second voltage across the (noise cancelled) impedance up-converted to a frequency of a LO signal received by the quadrature mixer. The second voltage across the LNA input impedance includes a frequency of an input signal of the quadrature mixer down-converted by a frequency of the in-phase and quadrature LO signals and filtered by the (noise cancelled) impedance. The quadrature mixer down-converts an input signal by a frequency of the in-phase and quadrature LO signals and transfers the noise cancelled impedance to a RF to achieve a noise cancelled match. | 10-02-2008 |
20080258806 | Phase-Locked Loop Based Controller for Adjusting an Adaptive Continuous-Time Filter - 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. | 10-23-2008 |
20080259219 | UNIVERSAL TUNER FOR MOBILE TV - A tuner for use in mobile television devices comprises at least one RF front end component comprising a LNA adapted to amplify mobile television signals; a PLL circuit to generate signals; and a pair of mixers to receive the signals from the LNA and the PLL circuit and downconvert the signals; an analog baseband component connected to the RF front end component, wherein the analog baseband component comprises I and Q channel signal paths each comprising a tunable high order impedance filter; at least one signal amplification stage; and a signal filter stage connected to the signal amplification stage, wherein the analog baseband component further comprises a plurality of switches operatively connected to the I and Q channel signal paths, and wherein the plurality of switches are selectively opened and closed in multiple configurations in order to allow the tuner to receive mobile TV signals for all mobile TV standards. | 10-23-2008 |
20090207311 | TECHNIQUE FOR TUNER AUTOMATIC GAIN CONTROL CIRCUIT FOR MOBILE TELEVISION APPLICATIONS - A technique for providing stable tracking performance to an AGC loop circuit comprises amplifying a wideband radio frequency signal; detecting signals and blockers adjacent to the radio frequency signal; lowering a gain of the radio frequency signal; mixing a local oscillator signal with the radio frequency signal; shifting a frequency of the radio frequency signal from a radio frequency to an intermediate frequency; continuously varying a gain of the intermediate frequency signal; converting the intermediate frequency signal into a digital output signal; comparing the digital output signal with predefined thresholds comprising an upper threshold and a lower threshold; switching a post mixer amplifier (PMA) to a high gain state when an input of a variable gain amplifier (VGA) is greater than the upper threshold, and switching the PMA to a low gain state when an input of the VGA is lower than the lower threshold. | 08-20-2009 |
20090302944 | NOISE-SHAPED BLOCKER-REJECT AMPLIFIER - A fully differential amplifier that amplifies and filters a signal band of a communications channel, the signal band including a desired signal and at least one blocker signal of an adjacent communications channel, the fully differential amplifier includes a fully differential operational amplifier (op-amp) with a common mode feedback, the fully differential operational amplifier amplifying the desired signal, a variable input resistance connected to an input of the fully differential op-amp, and an asymmetric floating frequency dependent negative resistance (AFFDNR) filter connected to the fully differential op-amp between the input and an output of the fully differential op-amp. A plurality of inputs of the fully differential op-amp may be virtually grounded to reduce swings in a voltage. The AFFDNR filter filters the at least one blocker signal and includes a plurality of resistors that implement a high order filtering of the at least one blocker signal. | 12-10-2009 |
20090311985 | SUBSAMPLING WIDEBAND RSSI CIRCUIT - A Received Signal Strength Indicator (RSSI) circuit includes a subsampling circuit that processes an input signal comprising a sampling frequency, fs, wherein the subsampling circuit subsamples the input signal, wherein the input signal is subsampled to concentrate a power in a narrow bandwidth; an analog-to-digital converter (ADC) operatively connected to the subsampling circuit, wherein the ADC digitizes the subsampled signal; and a baseband detector operatively connected to the ADC, wherein the baseband detector detects a power from the digitized subsampled signal and creates an output signal. The subsampling circuit and the ADC may operate as a single subsampling ADC. The RSSI circuit may further comprise ignoring higher order aliases at a multiple of the sampling frequency if the baseband detector is clocked at the sampling frequency. | 12-17-2009 |
20110003573 | System and Method for Performing RF Filtering - 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. | 01-06-2011 |
20110075777 | Phase-Locked Loop Based Controller for Adjusting an Adaptive Continuous-Time Filter - 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. | 03-31-2011 |
20120133426 | PHASE-LOCKED LOOP BASED CONTROLLER FOR ADJUSTING AN ADAPTIVE CONTINUOUS-TIME FILTER - 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. | 05-31-2012 |