Patent application number | Description | Published |
20090268849 | Passive Miser and Four-Phase Clocking Method and Apparatus - According to one embodiment, a radio frequency receiver comprises a quadrature mixer configured to convert radio frequency signals to baseband signals or intermediate frequency signals. The quadrature mixer comprises an in-phase passive mixer and a quadrature-phase passive mixer. Each passive mixer comprises a mixer core having a plurality of mixer input switch transistors and a plurality of output switch transistors connected to the mixer input switch transistors. Clock circuitry generates a plurality of quadrature pulsed clock signals and delayed versions of the quadrature pulsed clock signals. The quadrature pulsed clock signals and the delayed versions of the quadrature pulsed clock signals drive the mixer input switch transistors and the output switch transistors. | 10-29-2009 |
20090270062 | Passive Miser and Four-Phase Clocking Method and Apparatus - According to one embodiment, a radio frequency receiver includes a quadrature mixer for converting radio frequency signals to baseband signals or intermediate frequency signals. The quadrature mixer includes an in-phase passive mixer and a quadrature-phase passive mixer. Each passive mixer includes a mixer core having a plurality of mixer input switch transistors and a plurality of output switch transistors connected to the mixer input switch transistors. Clock circuitry generates a first set of clock signals and a second set of clock signals. The first set of clock signals has a frequency twice that of the second set of clock signals. The first set of clock signals is arranged to drive the mixer input switch transistors and the second set of clock signals is arranged to drive the output switch transistors. | 10-29-2009 |
20090280767 | TIME-MULTIPLEXED COMMON MODE FEEDBACK FOR PASSIVE QUADRATURE RF MIXERS - A passive, differential RF mixer reduces second order intermodulation interference while maintaining I/Q isolation via common mode feedback wherein the I and Q error signals in the feedback path are time multiplexing using a four-phase LO signal. An RF signal is received at a differential input having a center tap. The RF signal is mixed with an in-phase differential signal of the four-phase local oscillator signal in a differential mixer (I mixer). The RF signal is also mixed with a quadrature-phase differential signal Q components of the four-phase local oscillator signal in a differential mixer (Q mixer). The common mode levels of the I and Q differential mixer outputs are compared to a reference DC voltage to generate I and Q error signals. The I and Q error signals are time-multiplexed, and fed back to the RF input center tap. | 11-12-2009 |
20100081408 | Re-Configurable Passive Mixer for Wireless Receivers - A configurable passive mixer is described herein. According to one exemplary embodiment, the passive mixer comprises a clock generator, a controller, and a plurality of passive mixer cores connected in parallel. The clock generator comprises a local oscillator drive unit for each passive mixer core. The controller varies an effective transistor size of the passive mixer by separately configuring each of the passive mixer cores to enable/disable each passive mixer core. For example, the controller may selectively enable one or more of the passive mixer cores to vary the effective transistor width of the passive mixer. As the performance requirements and/or the operating communication standard change, the controller may re-configure each passive mixer core. | 04-01-2010 |
20100203860 | Passive Mixer Mismatch Tuning Using Self-Tests to Suppress IM2 - The second-order inter-modulation distortion, originating in a differential passive mixer core from imbalance between devices, is reduced by compensating for the mismatch or load, by means of tuning the differential output impedance at the mixer core, or the input impedance of a filter coupled to the output of the passive mixer. Compensating for the imbalance allows greater suppression of even-order harmonics in the differential structure, which reduces second-order intermodulation at the output of the mixers. The compensation is achieved by tunable resistive elements that are calibrated by a built-in self-test architecture. The calibration circuit is deactivated during receiver operation. | 08-12-2010 |
20110223877 | Radio White Space Sensing - User equipment comprising a receiver obtains information about a set of channels to be sensed in a sensing process, wherein each channel is associated with a respective one of a number of radio frequencies. The receiver obtains a radio frequency signal by simultaneously sensing two or more of the channels included in the set of channels. A total power level of the sensed two or more channels is measured, and a comparison result is generated by comparing the total power level of the sensed two or more channels with a predetermined power level. The user equipment is controlled based on the comparison result. For example, if the total power level is below a threshold, then the sensed channels can be considered to not be in use by external transmission equipment. | 09-15-2011 |
20110235553 | Technique for Suppressing Noise in a Transmitter Device - A technique of suppressing noise in a transmitter device ( | 09-29-2011 |
20120076056 | OFDMA Scheduling Method for Avoiding Leakage at the Mobile Stations - The present invention relates to scheduling of uplink and downlink resources between mobile terminals ( | 03-29-2012 |
20120313672 | Down-Conversion using Square Wave Local Oscillator Signals - In a method of frequency down-converting an input signal to an output signal, a first local oscillator signal is generated as a square wave having a duty cycle of 1/3 or 2/3, and the input signal is mixed with the first oscillator signal to achieve a first down-converted signal, A second local oscillator signal is generated as a modified square wave having the same period time and a duty cycle of 2/3, of which one part has a positive amplitude and another part has a negative amplitude. The input signal is mixed with the second oscillator signal to achieve a second down-converted signal. The first oscillator signal has a delay of 1/4 of the period time to achieve a phase shift of π/2 between the oscillator signals, and at least one down-converted signal is multiplied by a pre-calculated factor. The resulting down-converted signals are added to achieve the output signal. | 12-13-2012 |
20140370833 | DOWN-CONVERSION CIRCUIT WITH INTERFERENCE DETECTION - A down-conversion circuit for a receiver circuit is disclosed. It comprises a first mixer arranged to down-convert an RF signal with a first LO signal (LO | 12-18-2014 |
20150038097 | Method and Radio Receiver Enabling Harmonic Distortion Estimation - A method of estimation of harmonic distortion level for a radio receiver operative in a cellular communication system enabled to receive signals from transmitters of one or more cells is disclosed. The method comprises measuring, within a bandwidth of operation, a total received signal power; measuring, within the bandwidth of operation, a received signal power of signals received from the one or more cells, respectively; and estimating a level of harmonic receiver distortions by: determining whether a fraction of the total received signal power and a theoretical noise floor is below or above a first threshold; or determining whether a remaining part of the total received signal power, said remaining part not including said fraction, is above or below a second threshold. A such radio receiver, and a computer program for implementing the method are also disclosed. | 02-05-2015 |
20150282231 | Method, Apparatus and Computer Program for Selectable Operation of a Network Node - A network node ( | 10-01-2015 |
20150358910 | Timing for Radio Reconfiguration - A mobile communications terminal comprising a radio frequency interface configured to operate at least at a first configuration, and a controller, wherein said controller is configured to determine that a reconfiguration of the radio frequency interface is to be performed, determine a timing of the reconfiguration and reconfigure said radio frequency interface to operate at a second configuration at the determined timing, wherein said controller is configured to determine said timing based on the type of reconfiguration to be made. | 12-10-2015 |