Dantoni
Francesco Dantoni, Richardson, TX US
Patent application number | Description | Published |
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20090143022 | METHOD AND SYSTEM FOR CONTROLLING CARRIER LEAKAGE IN A DIRECT CONVERSION WIRELESS DEVICE - According to one embodiment of the invention, a system for controlling carrier leakage in a communications device is provided. The system includes a first mixer unit operable to receive a first signal, to convert the first signal into a second signal having a higher frequency than the first signal, and to transmit the second signal. The system also includes a second mixer unit. The second mixer unit is operable to receive the second signal, to convert the second signal into an in-phase signal and a quadrature signal each having lower frequency than the second signal, and to transmit the in-phase signal and the quadrature signal. The system also includes a processor coupled to the first mixer and the second mixer. The processor is operable to perform a leakage reduction procedure by receiving the in-phase signal and the quadrature signal from the second mixer, sampling the in-phase signal and the quadrature signal, determining that a result from the sampling is not equal to a predetermined value, initiating a transmission of a direct current offset signal to the first mixer unit, and adjusting a voltage of the direct current offset signal until a next result of the sampling approximately equals the predetermined value. | 06-04-2009 |
Francesco Dantoni, Atella (pz) IT
Patent application number | Description | Published |
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20090010358 | Methods and apparatus to pre-compensate for I/Q distortion in quadrature transmitters - Methods and apparatus to pre-compensate for in-phase/quadrature (I/Q) distortion in quadrature transmitters are disclosed. A disclosed example method comprises coupling a portion of an analog baseband in-phase signal to an analog baseband quadrature signal through an impedance, and selecting a resistance value for the impedance to pre-distort the analog baseband quadrature signal to compensate for an error introduced by modulation of the analog baseband in-phase signal and the analog baseband quadrature signal. | 01-08-2009 |
Francesco Dantoni, Roma IT
Patent application number | Description | Published |
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20110267146 | OPEN LOOP COARSE TUNING FOR A PLL - In many types of wireless applications (like wireless modems), it is important that the phase locked loops (PLLs) be able to synthesize clock frequencies in a wide tuning range. Because of the complexity of many conventional PLLs (which were deigned to cover wide tuning ranges), there was often a significant delay to achieve phase and frequency lock. Here, an open loop calibration system is provided to coarse tune a PLL very rapidly. Generally, this calibration system employs binary searches to coarsely adjust a voltage controlled oscillator (VCO) from a VCO bank to within a predetermined range around a target frequency. | 11-03-2011 |
20130294295 | TRANSMIT SIGNAL CANCELATION APPARATUS AND METHODS - Apparatus and methods disclosed herein implement an RF receive-band filter at a receive chain input of a wireless base station with a co-located transmitter and receiver. The RF receive-band filter includes an adaptive filter component to perform filtering operations on samples of a digital baseband or intermediate frequency signal x(n) from a transmit chain associated with the wireless base station. An adaptive filter transfer function is determined in real time such that samples of the baseband transmit signal x(n) are transformed into a cancellation baseband signal z(n). The digital cancelation baseband signal z(n) is then digital-to-analog converted and the resulting analog baseband signal z(t) is up-converted to obtain a subtractive RF cancelation signal c(t). C(t) is summed with a desirable received signal RF component r(t) and an undesirable transmitter leakage RF signal component l(t) appearing at the input to the base station receiver. C(t) cancels l(t), leaving r(t) to be processed by the receiver section of the base station. | 11-07-2013 |
Francesco Dantoni, Rome IT
Patent application number | Description | Published |
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20120155581 | IMPLEMENTATION OF A HIGH PERFORMANCE MULTI-CARRIER RECEIVER USING FREQUENCY SELECTIVITY AND DIGITAL COMPENSATION TECHNIQUES - A system has a first branch and a second branch. The system comprises a first intermediate frequency source of the first branch and a first mixer coupled to the first intermediate frequency source. The system has a second intermediate frequency source of the second branch and a second mixer coupled to the second intermediate frequency source. A frequency of the first intermediate frequency source is different than a frequency of the second intermediate frequency source. The system has an amplifier coupled to an input of the first mixer and an input of the second mixer. A first component of an analog to digital converter (“ADC”) is coupled to the first mixer of the first branch. A second component of the ADC is coupled to the second mixer of the second branch. | 06-21-2012 |