Patent ID: 7450923
Filing Date: 2008-11-11
Classification: H04B,H04W

Abstract:
1. A direct conversion unit for controlling carrier leakage in a wireless communications device, comprising: a transmit circuitry including a first mixer unit having a transmit output, an in-phase input, a quadrature input, a first amplifier, and a second amplifier, the first amplifier and the second amplifier coupled to the in-phase input and the quadrature input, respectively, the first mixer unit operable to convert a signal into a transmission signal having a higher frequency than the signal, and to transmit the transmission signal through the transmit output; a receive circuitry including a second mixer unit having a receive input, an in-phase output, and a quadrature output, the receive input coupled to the transmit output, the second mixer unit operable to receive the transmission signal through the receive input, to convert the transmission signal into an in-phase signal and a quadrature signal each having a lower frequency than the transmission signal, and to transmit the in-phase signal and the quadrature signal through the in-phase output and the quadrature output, respectively; a digital to analog converter unit coupled to the first amplifier and the second amplifier, the converter unit operable to apply a direct current offset signal to the in-phase input and the quadrature input through the first and the second amplifiers, respectively; a baseband processor coupled to the digital to analog converter unit, the in-phase output and the quadrature output, the baseband processor operable to receive the in-phase signal and the quadrature signal through the in-phase output and the quadrature output, respectively, to repeatedly sample the in-phase signal and the quadrature signal, to determine that a result from the sample is not equal to zero, and to direct the digital to analog converter unit to adjust a voltage of the direct current offset signal until a next result of the sample equals zero; and a gain controller coupled to the first amplifier and the second amplifier, the gain controller operable to adjust a power level of the transmission signal by controlling the first amplifier and the second amplifier.