Patent ID: 8913694

Claim:
An apparatus comprising: a direct conversion transmitter in a communication device, the direct conversion transmitter comprising: an input signal port to receive an input signal; an output signal port to output a transmit signal at a transmit frequency for transmission; a mixer stage to up-convert a representation of the input signal to a local oscillator (LO) frequency of a LO coupled thereto; and a DC offset circuit to apply a set of DC offset signal values to the input signal; a memory to store the DC offset signal values; and a processor configured to: determine an optimal set of the DC offset signal values by at most three differential spectral measurements made at the transmitter output port with a calibration signal applied at the input port, the set of optimal DC offset signal values being those that minimizes a LO leakage component of the transmit signal at the output signal port of the transmitter when the set of optimal DC offset signal values are applied to the input signal at the input port of the transmitter; store the optimal set of DC offset values in the memory; and apply the stored optimal set of DC offset values to information bearing signals provided as the input signal subsequent to the determination of the set of optimal DC offset signal values.