Direct digital frequency synthesizer with phase error correction, method therefor, and receiver using same

摘要

A receiver (1000) includes a direct digital frequency synthesizer (DDFS) (700) and first (1040) and second (1042) mixers. The DDFS (700) has a first output for providing a first local oscillator signal, and a second output for providing a second local oscillator signal offset from a quadrature relationship with the first local oscillator signal by a phase offset. The first mixer (1040) has a first input for receiving a radio frequency (RF) signal, a second input for receiving the first local oscillator signal, and an output for providing an in-phase signal at another frequency. The second mixer (1042) has a first input for receiving the RF signal, a second input for receiving the second local oscillator signal, and an output for providing a quadrature signal at the other frequency. The DDFS (700) may be implemented using first (702) and second (704) memories storing portions of a sinusoidal waveform and extra memories (706, 708) supporting the phase offset.