Modem with local oscillator phase correction

摘要

A carrier generator circuit (101) for use in a modem employed in a wireless communication system includes a voltage controlled oscillator (110) comprising an N-stage ring oscillator to generate N balanced vectors of equal magnitude and arbitrary phase difference. The carrier generator circuit also includes a phase corrector (112) to add two of the balanced vectors (V1,V1B;V2,V2B) to generate a sum vector and to subtract the two balanced vectors to generate a difference vector. The sum vector and difference vector have a phase difference of 90 degrees. The sum vector represents an I (in-phase) carrier signal component and the difference vector represents a Q (quadrature-phase) carrier signal component. These I and Q carrier signal components (on 114,116) can be used to transmit and receive data signals.