A modem having a phase corrector and a voltage controlled oscillator implemented using a multi-stage ring oscillator

摘要

A carrier generating circuit for use in a modem used in a wireless communication system is described. The carrier generating circuit includes a voltage controlled oscillator, which generates N balanced vectors of the same magnitude and any phase difference. The carrier generation circuit also includes a phase compensator that adds two of the balance vectors to generate a sum vector, and subtracts two of the balance vectors to produce a difference vector. The sum vector and the difference vector have a phase difference of 90 degrees. The sum vector represents the I (in-phase) carrier signal component, and the difference vector represents the Q (right phase) carrier signal component. I and Q carrier signal components may be used to transmit and receive data signals.