초록 ▼

A synchronizing apparatus for a differential OFDM receiver that simultaneously adjust the radio frequency and sample clock frequency using a voltage controlled crystal oscillator to generate a common reference frequency. Timing errors are found by constellation rotation. Subcarrier signals are weigh

A synchronizing apparatus for a differential OFDM receiver that simultaneously adjust the radio frequency and sample clock frequency using a voltage controlled crystal oscillator to generate a common reference frequency. Timing errors are found by constellation rotation. Subcarrier signals are weighted by using complex multiplication to find the phase differentials and then the timing errors. The reference oscillator is adjusted using the timing errors. Slow frequency drift may be compensated using an integral of the timing error. Frequency offset is found using the time required for the timing offset to drift from one value to another.

대표청구항 ▼

[ The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:] [1.] A method of processing an OFDM signal comprised of plural sub-carriers, in which information is carried in phase differentials between sub-carriers, the phase differentials having

[ The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:] [1.] A method of processing an OFDM signal comprised of plural sub-carriers, in which information is carried in phase differentials between sub-carriers, the phase differentials having a pre-determined distribution in the complex domain, the OFDM signal being received by a receiver having a reference oscillator, the method comprising the steps of:repeatedly detecting real and imaginary values of plural subcarriers wherein the real and imaginary values form a constellation of real and imaginary values of the plural sub-carriers;computing successive timing errors by repeatedly estimating the rotation required to rotate the constellations to coincide with the pre-determined distribution; andadjusting the reference oscillator according to the timing errors.