Receiving circuit having a frequency compensated local oscillation circuit

摘要

A receiving ckt for receiving a transmitted SIG including FRQ divided carriers, comprises: a FRQ conversion ckt responsive to the LO SIG with a LO for generating a LO SIG with LO FRQ controlled according to a FRQ CONT SIG for FRQ converting the transmitted SIG into an IF SIG; a orthogonal signal separation ckt separating the IF SIG into I and Q components; a complex FFT conversion ckt for complex FFT converting the I and Q components and outputting conversion SIGs to be decoded arranged in FRQ base; an ELEC PWR measurement ckt measuring values of ELEC PWRs of the conversion SIGs; and a prediction ckt for predicting a CTR FRQ of the FRQ divided carriers from a FRQ distribution of the values of ELEC PWRs from the ELEC PWR measurement ckt and generating the FRQ CONT SIG according to the predicted center FRQ. The CTR FRQ may be detected by a REF carrier detection ckt responsive to the complex FFT processing ckt detecting a REF carrier or a carrier pattern included in the transmitted SIG. A correlation between the conversion SIGs and a REF SIG having values varied every predetermined interval within a symbol period is detected to generate the FRQ CONT SIG, wherein a phase compensating ckt for compensating phase of the conversion SIGs in response to the FRQ CONT SIG may be provided.