| 摘要 |
PROBLEM TO BE SOLVED: To provide an RDS decoder which can reduce man-hour of processing related to the extraction of an RDS signal from an FM compounded audio signal and can be easily integrated into a digital signal processing system for performing main audio signal processing. SOLUTION: The RDS decoder has synchronous demodulation means 1 for generating a baseband RDS signal by inputting the FM compounded audio signal obtained by multiplexing the RDS signal based on digital data on an FM audio signal and a data restoring means 2 for restoring the digital data from the baseband RDS signal. In the synchronous demodulation means 1, an input signal is converted to two baseband signals of orthogonal phases, unwanted component is removed from these signals, and the baseband RDS signal is generated by detecting and correcting a residual phase error. In the data restoring means 2, a phase error between the data of a conversion ratio adjusted by a sampling frequency converting means 6 and a transmission symbol timing is detected, and on the basis of the phase error, the conversion ratio is adjusted. COPYRIGHT: (C)2003,JPO
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