Apparatus and method for generating a radio data system (RDS) bit clock

摘要

To generate the RDS bit clock in a car radio, a comparison is made between the period of a clock generator and the period of the demodulated RDS signal. A first counter that triggers the clock generator, counts the zero crossings in the RDS carrier detected by a first zero crossing detector. A second counter counts sampled values of the demodulated RDS signal lying between two zero crossings detected by a second zero crossing detector. If the number of sampled values counted by the second counter lies within a presettable tolerance range, an arithmetic unit calculates a synchronizing signal to synchronize the clock generator with the RDS data stream. The synchronizing signal increments or decrements the count of the first counter to achieve synchronization between the clock generator and the RDS data stream.