| 摘要 |
In an AFC ((Automatic Frequency Control) circuit, a frequency offset estimating circuit (11) produces a lock signal (102) if a calculated frequency error becomes smaller than a predetermined value. Then, a CPU (13) produces a control signal (104) to stop the operation of the frequency offset estimating circuit (11). A timing generating circuit (14) calculates a frequency error with reference to a frame timing correction amount from a delay profile/search circuit (12), and produces an unlock signal (103) if the frequency error becomes equal to or greater than the predetermined value. Then, the CPU (13) produces the control signal (104) to start the operation of the frequency offset estimating circuit (11). Thus, the frequency offset estimating circuit (11) stops its operation while the AFC operation is in the locked state.
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