| 摘要 |
PURPOSE: An automatic frequency control method and apparatus is provided to minimize the complexity of a receiving unit and increase the performance of receiving by using a portion configured for demodulation in the receiving unit as its component. CONSTITUTION: An automatic frequency control apparatus is comprised of an equalizer(301), a channel characteristic estimator(302), a remodulator(303), a phase comparator(304), a frequency error estimator(305), a digital-analog converter(306), and a reference synchronization word part(307). The reference synchronization word part(307) outputs reference synchronization words used in the time slot of a received signal. The channel characteristic estimator(302) calculates channel characteristics, an impulse response of a channel that the received signal has been transmitted through, using the reference synchronization words. The equalizer(301) equalizes an I channel signal and a Q channel signal using the channel characteristics and detects a binary data stream. The remodulator(303) remodulates the output of the equalizer(301) and calculates the size of the I and Q channel signals. The phase comparator(304), after calculating a receiving phase from the I and Q channel signals of the currently received time slot and a reference phase from the I and Q channel signals outputted from the remodulator(303), compares two phases and calculates a phase error value. The phase error value is inputted to the frequency error estimator(305), converted into a frequency error value and supplied to the digital-analog converter(306). The digital-analog converter(306) converts the frequency error value into an analog control voltage.
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