| 摘要 |
PURPOSE: An apparatus for detecting and controlling phase recovery in a satellite broadcasting receiving system is provided to be efficiently used in a high transmission speed by performing carrier recovery from vector phases of two baseband signals and detecting a phase recovery state by using a cosine ROM table. CONSTITUTION: A QPSK(Quadrature Phase Shift Keying) demodulating unit has a timing recovering unit(25) and a carrier recovering unit(30), and performs the QPSK demodulation of an input signal. A phase recovery vector output unit(26) stores an input carrier frequency and a function value of an output signal of the QPSK demodulating unit, and outputs a phase value of a QPSK vector signal by using n-bit sampled data of an inphase component and a quadrature component of the QPSK demodulating unit as an address. A multiplier(27) multiplies the vector phase value of the phase recovery vector output unit(26) by 4. A cosine vector output unit(28) outputs a vector phase value for indicating a phase recovery state of the QPSK demodulating unit by the vector phase value of the multiplier(27). An accumulation value comparing unit(29) accumulates the vector phase value of the cosine vector output unit(28), compares the accumulated vector phase value with a uniform threshold value, and outputs a phase recovery detecting signal.
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