| 摘要 |
PURPOSE: To obtain a phase modulation wave carrier recovery circuit in which a lock time for carrier recovery is short and a stable operation is attained. CONSTITUTION: The circuit is made up of an FFT arithmetic circuit 21 applying FFT operation to phase error detection data to analyze a frequency component, a discrimination control circuit 22 discriminating a frequency deviation based on the analysis result and sending corresponding control data, and a D/A converter circuit 23 applying D/A conversion to the control data and giving the result to a VCO 9 for carrier recovery. Then considering that the phase error detection data include a frequency component corresponding to a frequency difference between a recovery carrier frequency and a frequency of a received phase shift wave as a frequency spectrum component, the frequency is analyzed by applying FFT to the phase error detection data to discriminate a frequency deviation. Thus, the carrier recovery signal matches the vicinity of an object frequency instantaneously by controlling the oscillated frequency of the VCO 9 to eliminate the frequency deviation. |
