| 摘要 |
PROBLEM TO BE SOLVED: To improve the carrier recovery performance by decreasing number of latches being a cause of a loop delay so as to enlarge a frequency pull-in range. SOLUTION: The carrier recovery circuit is provided with a phase detector 21 that obtains a phase angle of a carrier phase from a symbol coordinate of an in phase and an orthogonal signals outputted from a complex multiplier 9, an error detection means 23, an output gain adjustment circuit 37, a numerical control oscillation circuit 43 that reproduces a carrier frequency with a level accompanied with an output of a low pass filter 39, an output phase angle cosine transform device 15, a sine transform device 17, a numerical control oscillation circuit 45 that is oscillated by an output of the low pass filter 39, a changeover device 47 that gives or not the output of the filter 39 to the complex multiplier 9 via the numerical control oscillation circuit 43, the cosine transform device 15 and the sine transform device 17, and a changeover device 25 that gives or not the output of the filter 39 to the error detection means 23 via the numerical control oscillation circuit 45. |
