| 摘要 |
PROBLEM TO BE SOLVED: To improve the precision of an automatic frequency control(AFC) method in a direct spread spectrum radio data transmitter. SOLUTION: In this AFC circuit, a carrier phase rotating speed detection circuit 17 obtains a carrier phase rotating speed for each information symbol from an output of a correlation device 15 of a receiver, an averaging circuit 18 averages the speed timewise, an interpolation circuit 19 applies interpolation at a time interval of a spread tip and a rotation matrix arithmetic circuit 14 provided to the input side of the correlation device 15 corrects the carrier phase rotation. Thus, the precision of the digital AFC is improved. |
