| 摘要 |
PROBLEM TO BE SOLVED: To provide a frequency difference arithmetic circuit capable of quickly arithmetically calculating a correct frequency difference.SOLUTION: A frequency difference arithmetic circuit 10 includes: a first frequency difference arithmetic calculation part 13 for arithmetically calculating a difference between a first input frequency f1 and an oscillatory frequency f3 of a non-integer multiple oscillation part 11 whose oscillatory frequency is a non-integer multiple of the first input frequency f1; and a second frequency difference arithmetic calculation part 15 for arithmetically calculating a difference between a second input frequency f2 whose difference from a frequency obtained by an integer multiplication of the first input frequency f1 falls within a predetermined error range, and the oscillatory frequency f3 of the non-integer multiple oscillation part 11. An addition part 17 arithmetically calculates a difference "&Dgr;f=f1-f2" between the first input frequency f1 and the second input frequency f2 by adding an arithmetic result of the first frequency difference arithmetic calculation part 13 and an arithmetic result of the second frequency difference arithmetic calculation part 15. |
