| 摘要 |
PROBLEM TO BE SOLVED: To reduce coherent noise by removing DC offsets by a digital filter.SOLUTION: The signal processing apparatus includes the digital filter 21 disposed on a prior stage to a detection circuit 22. The digital filter 21 is a high-pass filter which transmits components in a frequency band Fc±ΔF included in digital signals SD, but which removes DC offset components. As the digital filter 21 removes DC offsets before the DC offsets are input in the detection circuit 22, generation of noise N of a frequency Fc can be suppressed, and as a result, the coherent noise can be reduced. |
