US Patent 9261548 Hum noise detection device

A hum noise detection device includes: a frequency conversion unit (1) configured to perform a frequency converting process at a constant time interval on an input signal, and converting the input signal into a frequency signal; a peak frequency calculation unit (2) configured to calculate a stationary peak frequency based on the frequency signal; a fundamental frequency estimation unit (3) configured to estimate a fundamental frequency of hum noise based on the stationary peak frequency; and a hum noise judgment unit (4) configured to judge whether or not there is hum noise in the input signal based on the estimated fundamental frequency and the stationary peak frequency.