Data processing apparatus

摘要

A data processing apparatus is provided for detecting distortion of a data signal to which a template signal has been introduced into different frequency bands of the signal. The apparatus includes a frequency component processor operable to generate data representative of the frequency components of the first and the second frequency bands of the data signal, and a detection processor operable to identify the distortion of the data signal in accordance with a relative frequency change between the versions of the recovered template signal.