Patent ID: 7570577

Claim:
A communication parameter detecting apparatus, comprising: a correlation signal generating circuit which generates a duplicate signal for correlation processing based on a multiplex modulating signal; an autocorrelation circuit which performs autocorrelation processing through carrying out sliding processing on the duplicate signal with respect to a received signal as the multiplex modulating signal; an Nd detecting circuit which detects length of a data symbol of a multiplex modulating signal by detecting, from a correlation value output which is outputted by the autocorrelation processing, a correlation value peak obtained according to guard interval symbols which are identical signal components present in the received signal; a window generating circuit for generating a pair of data extracting windows for correlation processing, the windows having different window sizes and a space therebetween which corresponds to the detected length of the data symbol; a data correlation circuit which performs correlation processing mutually on extracted data which are extracted through the data extracting windows through the sliding processing by changing the window sizes; and an Ng detecting circuit which detects length of the guard interval symbol of the multiplex modulating signal by detecting a correlation value peak which is obtained when the length of the guard interval symbol and the window size become consistent based on the correlation processing performed mutually on the extracted data.