Signal transmission system for transmitting a signal with a guard interval and a demodulation method thereof

A receiving apparatus for receiving a transmission signal having a guard interval and a data interval, comprising:

• a receiving unit for receiving said transmission signal;
• a delay unit for delaying said transmission signal from said receiving unit by the data interval;
• a differential value calculating unit for calculating difference between said transmission signals from said receiving unit and said delay unit;
• a guard interval reference position detecting unit for detecting a reference position of said guard interval based upon the result of the calculation of said difference;
• and
• a demodulating unit for demodulating said transmission signal based upon said reference position of said guard interval.

A signal transmission system having a transmitting apparatus and a receiving apparatus, wherein:

• said transmitting apparatus for transmitting a transmission signal being a repetition signal of a guard interval and a data interval comprises:
• a modulating unit for modulating said transmission signal according to predetermined modulation technique;
• a guard interval inserting unit for inserting said guard interval into a modulated signal from said modulating unit and generating said transmission signal made by the repetition of the guard interval and said data interval;
• and
• an antenna for transmitting the output of said guard interval inserting unit;
• and
• said receiving apparatus comprises:
• a receiving unit for receiving said transmission signal;
• a delay unit for delaying said transmission signal from said receiving unit by said data interval;
• a differential value calculating unit for calculating difference between signals from said receiving unit and said delay unit;
• a guard interval reference position detecting unit for detecting a reference position of said guard interval based upon the result of the calculation of said difference;
• and
• a demodulating unit for demodulating said transmission signal based upon said reference position of said guard interval.