The Offset Fast Fourier Transform (OFFT)
M. Tomlinson · Defense Technical Information Center (DTIC) · 1976
It is shown that by changing the weighting factors, the fast Fourier Transform (FET) may be modified to produce a frequency offset. The technique may be used in digital modems to allow a receiver to effectively tune-in to two or more frequencies simultaneously. It may allow improved frequency acquisition in burst transmission systems and improve frequency tracking in conditions where there is rapid rate of change of frequency. (Author)