Differential detection of GFSK signal using decision feedback and preamble for carrier, clock and frame synchronization

摘要

This invention provides a method for bit detection of the GFSK signals at the receiver end. The bit detection is done digitally after the carrier is removed. It employs differential detection incorporated with decision feedback, which uses previous one (so-called on-bit differential detection), or two (so-called two-bit differential detection) bits as correcting information. In addition, synchronization for bit timing and frequency offset resulted from clocks between the transmitter and receiver are also performed with or without preamble as prior information. If preamble is available, the bit timing and frequency-offset bias are estimated from the preamble, which is the case of this present invention. If preamble is not available, this information is estimated directly from the unknown received signals. Once the information about the bit timing and frequency offset is obtained, it is used for the following bit detection.