| 摘要 |
<p>The present invention relates to a carrier recovery (CR) circuit for recovering carriers from offset quadrature phase shift keying (O-QPSK) modulated carriers, in which each of two orthogonal sequences of burst signals, to be modulated by the O-QPSK system, has a preamble field set in a prescribed bit pattern. In a Costas loop for recovering carriers by the QPSK system, a 1/2 symbol delay circuit (14) makes the phases of burst signals inputted to two orthogonal channels identical to each other. A phase comparator (19) for the bit timing recovery field adds with an adder (193) a detected carrier value detected by an arc tangent calculating circuit (191) and a value resulting from the delaying of the detected carrier value with a one-symbol delay circuit (192), and supplies the added detected carrier value. A switching circuit (22) switches and supplies the outputs of phase comparators (18 to 20), and enters the output into a loop filter (23). <IMAGE></p> |
