PURPOSE: To reduce an estimated phase error due to disturbance such as a noise and suppress deterioration in characteristics by providing an averaging part for degenerative phase data on a phase difference plane with a mean recalculating circuit.
CONSTITUTION: A demodulation part 10 converts a received IF input signal 100 into angle data on a phase plane through asynchronous orthogonal demodulation. A differential arithmetic part 20 delays the angle data by one symbol and calculates the difference between the delayed angle data and current angle data, and a phase degenerator 30 degenerates the phase plane. An estimation part 50 holds phase difference data, outputted in symbol units, in a storage device 51 for a certain period and subtracts a mean value found by an averaging circuit 52 from the data. Then a reaveraging circuit 54 averages the difference data 153 again in a similar section and a long-section averaging circuit 55 averages the data for a specific section. The output 155 of the circuit 55 is inputted to the phase correction part 41 of a correction and decision part 40 to correct the output 120 of the arithmetic part 20. A code decision unit 42 decides received data from the corrected phase.
KUNIEDA MASANORI
TAKAHASHI KENICHI
