| 摘要 |
PURPOSE:To allow the device to cope with even a coding system having four phase uncertain states or over even without complicated circuit configuration when a reception signal subject to trellis coding modulation is demodulated. CONSTITUTION:A branch metric generating circuit 21 calculates a branch metric based on I and Q signals. A branch metric correction circuit 22 consists of a barrel shifter 220 and replaces the order of branch metric based on a control signal from a carrier phase control circuit 26. An ACS circuit 23 executes maximum likelihood path calculation based on the inputted branch metric. A path memory 24 stores a prescribed stage number of the path selected based on the control from the ACS circuit 23. The carrier phase control circuit 26 identifies that the phase of the recovered carrier signal is deviated from the phase of the carrier signal of a transmitter based on the maximum likelihood path outputted from the ACS circuit 23 to control the branch metric correction circuit 22 thereby compensating the phase shift. |
