SYNCHRONIZATION DETECTION CIRCUIT

摘要

PURPOSE:To eliminate the need for a phase synchronization circuit of a receiver by predicting a carrier phase attended with signal discrimination so as to improve transmission efficiency of a burst signal. CONSTITUTION:A reception wave down-converted to an IF band is inputted from an input terminal 1. A carrier frequency recovery circuit 8 extracts a carrier frequency component from the reception wave. A multiplier 3 multiplies the reception wave with the carrier frequency component and inputs the product to a low pass filter 4. The filter 4 eliminates an undesired high frequency component from an output of the multiplier 3 to extract a base band modulation component. An A/D converter circuit 11 converts the base band modulation component into a digital signal and the signal is inputted to a branch metric arithmetic operation circuit 12. The circuit 12 receives the output of the circuit 11 and an output of a discrimination circuit 5 to output an estimate error signal being an index of carrier synchronization. The circuit 5 receives a square of the estimate error signal to estimate the state and outputs a complex symbol series and a signal discrimination value corresponding to the state transition.