| 摘要 |
PURPOSE:To demodulate a digital signal sent in a short burst in a preamble section at high speed and to lower a code error rate by switching the output of a delay detection circuit and a synchronizing detection circuit in a proper timing. CONSTITUTION:Before the data M2 of a differential PSK signal is inputted, a switch control circuit 7 throws a switch 6 at first to select a delay detection circuit 4. When the data M2 is inputted, the delay detection circuit 4 responds to the data at high speed and demodulates the data M2 and outputs a demodulation signal from an output terminal 9 via the switch 6. The data M2 is inputted also to a synchronizing detection circuit 3 at the same time and a synchronizing detection circuit 3 recovers the carrier. After the stable circuit operation, the switch 6 is switched to the synchronizing detection circuit 3 from the delay detection circuit 4. Thus, the synchronizing detection circuit 3 having an theroretically excellent code error rate characteristic is utilized to attain the demodulation with very stable and low code error rate.
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