| 摘要 |
PURPOSE:To remove a rapid phase change at a signal information changing point, by smoothing the phase change of a modulation wave through the insertion of a specific frequency at a certain time width including the signal changing point, in a digital communication system with digital phase modulation (PSK). CONSTITUTION:An output wave from an oscillation source 1 is branched into three; one is produced into a phase modulation wave in 0 or pi with a data signal delayed from an input terminal 2 at a two-phase modulator 4 and inputted to a gate circuit 11, and other two are inputted to producing circuits 5 and 6 in frequencies f1 and f2, and either of the circuits 5 and 6 is selected with a switch 7 so that the phase of the modulation wave is continuous, and the result is inputted to a phase control circuit 8 and applied to a gate circuit 11-2. A code pattren is detected from a data signal from a terminal 3 at a pattern detection circuit 9, a gate control pulse is formed from the circuit 10 with the output and the pulse is inputted to gate circuits 11-1 and 2, and the waveform at each gate circuit passing is added at an adder 12 to obtain an output signal. The output signal is not subject to rapid change by other frequency f1 and f2. |
