Optical heterodyne detection pulse receiving system and method专利检索- .以所用脉冲调制为特征的专利检索查询-专利查询网

Optical heterodyne detection pulse receiving system and method
申请号	EP84300603	申请日	1984-01-31	公开(公告)号	EP0115445A3	公开(公告)日	1988-05-11
申请人	NEC CORPORATION;			发明人	Minemura, Kouichi; Shikada, Minoru; Emura, Katsumi;
摘要	A photodiode (4) detects an intermediate frequency signal from an incoming pulse-modulated light carrier (1) and a local oscillator light beam (6) superimposed by means of a half-silvered mirror (2). The intermediate frequency (e.g. 128 MHz) is a multiple (e.g. 4 times) the modulating pulse repetition frequency (e.g. 32 MHz) which is extracted by a timing circuit (10). The intermediate frequency is divided in divider (14) by the said multiple and then phase-compared with the pulse repetition frequency in an oscillator control circuit (15) completing a phase-locked loop for the laser oscillator (5) which generates the local oscillator light beam (6). Jitter and wave form distortion problems with the regenerated pulses are thus avoided even with a significantly lower intermediate frequency than has heretofore been necessary.
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