| 摘要 |
PURPOSE:To improve the response and noise characteristic by providing a circuit not giving any output when an output pulse is small and outputting a setting width when the pulse width is less than the setting width to the post stage of a phase detection stage from which a phase error is outputted in terms of a pulse width. CONSTITUTION:Pulse width converting circuits 7-1, 7-2 consist each of a NAND circuit inputting an input pulse and an inverted output of a monostable multivibrator triggered at the negative edge of the input pulse and output a pulse width depending on the output pulse of the monostable multivibrator (between DELTAr and r) when the output pulse width of a phase frequency detector is less than the setting pulse width of the said monostable multivibrator. When the output pulse width of the phase frequency detector 3 is more than it, the pulse having the output pulse width is outputted. If the output pulse width of the phase frequency detector 3 is very small, no output pulse is given and a dead band is produced because of the delay characteristic of the pulse width converting circuits 7-1, 7-2. |
