| 摘要 |
PURPOSE:To obtain a high-speed phase locking without hang-up phenomena by providing hysteresis characteristics having two ways of phase comparison outputs in response to the history of phase change except points before and after locking stable point to a phase comparator. CONSTITUTION:The phase between an input signal and an output of a voltage controlled oscillator 2 is compared by a phase comparator 3', a signal via a loop filter 4 of the compared output controls the oscillator 2 to phase-lock the input signal and the signal from the oscillator 2 and the result is outputted from a terminal 5. In this case, when the phase difference theta between the input signal and the output signal of the oscillator 2 is within the range of -pi/2-+pi/2, the comparator 3' shows an output characteristic of sintheta, and when the theta is within the range of pi/2-3pi/2, +1 is outputted and when in the range of -3pi/2--pi/2, -1 is outputted by the hysteresis characteristic. Thus, when the phase difference theta is within -3pi/2-+3pi/2, the phase is slipped in the direction of the arrow in the figure and the output is converged to the zero point. |
