PHASE-LOCKED LOOP, PHASE COMPARATOR FOR USE IN THE PHASE-LOCKED LOOP, AND REPRODUCING DEVICE INCLUDING THE PHASE-LOCKED LOOP

摘要

A phase-locked loop comprises an input terminal (1) for receiving a binary signal, a phase comparator (3) having a first input (2) coupled to the input terminal (1), having a second input (4), and having an output (5) coupled to an input (9) of a control-signal-controlled oscillator (10) via a control-signal generator unit (7). An output (11) of the oscillator is coupled to the second input of the phase comparator. The phase comparator is adapted to derive a first pulse (P1) and a second pulse (P2) in response to a signal transition from a first value to a second value in the binary signal applied to the first input and an oscillation signal applied to the second input, which first pulse has a pulse width which is a measure of the phase difference between the binary signal and the oscillation signal and which second pulse has a pulse width proportional to 1/2.fo, where fo is said frequency of the oscillation signal. The control-signal generator unit (7) is adapted to derive a control signal from the first and the second pulse and to apply the control signal to the oscillator, and the control-signal generator unit is adapted to derive such a control signal from the first and the second pulse that the phase difference is controlled substantially toward zero.