| 摘要 |
PROBLEM TO BE SOLVED: To reduce a time till a normal locking state is reached at momentary interruption of a modulation signal at raising of a power supply or the like. SOLUTION: A voltage controlled oscillator VCO receives a VCO control signal Dc via a logic circuit 84 and generates a sampling clock Cs and outputs an asynchronous alarm signal A1 in the asynchronous state. A differential coefficient discrimination circuit 82 discriminates a differential coefficient of a waveform at a current sampling based on output data Di, Dq and detects a deviation from an optimum sampling point and outputs a VCO control signal Dc. A data area discrimination circuit 83 discriminates a data area based on output data and discriminates a faulty state, then outputs a fault discrimination signal A2. A logic circuit 84 masks the VCO control signal Dc when the asynchronous alarm signal Al indicates an a synchronous state and the fault discrimination signal A2 denotes a fault. |
