Phase-Locked Oscillator Charge Pump
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
In a direct-access storage device, the function of a phase-locked oscillator (PLO) is to provide a system clock that is phase-locked to data which has been read from recording media or that is phase-locked to the servo clock during write mode. The PLO also standardizes readback data to reject jitter due to bit shift, and provide fast synchronization to read data. The present PLO configuration, shown in Fig. 1, consists of a voltage-controlled oscillator (VCO), a filter network, and an error detector comprising phase discriminator and charge pump circuitry. The filter is a lead/lag network for compensation. The PLO has a run mode and a fast sync mode.