Spindle synchronization controller using advance calculation and offset values

A spindle synchronization control system for conducting a spindle synchronization control by synchronously rotating spindle motors supporting respective recording media of a plurality of storage units parallelly connected to a host computer having a reference index provided by said host computer as a reference signal, a medium index generated by reproducing each index recorded in each of said recording media, and a Hall index output from a spindle motor, said Hall index being used for detecting a phase change over time, said spindle synchronization control system including:

• reference index storing means for storing a count value corresponding to a time when said reference index is generated;
• Hall index storing means for storing a count value corresponding to a time when said Hall index is generated;
• medium index storing means for storing a count value corresponding to a time when said medium index is generated;
• discriminator means for discriminating the presence or absence of said reference index, said medium index and said Hall index;
• phase offset measuring means for measuring a phase offset value difference between said Hall index and said medium index before starting said spindle synchronization control;
• memory means for storing the thus measured offset value;
• phase difference measuring means for measuring a phase difference between said reference index and said Hall index during said spindle synchronization control;
• and
• determination means for determining a driving control value for rotating said spindle motor wherein the thus measured phase difference between said reference index and said Hall index becomes equal to said thus stored phase offset value between said Hall index and said medium index, so that the spindle synchronization control is carried out according to the thus determined driving control value.