Restoring and clocking pulse width modulated data

摘要

Width restoring to eliminate unintended width variations in pulse width modulated data in combination with a phase lock loop allows pulse width modulated data in high density optical recordings. The width restoration is accomplished by detecting the timing relationship of the leading and trailing edges of pulses relative to expected timing for the leading and trailing edges. Expected time is derived from a phase locked loop or the original write signal. The detected timing is compared to the expected timing and the timing of the leading and trailing edge signals is corrected. Either analog or digital width correction techniques are used. Width restoration may be used while reading data or while writing the data.