Information detection apparatus having a digital tracking oscillator

摘要

Double transition recorded information, such as phase encoded or frequency encoded information, is detected by use of a digital tracking oscillator which is responsive to either the data or the clock transitions of the recorded information and which produces a string of pulses in response thereto having a frequency which changes dependent upon the frequency of occurrence of the information. Clock pulses, and accordingly, a window, are thus generated, bracketing the data substantially in accordance with predetermined criteria, thereby enabling effective detection of the data included in the information.