Shared Variable Frequency Oscillator with Adjustable Windows for Multitrack Operation
Original Publication Date: 1978-Feb-01
Included in the Prior Art Database: 2005-Feb-20
One variable frequency oscillator (VFO) can be shared by all of the tracks of a magnetic recording device for determining the timing acceptance or window of data bit pulses from a multitrack system having statically skewed data. The VFO 1 is synchronized to a master track, and generates a plurality of phase-delayed clock windows by a shift register 2. The skew of data on each track is measured at the beginning of each data block by a counter 3, operated at a multiple of the master track frequency. As shown in the figure, the time delay between the data pulse from the master track and the reference clocking pulse is determined by the binary counter 3. The counter 3 is incremented by clocking pulses whose period is a small subinterval of the data window.