DATA Synchronizer With Parallel Flip-Flops
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-05
When transferring read data from a magnetic disk or tape storage device to an adapter/controller, it is frequently desirable to synchronize the data to the clock before sending it to the controller in order to obtain the widest possible data window. Typically, this synchronization is done with a series cascade of two D flip-flops. A parallel rather than a series arrangement, however, can result in higher speed operation, producing a wider data window. Basically, one flip-flop scans for a transition during DATA WINDOW high and is read out during DATA WINDOW low. The other flip-flop scans for a transition during DATA WINDOW low and is read out during DATA WINDOW high. The parallel flip-flop synchronizer is shown in Fig. 1. Signal waveforms that occur in the synchronizer are shown in the timing chart in Fig. 2.