Data Recovery Circuit
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Fig. 1 shows an improved circuit for recovering data read from a magnetic track of a diskette as a serial bit stream that has been encoded by an FM or MFM encoding technique. The circuit differs from prior-art arrangements in two respects. First, the phase detector 12 is provided with an input from the raw read data terminal whose function is to drive the filter 13 to increase the frequency of the voltage-controlled oscillator (VCO) 14. This permits the use of a digital single-shot as the sample pulse generator 15 rather than analog single-shots that have been used in the prior art. The digital single-shot is more accurate. The frequency of the VCO will tend to increase during the period from the arrival of the data pulse until the digital single-shot begins timing.