| 摘要 |
PURPOSE:To read data out of media which differ in recording density by inputting the output of a phase synchronizing circuit, the output of a synchronous detecting circuit for read data, and the output of a timer circuit, an switching the rotating speed of a floppy disk. CONSTITUTION:The phase synchronizing circuit 1 inputs read data (a) to generate sampling pulses S synchronously with the data, and a locking circuit 2 outputs a lock signal (e) on detecting the data (a) being synchronized with the pulse (s). A sink signal (c) outputted by a floppy disk controller and an index signal (b) are inputted to terminals MR and CP of a D type FF constituting a timer circuit 3. The signal (e) and the output (d) of the circuit 3 are inputted to a D type FF constituting a switching circuit 5 through an AND gate 4, and a motor control circuit 6 selects and outputs a motor control reference clock (g) or (h) from a clock source with a switching signal (f) outputted by the circuit 5. Thus, even one kind of equipment is capable of reading data out of media which differ in recording density. |
