| 摘要 |
PURPOSE:To check an MFM modulating circuit which is executing an actual work, by supplying a write data pulse train from the MFM modulating circuit to a clock demodulating circuit and a data demodulating circuit of a magnetic disk device, and using its 2 outputs. CONSTITUTION:An FF 31 is an FF circuit for demodulating a clock of a write data pulse train *MWDP, which is MFM-modulated from an MFM modulating circuit of a magnetic disk device or a magnetic disk controlling device, and an FF 32 is also an FF circuit for demodulating data of the write data pulse train *MWDP in the same way. A signal DMCL from an output terminal Q of the FF 31 is inputted to a comparing circuit 36, a signal DMDT from an output terminal Q of the FF 32 is inputted to a comparing circuit 37, and they are inputted to an OR gate 38 through AND gates 34, 35, respectively. If a malfunction occurs due to a fault, etc. of the MFM modulating circuit, a variation is generated in the outputs of the FF 31 and the FF 32, and an FF 39 is set. |
