摘要 |
A DISCRETE-TRACK-RECORDING (DTR) DISK (ALSO CALLED "PATTERNED" DISK) HAS A SECTORED SERVO FORMED BY MODULATION OF ITS SIDEWALLS IN A PREDETERMINED MANNER, WHEREAS SIDEWALLS OF DATA SECTORS ARE NOT MODULATED IN THIS MANNER. EACH SERVO SECTOR (121j) HAS TWO SIDE WALLS (133i), (134i) THAT ARE EACH RESPECTIVELY MODULATED IN TWO DIFFERENT WAYS. HENCE, A READBACK SIGNAL FROM A GIVEN SERVO SECTOR (121j) CONTAINS COMPONENTS OF EACH OF THE TWO DIFFERENT MODULATIONS, EVEN IN CASE OF 'DC' ERASE INITIATION. THEREFORE, THE JUST-DESCRIBED MODULATED SERVO SECTORS ELIMINATE SERVOWRITING. MOREOVER, DATA SIGNALS ARE READ WITHOUT FILTERING THE MODULATION, BECAUSE DATA SECTOR SIDEWALLS ARE NOT MODULATED. |