Thermic roughness detection method for magnetic disc

摘要

The method involves converting an analogue signal obtained from a magnetic recording medium into a digital signal using an A-D converter (43). The digital signal is analysed for detection of thermic roughness. The detected roughness is eliminated by removal of a DC component caused by the thermic roughness from the analogue signal using a digital filter (44). The digital filter is coupled to the output of the A-D converter. An offset correction can be provided by a negative feedback loop used for subtracting a signal corresponding to the DC component from the input to the A-D converter.