Contour biasing and AC biasing-a comparison

In direct magnetic recording, the distortion mechanism has been measured and found to be essentially cubic in structure. Using the dual input describing function approach, a mathematical model describes the linearising effect of AC biasing which agrees very well with practice especially at long wavelengths. A new method of making distortion-free recording is proposed, called Contour Biasing. With the removal of AC bias, the majority of the high frequency losses disappear giving substantially improved performance at short wavelength. A new model of the recording process is proposed and three more distortion mechanisms are defined