A technique using VHS high-fidelity equipment to record two different distinguishable signals on the same track is described. The first signal has to be recorded by a longer-gap-length head in order to obtain higher residual output after overwrite erasing by the second signal for coating-type materials. When the wavelength of the first signal is relatively short, the shorter the second signal wavelength, the greater is the erasure of the first signal. The azimuth angle should be chosen in such a way as to minimize the crosstalk between the first and second recorded signal. This phenomenon can be used for rotary erasing and overwrite erasing.
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