FM recording characteristics of Co-Ni obliquely evaporated tape

The recording and reproducing characteristics of Co-Ni obliquely evaporated (metal evaporated, or ME) tape in video recording were investigated in comparison with metal-particulate (MP) tape using a single-frequency signal and a frequency-modulated (FM) signal. The results indicate that the formation of the circulation magnetization mode is difficult, although in ME tape as in MP tape there is an effective recording depth which is estimated to be a quarter of the recording wavelength in short-wavelength recording. It has been clarified that the lower sideband enhancement and the upper sideband suppression of the reproduced FM signal are reduced as the recording current is increased. The bias recording characteristics were also measured, and it was found that the reproduced voltage of the low-frequency converted chrominance signal does not depend on the gap length of the recording head