Field-store standards conversion: Conversion between television signals with different field frequencies using ultrasonic delays

At the present time, standards conversion between television signals having different field frequencies is carried out by the image transfer method. This method results in a significant impairment of picture quality, and the convertors used require considerable maintenance and adjustment. In this paper, new methods of conversion are discussed which should overcome these disadvantages. The convertors proposed use fused-quartz ultrasonic delays capable of storing a complete field at the input standard and can be conveniently termed field-store convertors.