Abstract :
Many domestic television receivers do not interlace correctly even when the frame flyback is being initiated at the correct time. The principal causes of this effect are variations in the amplitude of the frame flyback. The mechanisms of such variations have been investigated, and means of reducing the variations are suggested. In particular, the design of the oscillator stage, which is at least as critical for good interlacing as is the design of the synchronizing separator, is discussed. Despite the presence of most of the variations referred to, it is practicable to maintain the flyback amplitude constant by a method which is applicable to the majority of domestic receivers.