| 摘要 |
<p>PURPOSE:To prevent overflow and underflow of a buffer memory by controlling a switch circuit selecting a moving picture signal or an inter-frame difference signal with an output of a remaining capacity discrimination circuit. CONSTITUTION:When a digital video signal is inputted to the title circuit, the signal and a one-frame delay data in a frame memory are subject to subtraction processing and the result is given to a switch circuit 9 selecting an in-frame signal or an inter-frame signal as an inter-frame difference signal. In this case, an output of a memory 4 is always read in the data transfer rate of a transmission system. Thus, a remaining capacity discrimination circuit 8 always takes a difference between a data quantity written in the memory 4 and a data quantity to be read, and a parameter of an SQ2 circuit 2 and an inverse SQ circuit 5 is revised and the switch circuit 9 is changed over so that underflow and overflow of the memory do not take place. Thus, the underflow and overflow of the buffer memory are prevented and a prescribed transfer rate is always ensured.</p> |
