| 摘要 |
PURPOSE:To expand a system application range and to obtain an optimum system particularly suited to an educational system by controlling to substitute a part corresponding to a sound-information inserted part by another picture obtained from a computer, etc., on a reproduction side. CONSTITUTION:A block part where the sound information is inserted is substitued with another video signal obtained from the computer, etc., by a video synthesize (or masking) circuit 15, or clamped to a constant level such as a pedestal level and a mean video level (APL) and outputted. An external sound signal is selected as an output voice signal when no sound information is outputted or when a switch 16 is operated forcibly. A part shown by a dotted line in a figure is necessary to provide this decoder with an LL (Language Laboratory) function, and a leaner's microphone input voice is digitized by an A/D converter 18 and written in a time-axis expansion memory 10. This memory 10 serves as a tape recorder. |
