Television screen display unit

Abstract

Abstract PURPOSE: To make it possible to superimpose an external video signal and pattern signal by providing a method of selecting either one of a synchronizing signal obtained by separating the external video signal and a similar synchronizing signal obtained from another generating method. CONSTITUTION: From a video signal inputted to terminal 38, both horizontal and vertical synchronizing signals H and V are obtained by synchronous separator circuit 30 and then supplied to contact (a) of change-over switch 32. To contact (b) of switch 32, generating circuit 31 is connected which generates a synchronizing signal of the same synchronism and pulse width as the above-mentioned signal. With swirch 32 at side (b), a pattern signal of a television game, etc., controlled by a microcomputer is displayed on a TV receiver. With switches 32 and 37 at side (a), a burst from the video signal is sampled by circuit 33 and a chrominance subcarrier signal is oscillated 34; and a clock is generated by clock generating circuit 35 and under the control of control circuit 36, the pattern signal read out from RAM17 is projected on the TV receiver being superimposed upon the video signal by mixer 23. Consequently, a complex and real screen can be seen. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Akira Matsushita

Bibliographic Details