JPH02141180U

JPH02141180U -

Info

Publication number: JPH02141180U
Application number: JP1989050417U
Authority: JP
Priority date: 1989-04-28
Filing date: 1989-04-28
Publication date: 1990-11-27

Description

[Brief explanation of drawings]

第１図は、この考案の多画面デイスプレイ装置
の一実施例を示す概略回路構成図、第２，３図は
、それぞれ第１図に示した無信号検出回路の回路
図及び回路各部の信号波形図、第４，５図は、そ
れぞれ従来の多画面デイスプレイ装置の一例を示
す概略回路構成図及び回路各部の信号波形図であ
る。３……切り替え回路、１１……バツフアメモリ
、１２……画像メモリ、１６……アドレス制御回
路、１７……親画面用同期分離回路、１８……子
画面用同期分離回路、２１……多画面デイスプレ
イ装置、２２……無信号検出回路、２３……同期
切り替え回路、２４……黒信号発生回路。 FIG. 1 is a schematic circuit configuration diagram showing an embodiment of the multi-screen display device of this invention, and FIGS. 2 and 3 are circuit diagrams of the no-signal detection circuit shown in FIG. 1, and signal waveforms of various parts of the circuit, respectively. 4 and 5 are a schematic circuit configuration diagram and a signal waveform diagram of each part of the circuit, respectively, showing an example of a conventional multi-screen display device. 3... Switching circuit, 11... Buffer memory, 12... Image memory, 16... Address control circuit, 17... Synchronization separation circuit for main screen, 18... Synchronization separation circuit for child screen, 21... Multi-screen display Device, 22...No signal detection circuit, 23...Synchronization switching circuit, 24...Black signal generation circuit.

Claims

[Claims for Utility Model Registration] (1) While intermittently synchronizing the video signal for the sub-screen with its synchronization signal, some lines are thinned out, written to the buffer memory, transferred to the image memory, and then included in the video signal for the main screen. A multi-screen display device that reads out a screen memory in synchronization with a synchronization signal and inserts and displays it as a sub-screen in a part of a main screen, the no-signal detection circuit detecting that there is no signal of a sub-screen video signal. and a synchronization switching means for receiving the detection output of the no-signal detection circuit and redirecting and supplying the synchronization signal of the main screen video signal to synchronization of writing to the buffer memory. 2. The multi-screen display device according to claim 1, further comprising a child screen erasing means for receiving the detection output of the no-signal detection circuit and stopping insertion and display of the child screen with respect to the main screen. (3) A substitute small screen signal generation circuit is provided which receives the detection output of the no-signal detection circuit and supplies a substitute small screen signal to the buffer memory in place of the small screen video signal which is determined to be no signal. Multi-screen display device. (4) The multi-screen display device according to claim 3, wherein the substitute small screen signal generation circuit is a black signal generation circuit that generates a black signal. (5) The multi-screen display device according to claim 3, wherein the substitute small screen signal generation circuit is a still image signal generation circuit that generates a still image signal. (6) The multi-screen display device according to claim 3, wherein the substitute small screen signal generation circuit is a character signal generation circuit that generates a character signal.