| 摘要 |
PURPOSE:To simultaneously display plural display tasks to be asynchronously processed on desired display screens by controlling plural screen display devices OSDs independently of one another to mix the output signals of OSDs. CONSTITUTION:Character broadcast display and channel selection display are processed in a first OSD 23 and a second OSD 24 respectively. Data of character broadcast are decoded by a CPU 22, and values of registers and a display data RAM of the OSD 23 are rewritten in accordance with this data. An RGB signal is outputted from the OSD 23 by horizontal and vertical synchronizing signals and a display clock which are given from the outside. In the case of channel selection display, each part of the OSD 24 is rewritten and the RGB signal is outputted from the OSD 24 in the same manner. RGB signal outputs of OSDS 23 and 24 are inputted to a mixing circuit 25, and the circuit 25 controls priorities of RGB signals to output signals from OSDs 23 and 24 and the mixing signal from an input terminal 29 and outputs the output to the outside through an output terminal 27. |
