A TV receiver with built-in multiple functions such as TV, PIP, and VCR functions, is disclosed. The TV receiver processes a PIP signal in response to switching control by a microcomputer without using a separate tuner for PIP processing, and causes picture and audio signals to be selected for main and...http://www.google.ca/patents/US5315391?utm_source=gb-gplus-sharePatent US5315391 - PIP main and subscreen selection from among TV, BS, and VCR playback signals
