Abstract: This invention addresses the digital transmission of wideband video, narrowband audio, and digital information over information networks. More specifically, the invention involves synchronous quantized subcarrier multiplexing (quantized-SCM) which results in purely electronic multiplexing of voice, data and multiple channel full bandwidth NTSC video for digital transmission over a communcation line and recovery of same signals at a receiving station.

Abstract: Apparatus for a monitoring and signalling system such as a home health care system. The monitoring and signalling system includes a plurality of ac-based sensors powered by an ac voltage and operative to monitor the occurrence of activities performed by an individual in his or her residence and to produce signals indicative of the occurrence of the monitored activities. Signals produced by the sensors during the presence of the ac voltage are processed by a microprocessor. A loss or absence of the ac voltage and the subsequent restoration of the ac voltage causes the ac-based sensors to produce signals falsely indicating the occurrence of monitored activities. In accordance with the present invention, the microprocessor operates to monitor the state of the ac voltage to detect a loss or absence of the ac voltage and a subsequent restoration thereof and, upon detecting the restoration of the ac voltage, to refuse to accept for processing, for a two-second interval, signals received from the sensors.