Patent · US Expired

Emergency alert system signal handling method and apparatus

US6020913A · kind A · utility

15Cited by
18References
21Claims
0Family size

Assignee

Inventors

Key dates

Filing dateApr 29, 1997
Grant dateFeb 1, 2000
Priority date
Expiry dateApr 29, 2017

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH04N7/165
  • WIPO fieldAudio-visual technology
  • WIPO sectorElectrical engineering

Abstract

A communication system includes a transmission channel, a relay having first and second states, an operating power port, a first signal input port, a second signal input port and a signal output port. A power supply supplies power to the relay to place the relay alternately in the first and second states. The system further comprises first and second sources of program material to be selectively and alternately transmitted in the channel. The first and second sources of program material are characterized by at least one program material frequency. The first signal input port of the relay is coupled to the first source of program material. The signal output port of the relay is coupled to the transmission channel. A first inductance is provided for coupling the power supply to the operating power port. The relay includes a second inductance coupled across the power port for controlling the relay's state. First and second capacitances are provided for coupling the second source of program material to the second signal input port.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.