|
PatentVote.com: Vote on your favourite invention!
|
|
 |
Title: Code operated switching device for communications systems and the like
Abstract:
The embodiment of the invention disclosed herein is directed to a code operated switching device having a receiver for handling RF frequencies in a superheterodyne fashion without the need of local oscillators, or the like at the receiver. Input means is provided for receiving first and second RF frequencies having a predetermined frequency difference. The RF frequencies are FSK modulated simultaneously, one frequency increasing and the other decreasing, so that the frequency difference will produce a control signal at the output of an FM audio discriminator circuit. The control signal can be code modulated with series digital pulse information and applied to a code logic circuit that will detect if the proper code for the receiver has been received. If the proper code is received the logic circuit will energize an active control element such as a relay or the like to allow data to be transmitted back through the switching device.
Other info: Inventors: McVoy, David S. (Sarasota, FL, US) Application Number: 376386 Filing Date: 1973-07-05 Publication_date: 1976-02-03 Assignee: Coaxial Scientific Corporation (Sarasota, FL) Primary Class(es): 340/7.43 340/7.21, 375/272, 725/97 Other Classes: US Patent Ref:
Other Refs: Other References: IRE Dictionary of Electronics Terms and Symbols, The Institute of Radio Engineers, Inc., 1961. | |