Samuel L Freeman

US Patent:

48022128, Jan 31, 1989

Filed:

Jun 1, 1987

Appl. No.:

7/057017

Inventors:

Samuel R. Freeman - Atlanta GA
Thomas G. Wright - Atlanta GA

International Classification:

G11B 1504
H04L 900

US Classification:

380 3

Abstract:

A device is disclosed to prevent the unauthorized copying of magnetic tapes (tape "piracy"). The device utilizes an inaudible signal encoded into the tape program as the master recording is being made. A separate decoding circuit is to be installed in commercially available stereo tape decks. Whenever the encoded signal is present on the original recording, the decoding circuitry will short the bias signal of the tape deck being used to attempt to make the copies. This will prevent the deck from recording any of the program on the original tape.