Before revision: However, numerous related patents have since been applied for or granted, referencing the original FMX patents.Google Patents References U.S. Patent4,485,483, FM Stereophonic system incorporating companding of difference signal, filed March 18, 1983, issued November 27, 1984.
After revision: However, numerous related patents have since been applied for or granted, referencing the original FMX patents.Google  U.S. Patent4,485,483, FM Stereophonic system incorporating companding of difference signal, filed March 18, 1983, issued November 27, 1984.