Earl D Hansen

US Patent:

41351827, Jan 16, 1979

Filed:

Jun 17, 1977

Appl. No.:

5/807765

Inventors:

Wayne D. Bell - Bountiful UT
Earl T. Hansen - Taylorsville UT

Assignee:

Sperry Rand Corporation - New York NY

International Classification:

G06F 314

US Classification:

358141

Abstract:

An electrical circuit for allowing the use of a TV receiver to display alpha/numeric data includes a pair of monostable multivibrators, logic circuitry and a tri-state gate for shaping and mixing digital horizontal and vertical retrace sync signals and alpha/numeric video signals to create a properly proportioned composite thereof. The circuit further includes an oscillator for generating a RF carrier signal, a field-effect transistor (FET) coupled between the oscillator and the output of the circuit which is adapted to be coupled to the antenna terminal of the TV receiver, and an emitter-follower device which feeds the composite signal to the FET for producing amplitude modulation of the RF carrier signal by the FET and transmission of the modulated signal to the TV receiver antenna terminals.