Dale A Gleitz

US Patent:

6587825, Jul 1, 2003

Filed:

Apr 18, 2000

Appl. No.:

09/551337

Inventors:

Dale Gleitz - Fort Worth TX
Thomas Forde Martin - Richardson TX
Harvey Rogers - Irving TX

Assignee:

General Instrument Corporation - Horsham PA

International Classification:

G10L 1900

US Classification:

704500

Abstract:

A system transmits two audio services, each related to a different video program, within the bandwidth typically reserved for a single audio channel. Each audio service may be processed as a mono, stereo or encrypted signal prior to modulation onto its own audio carrier. The two audio carriers are summed together and applied to an RF modulator. The frequencies of the audio carriers are selected to ensure that the quality of the video program is not degraded, the video channel mask bandwidth is not exceeded and interference from the unselected audio carrier is negligible.