David Lee Ham

US Patent:

49532219, Aug 28, 1990

Filed:

Jun 15, 1989

Appl. No.:

7/367301

Inventors:

Arthur C. Holly - Austin TX
Charles R. Culbertson - Austin TX
David L. Ham - San Antonio TX

Assignee:

Walkaway Technologies, Inc. - San Antonio TX

International Classification:

H03G 300

US Classification:

381108

Abstract:

A novel and improved automatic gain control (AGC) circuit which is ideally suited for use with sound systems which are operated in a very large environment, such as a supermarket or auditorium. The preferred embodiment of the circuit comprises first and second input channels and a single output channel. The first input channel is a feedback signal provided by a microphone which is placed near one of the speakers of the sound system. The second input channel receives a music signal which is being played by the sound system. The output of the circuit is a music signal which has a constant ratio relative to the noise detected in the environment. Constant power ratio operation of the system is achieved through the use of logarithmic processing of the signals in each of the respective input channels. Control circuitry is provided to maintain the gain level of the system at a constant level during periods of time when no music is present on the second input channel.

US Patent:

51684810, Dec 1, 1992

Filed:

Dec 29, 1989

Appl. No.:

7/458947

Inventors:

Charles R. Culbertson - Austin TX
Arthur C. Holly - Austin TX
David L. Ham - Malibu CA

International Classification:

H04B 120
G11B 1722

US Classification:

369 2

Abstract:

An automated digital broadcast system which is capable of reliable operation for long periods of time without human assistance. The system comprises a plurality of compact disc players or other audio devices which are controlled by computer to sequentially play a predetermined list of musical selections and commercial or informational messages.