Paul P Joyce

US Patent:

55331190, Jul 2, 1996

Filed:

May 31, 1994

Appl. No.:

8/250873

Inventors:

Gary E. Adair - Plantation FL
Paul Joyce - Boca Raton FL

Assignee:

Motorola, Inc. - Schaumburg IL

International Classification:

H04M 158

US Classification:

379391

Abstract:

A sidetone optimization circuit (230) provides the capability to adjust sidetone level received at a telephone handset to a desired level. A noise source (204) generates a noise signal that gets filtered by filter (206) in order to provide band limited noise to a telephone interface circuit (202). Telephone interface circuit (202) provides a sidetone signal (210), also known as a trans-hybrid loss signal. The trans-hybrid loss signal is filtered at filter (212) and transformed to a DC level at detector (214). The DC level is then compared to a predetermined threshold at comparator (224), and a variable impedance circuit (218) is adjusted until the DC level reaches the predetermined threshold in order to achieve a desired level of sidetone.

US Patent:

20150043739, Feb 12, 2015

Filed:

Aug 7, 2013

Appl. No.:

13/961399

Inventors:

- Framingham MA, US
Dilip Gopinath Warrier - Acton MA, US
Paul Joyce - Milford NH, US

International Classification:

H04R 3/00

US Classification:

381 59

Abstract:

A method for crest-factor based gain modification comprises sampling audio inputs to determine an energy for each input. The inputs are amplified to produce output channels. An average energy is determined for each frame by adding a percentage of a last average energy to a residual percentage of the energy. The last average energy is equal to zero for a first sampling of the audio inputs. The residual percentage is equal to one hundred minus the percentage of the last average energy. The amplifier gain is iteratively reduced by a decrease-step for a fixed period until a number of exceeding-inputs is less than or equal to a maximum. The exceeding-inputs have an average energy that exceeds a maximum-energy. The amplifier gain is iteratively increased by an increase-step for another fixed period until a number of exceeding-inputs is greater than a maximum.