05127053 is referenced by 174 patents and cites 2 patents.

A method of operating an autocorrelation pitch detector for use in a vocoder overcomes the pitch doubling and tripling problem using a heuristic rather than an analytic approach. The process tracks the times of occurrence of a highest and a second-highest autocorrelation peak. The amplitudes of the highest and the second-highest autocorrelation peaks are compared and, when these peaks are within a predetermined percentage difference in amplitude, the ratio of the time position (IPITCH2) of the second-highest peak to the time position (IPITCH) of the highest peak is checked to determine if that ratio is 1/3, 1/2 or 2/3, within a predetermined error limit .epsilon.. If so and if the ratio is either 1/2 or 1/3, then IPITCH is set equal to IPITCH2 as reepresentative of the pitch period while, if the ratio is 2/3, then IPITCH is divided by three in order to represent the pitch period.

Title
Low-complexity method for improving the performance of autocorrelation-based pitch detectors
Application Number
7/632552
Publication Number
5127053
Application Date
December 24, 1990
Publication Date
June 30, 1992
Inventor
Steven R Koch
Waterford
NY, US
Agent
James C Davis Jr
Marvin Snyder
Assignee
General Electric Company
NY, US
IPC
G10L 5/00
View Original Source