Method and apparatus for estimating the fundamental frequency of a signal
AssigneeMotorola, Inc.
InventorJames Patrick Ashley
Life of this patent
Estimating the term…
Abstract
A method and apparatus for improved pitch period (τ) estimation in a compression system is disclosed. The system uses original estimates of integer lag (τ0) and open-loop prediction gain (βol) as input to an adaptive filter parameter initialization block (304) which supplies inputs to a plurality of adaptive filter elements (306-308). Adaptive filter elements (306-308) provide information regarding the harmonics of the residual signal (ε(n)) to an adaptive filter parameter analysis block (310). Adaptive filter parameter analysis block (310) estimates the fundamental frequency of the residual signal based on the analysis of the harmonics and outputs a pitch period (τ) for eventual use in a delay contour computation.
Claims6
In an open-loop lag estimation system for use in a speech compression system, a method for estimating a fundamental frequency with improved pitch period estimation of a linear prediction residual signal, the method comprising the steps of:
- receiving the linear prediction residual signal;
- generating an integer lag and an open-loop prediction gain of the linear prediction residual signal;
- generating a plurality of initial parameters using the integer lag and the open-loop prediction gain;
- estimating the fundamental frequency of the linear prediction residual signal using the plurality of initial parameters.
In a speech compression system, an open-loop lag estimation system for estimating a fundamental frequency with improved pitch period of a linear prediction residual signal, wherein the open-loop lag estimation system comprises:
- an autocorrelation analysis block for receiving the linear prediction residual signal, wherein the autocorrelation analysis block produces an integer lag and an open-loop prediction gain;
- an adaptive filter parameter initialization block coupled to the autocorrelation analysis block and receiving the integer lag and the open-loop prediction gain, wherein the adaptive filter parameter initialization block produces a plurality of initial parameters;
- an adaptive harmonic filter bank coupled to the adaptive filter parameter initialization block, wherein the adaptive harmonic filter bank receives the plurality of initial parameters, and further wherein the adaptive harmonic filter bank estimates the fundamental frequency of the linear prediction residual signal using the plurality of initial parameters.
Dependencies are inferred from the claim text.