Minimum variance distortionless response (MVDR) modeling of voiced speech

In this paper we propose the MVDR method, which is based upon the minimum variance distortionless response (MVDR) spectrum estimation method, for modeling voiced speech. Developed to overcome some of the shortcomings of linear prediction models, the MVDR method provides better models for medium and high pitch voiced speech. The MVDR model is an all-pole model whose spectrum is easily obtained from a modest non-iterative computation involving the linear prediction coefficients thereby retaining some of the computational attractiveness of LPC methods. With the proper choice of filter order, which is dependent on the number of harmonics, the MVDR spectrum models the formants and spectral powers of voiced speech exactly. An efficient reduced model order MVDR method is developed to further enhance its applicability. An extension of the reduced order MVDR method for recovering the correct amplitudes of the harmonics of voiced speech is also presented.