We demonstrate two simple and inexpensive methods of using the force exerted by the light transmitted through an optical fiber to center a lens on the fiber core with submicrometer accuracy. By choosing the appropriate lens one can either focus, collimate, or defocus the light emerging from the fiber. We discuss extensions of this technique to a wider variety of lenses and light sources, including semiconductor lasers.

Aligning and attaching a lens to an optical fiber using light pressure force

The time-domain periodogram algorithm

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i Statement of copyright . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Table of

/pdf/modelling-and-extraction-of-fundamental-frequency-in-speech-3gv5ulq7uk.pdf

Modelling and extraction of fundamental frequency in speech signals

A cascaded voice biometric system

In this paper, we have proposed a new algorithm for pitch detection and an idea for harmonic separation based on pitch detection. Firstly, we have introduced the pitch algorithm. It is mainly consisted of five parts: mean value removal, extraction of alternative pitch periods, best pitch transfer path search, accurate pitch period search with time-varying filter and the search of fractional pitch period. Then we have brought in a harmonic separation algorithm based on the pitch detection. The pitch detection algorithm and harmonic separation algorithm proposed in this paper is mutually beneficialExperiments results show that the new pitch detection algorithm can achieve higher accuracy. And compared with some other algorithms, this approach owns a better noise immunity. The harmonic separation algorithm can separate each harmonic signal accurately.

Improved Algorithm for Pitch Detection and Harmonic Separation

In speech processing an estimation of the speech pitch period is important. Real time pitch detection is only possible by the selection of an efficient algorithm suitable for implementation on a programmable processor or in special-purpose hardware. The use of the periodogram algorithm (p.a.) is proposed to detect the pitch period of voiced speech. This algorithm is attractive for the following reasons: (a) it has no multiply operation; (b) when implemented on a 16-bit computer (e.g. microprocessor) the computation can be done in integer arithmetic without exceeding the microprocessor's dynamic range; (c) it is a simple technique for estimating the pitch period with reasonable accuracy. Results of the analysis of speech signals and sinusoids using the periodogram algorithm are presented and comparisons are made with the average magnitude difference function (a.m.d.f.) which is an alternative method of estimating the pitch period of the voiced speech.

G. D. Tattersall

Papers

Estimating the pitch period of voiced speech