Gte Laboratories Incorporated

In Usa, Inc.

Baruch Mazor

Dale E Veeneman

Scott Keller

Daniel Behr

Victor J Dosoretz

Systems and methods for providing an ultra-stable measurement of the density of a fluid/gas species such as ozone in a mixture. The technique is based on information extracted from multi-wavelength light absorption, at which the species exhibits different absorption properties (coefficient values). The technique provides real-time compensation for short- and long-term instability in the light source and detector, and for detectable changes in the optical characteristics of the cell, thus improving the accuracy of the measurement while making frequent zeroing of the instrument unnecessary. In addition, the invention provides a high-performance technique for measuring ultra-high ozone densities using absorption at the Chappuis band. The invention provides in an embodiment a system and method for detection of a gas component such as ozone in a gas mixture utilizing a light source providing light output in the visible spectrum corresponding to maximum and minimum absorption wavelengths for the gas component of interest. A process gas containing ozone or other gas component to be measured is supplied to a cell or cuvette having an optical input end and an optical output end. The light sources are desirably coupled to a first ('sample') optical path which provides light from the sources to the optical input end of the cell, and to a second ('reference') optical path which does not pass through the sample gas. A sensor apparatus is disposed to receive the light transmitted through the cell, and through the second optical path. The second optical path serves as a reference path, while the first optical path serves as a measurement path. The sensor apparatus provides electrical outputs representative of the intensity of light impinging thereon, the outputs being provided to a processor operative to calculate the concentration of the ozone or other gas component of interest in the gas cell.

Multi-wavelength based ozone measurement method and apparatus

In an adaptive subband excited transform speech encoding system, a range of quantizers are available and are dynamically selected for each window of speech. The quantizers designated for individual subbands are determined to minimize mean squared error distortion in the recreated signal while using no more than a predetermined number of quantization bits per window of speech.

Dynamic bit allocation subband excited transform coding method and

A method of encoding speech includes a limited search of a tree-code excitation codebook with a closed loop gain calculation for each test path under consideration. The gain calculation occurs when minimizing an error distance measurement between a synthetic signal defined by each test path being considered and the appropriate speech signal by optimizing a scaling factor of the synthetic signal. The encoding method achieves a significant reduction in computational complexity with minimal loss of performance.

Method for reducing the search complexity in analysis-by-synthesis coding

A comb filter minimizes framing noise resulting from block encoding of speech. The comb filter has both pitch and coefficients adapted to the speech data. Block boundaries may be centered on filter segments of a fixed duration.

Method for enhancing the quality of coded speech

In a speech coding system, scale factors are generated and encoded for each of a plurality of subbands of a Fourier transform spectrum of speech. Based on those scale factors, the spectrum is equalized. Coefficients of a limited number of subbands determined by the scale factors are encoded. The number of bits used to encode each coefficient of each transmitted subband is determined by the scale factor for each subband. At the receiver, coefficients of subbands which are not transmitted are approximated by means of a list replication technique.

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Newton Center, MA, United States of America

Baruch Mazor