This paper is concerned with estimating the performance of a multi-user frequency hopping (FH) spread spectrum mobile radio system with binary frequency-shift keying (BFSK) modulation over Rician and Rayleigh frequency-selective fading channels and, more specifically, with estimating the effect of time delay spread on that performance. Previous analyses of FH-BFSK communications over frequency-selective fading channels have typically assumed that the time delay spread models are symmetrical. This paper proposes the use of non-symmetrical time delay spread models, and introduces a new method to estimate average bit error probability, thus opening the way to the use of site-specific time-delay spread models in performance estimation and in mobile and personal communication system design.>

This paper presents studies and experiments in vocal-tract area function acoustical measurements and in speech synthesis from a physiological model of the vocal tract and the vocal cords. Following previous work by the same authors, problems associated with dynamic measurements of the vocal tract, with the quantization and interpolation of area functions are discussed and area function measurements for fixed and moving vocal tracts configurations corresponding, to sustained vowels and vowel transitions are presented. Experimental results illustrate the determination of lips and glottis position, and of the vocal tract length. Comparisons have been made with available data for vocal tract shape and formant characteristics. Speech synthesized from measured area functions is demonstrated.

Two methods are described for determining the vocal tract area function from measurements at the lips of the response to an impulsive acoustic pressure wave: - In one case, the impulse response at the lips obtained by deconvolution is used to compute the area function at all points; - Alternatively, the vocal tract is modeled by successive approximation, a search is made for the constrictions by decreasing order of importance rather than sequentially from the lips. Results obtained with both methods are good, the area functions are measured in absolute values rather than in arbitrary units. Advantages, difficulties and limitations of both methods are discussed.

This concise paper analyses the performance of noncoherentM-ary digital systems in presence of a generalized stationary Poisson impulsive noise process, with a receiver operating as a maximum likelihood detector in white Gaussian interference. Methods to bound the error probability for ASK, PSK, and FSK systems in the cases where the noise is impulsive and quasi-Gaussian are described and the results discussed.