To mark the completion of a ten-year effort to develop a high performance text-to-speech algorithm, we have established a benchmark system called “MITalk.” Components of the computer-simulated bench mark include: (1) conversion of abbreviations and special text symbols, (2) a lexicon consisting of about 11 000 morphs with pronunciation and parts of speech, (3) morpheme analysis, (4) letter-to-sound rules, (5) syntactic analysis, (6) rules for stress assignment, boundary placement and phonological recoding, (7) fundamental frequency and segmental duration prediction, (8) phonetic-to-parametric conversion, and (9) digital formant synthesis. The MITalk-79 system is being extensively documented and its performance is being evaluated. The presentation will summarize aspects of system organization and performance. (A more complete description will be given in a one-week course to be offered June 25–29, 1979.) The oral presentation will include a five-minute demonstration of synthetic speech generated from English text with absolutely no human intervention. While currently simulated on a large digital computer, MITalk-79 is amenable to practical IC technology. Implementation issues will be briefly discussed. [We gratefully acknowledge the synthesis-by-rule programs and advice provided by Dennis Klatt.]
This paper examines the effects on fundamental frequency (F0) patterns of modality operators, such as sentential adverbs, modals, negatives, and quantifiers. These words form inherently contrastive classes which have varying tendencies to produce emphasis deviations in F0 contours. Three speakers read a set of 186 sentences and three paragraphs to provide data for F0 analysis. The important words in each sentence were marked intonationally with rises or sharp falls in F0, compared to gradually falling F0 in unemphasized words. These emphasis deviations were measured in terms of F0 variations from the norm; they were larger toward the beginning of sentences, in longer sentences, on syllables surrounded by unemphasized syllables, and in contrastive contexts. Other results showed that embedded clauses tended to have lower F0, and negative contractions were emphasized on their first syllables. Individual speakers differed in overall F0 levels, while using roughly similar emphasis strategies. F0 levels changed in paragraphs, with emphasis going to contextually new information.
A macromodeling and timing simulation technique is presented that allows fast, accurate delay calculations for CMOS circuits. This method is well suited for delay calculations of regular structure VLSI circuits, as well as circuits designed from standard cell libraries. Timing models for both logic gate and transmission gate circuit forms are developed. For logic gates, output transition time and delay time are functions of input transition time and load impedance. Effective resistances for conducting transmission gates and switching transmission gates are functions of input transition time and load capacitance. Transmission gate circuits are then modeled as equivalent RC circuits. Separate waveform models and delay calculation methods exist for both types of circuit forms, with an interface to enable the use of both methods in the same simulation. An experimental event-driven simulator was developed to test the accuracy of the macromodels and to estimate improvements in execution time with respect to SPICE. Typical delay times were within 5% for logic gate circuits and 10% for transmission gate circuits when compared with SPICE. The execution time of the experimental simulator was over two orders of magnitude faster than SPICE.
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