Cynthia Ann Jaskie

A 600 bps LPC voice coder

The authors describe a 600 bit/s vocoder that is based on the LPC-10 (linear prediction coding) vocoder model. The coder operates on the principle of selecting a point on the 600 bit/s rate distortion bound that is optimal given the rate of spectral change within a four-frame superframe of speech. The authors describe the tradeoffs in spectral coding, pitch coding, voice encoding, RMS encoding, synchronization, and forward error correction. The perceptual weighting criteria used are shown to select reasonable operating points on the rate distortion bound as speech spectra change from quasi-stationary to rapidly dynamic.<<ETX>>

CipherVOX: scalable low-complexity speaker verification

Biometrics is gaining strong support for access control in the industry. It is not uncommon for individual users to be faced with a half-dozen or more passwords and personal identification numbers (PINs) controlling access to the systems required for them to do their job. The ubiquity of passwords actually relaxes system security since many users tend to use the same password across all applications, or collect the various passwords in a single location (perhaps a password protected spreadsheet, or a piece of paper in a desk drawer). The latter case is of extreme concern since security around the collection is much more easily compromised than that of the system. The use of biometrics not only recovers the ability to secure sensitive systems and data, but also does so in a user-friendly manner. In order to use biometrics successfully in server-based environments, several key concerns must be addressed. First, the authentication strategy must maintain acceptable levels of security. Second, the user community must accept the chosen biometric (unless there is a captive audience). The last major consideration is the scalability of the solution. In this paper we introduce CipherVOX, a speaker verification access control solution for server and standalone computing environments. We discuss the use of our polynomial-based classifier that combines high-accuracy and low-complexity via discriminative techniques, and give performance results for both a proprietary performance database and the standard YOHO database. We also review the challenges in designing for user acceptance, including the design of the speaker verification user interface, as well as the application programming interface (API).

Microcomputer‐based system for speech synthesis from a large English text data base

The basic goal for the described project is selective and interactive production of synthetic speech from a large data base such as a training manual. In a training environment at a sophisticated computer control console, an operator should learn more effectively and efficiently if both aural and visual senses are used and if his eyes and hands are free to concentrate on the panel before him. The system described includes an operator‐directed control strategy to selectively retrieve that part of text which is to be spoken, a considerable amount of text preprocessing in non‐real time to obtain synthesizer control parameters, and a microcomputerized cascade terminal analog speech synthesizer. The preprocessing of the English text utilizes an extensive set of translation rules, dictionary lookup of complete words, and morph lexicon lookup of parts of words to produce 123 distinct allophone designators with corresponding stress, pitch, and duration designators. Storage requirements for the preprocessed speech...