Accession Number:

ADA137999

Title:

Voice Preprocessing System Incorporating a Real-Time Spectrum Analyzer with Programmable Switched-Capacitor Filters.

Descriptive Note:

Final rept.,

Corporate Author:

MITRE CORP BEDFORD MA

Personal Author(s):

Report Date:

1984-01-01

Pagination or Media Count:

52.0

Abstract:

As part of a speaker verification program for BISS Base Installation Security System, a test system is being designed with a flexible preprocessing system for the evaluation of voice spectrumverification algorithm related problems. The main part of this report covers the design, construction, and testing of a voice analyzer with 16 integrating real-time frequency channels ranging from 300 Hz to 3 KHz. The bandpass filter response of each channel is programmable by NMOS switched capacitor quad filter arrays. Presently, the accuracy of these units is limited to a moderate precision by the finite steps of programming. However, repeatability of characteristics between filter units and sections seems to be excellent for the implemented fourth-order Butterworth bandpass responses. We obtained a 0.1 dB linearity error of signal detection and measured a signal-to-noise ratio of approximately 70 Db. The proprocessing system discussed includes preemphasis filter design, gain normalizer design, and data acquisition system design as well as test results. Author

Subject Categories:

  • Administration and Management
  • Voice Communications

Distribution Statement:

APPROVED FOR PUBLIC RELEASE