DID YOU KNOW? DTIC has over 3.5 million final reports on DoD funded research, development, test, and evaluation activities available to our registered users. Click
HERE to register or log in.
Accession Number:
AD0831090
Title:
MODIFICATION OF THE MODEL 254C SIMORAMIC (TRADE NAME) DOUBLE-SPECTRUM ('CEPSTRUM') ANALYZER FOR IMPROVED EXTRACTION OF PITCH DATA.
Corporate Author:
FEDERAL SCIENTIFIC CORP NEW YORK
Report Date:
1968-01-01
Abstract:
The AFCRL Cepstrum Pitch Extractor has been modified to make possible its use in a wide range of experiments in speech bandwidth compression. One of the changes permits the AFCRL Polymodal Vocoder to be supplied with cepstrum-extracted pitch data. To interface these systems, the measured values of pitch period and of speech voicing have been made available in forms which are compatible with the requirements of the vocoder. The rate at which these data are provided has been doubled by speeding the output of the spectrum analyzer section of the pitch extractor. Spectrum waveforms are now generated and updated continuously, permitting the generation of a new cepstrum waveform to begin immediately after generation of the preceding one has been completed. The peak, which is related to pitch period in this waveform, is now detected with greatly increased accuracy by a new cepstrum logic system. Unlike the previously used technique, the new logic varies amplitude and frequency detection thresholds adaptively with corresponding changes in the major cepstrum peak. As a result of these changes, the pitch extractor provides pitch data to the vocoder with a reliability of 98 percent or more down to signal-to-noise ratios of 10 dB. Author
Descriptive Note:
Final rept. Jun 66-Sep 67,
Pages:
0113
Contract Number:
AF 19(628)-5913
File Size:
0.00MB
