USE OF FREQUENCY TRACKERS IN LASER DOPPLER VELOCIMETRY FOR SOUND FIELD MEASUREMENT: COMPARATIVE STUDY OF TWO ESTIMATORS
✍ Scribed by C. MELLET; J.-C. VALIERE; V. VALEAU
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 267 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0888-3270
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✦ Synopsis
This paper deals with the processing of signals resulting from the measurement of sound "elds using the laser Doppler velocimetry technique. For such an application, the problem lies in the demodulation of signals whose instantaneous frequencies have small and fast variations. Two frequency trackers are systematically compared using Monte-Carlo simulations. The "rst tracker is parametric and is an adaptation of Kalman "ltering, while the second is non-parametric and based on the cross Wigner}Ville distribution. As opposed to time}frequency techniques, Kalman "ltering does not su!er from a limiting short-time assumption; its adaptability makes it able to accurately track any instantaneous frequency variation in a noiseless environment, even when very low modulation indices are involved. For low signal-to-noise ratios, the Wigner}Ville-based estimator performs better; for moderate signal-to-noise ratios (higher than 12 dB), Kalman "ltering represents the best compromise in terms of bias and variance.