K Nakahira et al 2004 Meas. Sci. Technol. 15 347 doi:10.1088/0957-0233/15/2/005
K Nakahira1, T Kodama2, T Furuhashi2 and S Okuma1
Show affiliationsThe logic capacity of programmable logic devices has reached a level which allows their use as digital correlators in sonar signal-processing applications. The devices can be modified at almost any point during use in response to changes in the input data or processing environment. This paper reports on the development of a self-adapting ultrasonic system consisting of digital polarity correlators for multiple-user ranging. The digital signal-processing system is integrated into the single programmable logic device. The system is able to provide good performance in different conditions by automatically changing both the signal that drives the transmitter and the range properties of the matched filter receiver. Such an approach allows distance measurements up to a few metres while still eliminating frequent misreadings caused by crosstalk or external ultrasound sources with the low-cost piezoelectric transducers.
43.60.+d Acoustic signal processing
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
84.30.Sk Pulse and digital circuits
85.50.-n Dielectric, ferroelectric, and piezoelectric devices
43.38.+n Transduction; acoustical devices for the generation and reproduction of sound
Issue 2 (February 2004)
Received 7 July 2003, accepted for publication 4 November 2003
Published 11 December 2003
K Nakahira et al 2004 Meas. Sci. Technol. 15 347
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