By Topic

SDFT-Based Ultrasonic Range Finder Using AM Continuous Wave and Online Parameter Estimation

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
Sumathi, P. ; Dept. of Electr. Eng., Indian Inst. of Technol. Madras, Chennai, India ; Janakiraman, P.A.

An amplitude-modulated (AM) ultrasonic range finder using an online parameter estimation procedure is presented, which uses the sliding discrete Fourier transform (SDFT) algorithm for extracting the sinusoidal envelope from the received reference and ultrasonic signals. The received ultrasonic envelope contains an additive noise, which resembles another sine wave whose frequency is very close to that of the envelope. This gives rise to a low-frequency beat in the phase shift between the transmitted and received envelopes. Consequently, the estimated phase shows an equivalent phase jitter. The desired sinusoidal envelope signal cannot easily be separated from the noise signal, even by sharply tuned SDFT filters with phase-locked loops (PLLs). A parameter estimation procedure has been applied to remove these interharmonic signals with the help of comb filters. The PLL was strengthened by a cosine lookup table (LUT). By locating the envelope frequency far away from the interharmonic noise frequency, the convergence time could greatly be reduced. Simulation studies were conducted in the Matlab-Simulink-DSP builder environment, and ideas were implemented in a Cyclone-II field-programmable gate array (FPGA)-based range finder fabricated in the laboratory. The test results of the AM ultrasonic range finder are presented to show its performance for static and slowly moving objects.

Published in:

Instrumentation and Measurement, IEEE Transactions on  (Volume:59 ,  Issue: 8 )