Title :
Analog signal pre-processing for performance enhancement of a distance meter based on frequency-modulated continuous-wave interferometry
Author :
Rovati, L. ; Minoni, U.
Author_Institution :
Dipt. di Elettronica per l´´Autom., Brescia Univ., Italy
Abstract :
A method for the processing of signal from an absolute distance meter based on a frequency-modulated continuous-wave (FMCW) interferometer is presented. FMCW is implemented using a laser diode driven by a current waveform obtained as the superposition of a triangular signal to a bias current kept well above the diode lasing threshold. The analog signal pre-processing includes a derivative block followed by the time-variant baseline restoration of the photodetector current. A high signal-to-noise ratio is ensured by avoiding the use of a resistive transimpedence preamplifier and subsequent voltage processing. The paper details the scheme of the pre-processing chain as well as the experimental results from an actual prototype of a distance meter
Keywords :
Michelson interferometers; analogue processing circuits; feedback amplifiers; frequency modulation; laser ranging; light interferometry; operational amplifiers; optical modulation; optical sensors; signal restoration; FM CW interferometer; Michelson interferometer; absolute distance meter; analog signal pre-processing; bias current; current waveform; frequency-modulated continuous-wave interferometry; high signal-to-noise ratio; inductive feedback preamplifier; laser diode; performance enhancement; photodetector current; time-variant baseline restoration; triangular signal; Amplitude modulation; Diode lasers; Frequency modulation; Laser beams; Optical interferometry; Optical modulation; Optical signal processing; Photodetectors; Photodiodes; Signal processing;
Conference_Titel :
Instrumentation and Measurement Technology Conference, 1998. IMTC/98. Conference Proceedings. IEEE
Conference_Location :
St. Paul, MN
Print_ISBN :
0-7803-4797-8
DOI :
10.1109/IMTC.1998.676902
