Establishing a Conventional Doppler Sodar cum Doppler Minisodar at the National Physical Laboratory

Abstract

A personal computer?based three-axis Doppler sodar, capable of working in Doppler minisodar mode too, has been established at the National Physical Laboratory, New Delhi, India. The fast Fourier transform technique has been used to extract the frequency shift in the signal received after scattering. Generation of audio tone bursts of a desired frequency and selectable duration, data acquisition, and data processing have been achieved through a menu-driven software. The system operates at a frequency of 2.25 or 4.5 kHz, depending upon the required version of Doppler sodar operation. Details of the system hardware, software, and some preliminary results are discussed.