Download or read book Acoustic Echo Sounding as Related to Air Pollution in Urban Environments written by W. R. Simmons and published by . This book was released on 1971 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: The feasibility of operating an acoustic echo sounder in an urban or industrial environment, without serious degradation in performance and without contributing to noise pollution, is confirmed. Anechoic absorbers placed about the acoustic antenna are the key to improving the sounder performance. Optimum operating frequencies are between 1 and 2 kHz. The design and operation of the all solid state circuitry is described.