The extension of digital acoustics measuring techniques to higher frequencies
Thesis (M.Sc.(Engineering))--University of the Witwatersrand, Faculty of Engineering, 1981. === The majority of acoustic measurement criteria are derived from the integral of the squared sound pressure. This work shows the development of an instrument capable of measuring any of the Integral Squar...
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| Format: | Others |
| Language: | en |
| Published: |
2015
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| Subjects: | |
| Online Access: | http://hdl.handle.net/10539/18827 |
| Summary: | Thesis (M.Sc.(Engineering))--University of the Witwatersrand, Faculty of Engineering, 1981. === The majority of acoustic measurement criteria are derived from the
integral of the squared sound pressure. This work shows the development of
an instrument capable of measuring any of the Integral Square (IS) criteria
l.n acoustic scale models of rooms using an impulse sound source.
The variety of measurements is made possible through the use of a
computer-based instrument. The microphone signal is filtered and then
digitised. All further signal processing is done digitally in the
computer. The results are either displayed numerically or plotted directly
on an X-Y plotter.
The instrument uses logarithmic quantisation of the signal and an
algorithm developed by Hanrahan (103-105) which greatly simplifies the IS
calculations to a process of table look-up and summation.
The decay curves are calculated using Schroeders Method (27).
This study shows the design and testing of the logarithmic converter
having 54dB dynamic range and 3dB quantising intervals and interfaced to a
NOVA 1200 minicomputer. The software to calculate RT, EDT and IRT was
developed and tested on a 1/8th scale model of a reverberation room with
known characteristics. |
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