Electronic Systems – Analogue
Sound Level Meter Design Case Study
The aims of this assignment are to:
• develop skills in the design of non-trivial analogue electronic systems
• introduce the use of behavioural models in the prototyping of analogue systems
• develop co-operative working in the design of non-trivial analogue electronic systems
A sound level meter is an instrument for measuring noise. A microphone is used to convert the sound pressure variation into an electrical signal. This electrical signal is then processed with filters and detector circuits to give an averaged value that has good correlation with subjective response to the noise. The averaged value is displayed in decibels (dB) as the amplitude response of the ear has a very large range (approximately 107:1) and is approximately logarithmic. The aim of this case study is to investigate the design of the electrical processing stages of a sound level meter using analogue techniques and to evaluate the performance against given criteria.
The basic electrical elements of the instrument are shown in Figure 1.
Figure 1 Basic elements of a sound level meter