Abstract: A method of processing electrical signals which span a large dynamic range in order to enable the signal to be processed in its entirety without the need for any alteration to the signal gain or signal attenuation, comprises splitting of the signal along two or more paths each having a different amount of amplification or attenuation, the passing of each of these two or more different signals into one of two or more smaller dynamic range circuits which produce a logarithmically scaled representation of the average magnitude of the signal level at its input and the summation of the logarithmic outputs of the two or more smaller dynamic range circuits to produce a resultant logarithmically scaled signal representative of the average magnitude of the input signal over a very large dynamic range. The invention also includes apparatus for carrying out the above defined method.

Abstract: An acoustic emission transducer consists of a resonant detection element (10) which is attached to the base-plate (16) by a small area in comparison to the overall surface area of the resonant detection element (10) where this area of attachment is positioned with respect to the wave motion during the resonance of the resonant detection element (10) so as not to have a significant effect on the resonant detection element (10) other than to physically couple the resonant detection element (10) to the baseplate (16) and introduce elastic waves from the baseplate (16) to the resonant detection element (10) at the desired frequency, while allowing damping materials (24) to be acoustically coupled to the larger part of the resonant detection element surface area to produce a resonant acoustic emission transducer having reproducible characteristics of resonant frequency and rate of damping.