Patent ID: 7221167

Claim:
An arrangement for measuring and assessing properties of a system ( 28 ) which transfers an electrical, acoustical or mechanical signal or converts such a signal into an arbitrary signal, whereas the system has at least one signal input and at least one signal output, said at least one signal output including an expected nonlinear distortion component due to nonlinearities inherent in said system and an excessive nonlinear distortion component which arises due to system defects, comprising: a signal source ( 26 ) which provides an excitation signal x(t) to said system's at least one signal input, an error system ( 29 ) having a first input connected to receive the excitation signal provided to said system's at least one signal input and a second input connected to receive one of said system's at least one signal outputs y(t), said error system arranged to produce an instantaneous error signal e(t) at an error output, said error system arranged such that e(t) indicates the excessive nonlinear distortion component present in signal output y(t) at any time instance, and an assessment system ( 44 ) having at least one input connected to receive said error signal and having at least one assessment output ( 45 ), said assessment system arranged to indicate the quality and/or properties and/or malfunctions of said system.