Patent ID: 8401823

Claim:
An arrangement for diagnosing the operating state of a device under test in the presence of ambient noise source and detecting, localizing and classifying defects of said device, characterized in that said arrangement comprises: an excitation means which provides a stimulus u(t) for exciting the device under test, at least two sensors measuring signals p(t,r i ) at arbitrary positions r i with 1≦i≦I, and providing said measured signals to respective sensor outputs, at least two filters, each having an input which receives a respective one of said measured signals p(t,r i ) from said sensors, and an output which provides a filtered signal p′(t, r i ) which is incoherent with the stimulus u(t), a source analyzer having at least two inputs, each of which receives a respective one of the filtered signals p′(t,r i ) from said filter outputs, and having at least one analyzer defect output providing a defect vector D(t,r d,j ) which contains analyzed properties of the signal q(t,r d,j ) emitted by a defect source at position r d,j with 1≦j≦J of said device under test while suppressing the signals q(t,r n,k ) emitted by an ambient noise source at a different location r n,k ≠r d,j , and a classificator having at least one vector input connected to receive said analyzer defect output and having a classificator output which indicates the quality status of the device under test, wherein said defect vector D(t,r d,j ) comprises a deterministic component d det (t,r d,j ), a stochastic component d stoch (t,r d,j ), and information about the location r d,j , and wherein said source analyzer has at least one analyzer noise output providing a noise vector N(t,r n,k ) which contains analyzed properties of the signals q(t,r n,k ) emitted by said ambient noise source at position r n,k with 1≦k≦K while suppressing the signals q(t,r d,j ) emitted by any defect source, said classificator including an ambient noise remover having at least one device input connected with said device vector input and at least one noise input connected with said at least one noise source output, and having at least one output providing a valid defect vector D′(t,r d,j ) with 1≦j≦J containing valid properties of the signal q(t,r d,j ) emitted by said defect signal source on the device under test which is not corrupted by said ambient noise source.