DIN EN IEC 61757-3-2:2024-04

This part of IEC 61757 specifies terminology, characteristic performance parameters, related test and calculation methods, and specific test equipment for interrogation units used in distributed fibre optic acoustic sensing and vibration measurement systems. This document refers to Rayleigh backscatter and phase detection method by phase-sensitive coherent optical time-domain reflectometry (Φ-OTDR) only. The following requirements are described: a) dynamic range; b) frequency response; c) fidelity; d) intrinsic noise; e) spatial resolution limit; f) crosstalk; g) attenuation budget; h) reflection stability of the sensor. There are no restrictions on the scope of application of this document. Manufacturers and users of a measurement setup consisting of a distributed fiber optic sensor connected to an interrogation unit with a processor, data archive, and user interface that can locally detect acoustic or vibration-induced disturbances (phase change of the backscatter centers) in the fiber can increase investment security for manufacturers and users by applying the standard. In addition, the standard provides test laboratories and manufacturers with defined specifications for testing.