| 摘要 |
A method for distributed fibre sensing, especially distributed acoustic/strain sensing, involves launching at least first and second pulse pairs into an optical fibre, the first and second pulse pairs having the same frequency configuration as one another and being generated such that the phase relationship of the pulses of the first pulse pair has a predetermined relative phase difference to the phase relationship of the pulses of the second pulse pair. The frequency difference between the pulses in a pulse pair may be related to the launch rate of the pulse pairs. The phase difference between the pulses in a pair may be varied between successive launches. An analytic version of the backscatter interference signal can be generated within the baseband of the sensor. Processing circuitry coupled to a detector determines a phase value for a section of the optical fibre based on detected backscatter from the pulse pairs. |
