The distributed acoustic system uses phase-sensitive optical amplitude reflectance technology to detect and detect events, even weak vibrations. When vibration is applied to the sensing fiber / cable, the fiber associated with the location also vibrates. Due to the effect of light, the refractive index and the length of the optical fiber change slightly, which leads to a change in the phase of the transmission signal in the optical fiber. This system uses a very coherent pulse light source, so interference occurs between Rayleigh signals that are scattered in the pulse width region. Vibration changes the phase and intensity of the interfering signal. By changing the optical signal detection power of Rayleigh scattering at different times and situations, it detects the vibration signal in the optical fiber and can warn of instantaneous penetration position events in the sensor cable.