Is it possible to time align data samples from different DAS?
The data sample is accurately tagged (usually), but is not aligned with any arbitrary boundary (on the second for example). To align data from different DAS, not just plot them on the same absolute time scale, the data must be resampled, interpolating datapoints at a chosen time between the actual samples. The broad bandwidth of recorded data (80% nyquist) means that cubic spline interpolation methods are often inadequate and more robust techniques (e.g., (sine x)/x deconvolution) should be used. This is a computationally extensive job and not usually necessary. Phases can be accurately picked from any trace. In refraction work, the sample closest to the second boundary is chosen as the starting point with the offset included as a static.
