I have two time-domain signals sampled at 100 Hz that were measured using two different oscillators and therefore have a time drift between them. I have two synchronization points, one at the start and one at the end of the measurement (usually about 24h long).
The drift is very small, about 1 second for a 24h measurement, i.e. about 0.001% or 1/86400. I assume a linear model for the drift.
The length of the measurement and the relative scale of the drift prohibit usual resampling techniques: I'd have to up- and down-sample the longer signal by large factors.
My approach would be to drop every 86400th sample of the longer measurement, the questions I have are:
- Is there a better approach?
- What's the frequency-domain equivalent of dropping a sample? I imagine it would shift the spectrum by a tiny amount and introduce some high-frequency noise.
To be honest, the second question is more academic than practically relevant; most of the analysis is done in small chunks and I can just exclude the chunks with the dropped samples from the analysis.