Specify some data:
Fit a linear model to the data:
It can be observed that from the plot of the data and the linear model that there is some upward trend.
The Detrend command removes any trend from the data.
This can be observed in the following plot:
Generate a random signal with an added trend.
Plot the signal and the trend line.
Plot the signal, the detrended signal, the trend line and the mean of the detrended data.