# Why the radar (moving) target return is not centered at zero frequency

In Radar signal processing, one has to separate clutter(unwanted signals) from moving target signals. The picture given below is an example of Radar Signal Power Spectum(taken from the book Radar Systems Analysis and Design Using MATLAB by B.R. Mahafza).

Why target return is coming in between 0(DC) and $f_{r}$ where $f_{r}$ is the pulse repetition frequency.