This paper presents a low-cost solution to perform power and spectral measurements on RF signals. More specifically, we target RF modulated signals such as 2.4 GHz signals delivered by ZigBee transmitters. The solution is based on 1-bit under-sampled acquisition of the RF signal, acquisition that can be realized using a standard digital ATE channel. The captured binary sequence is then fed to a dedicated post-processing algorithm, which (i) extracts amplitude and phase variations and (ii) reconstructs the RF signal. From the reconstructed signal, it is possible to perform power and spectral measurements. The different steps of the post-processing algorithm are detailed in the paper. The validity of the technique is demonstrated through both simulations and hardware measurements.