In this paper, we investigate the use of standard digital ATE for the analysis of FM-modulated RF signals. The key idea is to use the 1-bit digitizer of a digital test channel in order to convert the frequency information contained in a FM-modulated signal into a timing information contained in a digital bit stream; a post-processing algorithm based on the concept of zero-crossing detection is then employed to retrieve this information. Coherent under-sampling is exploited to extend the capabilities of test equipment with a limited sampling frequency for the analysis of high-frequency signals. The proposed approach is evaluated on two different case studies related to LTE and GSM communication standards. Both simulation and hardware experiments are presented to demonstrate the viability of the technique.