Digital intercept receivers have moved away from Fourier-based analysis techniques, towards classical time-frequency analysis techniques, for the purpose of analyzing low probability of intercept radar signals.  This paper presents the novel approach of characterizing low probability of intercept frequency modulated continuous wave radar signals through utilization and direct comparison of the Spectrogram versus the Reassigned Spectrogram. Triangular modulated frequency modulated continuous wave signals were analyzed. The following metrics were used for evaluation:  percent error of:  carrier frequency, modulation bandwidth, and modulation period. Also used were: percent detection, lowest signal-to-noise ratio for signal detection, and time-frequency localization (x and y direction).  Experimental results demonstrate that overall, the Reassigned Spectrogram produced more accurate characterization metrics than the Spectrogram.