Characteristics of radio transmitter fingerprints

In this paper, the characteristics of radio transmitter fingerprints will b e examined by analyzing both the amplitude and phase information obtained f rom complex envelope recordings of transmitter turn-on transients. The inte rest in the analysis of such transients is related to the identification of malfunctioning or illegally operated radio transmitters in support of radi o spectrum management practices. Of the 28 VHF radios considered in this st udy, many were found to produce fingerprints having uniquely distinctive fe atures which could be used for identification purposes. Unfortunately, some of these radios were found to have fingerprints that were virtually indist inguishable from each other, making the identification process more difficu lt, if not impossible. Details of the equipment, analyses, and data collect ion procedures will be presented along with a discussion of the experimenta l results. The merits of this technique over others currently in use will a lso be presented.