The Oscillator Never Lies: Specific Emitter Identification

Every radar of a given type is built to the same specification, so parameters can only ever tell you what kind of radar you are looking at — never which individual unit. Specific Emitter Identification closes that gap by reading manufacturing imperfections: the unintentional modulation an oscillator and power amplifier impose on every pulse. We cover turn-on transients, the eight-component fingerprint taken from the detrended phase residual, and Allan variance as an oscillator's noise personality — then get honest about what a machine-learning classifier can and cannot tell you.