Power measurements of a signal having a changing frequency are corrected by acquiring samples of the signal, matching the samples of the signal to a sequence of frequencies indexed to correction transforms, and applying the correction transforms to the samples of the signal. Additionally, an apparatus corrects power measurements of a signal having a changing frequency and includes an acquisition block for acquiring samples of the signal, a sequence controller for matching the samples of the signal to a sequence of frequencies indexed to correction transforms and a correction block for applying the correction transforms to the samples of the signal.