An optimal waveform for range-Doppler resolution is the symmetric quadratic fm. When the transmitter signal processing is ineffective in generating this waveform, due perhaps to limitations in modifying the natural chirp response of the oscillator, the resultant waveform has amplitude modulation distortion. This distortion will degrade resolution both in range and Doppler. A simple step approximation to this am distortion displaying the cogent properties is considered, and the resul-tant degradation in performance is analyzed in terms of the ambiguity function output. The am distorted waveform is less efficient in resolution than the purely fm pulse. This is because the pulse-like components have lower bandwidths, degrading compressed pulse range resolution; have shorter durations, degrading Doppler resolution; and contribute to the wave-form asymmetry, enhancing range-Doppler ridge ambiguities. Parametric analytical results, a specific example, and associated graphic illustrations are described.