Abstract: Techniques are disclosed related to determining delay in a radio frequency (RF) communications device configured to perform envelope tracking. The RF communications device may comprise a power amplifier and an envelope tracker. First and second input stimuli signals may be transmitted to each of the power amplifier and envelope tracker, respectively. The RF communications device may output, by the power amplifier, an output signal to a vector signal analyzer (VSA). The VSA may determine a first delay offset by cross-correlating the output signal with a reference signal, and the VSA may determine a second delay offset based on an amplitude distortion of the output signal. A relative delay between the first and second input stimuli signals may be determined based on a difference between the first and second delay offsets.