A waveform generator includes circuitry configured to: generate a digital representation of a pulse and apply the digital representation of the pulse to a digital interface of a radio system configured to propagate the pulse and convert the digital representation of the pulse to a radio frequency signal transmitted at the antenna; and mark the digital representation of the pulse with respect to a frame of digital data with a marker. Measurement of when the pulse occurs in the radio frequency signal based on the marker occurs by a spectrum analyzer. Determination occurs of a downlink propagation delay for the radio system between application of the digital representation of the pulse at the digital interface and transmission of the radio frequency signal at the antenna.