What is the current thinking about the waveform of photons? How can finite signals in the time domain produce a discrete frequency response in the frequency domain? As anyone who has worked with signal analysis remembers, the Fourier transforms of time signals in the real world always produce imperfect frequency plots. The transform of the product of time signals equals the convolution of the transforms of each signal - convolution theorem, hanning windows, etc. One can never get a clean impulse in the frequency domain. Consider an AM RF transmitter and receiver. Presumably the fixed frequency and amplitude modulated signal is sent from the transmitter to the receiver antenna via photons. Each photon has a fixed amount of energy - E=hf - and some finite duration in the time domain. Yet it produces a single frequency response in the receiver antenna. I am no RF engineer, but I think that is correct. So how can such finite wave packets in the time domain produce clean single-frequency responses in the receiver?