Recovery of undersampled periodic waveforms

A periodic waveform, with known period, sampled every T seconds, can be recovered by plotting each sample in the appropriate place in a "composite" period, even when T is greater than the period of the waveform. When the period is unknown, a multiplicity of trial periods are used and the most satisfactory reconstruction is chosen. This paper discusses an organized technique for making such trials. An example is given in which the technique has been used to reconstruct a sampled waveform of infrared radiance of the earth as seen from the LES-9 satellite.