Breaking Nyquist criteria using alias frequencies interpretation

Hardware and software architecture of a smart meter based on electrical signature analysis

“…Nonlinear loads, unlike the linear loads, don't draw only currents of fundamental frequency but also currents of harmonic frequencies. Using different frequency estimation techniques [16][17][18] the spectral content can also be used to detect the presence of a consumer in total load. Different researchers have found that there are correspondences between the fundamental and different harmonic components [11,15].…”

Beyond the frame rate: measuring high-frequency fluctuations with light-intensity modulation

“…Unfortunately, limited acquisition rate and detector frequency response restrict PSD measurements in frequency space, which is especially detrimental to video applications. Notably, the highest frequency that can be sampled directly, with few exceptions [8][9][10][11], is half the acquisition rate, or Nyquist frequency.…”

“…heterodyne detection, lock-in techniques), or extract high-frequency information folded down via aliasing (e.g. undersampling [11,12]). Practically, IMSA can dramatically extend the frequency range of an existing measurement device, allowing, for example, an inexpensive camera to be used in place of a significantly more expensive one.…”