Fourier transform alternate convention

An alternative symmetrical convention that has gained popularity specifies the Fourier transform pair g(x) and G( ) to be related by... 

Another interesting photoelectroanalytical method for the characterization of polymer films is a method which might be called photoimpedance spectrum. A small-amplitude sine-wave signal is applied to the working electrode and the resulting absorbance response is recorded at different frequencies. Alternatively, several frequencies are applied simultaneously and the response analyzed by using Fourier transform. The main advantage compared with the conventional electrical impedance measurements is naturally that only faradaic current... 

In the Fourier transform ion cyclotron resonance (FT-ICR) spectrometer s,10"24 the cyclotron motion of ions of many different masses is excited essentially simultaneously (see Figure 2). The presence of excited cyclotron motion is then detected as the alternating voltage (Equation 2) after the exciting oscillator is turned off. Thus, unlike the conventional ICR spectrometers in which ion excitation and ion detection are simultaneous, ion excitation and ion detection in the FT-ICR spectrometer are temporally distinct. 

---