With increasing amount of equipment which works in pulse mode and with increasing number the number of unstable interference usual Frequency Domain (FD) measurements, which standards use a lot, become impractical. FD measurements as Time domain measurements were invented in the last century. But because of limitations of hardware, either due to the limited Analog to Digital Converter (ADC), sampling rate, memory or dynamic range during that time TD measurements were useless. Nowadays Time Domain (TD) measurements become more and more popular. With scientific progress, new technologies have made it possible to make TD measurements with the same accuracy as with FD measurements.
So, what the main difference between FD and TD measurements and why TD measurements are superior to FD. Instead of FD measurements where each frequency is measured separately, with small bandwidth, TD measurements measure all frequency range at the same time. Also due to the fact that for low frequencies range using FD measurements where bandwidth of 10 Hz is used, minimum dwell time per frequency step will be 100 ms. Using frequency domain measurements can be received next information about the measurement signal: