Swept CW measurements as a tool for system EMC assessment

Low-level continuous-wave measurements (LLCW) have been used for determining of the transfer function of disturbance signals between different points in a system. The general principle of the method is that low-level sinusoidal signals are generated and fed, via a proper feeder, for source simulation. The sinusoidal signal is frequency swept through the proper part of the spectrum and a frequency-dependent transfer function is thus determined. The effect of a real threat at the component interface point is calculated from the threat-level spectrum multiplied by the measured transfer function. The transfer function measured using sinusoidal waves can also be used for determination of a transient response. LLCW measurement equipment, signal treatment, and applications of the LLCW technique are discussed. The LLCW technique has many advantages over conventional system test techniques. However, this technique also has some limitations