## 3 Characteristic of the Laboratory Hardware and Software Setup
\begin{table}
\begin{tabular}{c c} \hline
**Programmable AC Source/Kikusui PCR500 LA** & **Specification** \\ \hline Power capacity & 500 VA \\ Input voltage variation (with respect to changes in the rated range) & \(\pm\)0.1\% \\ Output current variation (with respect to 0\% to 100\% changes in & Within \(\pm\)0.1 V/\(\pm\)0.2 V \\ the rating) & (output voltage range 100 V/200 V) \\ Output frequency variation in AC mode (40–999.9 Hz) & Within \(\pm\)0.3\% \\ Ripple noise: DC mode (5 Hz to 1 MHz component) & 0.1 Vrms or less \\ Output frequency stability (with respect to changes in the & Within \(\pm\)5 \(\times\) 10\({}^{-5}\) \\ rated range) & \\ Output voltage waveform distortion & 0.3\% or less \\ Output voltage response speed & 30 \(\upmu\)s \\  & EMC Directive 89/336/EEC \\  & EN61326:1997/ A2:2001 Emission Class A \\ Compliant standards & IEC 61000-3-2:2001 \\  & IEC 61000-3-3:1995/A:2001 \\ \hline Reference impedances/authorised university solution & Specification \\ \hline Nominal frequency & 50 Hz \\ Nominal RMS current & 5 A \\  & Phase wire \(\rm{Z_{A}}\) = (0.24 + 0.15)\(\Omega\) for 50 Hz \\  & \(\rm{R_{A}}\) = 240 m\(\rm{\Omega}\)\(\pm\) 0.2\%, \(\rm{L_{A}}\) = 477.5 uH \(\pm\) 1\% \\ Nominal impedance & Neutral wire \(\rm{z_{N}}\) = (0.16 + 0.10) \(\Omega\) for 50 Hz \\  & \(\rm{R_{N}}\) = 160 m\(\rm{\Omega}\)\(\pm\) 0.2\%, \(\rm{L_{N}}\) = 318.3 uH \(\pm\) 1\% \\ \hline Signal recorder/authorised university solution & Specification \\ \hline FPGA platform & National Instrument cRIO FPGA 1 MS/s \\ Voltage input module & \(\pm\)10 V, 1 MS/s, 16-Bit, Simultaneous Input, \\  & 4-Differential Channel \\  & LEM CV 3–1000 \\  & Primary voltage \(\pm\)1000 V \\ Voltage Transducer & Secondary voltage \(\pm\)10 V \\  & Frequency bandwidth DC \(\div\) 500 kHz \\  & Accuracy 0.2\% \\ \hline \end{tabular}
\end{table} 
Table 1: Specification of the hardware components of the laboratory test circuits. The intentional transmission signal used by the power line communication systems has usually time-variant nature. The narrow or broadband signals are transmitted in time packages. In order to investigate the coexistence of these time-variant spectrum components and non-intentional emission of the equipment, the short-Fourier transform (STFT) in the range 2-150 kHz was implemented. The rectangle data acquisition window without overlapping was used. The window width was 100 ms and the DFT output was grouped using a 200 Hz band centralized at frequencies being a multiplication of 100 Hz starting from 2000 Hz. The selection of the shorter window width was dictated by two conditions. First, the time resolution of the STFT is enhanced by using a short window. Second, one of the commercial spectrum analyser used for the validation used a 10 Hz resolution spectrum. Additionally, the inherent effect of short window width is smoothed by grouping concept with 100 Hz resolution. The recording time was 20 s. Therefore, it was possible to observe changes in the spectrum and capture the voltage spectra on the load both with and with communication represented by intentional emission in the 42-89 kHz frequency band used by the PRIME PLC system. A set of loads representing end-user equipment was based on:  
* LED light sources (the three-phase circuit was made using three single-phase LED with a power of 8 W connected in a star, the LED have implemented active power factor correction by an active power filter (APF) in order to keep \(\cos\varphi=0.9\)). * CFL compact fluorescent lamps (the three-phase circuit was made of three single-phase compact fluorescent lamps with the power of 11 W, 18 W and 20 W connected in a star). * Three-phase asynchronous induction motor 300 W/400 V/50 Hz rated speed 1390 rpm, powered by a single-phase frequency converter with input voltage 230 V, output voltage 3 \(\times\) 230 V, power 400 W.