Impulse Train Test Accuracy versus Resources for Evaluation of Supraharmonics Assessment Methods.

This paper shows that FPGA resources should not be the primary concern in developing a supraharmonic instrument for field measurement. Instead, the coherence of the results with impulse trains should be the primary target, as described in the CISPR16-1-1 standard. An FPGA resource analysis and simulations were performed to demonstrate this. For the implementation test, the Digital CISPR (D-CISPR) and the Light-Quasi-Peak (Light-QP) methods were implemented on FPGA. The two methods necessitated a low level of resources and required the same FPGA. For the simulations, the D-CISPR, the Light-QP and the proposed Numerical-Heterodyne methods were studied with the impulse train test and two examples of real-world signals. It was noted that the results were similar for the Numerical-Heterodyne and D-CISPR, closely matching the CISPR impulse train test targets, but were different for the Light-QP. A real-world example of an industrial plant shows the impact of the impulse train test behaviour. When a sharp transition is made in the signal, the Numerical-Heterodyne and D-CISPR methods have an overshoot while the light-QP does not, yielding a difference of 20% on the maximal measurements. Whether such an overshoot is desirable or not is discussed and should be the main criterion to select the best supraharmonic measurement method.