In this paper, the design and experimental validation of a prototype phasor measurement unit (PMU) that simultaneously meets the P and M class requirements of the IEC/IEEE Std 60255-118-1-2018 are presented. The device is based on a synchrophasor estimation (SE) algorithm, previously formulated by the authors, which exploits the generation and use of a delayed in-quadrature complex signal to mitigate the self-interference of the fundamental tone. The method is deployed to a NI CompactRIO-9039 platform, requiring a total use of 19.2% flip-flops, 50.6% LUTs, 77.9% DSPs and 13.7% BRAM for a single-channel configuration and operating under a 50-fps report rate, 50 kHz sampling rate, and three nominal cycle observation windows. A PMU calibrator is used to perform a comprehensive metrological analysis of the device and verify its compliance with the standard. The results show that the prototype meets the requirements of both P and M classes with a worst-case measurement reporting latency of 36.21 ms.