An alternative formulation of the second-order generalized integrator (SOGI) IpDFT algorithm is presented to simultaneously comply with both the P and M phasor measurement unit (PMU) performance classes while reducing the observation window from three to two nominal periods. The SOGI filter, which attenuates the self-interference of the fundamental tone, is combined with a three-point IpDFT and a two-cycle Hanning window. Its performance, with respect to all the operating conditions defined by the IEC/IEEE Std. 60255-118, is evaluated and compared with the already proposed three-cycle implementation. Compliance with all standard requirements is verified in a simulated environment.