Single-Phase Frequency-Fixed All-Pass Filter QT1-PLL With Inherent DC Offset Suppression. - Samir Gautam; Anant Kumar Verma; Claudio Burgos-Mellado; Diego Muñoz-Carpintero; Foad Taghizadeh; Binod Prasad Rimal; Pedro Roncero-Sánchez (IEEE Trans. Instrum. Meas., 2024)