A method of performing modulation of a data signal at a phase-locked loop (PLL) includes generating, at an upper frequency port of the PLL, a digital loop signal based at least in part on the data signal. The method further includes differentiating the digital loop signal to generate a digital input signal and converting the digital input signal to an analog current signal. A first feedback signal is generated based on the analog current signal. The method further includes generating, at a lower frequency port of the PLL, a second feedback signal based on the first feedback signal and further based on the data signal. According to further embodiments, apparatuses and a computer-readable medium are disclosed.