Fundamentals of HVAC Control Systems, by Robert McDowall, p. 21
doi.org
Hausmair, Katharina; Shuli Chi; Peter Singerl; Christian Vogel (tháng 2 năm 2013). “Aliasing-Free Digital Pulse-Width Modulation for Burst-Mode RF Transmitters”. IEEE Transactions on Circuits and Systems I: Regular Papers. 60 (2): 415–427. doi:10.1109/TCSI.2012.2215776.