Page 33 - Phase-Locked Loops Design, Simulation, and Applications
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MIXED-SIGNAL PLL BUILDING BLOCKS Ronald E. Best 24
Figure 2.13 Waveforms of the signals for the PFD. (a) Waveforms for zero phase error. The
output signal of the PFD is permanently in the 0 state (high impedance). (b)
Waveforms for positive phase error. The PFD output signal is pulsed to the 1 state.
(c) Waveforms for negative phase error. The PFD output signal is pulsed to the −1
state.
