Primary fractional spurs occur at multiples of f_PD/DEN and are not integer boundary spurs. For instance, if the phase detector frequency is 100 MHz and the fraction is 3/100, the primary fractional spurs are at 1 MHz, 2 MHz, 4 MHz, 5 MHz, 6 MHz, and so forth. These are impacted by the loop filter bandwidth and modulator order. If a small frequency error is acceptable, then a larger equivalent fraction can improve these spurs. This larger nonequivalent fraction pushes the fractional spur energy to much lower frequencies where the energy does not significantly impact the system performance.