Jitter reduction of a digital phase-locked loop

This letter presents a jitter reduction technique for the digital phase-locked loop proposed by G. Pasternack and R. L. Whalin. In this technique, the lower N bits of load data from the first register are cut down and loaded into the final register as the round-off data. According to the experimental results, rounding off 5 bits in the second-order loop causes jitter to be reduced by 19.5 dB; therefore, this technique is useful for carrier tracking applications.