This thesis details a technique of eradicating reference spurs (in theory). It involves a Fixed Width Variable Amplitude Charge Pump (FWVACP) which is inherently insensitive to current mismatch. Charge pump current pulses are modified such that they have a fixed width and occur on the falling edge of the reference signal. Phase error information is embedded in the amplitude of the current pulses. The periodic nature of these pulses creates nulls at integer multiples of the reference frequency. At the VCO output, this translates into nulls at offsets equal to integer multiples of the reference from the carrier effectively eradicating the reference spurs. The spectrum of the current pulses has a sync null whose position depends on their duty cycle. This means that in addition to getting rid of the reference spurs, any spur at an offset greater than the reference frequency can be targeted by choosing the appropriate duty cycle. Charge pump noise contribution can be reduced by using narrow current pulses which limit its on-time when the loop is locked.The FWVACP and a standard charge pump were fabricated using IBM 0.13 micron CMOS technology. The prototype occupies less than 1mm 2 . The measured reference spur with the FWVACP is more than 10 dB lower than with the standard CP.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.