Fractional / Integer - N PLL Basics
نویسنده
چکیده
Phase Locked Loop (PLL) is a fundamental part of radio, wireless and telecommunication technology. The goal of this document is to review the theory, design and analysis of PLL circuits. PLL is a simple negative feedback architecture that allows economic multiplication of crystal frequencies by large variable numbers. By studying the loop components and their reaction to various noise sources, we will show that PLL is uniquely suited for generation of stable, low noise tunable RF signals for radio, timing and wireless applications. Some of the main challenges fulfilled by PLL technology are economy in size, power and cost while maintaining good spectral purity. This document details basic loop transfer functions, loop dynamics, noise sources and their effect on signal noise profile, phase noise theory, loop components (VCO, crystal oscillators, dividers and phase detectors) and principles of integer-N and fractional-N technology. The approach will be mainly heuristic, with many design examples. This document is written for designers, technicians and project managers. Design procedures, equations, performance interpretation, CAD and examples are included to help those who have little experience. A list of reference books and articles is also included.
منابع مشابه
Fractional/Integer-N PLL Basics
Phase Locked Loop (PLL) is a fundamental part of radio, wireless and telecommunication technology. The goal of this document is to review the theory, design and analysis of PLL circuits. PLL is a simple negative feedback architecture that allows economic multiplication of crystal frequencies by large variable numbers. By studying the loop components and their reaction to various noise sources, ...
متن کاملFast-lock Hybrid PLL Combining Fractional- & Integer-N Modes of Di®ering Bandwidths
We report a single-loop PLL that operates in a wide-bandwidth, fractional-N mode (with no fractional spur reduction scheme) during transient but in a narrow-bandwidth, integer-N mode during phase lock. This hybrid PLL, as an extension of the conventional fast-lock PLL (that shifts only its bandwidth while retaining the same frequency division mode), simultaneously achieves the fastlock advantag...
متن کاملDelta-Sigma Fractional-N Phase-Locked Loops
This paper presents a tutorial on delta-sigma fractional-N PLLs for frequency synthesis. The presentation assumes the reader has a working knowledge of integer-N PLLs. It builds on this knowledge by introducing the additional concepts required to understand ΔΣ fractional-N PLLs. After explaining the limitations of integerN PLLs with respect to tuning resolution, the paper introduces the delta-s...
متن کاملAnalysis and Minimization of Substrate Spurs in Fractional-N Frequency Synthesizers
This paper analyses substrate-related spurious tones in fractional-N phaselocked loops with integrated VCOs. Spur positions are calculated and experimentally verified as a function of the divider ratios of prescaler and programmable divider. For an integrated wideband PLL in SiGe BiCMOS technology the spur power levels are measured and compared with theoretical expectations. The power in these ...
متن کاملA Straightforward - Fractional-N Phase-Locked Loop HDL Design for RF Applications
The present paper describes a systematic straightforward design of a - fractional-N PhaseLocked Loop based on HDL behavioral modeling. The proposed design consists in describing the mixed mode behavior of this - fractional-N PLL architecture starting from the specifications of each building block. The HDL models of critical PLL blocks have been described in VHDL-AMS to predict the different...
متن کامل