Fractional-N Frequency Synthesis: Overview and Practical Aspects with FIR-Embedded Design
نویسندگان
چکیده
This paper gives an overview of fractionalN phase-locked loops (PLLs) with practical design perspectives focusing on a ∆Σ modulation technique and a finite-impulse response (FIR) filtering method. Spur generation and nonlinearity issues in the ∆Σ fractional-N PLLs are discussed with simulation and hardware results. High-order ∆Σ modulation with FIR-embedded filtering is considered for low noise frequency generation. Also, various architectures of finite-modulo fractional-N PLLs are reviewed for alternative low cost design, and the FIR filtering technique is shown to be useful for spur reduction in the finite-modulo fractional-N PLL design.
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