Analysis of Quantization Noise Reduction Techniques for Fractional-N PLL

Analysis of Quantization Noise Reduction Techniques for Fractional-N PLL

A 1GHz Fractional-N PLL Clock Generator with Low-OSR ΔΣ Modulation and FIR-Embedded Noise Filtering

Offering less than 1ppm frequency resolution, a ΔΣ fractional-N PLL enables flexible frequency planning and reliable spread spectrum modulation for digital clock generation [1, 2]. Use of low-cost ring VCOs however, mandates a wideband PLL design, which makes it difficult for the PLL to filter out high-frequency quantization noise from the ΔΣ modulator. In many digital clocking systems, such as...

Fractional-n Frequency Synthesizers

At the Microsystems Technology Laboratory at MIT, we have developed two techniques that allow fast and accurate simulation of both dynamic and noise performance of fractionalN synthesizers at a detailed behavioral level. We incorporated these techniques into a custom C++ program to simulate the dynamic and noise performance of a prototype Σ-∆ frequency synthesizer. This class of fractional-N sy...

Quantization Noise Cancellation for FDC-Based Fractional-N PLLs

This paper presents a quantization noise cancellation technique for frequency-to-digital converter-based fractional-N phase-locked loops (FDC-PLLs). The technique cancels quantization noise prior to the loop filter so the PLL bandwidth can be increased without a significant phase noise penalty. The paper also presents an FDC-PLL architecture enhancement that achieves the effect of a charge pump...

UNIVERSITY OF CALIFORNIA, SAN DIEGO Enabling Techniques for Low Power, High Performance Fractional-N Frequency Synthesizers

Figure 12: a) High-level block diagram of the segmented quantizer; b) quantization block details; c) signal processing model .. Figure 16: Estimated power spectra of a) the quantization noise sequences, and b) the running sums of the quantization noise sequences of the first-order ∆Σ modulator and the segmented quantizer presented in Section IV before and Ian Galton supervised the research whic...