High-precision frequency synthesizer with FPGA-based adaptive spur detection and cancellation techniques

Abstract

High-precision frequency synthesizers are critical components in modern communication systems, radar applications, and measurement instruments, where signal fidelity and spectral purity are paramount. However, conventional synthesizers suffer from spurious spectral components (spurs), phase noise, and limited adaptability, which degrade system performance. This study addresses these challenges by proposing an FPGA-based adaptive spur detection and cancellation system designed to dynamically monitor, detect, and suppress spurious signals in real-time. The primary objective was to enhance spur amplitude reduction, signal-to-noise ratio (SNR), and phase noise performance across a wide frequency range. The system utilized an FPGA development board (Xilinx Zynq Ultra Scale+ MPSoC) integrated with Direct Digital Synthesizer (DDS) and Phase-Locked Loop (PLL) architectures, combined with high-speed ADC/DAC modules and custom adaptive filtering algorithms. Experimental testing was conducted across 10 frequency points (100-1000 MHz), and performance metrics were validated using statistical tools, including paired t-tests. The results demonstrated an average spur amplitude reduction of 15 dBc, a 10-dB improvement in SNR, and a 10 dBc/Hz reduction in phase noise at a 1 kHz offset. All improvements were statistically significant (p