Design of Ultra-Wideband Frequency Synthesis Source Based on DDS and PLL

Ultra-wideband frequency synthesis source is an important part of vector network analyzer. It mainly provides excitation source signal and local oscillator source signal for vector network analyzer. Its main technical indicators include: frequency range, frequency resolution, phase noise, spurious, harmonic suppression, output power, etc. According to the hardware scheme and technical specification requirements of the vector network analyzer, this paper studies the frequency synthesis technology, designs and implements an ultra-wideband frequency synthesis source based on DDS and PLL, DDS output frequency range: 10MHz~250MHz, PLL output Frequency range: 2000~4000MHz, the frequency resolution is better than 1Hz, and it has excellent spectral characteristics. After testing, the frequency synthesis source meets the design index requirements, and can be widely used in the excitation source and local oscillator source of the vector network analyzer(VNA).