摘要
ADF4351是美国ADI公司推出的新型集成VCO的频率合成器,具有分频可编程、极低相位噪声、小数和整数N分频合成等优点,本文以ADF4351为核心设计了一个频率稳定度高、可程控的频谱分析仪。系统主要由本振、混频、滤波、幅值检测等模块构成。ADF4351和可变增益程控放大器VCA824构成了输出频率可步进、幅度可调的本振源模块。四象限模拟乘法器AD835实现混频。本振源输出信号与其他信号叠加经过低通滤波电路后得到混频后的正弦信号。幅值检测模块测量混合波形的幅值,并在TFT屏上显示。实验测试表明,系统本振输出频率稳定(90MHz-110MHz),幅度可调(10-100mV),能实现频谱测量功能。
ADF4351 is the new VCO frequency synthesizer produced by American company ADI. It has very advantages. For example, it is programmable, has very low phase noise and can divide frequency in in decimal or an integer. In this paper, based on ADF4351, we design a spectrum analyzer that is programmable and has high frequency stability. The system is made up with local oscillator, frequency mixer, filter, and amplitude detection. ADF4351 and VCA824 make up the local oscillator which has adjustable output frequency and amplitude. AD835 can realize mixing frequency. We can get a sine signal after the mixed signal of local oscillator output signal and other signals. The circuit of amplitude detection can measure the amplitude of mixed signals and shows the result in TFT. As is indicated in experiments, the system can output stable frequency from 90MHz to 110MHz and adjustable amplitudes from 10mV to 100mV. It can measure the spectrum.
出处
《科技创新导报》
2018年第15期100-103,共4页
Science and Technology Innovation Herald
