论文部分内容阅读
为了满足高功率微波对相位和频率测量的要求,提出了一种联合使用FFT和非线性最小二乘法拟合的测量系统,包括前端变频电路和后端数字化处理部分。论述了设计和实现前端变频电路中的本振电路、本振监测电路、本振低通滤波电路、本振功分电路、变频电路和中频低通滤波等电路,介绍了使用FFT和非线性最小二乘法拟合测量频率和相位的方法,并分析了测量相位误差与信噪比和A/D转换位数之间的关系。
In order to meet the requirements of phase and frequency measurement of high power microwaves, a measurement system combining FFT and nonlinear least square method is proposed, which includes front-end frequency conversion circuit and back-end digital processing part. This paper discusses the design and implementation of local oscillator circuit, local oscillator monitoring circuit, local low-pass filter circuit, local oscillator power divider circuit, frequency conversion circuit and IF low-pass filter circuit in the front-end inverter circuit, introduces the use of FFT and nonlinear minimum The method of fitting the measured frequency and the phase by the second-order multiplication method and the relationship between the measured phase error and the signal-to-noise ratio and the number of A / D conversion bits are analyzed.