摘要
地球物理探测领域中的频率域电磁法仪器，需要对低频微弱信号进行检测，有时受某些条件的制约，很难采用增大人工场源的方法来增大信噪比（s／N），因而采用常规的滤波放大方法难于提纯有用信号。本文设计了一款低频低噪声频谱搬移电路，电路由低噪声前置放大器（LNA）、基准信号源（Fref）、开关式相敏检波器（PSD）及固定频率的窄带通滤波器组成，经组装、调试与测试，折合到输入端短路时的噪声电压为，由于Fref放置范围为1-9999Hz，步进为1Hz，通过改变Fref的频率就可实现对不同频率的微弱信号的检测。
The frequency domain electromagnetic method apparatus, used in the field of geophysical exploration, which need for low-frequency weak signal detection, sometimes subject to certain conditions, is very difficult to increase the use of factory methods to increase the source signal to noise ratio （S / N）,And thus enlarge the use of conventional methods of filtering the useful signal difficult to purify. In this paper, the design of a spectrum of low-frequency low-noise removal circuit, Circuit by the low-noise preamplifier （LNA）, reference signal source （Fref）, switch-mode phase-sensitive detector （PSD） and fixed-frequency components of narrow-band-pass filter, After assembly, debugging and testing, or to short-circuit input noise voltage of ,Fref set up as a result of the range of 1 - 9999Hz, stepping to 1Hz, the frequency by changing the Fref different frequencies can be achieved in weak signal detection.
出处
《电测与仪表》
北大核心
2010年第2期73-76,共4页
Electrical Measurement & Instrumentation
基金
国家"863"资助项目(2008AA09Z203)
关键词
低噪声
低频
微弱信号检测
频谱搬移
low-noise, low-frequency, weak signal detection, spectrum move
