基于开关电容技术的锁定放大器设计 | |
所属分类:技术论文 | |
上传者:serena | |
标签:锁定放大器开关电容 | |
所需积分:1分积分不够怎么办? | |
文档介绍:锁定放大是微弱信号检测的重要手段。基于相关检测理论,利用开关电容的开关实现锁定放大器中乘法器的功能,提出开关电容和积分器相结合以实现相关检测的方法,并设计出一种锁定放大器。该锁定放大器将微弱信号转化为与之相关的方波,通过后续电路得到正比于被测信号的直流电平,为后续采集处理提供方便。测量数据表明锁定放大器前级可将10-6 A的电流转换为10-1 V的电压,后级通过带通滤波器级联可将信号放大1×105倍。该方法在降低噪声的同时,可对微弱信号进行放大,线性度较高、稳定性较好。 Lock-in Amplifying(LIA)is one of important means for weak signal detection. Based on cross-correlation detection theory, switch in the swithched capacitor was used as multiplier of LIA, and a new method of correlation detection was proposed combining swithched capacitor with integrator. A kind of LIA was designed which can convert the weak signal to square-wave, then DC proportional to measured signal was obtained through follow-up conditioning circuit, providing convenience for signal acquisition and processing. The measured data shows that the electric current(10-6 A) can be changed into voltage(10-1 V) by LIA, and the signal is magnified 1×105 times by cascade band-pass filter. The noise is suppressed and the w | |
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