基于线性相位的弱信号调理电路的设计

Design of Weak Signal Conditioning Circuit Based on Linear Phase

针对应力波反射法应用于锚杆锚固质量检测时,二次反射信号很弱以及对反射信号的频率响应和时延特性要求高的特点,设计了一种具有线性相位的弱信号调理电路。该信号调理电路将压电式加速度传感器采集的声频应力波信号,进行隔直、交流放大和线性滤波处理,采用五阶贝塞尔有源低通滤波器,使通带内具有近似恒定的增益和群延,从而保证后续对信号相位信息处理更精确,该电路经实际应用,可以满足弱信号调理要求。

For the secondary reflection signal is very weak and strict with characteristics of frequency response and time delay,a weak signal conditioning circuit was designed based on the linear phase. The conditioning circuit processed the audio frequency stress wave signal of piezoelectric acceleration sensor acquisition,which included eliminating DC signal,AC amplifier and linear filter. 5 order Bessel active low-pass filter was used,making the pass-band has a constant gain and group delay,thus ensuring that the follow-up of more accurate phase information processing. According to practical application,the circuit can meet the requirements of weak signal disposal.