EAS自动增益控制电路设计

Design of Auto Gain Control Circuit in EAS System

EAS电子标签的信号变化范围很大,为了提高EAS系统对电子标签的检测距离和减少误报率,EAS的接收机必须同时具有很高的灵敏度和大动态范围。针对检测过程中的远距离信号微弱和强磁场环境下的误报问题,利用可变增益放大器AD8338设计了自动增益控制(AGC)电路,动态范围达到80dB。经过实验测试,该AGC结构简单,无需外部控制器件,在远端和强磁场环境下时接收信号保持在合理的幅度范围,有效解决强磁场下的误报问题,提高了检测距离。

Because of the wide range of electronic article surveillance(EAS) tag signals and the requirement of the large detection distance and lower false alarm rate of the EAS system, the EAS RF receiver must have a high sensitivity and large dynamic range. Considering the distant signal is weak and false alarm in high-intensity magnetic field during detection, the paper designed 80 dB large dynamic range auto gain control(AGC) circuit with variable gain amplifier AD8338. Tested by the experiment, the AGC circuit is simple and don’t need other control units. In addition it can keep the received signal in a reasonable range in high-intensity magnetic field, effectively compensate the false alarm in high-intensity magnetic field and improve the detection range.