论文部分内容阅读
采用0.18μm CMOS工艺设计了一种符合ISO/IEC 14443 Type B协议标准的非接触式智能卡ASK解调器。电路工作在电压模式,通过具有相同直流通路的低通滤波电路提取射频信号包络和基准电压,然后通过迟滞比较器与输出级还原出最终信号。解调器电路结构简单,对工艺敏感度低,支持高速率、浅调制深度的数据解调。仿真结果表明,输入信号幅度为4~8 V,该解调器可以实现对数据速率为106,212,424和848 kbit/s的NRZ(non-return-to-zero)编码的ASK调制信号的解调,其调制深度可达到1%~20%。
A 0.38μm CMOS process is used to design a contactless smart card ASK demodulator that conforms to the ISO / IEC 14443 Type B protocol standard. The circuit operates in voltage mode and extracts the RF envelope and reference voltage through a low-pass filter with the same DC path, then restores the final signal through the hysteresis comparator and output stage. The demodulator circuit is simple in structure, low in process sensitivity, and supports data demodulation at high speed and shallow modulation depth. The simulation results show that the demodulator can demodulate the ASK modulated signal of NRZ (non-return-to-zero) coded at data rates of 106, 212, 424 and 848 kbit / s with input signal amplitude of 4 ~ 8 V Modulation depth can reach 1% ~ 20%.