数字声呐接收机调理电路单芯片设计与噪声优化方法研究

In order to improve the huge and complex conditioning circuit of digital sonar receiver, the research puts forward a single-chip integrated technical solution and according to the solution, we design a special chip for digital sonar receiver that is integrated with automatic gain controller (AGC), pre-band-pass filter, Sigma Delta ADC, digital IQ mixers, etc. The solution improves the attenuation of AGC, realizes a wider scope gain control with the same bit-wide, and proposes a design of off-chip configured band-pass filter that meets the requirements. It provides a new mixed continuous-time/discrete-time, single-loop, fourth-order, 4-bit sigma delta ADC with capacitor digital self-calibration for RC spread compensation. This ADC combines the benefits of CT and DT circuits, removes extra need for driver amplifier, and, in the meantime, eliminates the noise coupling into the system by switch capacitive, enhances the overall system performance, reduces power consumption. The solution integrates digital controlled oscillator and digital IQ mixer. Compared with analog mixer, it has better accuracy and anti-interference performance. The special chip reduces the size of each analog signal channel, enhances system performance in processing array signals, achieves independent research and development of chips and removes concerns over chip shortage and embargo.

课题以改进数字声呐接收机庞大而又复杂的调理电路为切入点，提出了一种声呐接收机调理电路单芯片集成实现的技术解决方案，并根据该解决方案，设计实现一款将自动增益控制器、前置带通滤波器、Sigma Delta模数转换器、数字IQ正交混频器等集成在一起的数字声呐调理电路专用芯片。芯片改进了自动增益控制器的衰减量，在相同位宽时实现了更大范围的增益控制；提出了满足要求的片外可配置的带通滤波器设计方案；提出了一种新型的连续/离散混合调制器结构的电容数字自校准Sigma Delta模数转换器，消除了对驱动放大器的额外要求，同时没有了开关电容耦合到系统中的噪声，改善了系统的整体性能，降低了功耗；内部集成了数控振荡器和数字IQ正交混频器，比模拟混频器具有更好的精度、更好的抗干扰性能。专用芯片减小了每路模拟通道信号处理电路的体积，提升了系统的阵列信号处理能力，实现芯片的自主研发制造,解决芯片的断货和禁运之忧。

课题以改进数字声呐接收机庞大而又复杂的调理电路为切入点，提出了一种声呐接收机调理电路单芯片集成实现的技术解决方案，并根据该解决方案，设计实现了一款大动态范围模数转换器芯片。芯片采用了一种混合调制器结构的24比特Sigma Delta模数转换器，消除了对驱动放大器的要求，改善了系统的整体性能，降低了功耗；芯片通过实时分析输入峰值包络，对双通道数据进行补偿，将不同放大倍数的双通道输入融合为单通道输出，提升了芯片的动态范围；芯片采用SMIC 0.18μm CMOS工艺设计，通过流片验证芯片实现的性能指标。芯片具有面积小、功耗低、电路简单、供电容易、性能高等优点，可用在声呐、自导系统、水下通信、水下传感器网等应用场合。芯片减小了每路模拟通道信号处理电路的体积，在有限空间内可以集成更多通道的模拟信号处理电路，提升了系统的阵列信号处理能力，实现芯片的自主研发制造，自主知识产权，解决芯片的断货和禁运之忧。