中频数字接收机的工程实现

Project Realization of a Digital Intermediate Frequency Receiver

介绍了一种数字中频接收机的工程实现办法,该数字接收机具有较大的动态范围,较高的I、Q输出精度,采用的是带通采样法进行单路中频采样,数字滤波法进行数字正交相干检波。介绍了传统模拟接收机的不足和数字接收机的优点,讨论了两种数字正交相干检波方法,研究了带通欠采样的原理;根据本课题的技术指标要求进行了设计工作,设计了中频放大电路和AGC控制电路,进行了AD采样和数字相干检波部分的设计工作。结果表明,两路信号幅度的误差≤0.5%,相位的正交误差≤0.5°,满足了设计指标要求,技术指标明显优于传统的模拟接收机。

A digital IF receiver was introduced for achieving the project approach. The digital receiver is with larger dynamic range, higher I, Q output precision, using bandpass sampling method for single-channel IF sampling, digital filtering method digital quadrature coherent detection. The shortage of traditional analog receiver and the advantages of digital receiver was described, two digital quadrature coherent detection methods were discussed, and the bandpass undersampling principle was studied. In accordance with the technical specification of the subject requirements, IF amplifying circuit and AGC control circuit were designed, the design of AD sampling and digital coherent detection part were carried out. The results show that the error of amplitude is ≤ 0.5 % and the error of phase quadrature is ≤ 0.5°, it meets the technical requirements and better than traditional analog receiver.