| 摘要: |
| 在统一S频段（USB）测控应答机中频数字化处理的基础上，提出了一种健壮的相位调制(PM)信号捕获算法。针对USB测控应答机输入信号存在副载波时捕获易于假锁的问题，采用快速傅里叶变换(FFT)与锁频锁相环结合的算法，利用PM信号频谱对称的特点，快速获得残差载波的正确频率，防止捕获到副载波信号或者其他干扰信号上；采用锁频锁相环实现PM信号的精确捕获与跟踪，适应USB测控应答机大动态多普勒变化及高灵敏度的要求。通过仿真试验验证了该方案载波正确捕获的有效性，且接收灵敏度达到-121 dBm。 |
| 关键词: 统一S频段 测控应答机 相位调制 信号捕获 快速傅里叶变换 |
| DOI： |
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| 基金项目: |
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| A robust signal acquisition method for USB TT&C transponder |
| DU Jianlai,YANG Ne,HE Hui,ZHANG Hui |
| (Shanghai Aerospace Electronic Corporation Ltd.,Shanghai 201821,China) |
| Abstract: |
| A new robust phase modulation(PM) signal acquisition method is proposed on the basis of the intermediate frequency digitization of the Unified S-band(USB) Telemetry,Tracking and Command(TT&C) transponder.When a subcarrier is contained in the input signal,the carrier may be locked in a certain error frequency.For this problem,a joint method of Fast Fourier Transform(FFT) & Frequency and Phase-locked Loop(FPLL) is adopted.According to the symmetry of PM signal spectrum,the residual carrier frequency can be obtained correctly,instead of the subcarrier or other interference signals.The FPLL ensures accurate PM signal acquisition and tracking under large dynamic Doppler and high sensitivity of USB transponder.Simulation results show that the carrier can be captured correctly,and the sensitivity is above -121 dBm. |
| Key words: unified S-band(USB) transponder phase modulation(PM) signal acquisition fast Fourier transform(FFT) |
《电讯技术》编辑部 