机载合成孔径雷达的宽带线性调频源设计  

Design of a wideband chirp source used for airborne synthetic aperture radar

作　　者：章小梅[1] 费元春[1] 吕良飞[2] 

机构地区：[1]北京理工大学电子工程系,北京100081 [2]海军航空工程学院青岛分院航空电子系,山东青岛266041

出　　处：《光电工程》2005年第7期7-10,共4页Opto-Electronic Engineering

基　　金：国家863项目

摘　　要：采用“DDS+正交调制+倍频”的结构方式,设计研制出带宽500MHz,时宽15μs的线性调频信号源。该设计在DDS信号产生部分运用外部时钟倍乘方式和防止时钟泄漏等措施,获得了更好的杂散与噪声特性;正交调制部分采用误差调整与补偿电路,不仅稳定了直流偏置,而且还对信号进行了调理,从而有效控制了I,Q通道的幅相不一致性。通过实测,该宽带线性调频信号源的无杂散动态范围(SFDR)优于100dB,杂散抑制小于-60dBc,且在带宽内最大幅度起伏为±0.5dB,相位起伏为5°,很好地满足了机载合成孔径雷达系统的要求。The wideband chirp source with 500 MHz bandwidth and 15μs temporal width is produced by means of DOS + quadrature modulation + frequency multiplier. The scheme of external clock frequency multiplying and measures for preventing clock leakage are adopted in DDS signal generator, thus featuring better spurious and noise characteristic. Stabilization of DC biasing, and signals deviation adjustment and compensation circuit are adopted in the quadrature modulator, so the problems on the incompatibility of channel I and Q in amplitude and phase are effectively solved. The performance of wideband chirp source are tested with the results of output chirp's SFDR (Spurious Free Dynamic Range) > 100 dB and spurious suppression equal to -60 dBc, maximum amplitude fluctuation and phase fluctuation for ±0.5 dB and 5° within signal bandwidth respectively. The results satisfy the requirement of airborne synthetic aperture radar.

关 键 词：机载合成孔径雷达 正交调制 数字频率合成 线性滤波器 

分 类 号：TN958[电子电信—信号与信息处理]