分析了采用多通道并行解复用架构的光子模数转换(PADC)样机用于宽带雷达接收时的通道失配问题,建立了通道失配模型和失配量提取算法,给出了通道失配补偿方法。对比分析角反射器和无人机的回波信号进行通道失配补偿前后的短时傅里叶变换(STFT)谱,结果表明该补偿方法可有效抑制因样机多通道并行解复用架构所导致的固有幅度和延迟失配,从而实现了4 GHz瞬时带宽的X和Ka波段的有效接收。在X和Ka波段下进一步开展了角反射器在近距离静态和远距离动态时的测试和对比实验,结果表明该PADC样机均有效实现了间距约10 cm的角反射器一维成像测量。

We analyze the channel mismatches in a multi-channel demultiplexing photonic analog-to-digital converter (PADC) applied in wideband radar receiving. We demonstrate a model of the channel mismatches and a method for extracting the mismatch information, and develop a channel-mismatch compensation algorithm. We analyze and compare the short-time Fourier transform spectra of the echo signals from the corner reflectors and the drone before and after the channel-mismatch compensation. The results confirm that the compensation algorithm can effectively suppress the intrinsic mismatches in the amplitude and delay mismatch caused by the multi-channel demultiplexing architecture of the PADC. The radar achieves wideband detection, covering a 4 GHz-bandwidth segment of the X-band and Ka-band signals. By comparison between the target detections of static and long-distance flying corner reflectors, we find that the compensated PADC effectively performs one-dimensional imaging of the corner reflectors installed 10 cm apart.