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雷达与通信接收机中的相干检波器通常采用两个并行的基带信道的形式,这两个信道形成了射频和(或)中频接收信号的同相(Ⅰ)分量和正交(Q)分量。由于这两个分离的信道不完全匹配而产生的几度相位误差,限制了象动目标显示器(MIT)、相干积分器、多卜勒滤波器、天线阵处理机和相干旁瓣对消器一类的信号处理机原先可达到的性能。用单个模-数(A/D)转换器直接对中频信号取样并使之数字化的方法,不需要中频-基带变换。这种方法在目前已经引起人们的注意,它是本文所要讨论的问题。为了从接近尼奎斯特速率取得的中频样品值中获得精确的相干检波,需要采用一种以许多存储样品为基础的内插法。本文对从取样理论得出的一种算法作了规定,这种算法可以用来证明由数字化的样品精确地复现原中频信号。本文证明了信号的同相分量和正交分量可以从已处理的样品中得到,而相位误差小于0.2°
Coherent detectors in radar and communications receivers typically take the form of two parallel baseband channels that form the in-phase (I) and quadrature (Q) components of the RF and / or IF received signal. Several phase errors due to an imperfect match between the two separate channels limit the performance of a moving target display (MIT), coherent integrator, Doppler filter, antenna array processor and coherent sidelobe canceller Class of signal processor originally achievable performance. A single analog-to-digital (A / D) converter to directly sample and digitize the IF signal without IF-to-baseband conversion. This method has attracted people’s attention so far, and it is the issue to be discussed in this article. In order to obtain accurate coherent detection from intermediate frequency sample values near the Nyquist rate, it is necessary to use an interpolation method based on many stored samples. This article provides an algorithm derived from sampling theory that can be used to demonstrate the accurate reproduction of the original IF signals by digitized samples. This paper proves that the in-phase and quadrature components of the signal can be obtained from the processed samples, while the phase error is less than 0.2 °