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本文介绍95GHz 相干雷达系统采用频控方法所能得到的频谱纯度特性。该雷达设计成具有多方面功能的通用仪器。它能在脉宽、极性以及脉冲重复周期变化的情况下,保证对目标及杂乱回波后向散射数据的采集。将此类数据以数字形式存贮在磁带上,并用来研究对目标检测、鉴别和分类的有效算法。为了达到研究算法的目的,将该系统设计成能够提供最小为40dB 的杂波中能见度。由于数据的完整性相干几乎完全取决于系统的频谱纯度,所以系统的主要设计就着重于有关信号的产生和控制。该系统的信号产生技术是采用了一个100MHz 的振荡器作信号源来建立系统的定时信号、发射信号以及本振信号。在发送接收状态时,利用一个相位锁定甘氏振荡器和一个注入锁定连续波(CW)式和脉冲式 IMPATT 振荡器来保证信号的相干性。在信号通路的关键点上,测量信号的相位噪声谱密度数据,并把它所要求的指标进行比较。本文扼要地介绍有关测量技术问题。该系统的处理数据表明,在大于2公里的目标距离上,杂波中能见度大于40dB。
This article describes the spectral purity characteristics of the 95 GHz coherent radar system that can be obtained using the frequency control method. The radar is designed as a versatile instrument with versatile functions. It ensures acquisition of target and clutter echo backscatter data with varying pulse width, polarity, and pulse repetition period. Such data is stored digitally on tape and used to study efficient algorithms for detecting, identifying and classifying objects. For the purpose of studying algorithms, the system was designed to provide in-stream visibility of a minimum of 40 dB. Since the data integrity is almost entirely dependent on the spectral purity of the system, the primary design of the system focuses on the generation and control of the signal. The system of signal generation technology is the use of a 100MHz oscillator as a signal source to establish the system timing signals, transmit signals and LO signals. In the transmit receive state, a phase-locked Gann oscillator and an injection-locked continuous-wave (CW) and pulsed IMPATT oscillator are used to ensure signal coherence. At the critical point of the signal path, the phase noise spectral density of the signal is measured and compared to the index it requires. This article briefly introduces the measurement techniques. The system’s processing data shows that visibility at clutter is greater than 40 dB at target distances greater than 2 km.