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概述本文对噪声及杂波极低的645A型综合器采用的直接综合法作全面探讨。该仪器在50兆赫处的1赫取样点剩余相位噪声为L(1H_z)=-100分贝/赫。L(fm)以每十倍频程12分贝降低到-137分贝/赫的背景噪声。非谐波的杂波含量低于100分贝。频率程序控制转換时间小于20微秒。本文分三节: 第一节:讨论相位噪声特性的基本定义及其测量方法。说明目前所用的各种相位噪声特性量度之间的关系,并确定最适用的综合器噪声特性测量度。还讨论了测量方法。第二节:直接式综合器制造中的主要问
Overview This article provides a comprehensive discussion of the direct synthesis method used in the 645A Synthesizer with very low noise and clutter. The remaining phase noise of the instrument at 1 MHz at 50 MHz is L (1H_z) = -100 dB / Hz. L (fm) drops to -137 dB / Hz background noise at 12 decibels per decade. Non-harmonic clutter content of less than 100 dB. Frequency Program Control Conversion Time Less than 20 microseconds. This article is divided into three sections: Section I: to discuss the basic definition of phase noise characteristics and measurement methods. Explain the relationship between the various measures of phase noise presently used and determine the most appropriate measure of the noise characteristics of the synthesizer. Also discussed is the measurement method. Section II: The main question in the manufacture of direct synthesizers