低噪声合成调频信号发生器的设计

Design of low noise synthesis FM signal generator

为了满足大容量的现代军事通信测试需求,要求合成信号发生器具有极低的相位噪声、高速率、大频偏的高精度调频性能,而传统的合成信号发生器不能满足使用要求。介绍了一种低噪声合成调频信号发生器的设计方案和工作原理,包括了锁相环路和锁频环路。重点讨论了低噪声延迟线鉴频器的实现方法和在降低信号相位噪声方面的作用,以及如何利用多点频率调制、数字化调频、高速率大频偏线性调频等关键技术,克服锁相环路和锁频环路对调频性能的限制,实现高速率、大频偏的调频能力。设计信号相位噪声可达-125dBc/Hz(1GHz,10kHz频偏)、最大调频速率可达10 MHz、最大调频频偏可达10 MHz,是传统合成信号发生器所无法比拟的。

To meet the test requirements of a large capacity modern military communication system .Requires the synthet-ic signal generator to have very low phase noise ,high rate ,high deviation and high accuracy frequency modulation per-formance .But the traditional synthetic signal generator can＆#39;t meet the requirements .In this paper ,the design and princi-ple of a low noise synthesis FM signal generator is introduced ,including a phase locked loop and a frequency locked loop . This paper focused on the implement method of low noise delay line discriminator and the functions of decreasing signal phase noise .how to overcome the limitation of the PLL and FLL to FM performance and how to realize high rate ,high de-viation frequency modulation by using the key design technology of many paths frequency modulation ,digitized FM ,high rate high deviation linear FM etc .The signal phase noise is -125 dBc/Hz（1 GHz ,10 kHz offset） ,the maximum FM rate is 10 M Hz ,the maximum FM deviationthe is 10 M Hz .It is incomparable to the traditional synthetic signal generator .