【作者】 胡华；

【导师】 陈抗生；

【作者基本信息】 浙江大学 ， 物理电子学， 2005， 硕士

【摘要】 跳频通信是扩频通信的一种，具有抗干扰、抗截获的能力，并能作到频谱资源共享。所以，在当前现代化的电子战中，跳频通信已显示出巨大的优越性。在跳频系统中，频率合成器是核心部件。本论文结合某部国防科技预研项目和实际工程，对某型号宽带快速跳频电台的频率合成器进行了研究与设计。 宽带跳频电台要求我们设计的跳频频率合成器输出频率转换时间快、跳频带宽宽、输出的杂散和相位噪声低以及体积小、重量轻等特点。对此，在分析总结了频率合成技术及其各种实现方案利弊的基础上，针对实际应用，本文选择了DDS小数分频频率合成器方案。 DDS小数分频频率合成器方案利用DDS完成小数分频，将锁相式频率合成以及直接式数字频率合成的优点集成起来，解决了整数锁相频率合成器频率分辨率和换频速率相互制约、小数分频频率合成输出相位抖动、DDS频率上限不够、高功耗等技术难题。DDS部分采用ADI公司2004年最新推出产品AD9956。 本次设计的频率合成器的输出频率范围为225～512MHz，频率间隔200KHz，换频时间要求小于50.s，跳速为1000Hops／s，相噪低于-75dBc／1KHz，完全满足某型号宽带快速跳频电台频段覆盖宽、换频时间短、相位噪声低等要求。 该频率合成器在某型号跳频电台样机中得到应用，达到同类设备国内领先水平。更多还原

【Abstract】 Frequency hopping technology has the capabilities of anti-interference and anti -interception. And it can increase the bandwidth efficiency as well. So it becomes more and more important in electronic counter systems. The core of a frequency hopping system is the frequency synthesizer. This paper makes a design on a frequency synthesizer for a wideband and high-speed frequency hopping transmitter-receiver, combined with the background of National Defense Technology Pre-research Project and practical engineering.It is necessary for the frequency synthesizer we design for the transmitter-receiver to have the following features: fast frequency-hopping rate, wide frequency-hopping band, low outputting spur and low phase noise, small size and lightweight. So, after analyzing and summarizing the technique for frequency-hopping synthesis and the advantage & disadvantage of several realization schemes of it, the fractional-divider synthesizer/PLL with the DDS in the feedback path of a closed loop is chosen in the paper.The scheme offers the benefits combining the DDS and PLL. The application of such a synthesizer used in the wideband and high-speed frequency hopping transmitter-receive not only solves the questions about between the frequency resolution and the rate of frequency change in the integer-N PLL, the phase jitter of the fractional-divider PLL, but also achieves high frequency and low power. We choose the chip AD9956 as the DDS.The range of the output frequency is from 225 Megahertz to 512 Megahertz, the space frequency is 200 Kilohertz, the time of frequency-agile is less than 50μs and the rate of frequency-agile is up to l000hops /s, and the phase noise is less than -75dBc/lKHz .So, the frequency synthesizer is just sufficient to the need of the wideband and high-speed frequency hopping transmitter-receiver because of its broad band frequency, the short time of frequency-agile and the little phase noise.The frequency synthesizer is used in the specimen of the wideband andhigh-speed frequency hopping transmitter-receivers, and it keeps ahead in the same class of the domestic equipments.更多还原