多带超宽带OFDM系统射频频率合成器的研制

Development of RF frequency synthesizers for MB-OFDM ultra-wideband(UWB)systems

针对通信系统中使用的传统锁相式频率合成器难同步的缺点,提出了采用直接数字频率合成器(DDS)和锁相环(PLL)技术设计应用于多带一正交频分复用超宽带(MB-OFDM UWB)系统的射频频率合成器方案,并研制了用于试验的合成器。该方案可有效解决系统射频电路的同步问题,提高频率分辨率,降低相位噪声,改善载波频偏对 OFDM 系统影响,提高系统性能,同时还可以降低基带算法的复杂度。仿真与测试结果表明,该频率合成器指标满足 MB-OFDM UWB 系统要求,可应用于实用系统中。

To overcome the synchronization difficulties caused by the carrier frequency offset in an ultra-wideband （UWB） telecommunication system based on multi-band orthogonal frequency division multiplexing （MB-OFDM）, a novel RF frequency synthesizer for the system was designed based on the techniques of direct digital synthesis （DDS） and phase locking loop （PLL）. The synthesizer is characterized by the higher frequency resolution, lower phase noise and elevates the performance of the system by effectively diminishing carrier frequency offset. The simulation and measurement results indicate the frequency synthesizer＇ s effectiveness. It can satisfy MB-OFDM UWB systems perfectly.