低相位噪声微波频率源的研究

通过对微波频率源相位噪声的分析,针对一个C波段微波频率源低相位噪声的要求,对比分析了直接倍频、数字锁相以及高频鉴相之后再倍频三种方案之间的相位噪声差别。最终得出采用直接在超高频(UHF)波段对输入信号进行模拟鉴相并锁定之后再倍频才能达到所要求的相位噪声指标。对制成的样品进行了测试,取得了预期的相位噪声指标。该C波段微波频率源的相位噪声可以达到:≤-120 dBc/Hz@1 kHz,≤-125 dBc/Hz@10 kHz,≤-130dBc/Hz@100kHz,≤-140 dBc/Hz@1 MHz。直接在UHF波段进行高频鉴相的技术,通过提高鉴相频率大幅降低了微波锁相频率源的相位噪声。

Study of Low Phase-Noise Microwave Frequency Generator

The phase-noise of microwave generator was analyzed for the low phase noise desire of the C band microwave frequency source.Through counted,the difference of phase noise about multiplier-frequency,phase locking loop(PLL)and detect phase at the high frequency then multiple were analysed.As a result,the technology of detect phase in UHF band with the input signal,and multiple-frequency after phase locked,can achieve the need of phase noise.The sample was tested and the anticipative phase noise was acquired.The C band microwave frequency source phase noise can achieve≤-120 dBc/Hz@1 kHz,≤-125 dBc/Hz@10 kHz,≤-130 dBc/Hz@100 kHz,≤-140 dBc/Hz@1 MHz.The technology of the high detect phase in UHF band heighten the detect frequency,thus greatly reduced the phase noise of the microwave generator.