Synthesizers with low phase noise , highly pure spectrum , high resolution and fast frequency jump speed have dominating development direction of the frequency synthesis technology 低相位噪声、高纯频谱、高分辨率和高速频率捷变成为频率合成技术发展的主要趋势。
Some hybrid frequency synthesis methods for dds + pll which used usually are presented in the following section , and its analysis for phase noise , spur , and frequency jump speed was also introduced 接着对dds + pll频率合成器常用组合方案进行了介绍,并对dds + pll系统的相位噪声、杂散、频率转换速度进行了分析。
Even under the condition that the filling pressure was up to 1 . 5mpa , the onset temperature was only 237 ? . with the filling nitrogen of 0 . 9 mpa , the maximal pressure ratio reaches 1 . 21 and the operation frequency is 25 hz . the ratio of the harmonic wave of the engine was very little and the frequency jumping was not found in present experiments 在充气压力为0 . 9mpa的条件下,该热声发动机最大压比可达1 . 21 ,远高于驻波型热声发动机,实验结果和理论分析均表明系统的工作频率为25hz左右,实验装置的谐波比例非常小,且也没发现频率跳变等现象。