在通信测试仪表中，对频率稳定度的要求都较高。为了得到较高的频率稳定度，以往采用锁相环（PLL）或高德定性振荡电路来实现。但无论采用什么方法，其电路和结构都比较复杂。直接数字式频率合成器DDS具有极高的频率分辨率、低的相位噪声、全数字接口等特点，将其用在通信测试? In the communication test instrument, the requirements of the frequency stability are higher. In order to get higher frequency stability, the past, the use of phase-locked loop (PLL) or high German qualitative oscillation circuit to achieve. But no matter what method, the circuit and structure are more complicated. DDS direct digital frequency synthesizer with high frequency resolution, low phase noise, all digital interfaces, etc., used in communications testing?