基于正交DDS单边带调制扫频源电路设计与实现

通过频谱的线性搬移原理，提出了一种100～1000 M Hz扫频源电路设计方案。该方案基于正交单边带调制的方法，将DDS芯片产生的正交信号与正交的本振信号分别相乘后再相加，输出信号中本振和其中一个边带信号会被抑制，另一个边带信号就是直接变频得到的信号将会得到保留。研究测试表明该电路的无用边带和载波信号均被抑制了－40 dBm左右，且该电路还具有较高的频率精度和频率范围，既保留了DDS极好的频率分辨率和频率捷变的特性，又实现了在宽频带扫频的功能。

Design and implementation of single side band modulation scan source circuit based on orthogonal DDS

By moving the linear spectrum principle ,we proposed a 100 ~ 1 000 MHz sweep source circuit design . Quadrature signal with the quadrature local oscillator signal of the program orthogonal single sideband modulation method based on the DDS chip are generated by multiplying the sum output signal and local oscillator signal one sideband is suppressed ,another sideband signal is the signal obtained by direct conversion will be retained .Study tests show unwanted sideband and the carrier signal of the circuit were inhibited by about -40 dBm ,and the circuit also has a higher frequency accuracy and frequency range ,not only retains the DDS frequency resolution and excellent frequency agility features but also achieved a wide band sweep function .