Double-IF quadrature demodulation of super-heterodyne radar receiver

In radar, sonar and communication applications, and especially in all-digital receivers and software radio systems, baseband in-phase and quadrature (denoted by I and Q) components are usually needed. In a super-heterodyne radar receiver, the conventional method to obtain quadrature components of signals is to multiply the original signal with a complex exponential. In this paper, the fundamental principles of obtain digital quadrature components of the super-heterodyne radar receiver are introduced. Double-IF quadrature demodulation topology is synthesized and fully analyzed in this paper.