Passive monopulse CW-doppler seeker plays the main role in the guidance and control of semiactive radar homing guided missiles. The most common seeker configuration involves frequency-locked loop (FLL) connected with a phase-locked loop (PLL) through a common phase detector and a local voltage controlled oscillator (LVCO). In this paper, analysis of the operation of such seeker system is presented. The control equations are derived wherefrom the system transfer function is obtained. Stability analysis is also carried out. It is shown that the presence of low-pass filter at the input of the LVCO is essential for system stability. Moreover, the filter time constants should be carefully adjusted to ensure stable operation.