Effect of LO Phase Noise on Front-end Receiver Performance

Low phase noise is an important parameter, which determines the overall performance of the pulsed radar receivers in terms of range, Doppler and also operational robustness. Poor local oscillator (LO) phase noise causes reduction in the IF signal power as well as deterioration in phase noise. Considerable efforts are made to improve the LO phase noise. However, there is always an uncertainty as to how much phase noise should be tolerable and at the cost of what amount of performance. In this paper, a method is being proposed to ascertain the minimum tolerable phase noise or threshold LO phase noise and the impairments in performance thereof. It has also been shown that beyond a certain value, the improvement in performance vis-a-vis the cost and complexity is negligible.