EMI/EMC issues are the most important design challenges for modern electronic systems. The problem becomes quite complex in case of mixed signal processing. Traditional techniques for noise and interference reduction may not produce desirable solutions in such situations. Frequency Modulated Continuous Wave (FM-CW) Radar Altimeter required for altitude measurement during landing aerial vehicles is realized as a mixed signal processor. The receiver design is based on digital signal processing of the down converted and digitized signal in the frequency domain using Fast Fourier Transform (FFT). The highest peak component in the FFT output represents the measured altitude. The level of noise suppression required is very high to achieve better receiver sensitivity which in turn can provide higher altitude measurement. This paper depicts the factors which contributed in the reduction of sensitivity in FM-CW Radar Altimeter. It tells special requirements for power supply filtering and proper regulation schemes. It also illustrates the reasons for sensitivity reduction in the Conducted Susceptibility (CS01) as well as vibration tests. The design is implemented and tested for its functional objectives by way of simulation tests.