A short discussion on antennas is included to help in understanding the signal
behavior when it propagates from transmitter to receiver. The Friis transmission
formula and the radar range equation are important in order to understand effects of
frequency, range, and operating power levels on the performance of a communication system. Note that radar concepts now find many other applications. such as
proximity or level sensing in an industrial environment. Therefore, a brief discussion
on Doppler radar is also included in this chapter. Noise and distortion characteristics
play a significant role in analysis and design of these systems. Minimum delectable
signal {MDS). gain compression, intercept-point, and the dynamic range of an
amplifier (or the receiver} are subsequently introduced. Other concepts associated
with noise and distortion characteristics are also introduced in this chapter.