Page 227 - Fundamentals of Radar Signal Processing

FIGURE 4.1 Examples of common pulsed radar waveforms: (a) simple pulse,
(b) linear frequency modulated (LFM) pulse, (c) binary phase-coded pulse.

As discussed in Chap. 1, the real-valued waveform of Eq. (4.1) is more
conveniently modeled by its complex equivalent

(4.2)

The portion of other than the carrier term, or equivalently the complex
baseband signal after demodulation, is called the complex envelope of the
waveform

(4.3)

It is this function that describes the amplitude and phase or frequency

modulation applied to the RF carrier and is considered to be “the waveform” in
this chapter.
Radar waveforms can be characterized in several ways. Perhaps first is
whether the waveform is continuous wave (CW) or pulsed; sometimes
variations such as “interrupted CW” are defined as well. Pulsed waveforms can
be defined based on a single pulse, or “the waveform” can be considered to be
a multipulse burst. Both pulsed and CW waveforms can be further categorized
based on the presence or absence of frequency or phase modulation. If present,