Graphics Programs Reference
In-Depth Information
Radar Waveforms
Chapter 3
Choosing a particular waveform type and a signal processing technique in a
radar system depends heavily on the radarÓs specific mission and role. The cost
and complexity associated with a certain type of waveform hardware and soft-
ware implementation constitute a major factor in the decision process. Radar
systems can use Continuous Waveforms (CW) or pulsed waveforms with or
without modulation. Modulation techniques can be either analog or digital.
Range and Doppler resolutions are directly related to the specific waveform
frequency characteristics. Thus, knowledge of the power spectrum density of a
waveform is very critical. In general, signals or waveforms can be analyzed
using time domain or frequency domain techniques. This chapter introduces
many of the most commonly used radar waveforms. Relevant uses of a spe-
cific waveform will be addressed in the context of its time and frequency
domain characteristics. In this topic, the terms waveform and signal are used
interchangeably to mean the same thing.
3.1. Low Pass, Band Pass Signals, and Quadrature
Components
Signals that contain significant frequency composition at a low frequency
band including DC are called Low Pass (LP) signals. Signals that have signifi-
cant frequency composition around some frequency away from the origin are
called Band Pass (BP) signals. A real BP signal
can be represented math-
x ()
ematically by
x () r ()
=
cos
(
f 0 t
+
φ x
()
)
(3.1)
 
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