Microwave and Wireless Communications Technology

388 RADAR SYSTEMS

Range resolution can be improved by a process called

pulse compression. One

of the

most common forms of compression is

FM chirp, in

which the radar carrier fre-

quency is swept over a fixed range by a ramp function. If B is the change of fre-

quency and T is the pulse width, then the compressed range resolution is the

simple range resolution, Eq. (19-6), divided by BT:

AR

aRC = B/; (19 7A)

or

r

AR~

= 2B (19- 7B)

19-2.1 Pulse Properties

The radar transmits relatively short-duration (T) pulses and then pauses to listen for

the echo. The actual number of cycles in the pulse is the product of pulse width ...