Radar and ARPA Manual

40

RADAR AND ARPA MANUAL

ing the necessary rest period, consideration must be

given to the pulse length which is to be employed on the

chosen range

scale.

Longer pulse lengths will increase the

maximum range from which returns can be reasonably

expected (see Sections 2.5.2.4, 3.2.1 and 3.2.3) and thus

necessitate a longer receiver rest period, a longer pulse

repetition period and hence a lower

PRF.

This represents

a major reason why each available pulse length is assoc-

iated with a particular PRF (see Table 2.1).

The pattern which emerges from Table

2.1

is that the

long pulses are used on the longer range scales and are

associated with the