Page "Pulse repetition frequency" Paragraph 2

The reciprocal of PRF ( or PRR ) is called the Pulse Repetition Time ( PRT ), Pulse Repetition Interval ( PRI ), or Inter-Pulse Period ( IPP ), which is the elapsed time from the beginning of one pulse to the beginning of the next pulse.

Within radar technology PRF is important since it determines the maximum target range ( R < sub > max </ sub >) and maximum Doppler velocity ( V < sub > max </ sub >) that can be accurately determined by the radar.

Conversely, a high PRR / PRF can enhance target discrimination of nearer objects such as a periscope or fast moving missile leading to practices of employing low PRRs for search radar, and very high PRFs for fire control radars, with many dual-purpose and navigation radars, especially naval designs having variable PRRs which might allow a skilled operator to also use a PRR adjustment to enhance and clarify a unclear radar picture, for example in bad sea states where wave action generates false returns, and in general for less clutter, or perhaps a better return signal off a prominent landscape feature ( e. g. a cliff ).