Radar Detection - MATLAB Simulations for Radar Systems Design - page 92

Figure 2.7. The incomplete Gamma function for four values of N .

MATLAB Function Ðthreshold.mÑ

The function Ðthreshold.mÑ calculates the threshold using the recursive for-
mula used in the Newton-Raphson method. It is given in Listing 2.12 in Sec-
tion 2.11. The syntax is as follows:

[pfa, vt] = threshold (nfa, np)

where

Symbol Description Units Status

nfa MarcumÓs false alarm number none input

np number of integrated pulses none input

pfa probability of false alarm none output

vt threshold value none output

Fig. 2.8 shows plots of the threshold value versus the number of integrated
pulses for several values of ; remember that . This figure
can be reproduced using MATLAB program Ðfig2_8.mÑ given in Listing 2.13.
This program uses both Ðthreshold.mÑ and Ð incomplete_gammaÑ.

n fa P fa ≈ ln () ⁄ n fa