www.gusucode.com > phased 案例源码 matlab代码程序 > phased/ComputeDetectionThresholdFromPfaExample.m
%% Compute detection threshold from Pfa % Calculate the detection threshold that achieves a probability of false alarm % (pfa) of 0.01. Assume a single pulse with a |real| detection type. Then, % verify that this threshold produces a pfa of approximately 0.01. Do this % by constructing 10000 real white gaussian noise (wgn) samples and computing the % fraction of samples exceeding the threshold. % Copyright 2015 The MathWorks, Inc. %% % Compute the threshold from pfa. The detection threshold is % expressed as a signal-to-noise ratio in db. pfa = 0.01; numpulses = 1; snrthreshold = npwgnthresh(pfa,numpulses,'real') %% % Compute fraction of simulated noise samples exceeding the threshold. The % noise has unit power with 10000 samples. noisepower = 1; Ntrial = 10000; noise = sqrt(noisepower)*randn(1,Ntrial); %% % Express the threshold in amplitude units. threshold = sqrt(noisepower*db2pow(snrthreshold)); calculated_Pfa = sum(noise>threshold)/Ntrial