www.gusucode.com > signal 案例源码程序 matlab代码 > signal/VisualizeOrderMapOfChirpWith4OrdersExample.m
%% Order-RPM Map of Chirp with 4 Orders % Create a simulated signal sampled at 600 Hz for 5 seconds. The system % that is being tested increases its rotational speed from 10 to 40 % revolutions per second during the observation period. % Copyright 2015 The MathWorks, Inc. %% % Generate the tachometer readings. fs = 600; t1 = 5; t = 0:1/fs:t1; f0 = 10; f1 = 40; rpm = 60*linspace(f0,f1,length(t)); %% % The signal consists of four harmonically related chirps with orders 1, % 0.5, 4, and 6. The order-4 chirp has twice the amplitude of the others. % To generate the chirps, use the trapezoidal rule to express the phase as % the integral of the rotational speed. o1 = 1; o2 = 0.5; o3 = 4; o4 = 6; ph = 2*pi*cumtrapz(rpm/60)/fs; x = [1 1 2 1]*cos([o1 o2 o3 o4]'*ph); %% % Visualize the order-RPM map of the signal. rpmordermap(x,fs,rpm)