function wave = wavefuc(time,fs,freq)
    t = 0:1/fs:4/time;
    wave = sin(1*2*pi*freq*t).*exp(-0.004*2*pi.*freq*t)/1;
    wave = wave+sin(2*2*pi.*freq*t).*exp(-0.004*2*pi.*freq*t)/2;
    wave = wave+sin(3*2*pi.*freq*t).*exp(-0.004*2*pi.*freq*t)/4;
    wave = wave+sin(4*2*pi.*freq*t).*exp(-0.004*2*pi.*freq*t)/8;
    wave = wave+sin(5*2*pi.*freq*t).*exp(-0.004*2*pi.*freq*t)/16;
    wave = wave+sin(6*2*pi.*freq*t).*exp(-0.004*2*pi.*freq*t)/32;
    wave = wave+(wave.*wave.*wave);
    wave = wave/6;
end