Use sig_noise to generate a 256-point waveform consisting of a 300-Hz sine wave with an SNR of −12 dB (x=sig_noise(300, −12,256); ). Calculate and plot the power spectrum using 2 different approaches. First use the direct approach: take the Fourier transform and square the magnitude function. In the second approach use the traditional method defined by Equation 4.11: take the Fourier transform of the autocorrelation function. Calculate the autocorrelation function using axcor, then take the absolute value of the fft of the autocorrelation function. You should only use the second half of the autocorrelation'