27.1. SNR Variations

The MATLAB code in Computer Listing 27.1 generates two cosine waves embedded in additive white Gaussian noise (AWGN) and then computes the unmodified periodogram for the composite signal. This code was run for the combinations of frequency and SNR listed in Table 27.1, with the results plotted in the figures as indicated by the table entries.

Table 27.1. Cases Demonstrated in Section 27.1

Case	freq1	freq2	Δf	snr	Figure
1	31.555/N = 0.123262	32.445/N = 0.126738	0.89/N = 0.003477	200	27.1
2	31.555/N = 0.123262	32.445/N = 0.126738	0.89/N = 0.003477	0	27.2
3	31.555/N = 0.123262	32.445/N = 0.126738	0.89/N = 0.003477	–10	27.3
4	31.95/N = 0.124805	33.05/N = 0.129102	1.1/N = 0.004297	200	27.4
5	31.55/N = 0.123242	33.45/N = 0.130664	1.9/N = 0.007422	200	27.5