What are the different frequency modulation profiles?
There are three major types of frequency modulation profiles: Sinewave, Linear (or triangle), and Non-linear (or optimized). Each of these three modulation profiles result in different EMI reduction performance. An example of each modulation profile and the resultant output is shown in Figure 6 below. The sinewave modulation profile is not typically used in spread spectrum clocks due to its large edge peaking. The most popular modulation scheme is the linear modulation profile. This profile reduces edge peaking producing an efficient EMI reduction profile.
There are three major types of frequency modulation profiles: Sinewave, Linear (or triangle), and Non-linear (or optimized). Each of these three modulation profiles result in different EMI reduction performance. An example of each modulation profile and the resultant output is shown in Figure 6 below. The sinewave modulation profile is not typically used in spread spectrum clocks due to its large edge peaking. The linear modulation scheme has improved peaking at the edges, but the small trough in the middle of the profile often reduces the total EMI reduction. The best modulation scheme is the non-linear or optimized modulation profile. This profile reduces edge peaking and troughing, producing the most efficient EMI reduction profile.
