What is output frequency modulation width (or spread percentage)?
Figure 5 below shows a plot of output frequency versus time for an output of a linear (triangular) modulated spread spectrum clock oscillator. As you can see from the figure, the output frequency has a minimum (FMIN), center (Fc), and maximum (FMAX) frequency. The output frequency is swept linearly though a range of frequencies rather than being held at one constant frequency. This ‘range’ parameter is often called output modulation width, output frequency spectrum, or frequency spread percentage. The maximum and minimum output frequencies are often stated as a percentage (%) with respect to the center frequency. The Ecliptek EMS series oscillators offer a range of programmable output frequency modulation widths from 0.5%, 1%, and 2.0% (FMAX minus FMIN). The wider the modulation frequency spread percentage, the larger the bandwidth of frequencies over which the energy is distributed, and therefore the more EMI peak reduction.
Figure 5 below shows a plot of output frequency versus time for an output of a linear (triangular) modulated spread spectrum clock oscillator. As you can see from the figure, the output frequency has a minimum (FMIN), center (Fc), and maximum (FMAX) frequency. The output frequency is swept linearly though a range of frequencies rather than being held at one constant frequency. This ‘range’ parameter is often called output modulation width, output frequency spectrum, or frequency spread percentage. The maximum and minimum output frequencies are often stated as a percentage (%) with respect to the center frequency. The Ecliptek EPS series oscillators offer a range of programmable output frequency modulation widths from 0.5% to 4.0% (FMAX minus FMIN). The wider the modulation frequency spread percentage, the larger the bandwidth of frequencies over which the energy is distributed, and therefore the more EMI peak reduction.
