SPRUJ28E November 2021 – September 2024 AM68 , AM68A , TDA4AL-Q1 , TDA4VE-Q1 , TDA4VL-Q1
The aim of the SSMOD is to add a variation to the frequency of an original clock, which spreads the generated interference over a larger band of frequencies.
In theory, SSMOD means that the clock signal is varied around the desired frequency. For example, for a 1 GHz clock, the frequency might be 999.5 MHz at one time and 1.0005 GHz at another. Doing this constantly causes the power of the tone to be spread out more over a broader band of tight frequencies (centered at the desired tone). To realize this constant variation on the original signal, a modulation with an additional signal (called spreading waveform) is realized.
Creating an SSMOD by spreading the initial clock frequency is done by defining the following parameters: