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Low frequency sidebands are not expectable in PWM. You get +/- 50 Hz sidebands of the pwm carrier and it's multiples, as expectable for any AM process.
I agree that the sidebands may be caused by an incorrectly implemented sine table, Measurement artefacts (aliasing of oscilloscope sampling rate with pmw carrier) are another possible cause, as previously discussed. But they can be excluded if the 5 Hz modulation stays the same with different oscilloscope settings.
Presumed the modulation is real, we have to go into the code details. No sense of general considerations.
I agree that the sidebands may be caused by an incorrectly implemented sine table, Measurement artefacts (aliasing of oscilloscope sampling rate with pmw carrier) are another possible cause, as previously discussed. But they can be excluded if the 5 Hz modulation stays the same with different oscilloscope settings.
Presumed the modulation is real, we have to go into the code details. No sense of general considerations.