I want to digitise a sweep signal. The frequency range is 1-100 Hz and the sweep time is 2 seconds. The amplitude is 4.08 Volts and an offset of 2.04 volts is added. ADC range = 0-4.04 Volts. I am currently using an SAR ADC and it is working fine. Would it be better to use a Delta-Sigma ADC? I need a fast and low power ADC. I can have a resolution up to 12-bits with the SAR and I don't think I need more than that. So the ADC resolution is not an issue.