JK,
Since the 9233 has built in AC coupling capacitors, any low frequency information will be seriously attenuated. Even if you could calibrate out the offset, there wouldn't be any data there for you to analyze. For that reason I would just assign the low frequncy bins to "0" in software so that your overall analysis isn't skewed by the DC offset introduced by the ADCs. Again if you want to make measurents on low frequency signals, I would recommend using a device that supports DC coupling (like the 9234).
Regards,
Jeff Tipps
Product Support Engineer - Sound and Vibration
