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Calibrating AD5933 with Arduino

Question asked by jareality on Apr 30, 2014
Latest reply on Apr 19, 2018 by Ar@sh

Hi,

 

I am trying to interface the ad5933 with an arduino. Using the arduino I2C library, I am able to communicate with the ic, read temperature measurements, and program registers and initiate a frequency sweep. I have probed the excitation voltage and I am certain it corresponds with the programmed frequency and amplitude. However, when attempting to calibrate, the values the real and imaginary register values are off and the gain factor is off. I have used the suggested set up in the datasheet with a ZCal=200K and RFB=200K. Yet, the computed gain factor is about 256*10^-12, compared to the 515.8*10^12 in the datasheet. I know my gain factor doesnt need not be the same as the datasheet's but it should be similar at least. And with the current gain factor i'm getting, all test measurements within the range of the Zcal (Zmin - Zmax), are all wrong. I've attached my code herein. Kindly let me know if I'm doing something wrong or missing something. Thanks.

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