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ADC selection for measuring ratio of two 50 Hz sine wave with high accuracy (better than 0.1%)

Question asked by apoorv on Aug 29, 2014
Latest reply on Sep 1, 2014 by jtee

I have 2 sine waves, where a potential divider (inductive) is used to generate the 2nd wave(Vout)  from the 1st(Vin). I want to measure the attenuation of the potential divider with a high accuracy (better than 0.1%). The ratio of the divider can vary from 1:1 to 1:1000. So, basically I want to build a measurement circuit which can do the following:

Impedance_Voltage_divider.png

- Measure RMS value of 2 sine waves (50Hz) with accuracy better than 0.1 % and I think both the channels should be sampled simultaneously also, though it might work otherwise too.

- Vin will be fixed, probably generated from the power line, and fed to an ADC channel.

- Vout will vary with a dynamic range of 1:1000 based on the ratio, and it can have phase difference of around 3-4 degrees fro Vin

- Z2's impedance will be around few 100's of Ohms

 

I have looked into energy measurement ADCs like ADE7953, and it might work for this application, but the front ends of it's 2-channels are different as one needs to measure the voltage and other current.

 

Thank you in advance.

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