Hi,
I have sensors (pyranometers that consist of thermopiles and measure sun irradiation) that ouput a low voltage signal so I need to amplify them using an instrumentation amplifier. I have chosen the AD8237 for this task: Datasheet
Im using a gain of 100 to amplify the initial low voltage signal (ranging 0-20mV) to 0-2V range.
Im then feeding the amplified signal to the ADC (MCP3422): Datasheet
My sensor values change very slowly and I will read out the digitized ADC values only once every second, so speed is not important in my case.
Now after some research I found that a filter between the INA-output and the ADC input is needed. Often a passive RC lowpass filter is suggested between the INA and the ADC.
As I intend to use the delta sigma ADC above, would I care about aliasing effects and do I need to watch out for that? As I'm only interested in the DC signal...
I hope you can point me into the right direction here as im a bit confused right now.
Could I just use smth. like this:??
This is the filter response:
Or what kind of problems do you see with this approach?
Thank you in advance.
I have sensors (pyranometers that consist of thermopiles and measure sun irradiation) that ouput a low voltage signal so I need to amplify them using an instrumentation amplifier. I have chosen the AD8237 for this task: Datasheet
Im using a gain of 100 to amplify the initial low voltage signal (ranging 0-20mV) to 0-2V range.
Im then feeding the amplified signal to the ADC (MCP3422): Datasheet
My sensor values change very slowly and I will read out the digitized ADC values only once every second, so speed is not important in my case.
Now after some research I found that a filter between the INA-output and the ADC input is needed. Often a passive RC lowpass filter is suggested between the INA and the ADC.
As I intend to use the delta sigma ADC above, would I care about aliasing effects and do I need to watch out for that? As I'm only interested in the DC signal...
I hope you can point me into the right direction here as im a bit confused right now.
Could I just use smth. like this:??
This is the filter response:
Or what kind of problems do you see with this approach?
Thank you in advance.