ADPD4100/ADPD4101 Integrator chopping SUBTRACT_x and REVERSE_INTEG_x

Would the bit pattern for these two fields ever be different? If so, why?

Thanks.

  • 0
    •  Analog Employees 
    on Jan 4, 2021 3:36 PM

    Hello HarjitS,

    Thanks for your question! 

    SUBTRACT_x and REVERSE_INTG_x work together to achieve the integrator chopping where SUBTRACT_x is a math operation and REVERSE_INTG_x is a physical connection change by the switch matrix in front of the integrator.  

    For example:

    Assuming s denotes the signal and n is the integrator noise per pulse, the integrator outputs s+n without REVERSE_INTG_x being set and the integrator output -s+n when REVERSE_INTG_x is set. To keep the signal and cancel the noise, a subtraction operation is applied so that (s+n) -(-s+n) = 2s.

    For 4-pulse sequence, [0x010D]0x0066 will flip the integrator polarity for 2nd and 3rd pulses and apply subtraction to these two pulses and the result will be 4s. With  [0x010D]0x0096 or [0x010D]0x0069, the result will be -4s. 

    Hope the example above helps.

    Thanks!

    Glen B.

  • Okay, that makes sense. Thanks for the answers.