So this circuit is from ICL7106 datasheet, dual-slope ADC ASIC, what I want to understand is the circuit connected to IN HI and IN LO. So to understand at what my confusion is I need to tell what I understand first:
I fully understand how the ICL7106 works, and how dual-slope ADC works in general.
This ICL7106 works by charging the INT capacitor with (REF_HI - REF_LO) for a fixed amount of time and then the INT capacitor is discharged by (IN_HI - IN_LO) until empty. This discharge time is measured and from those we can get the ratio (REF_HI-REF_LO) and (IN_HI-IN_LO)
The circuit attached on IN_HI and IN_LO is used to get AC input and get the RMS of the AC after the whole process of integration. Meaning Ideally the output of that circuit after integration should get the same result as Integral(VAC^2 dt)
What I don't understand:
How does the circuit attached to IN_HI and IN_LO works? Are there any technique names for changing AC to RMS like this?
How to analyze the circuit?
What does "FOR OPTIMUM BANDWIDTH" below 100pF capacitor means?
How to start tweaking this circuit?