The document details a method to autorange an AD736 rms-to-DC converter, allowing it to measure input signals up to 10 V while maintaining high accuracy. This is achieved by using the hysteresis of a voltage comparator IC to automatically switch in an attenuator network and a gain stage when the input signal exceeds the device's standard full-scale range.
The circuit can resolve input signals from 1 mV to 10 V with less than 1% total error.
The low frequency cutoff (-3 dB) is 20 Hz.