Simple square-rooting voltage-to-frequency converter

This paper presents a simple method based on commercially available devices for realizing the square-rooting voltage-to-frequency converter (VFC). The output frequency is proportional to the square root of the input voltage signal. The realization technique employs an operational transconductance amplifier (OTA)-based square root extractor and a NOR-based Set-Reset (S-R) latch. The scale factor of the square root extractor can be electronically varied by changing the external bias currents of the OTAs. Experimental results verifying the performances of the proposed square-rooting VFC are agreed with the expected values.