A Fundamental Voltage To Frequency Converter {March 2023}

A confirmed option to ship an analogue sign a protracted distance is to move the sign as a frequency utilizing a voltage to frequency converter (VFC), a particular circuit whose output is a frequency that’s proportional to its enter voltage.

In precept, it’s comparatively simple to ship a frequency sign over a protracted transmission path with out interference by way of optical, coaxial, or radio hyperlinks. The frequency is then reconverted to an analogue voltage by a FVC that’s normally tailor-made to carry out its inverse perform, usually utilizing a phase-locked loop (PLL). Block diagram of the challenge is proven in Fig. 1.

Fig. 1: Block diagram of voltage to frequency converter

This challenge makes use of an odd strategy to design and construct a hobby-level VFC module utilizing a handful of simply accessible and cheap digital parts. Creator’s circuit of the VFC module wired on a breadboard is proven in Fig. 2.

Fig. 2: Author’s circuit on a breadboard — Fig. 2: Creator’s circuit on a breadboard

Schematic diagram of the VFC module is proven in Fig. 3. Please observe, a well-regulated 5V DC energy supply is totally essential to run this VFC circuit. Coronary heart of the circuit is the venerable CMOS micropower phase-locked loop IC HEF4046B.

The HEF4046B (IC1) features a VCO sub-system along with part comparators and different components. It could generate a sq. wave with 50% responsibility cycle. The frequency in all fairness near 0Hz-1kHz vary, which is curbed by the 100nF capacitor (C1) and the 10k resistor (R1).

This challenge might be printed in a couple of weeks. If you wish to entry it now, confer with Electronics For You’s October 2022 Problem–print or ezine version.