Analog Interfacing to Embedded Microprocessor Systems, 2nd Edition

transfer the analog value to the microprocessor. Of course, the optocoupler has to

be capable of operating at the maximum frequency the V-F will generate.

A V-F converter is also useful any time an analog signal needs to be transmitted

over a wire that is electrically noisy. As long as the noise levels aren’t large enough

to affect the switching point (thereby affecting the frequency measured at the

receiving end), the receiver will be able to extract valid data.

Filtering

Using a divider with a V-F converter (Figure 4.7) provides an automatic filtering

function. Figure 4.7 shows a V-F connected to a microprocessor through a divide-

by-16 counter.