ABSTRACT
Most transducers have an analog output signal, usually in the form of a voltage proportional to the measured quantity. To obtain a digital version of such a signal, which can be accessed by a digital computer, we generally send it into an electronic analog-to-digital converter of some type. An alternative approach, used in many instruments, designs the transducer so that its output voltage is an oscillating signal whose frequency is proportional to the measured quantity. Note that this is still really an analog signal since the frequency changes smoothly with changes in the measured quantity. However, once our information is in the form of a frequency, we can use digital counter/timers like the general-purpose counter/timers regularly used in labs to measure frequency, time interval, etc., to get a digital display of our information. There are several advantages to this approach.
