Transducer with phase modulation and adjustable sensitivity

Résumé

The work presents an easy converter in order to be used at little displacement. The circuit gives two electrical signals with the same frequency and with different phases, dependent on the displacement. Both signals go to the stereo sound plate input of a calculator and are numericalyl operated with an easy software. The transducer presents the following advantages: it directly measures the shifts (it is a vibrometer) and not the accelerations, which in order to provide shifts must be incorporated twice and the parasite accelerations filtered (for example the gravitational acceleration); it is less sensitive to disturbances because the transmission of the information is performed through phase modulation; it supplies signals of very low frequency, which can be taken over directly by any computer with a sound card, without complicated interfaces; the sensitivity can be conveniently adjusted, by acting directly on some potentiometers.