Radiocontrol in Switzerland

The first country to measure radio listening electronically

Matthias Steinmann
Swiss Broadcasting Corporation
Manuel Dahler
Swiss Broadcasting Corporation
Knut Hackbarth


The technological main issue of the Radiocontrol system consists of a wristwatch with an additional function. A built-in microphone regularly records the ambient sound around the test persons carrying the watch, i.e. at home, out of home, at work, etc. minute by minute. After an analog-digital conversion, a microchip inside the watch reduces the recorded short sound clips by a factor of 120. What is left is a digital sound pattern, a sort of acoustic fingerprint that is unique to each sound sample collected. The data reduction is irreversible which is important for the test person's data protection: the original sounds cannot be reconstructed.(See figure 1).