APPARATUS AND METHOD FOR SCANNING AN INFORMATION TRACK AND RECORD CARRIER

摘要

In order to follow an information track (1) on an information carrier (2), a push-pull signal (PP) is generated. The polarity of the push-pull signal (PP) is different for different types of information carriers (2). Tracking means (8) should react differently to a push-pull signal (PP) with a positive polarity than to a push-pull signal (PP) with a negative polarity. The invention described is a method for scanning an information track (1) by determining the polarity of the push-pull signal (PP) first and putting the tracking means (8) in a first or second mode dependent on the polarity of the push-pull signal (PP). In the first mode the tracking means (8) react differently to the push-pull signal than in the second mode. The determination of the polarity of the push-pull signal (PP) can be done in several ways. The polarity can be stored on the information carrier (2), and the polarity determining means (9) read the polarity from the information carrier (2). Alternatively, the polarity determining means (9) can determine the polarity by directing the tracking means (8) to operate in the first and second mode subsequently, and check in which mode the scanning-location (6) was on-track.