Auto Tape Time Select
The Auto Tape Time Select is a process developed and patented by Grundig in 1976 to determine the elapsed playing time of tape or video cassettes or reels with wound magnetic tape . The system enables a playback device to determine the current tape position after inserting a cassette without the aid of a time code or similar information. At the time of the video recorder format war , Grundig used the process to exclusively equip its devices with a real-time counter to set them apart from the competition.
Working principle
The functional principle is based on the precise measurement and subsequent comparison of the angular momentum of the tape lap. After inserting a cassette, the system starts the measurement by transporting the tape at a fixed speed specified by the capstan shaft , while the angular momentum of the tape reel is counted. Using this information, the current diameter of the tape lap can be calculated and the playback position can thus be inferred . The system only needs the tape thickness and the core diameter of the winding spools as fixed parameters.
The patent specifies an accuracy to the second, but only devices with a counter that is accurate to the minute are known.
application
The first notable application of the technology was found in the second generation Video 2000 devices (e.g. Video 2x4 super), where it was still known as “real-time display”. Grundig later also offered the system in numerous VHS models, under the abbreviation “ATTS”.