Tape position measurement in cassette - involves determination of rotational speed of reel and electronic processing of data

摘要

The reels are pref. those mounted in a standard cassette, and magnetic tape is wound from one reel to the other. The speed of one reel is measured; the speed of the other reel may also be measured and the measurement result is applied to a processor to which a variable depending on the take thickness is also applied. If speed is measured on one reel only, a further variable is applied to the processor, representing a function of the tape speed transport. The processor calculates then the tape length on one of the reels, or the tape playing time, and its signal is applied to a control device and/or a display device. Code markings (5) are used as an aid to speed measurement.