Method for determining the elapsed and/or still available playing time in a magnetic tape

摘要: The time taken by a bobbin to effect one revolution is measured and the number of turns wound about carrier hub (2, 2') determined in relation diameter (Do) bobbin-carrier hub, tape thickness time. This value recorded counter (10, 10') which from that instant increments or decrements pulse per according winding direction. result compared with table expressed steps minute minutes displayed.