REEL WINDING DIAMETER DETECTING DEVICE

摘要

PURPOSE:To increase the resolution of reel winding diameter detection and to decrease the detection time by forming a pulse from a lengthwise time code signal and an LTC signal reproduced from a tape and detecting the frequency ratio of an output of a pulse generating means and an output of a number of revolution detecting means so as to obtain an output in response to the tape winding diameter of the reel. CONSTITUTION:A pulse generating means 1 generating a periodic pulse B from an LTC signal A, a number of revolution detecting means 2 detecting the number of revolutions of a reel or a reel motor and a frequency ratio detection means 3 detecting the frequency ratio of the output of the means 1 to the output of the means 2 are provided and a reel winding diameter detection output is obtained from the output of the frequency ratio detecting means 3. The frequency of the periodic pulse B obtained by detecting the transition of each bit period of the LTC signal A is 2.4kHz. In taking the frequency ratio with the frequency (nearly 19.9Hz-6.01Hz) of a reel FC signal, the result is nearly 120-399 and the resolution of nearly 280 is obtained. Thus, the reel winding diameter is detected with high resolution and excellent response.