| 摘要 |
PURPOSE:To evaluate the strength of a coated film quantitatively and automatically by recording an information signal for measurement on the film and regenerating continuously by a reproducing head, in an abrasion resistance test for a film of a magnetic recording medium. CONSTITUTION:An information signal for measurement is recorded on a magnetic coated film 2 on the surface of a magnetic disk 1, and a magnetic head 4 repeats operations of stop and start-up. Signal which is outputted from the head 4 is inputted to an analog comparator 9 and a threshold value setting circuit 10 through a preamplifier 8. A detector for rotatinal frequency 11' is provided to a revolving plate 18 equipped to a rotating shaft of the disk 1, and its output is inputted to a gate 11 and operation signal is outputted only in the time when the disk 1 is stationarily rotating. When the output from the head 4 becomes smaller than the input signal to the coated film 2 in a certain degree, the comparator 9 stops the output of a counter 12 and a motor 17 is stopped and then the test is finished. |
