| 摘要 |
1,208,915. Gramophone records. TELDEC TELEFUNKEN - DECCA SCHALLPLATTEN G.m.b.H. 20 Dec., 1967 [22 Dec., 1966], No. 57899/67. Heading G5R. To minimize the effect of surface irregularities, a spiral record groove of constant pitch and triangular section is cut (by a stylus 1) so that none of the original surface of the record medium remains between adjacent convolutions of the groove. The knife edges of the lands 7 may be cut away by a second stylus 8 linked to the first and having a cutting edge 11 parallel to the plane of the record. The signal to be recorded is modulated on to a carrier oscillation of such amplitude as to cause a stylus deflection not greater than 25% of the depth or width of the initial groove cut by the stylus 1. |
