| 摘要 |
<p>PURPOSE:To perform the best ATF servo at all times regardless of the level variation of an input pilot signal by adjusting the gain of the circuit automatically so that the pilot signal has a prescribed level in an on-track state. CONSTITUTION:When the value of a fed-back tracking error signal becomes 0, namely, when an on-track state wherein a magnetic head travels on the center line of its track is entered, an automatic gain control circuit 18 controls the gain automatically so that the signal level of the input pilot signal reaches the predetermined specific level. Consequently, even if the signal level of the pilot signal recorded on a magnetic tape varies from the prescribed level owing to the kind of a magnetic tape and variance of electric characteristics of the device used for sound recording, the signal level of the pilot signal of each tape is controlled automatically to the specific level. Consequently, the invariably accurate ATF servo is performed.</p> |
