| 摘要 |
<p>PURPOSE:To fix the position of noise on a reproduction screen in such as fast-forward mode by exercising phase-synchronizing control over the rotary phase, etc., of a rotary magnetic head by specifying the output frequency, etc., of a servo reference signal generating circuit in such as fast-forward mode. CONSTITUTION:Double-speed ratio (n) of a magnetic tape carriage speed to a normal playback speed in fast-forward or rewind mode and output frequency Rfv' of servo reference signal generating circuits 16, 18, etc., are specified as shown by the expressions, where fV is a field frequency, VT a magnetic tape carriage speed in normal recording and playback mode, (m) a control signal frequency-division ratio, (phi) the diameter of the rotary magnetic head cylinder, and H the number of heads. In the - or + expression, sign ''-'' is used when the tape carriage direction agrees with the rotating direction of the cylinder, and ''+'' is used when the both disagree. Then, the rotary phase of the magnetic head and the phase of a control signal reproduced from the magnetic tape are synchronized with the output signals of said servo reference signal generating circuits 16, 18, etc.</p> |
