Rotating head magnetic recording and reproducing device having automatic tracking control function

Abstract

A magnetic recording and reproducing device with an automatic tracking control function which can record and reproduce signals by means of a rotary head incorporating plural heads. The device performs tracking control by detecting, based on a timing of a synchronizing signal of a track, crosstalks of pilot signals obtained from adjacent tracks and comparing the crosstalks to use the difference as a tracking error signal. In a first example of the invention, the device comprises means which, when time points at which the tracking error signals is obtained are located at uneven time interval, transmits the tracking error signal to the tracking control system with a transfer gain which varies substantially in inverse proportion to the time interval. According to the invention, when the time interval for obtaining the tracking error signal is long, the transfer gain becomes low whereas when the time interval is short, the transfer gain becomes high. Therefore, even if the tracking error detection interval varies, its effect on the tracking servo is substantially equalized whereby the amount of data untraced by the heads can be minimized. In a second example of the invention, the device includes circuitry for separately sampling and holding alternate tracking error signals. The alternate tracking error signals are held until the next corresponding tracking error signal occurs, typically corresponding to a half rotation of the rotary head. Therefore, although the alternating tracking error signals occur at uneven time intervals, the time which these signals are held is the same with the result that the influence of the tracking error signals is equal and tracking is optimized.

Dependencies are inferred from the claim text.