Automatic tracking circuit for transverse scan magnetic tape transport

Claim 1

An automatic tracking control circuit for a transverse scan tape transport which includes a capstan drive for longitudinal translation of magnetic tape and a rotary magnetic head assembly rotating in a path transverse to said tape for reproducing transverse tracks of prerecorded information, wherein said circuit comprises: an electrical source issuing a sinusoidally varying electrical signal, said source being connected to the capstan drive for sinusoidally varying the translation speed of the tape; amplitude detector means coupled to the magnetic head assembly for detecting amplitude variations in the reproduced transverse track signal information, said detector having a frequency sensitivity below a predetermined frequency range of said prerecorded information; filter means passing signal frequencies at the frequency of said source signal, said filter being connected to the output of said detector means; a comparator having electrical storage means, an output means connected to said storage means and input switching means connected between said filter means and said storage means, said switching means being connected and responsive to said source for sampling and passing the instantaneous magnitude of the signal issued by said filter means to said storage means in response to each cycle of said sinusoidal source signal; and feedback circuit means connected between said comparator output means and the capstan drive and being responsive to frequency and phase correspondence of signals from said source and said comparator means to issue a control signal to said capstan drive for adjusting the translation of said tape to maintain optimum registration between said head assembly and said transverse tracks.