A method and apparatus for video signal recording comprises helically scanning a plurality of transducer heads (20-23) sequentially along separate parallel paths (30-32) of equal width on a record medium (10) at a rate such that a plurality of the scans occur within a field interval, and diverting the signal in predetermined sequence to different ones of the heads. The scanning of said heads and diverting of the signal to different heads is arranged to cause some redundant recording of information in different ones of the paths, information recorded in a path that is adjacent an edge of the medium having corresponding redundant information recorded in an internal path that is bounded by other parallel paths. The apparatus includes a rotary scanner (12) having at least three transducer heads spaced along and around the axis of rotation of the scanner whereby each head scans along a different circular orbit and at a different time across a segment of a cylindrical surface defined by the plural orbits, and a transport for moving a recording tape across a segment of such cylindrical surface in timed relation to scanning rotation of the heads and at an angle to the axis of rotation such that each head traces a series of helical scans on the medium within non-overlapping paths along the direction of motion of the medium. The heads rotate at a speed sufficient to separate each scan of a head along the corresponding path.
For recording on, and reading of, a magnetic tape guided around a cylinder, there are several magnet heads arranged on a common circle diameter. The magnet heads revolve about a common axis extending obliquely with respect to the travel direction of the tape. The magnet heads interact with the tape through a slot-shaped aperture formed in the cylinder. For the purpose of achieving a very simple tape-guiding system, the tape is guided in a direction perpendicular to the cylinder longitudinal axis over a cylinder surface which, at least in its tape-guiding zone, and viewed in a section perpendicular to the cylinder longitudinal axis, corresponds at least approximately to a projection of the circular motion performed by the magnet heads in a direction perpendicular to the tape travel direction.
A digital video tape recorder comprises a head drum, four transducer heads mounted in pairs on the head drum for recording oblique tracks on a magnetic tape, a demultiplexer for distributing digital data to be recorded and corresponding to a video signal such that each field of the video signal is divided into 50-line segments, the digital data corresponding to each field are evenly distributed between all four of the heads for recording, and each track comprises a block of digital data relating to one 50-line segment and a block of digital data relating to another 50-line segment, the two blocks of digital data being separated by an edit gap.
A helical scan video recorder having a reduced drum diameter in comparison with a two-head video recorder by the use of n heads, n being greater than two, and a tape wrap angle greater than ##EQU1## An important additional advantage of this recorder is that reproduction during recording (monitoring) is possible without the use of additional heads.
A method and apparatus for accurately positioning a transducing means along a desired path for recording parallel tracks of information being transmitted at varying rates. The apparatus also is arranged to control the transducing means so that accurately follows the tracks during reproducing at various tape transport speeds. In a magnetic recording/reproducing apparatus having transducing means operably supported by rotation means for scanning a magnetic tape along a plurality of adjacent sets of tracks, the rotation means including movable means carrying the transducing means and in response to electrical signals effecting movement of the transducing means in opposite directions from a home position in which the movement is generally transverse to the direction of the sets of tracks, wherein the improvement includes the signal producing means being operable to produce signals in response to the transverse position data for positioning the transducing means to either accurately simultaneously record a set of tracks along a desired path or simultaneously reproduce from the tracks and, during recording, to record additional sets of tracks subsequent to the completion of the preceding set of tracks along paths parallel to the selected path, the selected path being determined as a function of the speed and direction of transport of the tape.
Apparatus is provided for use in a digital video signal playback device of the type having a record medium in which plural channels of digital video signals are recorded in a like plurality of tracks. Plural transducers, such as playback heads, are associated with respective ones of the channels and reproduce the digital video signals from the plural tracks, each transducer normally reproducing a respective, predetermined channel of the digital video signals. A detector detects the particular channel with which the digital video signal reproduced by each transducer is associated. A signal interchanger is provided with plural channel outputs and is responsive to the detector for directing digital video signals which have been reproduced by transducers associated with channels which differ from the channels of the reproduced digital video signals to the proper channel outputs as determined by the detector. Thus, regardless of the particular transducer which reproduces the digital video signals from a track, that digital video signal nevertheless is supplied to its proper channel output.
