Abstract: A helical scan magnetic tape recorder includes a rotary scanner having magnetic heads which record and reproduce data on slant tracks of magnetic tape helically transported about the rotary scanner. Low frequency tones representing a time code or other digital information are recorded by the data heads of the rotary head scanner in the same lateral location such as preamble segments of the data tracks. The recorded time code is recovered by means of a stationary magnetic head. The recovered low frequency tones are converted into digital information such as a digital time code which provides tape location information for editing or searching purposes as well as other auxiliary information such as recorder serial number, data rate codes, etc.

Abstract: Disclosed is a system for bidirectionally guiding web, such as tape in magnetic tape recording/reproducing apparatus. The system eliminates the necessity for edge guides, reduces stresses in web resulting in longer web life, and effects accurate tracking of the web as it is transported in opposite directions. The system includes a plurality of edgeless cylindrical guide rollers mounted on members which are pivoted together. The system includes a plurality of edge sensors and linear servo motors. The edge sensors measure the web edge position and the linear servo motors control the amount of rotation about a pivotal axis which coincides with the center line of a span of web. In this way, web edge position is controlled without any frictional sliding contact between the web and guiding rollers and without the use of edge guides which damage the web edge.

Abstract: Tape guiding methods and apparatus advance a tape through an arcuate bend having equal radii at both edges. Within that bend an unbalance providing a net force transversely of the tape is created at the tape edges while maintaining the equal radii. The advancing tape is guided by applying it with the created net force to a reference surface while maintaining the equal radii.