Method and apparatus for increasing the recording time of a digital video tape recorder

A method of operating a digital tape recorder, capable of recording digital data on a tape at a first data rate, to record digital data on the tape at a second data rate, the second data rate being 1/n.sup.th the first data rate, where n is a positive odd integer greater than one, the digital tape recorder including a headwheel having an H number of heads of alternating azimuths uniformly distributed around the outer edge of the headwheel positioned at locations on the headwheel located (360/H) degrees apart, where H is an even positive integer, the digital tape recorder rotating the headwheel at a preselected rotation rate and moving the tape at a preselected tape speed when recording data at the first data rate, the method of recording digital data at the second data rate comprising the steps

• a) positioning the tape in close proximity to the headwheel;
• b) moving the tape around the headwheel at a speed of 1/n.sup.th the preselected tape speed;
• c) rotating the headwheel at the preselected rotation rate, one of the H heads beginning a pass over the moving tape during each (360/H) degree rotation of the headwheel, each of the H heads passing over the moving tape on a diagonal relative to the length of the tape once during each complete 360 degree revolution of the headwheel;
• d) passing a first one of the H heads over the tape by continuing to rotate the headwheel at the preselected rotation rate;
• e) controlling the first one of the H heads to commence recording data on the tape as the first one of the H heads begins to pass over the tape and to continue recording data on the tape until the first one of the K heads completes passing over the tape;
• f) inhibiting the recording of data by the next (n-1) of the H heads to pass over the tape while continuing to rotate the headwheel at the preselected rotation rate;
• g) controlling the head located 360 n/H degrees from the head last used to record data on the tape to commence recording data on the tape when the head located 360 n/H degrees from the head last used to record data on the tape begins to pass over the tape and to continue recording the data on the tape until the head located 360 n/H degree from the head last used to record data on the tape completes the pass over the tape;
• and
• h) repeating steps f and g.

A method of operating a digital tape recorder, capable of recording digital data on a tape at a first rate, to record digital data on the tape at a second rate, the second rate being 1/n.sup.th the first rate, where n is a positive odd integer greater than one, the digital tape recorder including a headwheel having an H number of heads of alternating azimuths uniformly distributed around the outer edge of the headwheel at locations approximately (360/H) degrees apart, where H is an even positive integer, the digital tape recorder rotating the headwheel at a preselected rotation rate and moving the tape at a preselected tape speed when recording digital data at the first rate, the method of recording digital data at the second rate comprising the steps of:

• a) moving the tape at a speed of 1/n.sup.th the preselected tape speed;
• b) rotating the headwheel at the preselected rotation rate;
• c) passing a first one of the H heads over the tape by continuing to rotate the headwheel at the preselected rotation rate;
• d) controlling the first one of the H heads to commence recording digital data on the tape as the first one of the H heads begins to pass over the tape and to continue recording digital data on the tape until the first one of the H heads completes passing over the tape;
• e) inhibiting the recording of digital data by the next (n-1) of the H heads to pass over the tape while continuing to rotate the headwheel at the preselected rotation rate;
• f) controlling the head located 360 n/H degrees from the head last used to record digital data on the tape to record digital data on the tape as the head located 360 n/H degrees from the head last used to record data on the tape passes over the tape;
• and
• g) repeating steps e and f.