Method for recording digital data using a set of heads including a pair of co-located heads to record data at a rate lower than the full recording rate possible using the set of heads

Claim 1

A method of operating a digital video tape recorder, capable of recording a full rate bit stream on a tape, to record on the tape a reduced rate bit stream having a data rate of 2/xH the data rate of the full rate bit stream, where x is a positive integer greater than one and H is an even positive integer, the digital video tape recorder including a headwheel having heads of alternating azimuths uniformly distributed around the outer edge of the headwheel, at least one head being located at each one of H locations on the headwheel located (360/H) degrees apart, at least one pair of co-located heads located at at least one of the H locations, the at least one pair of co-located heads including a first head of a first azimuth and a second head of a second azimuth, the one of the H locations located 180 degrees from the at least one pair of co-located heads containing a head of a second azimuth, the digital video tape recorder rotating the headwheel at a preselected rotation rate and moving the tape at a preselected normal play tape speed when recording the full rate bit stream, the method of recording the reduced rate bit stream comprising the steps of: a) positioning the tape in close proximity to the headwheel; b) moving the tape around the headwheel at a speed of 2/xH the preselected normal play tape speed; c) rotating the headwheel at the preselected rotation rate, one of the head locations beginning a pass over the moving tape during each (360/H) degree rotation of the headwheel, each of the H head locations 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 the at least one pair of co-located heads over the tape for a first time by continuing to rotate the headwheel at the preselected rotation rate; e) controlling the first head of the first azimuth of the at least one pair of co-located heads to commence recording data from the reduced rate bit stream on the tape as the first head begins to pass over the tape and to continue recording the data on the tape until the first head completes passing over the tape; f) continuing to rotate the headwheel at the preselected rotation rate to rotate the headwheel (360/H)(xH/2-1) degrees from the point recording was last commenced; g) controlling the record heads to inhibit recording of data by any of the record heads that begin to pass over the tape as the tape rotates the (360/H)(xH/2-1) degrees from the point recording was last commenced; h) continuing to rotate the headwheel at the preselected rotation rate to begin passing a next one of the head locations, located on the headwheel (360x/2) degrees from the one of the recording locations where the head last used to record data on the tape is located; i) controlling a next one of the heads located at the next one of the record head locations and having an azimuth differing from the azimuth of the last head used to record data on the tape, to commence recording data from the reduced rate bit stream on the tape using the next one of the heads when the next one of the heads begins to pass over the tape and to continue recording the data on the tape until the next one of the heads completes the pass over the tape; j) repeating steps f through i.

Claim 2

A method of operating a digital video tape recorder, capable of recording a full rate bit stream on a tape, to record on the tape a reduced rate bit stream having a data rate of 2/xH the data rate of the full rate bit stream, where x is a positive integer greater than one and H is an even positive integer, the digital video tape recorder including a headwheel having heads of alternating azimuths uniformly distributed around the outer edge of the headwheel, at least one head being located at each one of H locations on the headwheel located (360/H) degrees apart, at least one pair of co-located heads located at at least one of the H locations, the at least one pair of co-located heads including a first head of a first azimuth and a second head of a second azimuth, the one of the H locations located 180 degrees from the at least one pair of co-located heads containing a head of a second azimuth, the digital video tape recorder rotating the headwheel at a preselected rotation rate and moving the tape at a preselected normal play tape speed when recording the full rate bit stream, the method of recording the reduced rate bit stream comprising the steps of: a) positioning the tape in close proximity to the headwheel; b) moving the tape around the headwheel at a speed of 2/xH the preselected normal play tape speed; c) rotating the headwheel at the preselected rotation rate, one of the head locations beginning a pass over the moving tape during each (360/H) degree rotation of the headwheel, each of the H head locations 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 the at least one pair of co-located heads over the tape for a first time by continuing to rotate the headwheel at the preselected rotation rate; e) controlling the first head of the first azimuth of the at least one pair of co-located heads to commence recording data from the reduced rate bit stream on the tape as the first head begins to pass over the tape and to continue recording the data on the tape until the first head completes passing over the tape; f) continuing to rotate the headwheel at the preselected rotation rate to rotate the headwheel (360/H)(xH/2-1) degrees from the point recording was last commenced; g) controlling the record heads to inhibit recording of data by any of the record heads that begin to pass over the tape as the tape rotates the (360/H)(xH/2-1) degrees from the point recording was last commenced; h) continuing to rotate the headwheel at the preselected rotation rate to begin passing a next one of the head locations, located on the headwheel (360x/2) degrees from the one of the recording locations where the head last used to record data on the tape is located; i) controlling a next one of the heads located at the next one of the record head locations and having an azimuth differing from the azimuth of the last head used to record data on the tape, to commence recording data from the reduced rate bit stream on the tape using the next one of the heads when the next one of the heads begins to pass over the tape and to continue recording the data on the tape until the next one of the heads completes the pass over the tape; j) repeating steps f through i.

Claim 12

A method of operating a digital tape recorder, capable of recording a full rate bit stream on a tape, to record on the tape a reduced rate bit stream having a data rate of 2/xH the data rate of the full rate bit stream, where x is a positive integer and H is an even positive integer greater than two, the digital tape recorder including a headwheel having heads of alternating azimuths uniformly distributed around the outer edge of the headwheel, at least one head being located at each one of H locations on the headwheel located (360/H) degrees apart, at least one pair of co-located heads located at at least one of the H locations, the at least one pair of co-located heads including a first head of a first azimuth and a second head of a second azimuth, the one of the H locations located 180 degrees from the at least one pair of co,located heads containing a head of a second azimuth, the digital tape recorder rotating the headwheel at a preselected rotation rate and moving the tape at a preselected normal play tape speed when recording the full rate bit stream, the method of recording the reduced rate bit stream comprising the steps of: a) positioning the tape in close proximity to the headwheel; b) moving the tape around the headwheel at a speed of 2/xH the preselected normal play tape speed; c) rotating the headwheel at the preselected rotation rate, one of the head locations beginning a pass over the moving tape during each (360/H) degree rotation of the headwheel, each of the H head locations 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 the at least one pair of co-located heads over the tape for a first time by continuing to rotate the headwheel at the preselected rotation rate; e) controlling the first head of the first azimuth of the at least one pair of co-located heads to commence recording data from the reduced rate bit stream on the tape as the first head begins to pass over the tape and to continue recording the data on the tape until the first head completes passing over the tape; f) continuing to rotate the headwheel at the preselected rotation rate to rotate the headwheel (360/H)(xH/2-1) degrees from the point recording was last commenced; g) controlling the record heads to inhibit recording of data by any of the record heads that begin to pass over the tape as the tape rotates the (360/H)(xH/2-1) degrees from the point recording was last commenced; h) continuing to rotate the headwheel at the preselected rotation rate to begin passing a next one of the head locations, located on the headwheel (360x/2) degrees from the one of the recording locations where the head last used to record data on the tape is located; i) controlling a next one of the heads located at the next one of the record head locations and having an azimuth differing from the azimuth of the last head used to record data on the tape, to commence recording data from the reduced rate bit stream on the tape using the next one of the heads when the next one of the heads begins to pass over the tape and to continue recording the data on the tape until the next one of the heads completes the pass over the tape; j) repeating steps f through i.

Claim 13

A method of operating a digital tape recorder, capable of recording a full rate bit stream on a tape, to record on the tape a reduced rate bit stream having a data rate of 2/xH the data rate of the full rate bit stream, where x is a positive integer and H is an even positive integer greater than two, the digital tape recorder including a headwheel having heads of alternating azimuths uniformly distributed around the outer edge of the headwheel, at least one head being located at each one of H locations on the headwheel located (360/H) degrees apart, at least one pair of co-located heads located at at least one of the H locations, the at least one pair of co-located heads including a first head of a first azimuth and a second head of a second azimuth, the one of the H locations located 180 degrees from the at least one pair of co,located heads containing a head of a second azimuth, the digital tape recorder rotating the headwheel at a preselected rotation rate and moving the tape at a preselected normal play tape speed when recording the full rate bit stream, the method of recording the reduced rate bit stream comprising the steps of: a) positioning the tape in close proximity to the headwheel; b) moving the tape around the headwheel at a speed of 2/xH the preselected normal play tape speed; c) rotating the headwheel at the preselected rotation rate, one of the head locations beginning a pass over the moving tape during each (360/H) degree rotation of the headwheel, each of the H head locations 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 the at least one pair of co-located heads over the tape for a first time by continuing to rotate the headwheel at the preselected rotation rate; e) controlling the first head of the first azimuth of the at least one pair of co-located heads to commence recording data from the reduced rate bit stream on the tape as the first head begins to pass over the tape and to continue recording the data on the tape until the first head completes passing over the tape; f) continuing to rotate the headwheel at the preselected rotation rate to rotate the headwheel (360/H)(xH/2-1) degrees from the point recording was last commenced; g) controlling the record heads to inhibit recording of data by any of the record heads that begin to pass over the tape as the tape rotates the (360/H)(xH/2-1) degrees from the point recording was last commenced; h) continuing to rotate the headwheel at the preselected rotation rate to begin passing a next one of the head locations, located on the headwheel (360x/2) degrees from the one of the recording locations where the head last used to record data on the tape is located; i) controlling a next one of the heads located at the next one of the record head locations and having an azimuth differing from the azimuth of the last head used to record data on the tape, to commence recording data from the reduced rate bit stream on the tape using the next one of the heads when the next one of the heads begins to pass over the tape and to continue recording the data on the tape until the next one of the heads completes the pass over the tape; j) repeating steps f through i.

Claim 15

A method of operating a digital tape recorder, capable of recording digital data on tape at a first data rate, to record the digital data on the tape at a second data rate that is 2/xH the first data rate, where x is a positive integer greater than one and H is an even positive integer, the digital tape recorder including a headwheel having heads of alternating azimuths uniformly distributed around the outer edge of the headwheel, at least one head being located at each one of H locations on the headwheel located (360/H) degrees apart, at least one pair of co-located heads located at at least one of the H locations, the at least one pair of co-located heads including a first head of a first azimuth and a second head of a second azimuth, the one of the H locations located 180 degrees from the at least one pair of co-located heads containing a head of a second azimuth, the tape digital recorder rotating the headwheel at a preselected rotation rate and moving the tape at a preselected normal play tape speed when recording digital data at the first rate, the method of recording the reduced rate bit stream comprising the steps of: a) positioning the tape in close proximity to the headwheel; b) moving the tape around the headwheel at a speed of 2/xH the preselected normal play tape speed; c) rotating the headwheel at the preselected rotation rate, one of the head locations beginning a pass over the moving tape during each (360/H) degree rotation of the headwheel, each of the H head locations 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 the at least one pair of co-located heads over the tape for a first time by continuing to rotate the headwheel at the preselected rotation rate; e) controlling the first head of the first azimuth of the at least one pair of co-located heads to commence recording data on the tape as the first head begins to pass over the tape and to continue recording the data on the tape until the first head completes passing over the tape; f) continuing to rotate the headwheel at the preselected rotation rate to rotate the headwheel (360/H)(xH/2-1) degrees from the point recording was last commenced; g) controlling the record heads to inhibit recording of data by any of the record heads that begin to pass over the tape as the tape rotates the (360/H)(xH/2-1) degrees from the point recording was last commenced; h) continuing to rotate the headwheel at the preselected rotation rate to begin passing a next one of the head locations, located on the headwheel (360x/2) degrees from the one of the recording locations where the head last used to record data on the tape is located; i) controlling a next one of the heads located at the next one of the record head locations and having an azimuth differing from the azimuth of the last head used to record data on the tape, to commence recording data on the tape using the next one of the heads when the next one of the heads begins to pass over the tape and to continue recording the data on the tape until the next one of the heads completes the pass over the tape; j) repeating steps f through i.

Claim 16

A method of operating a digital tape recorder, capable of recording digital data on tape at a first data rate, to record the digital data on the tape at a second data rate that is 2/xH the first data rate, where x is a positive integer greater than one and H is an even positive integer, the digital tape recorder including a headwheel having heads of alternating azimuths uniformly distributed around the outer edge of the headwheel, at least one head being located at each one of H locations on the headwheel located (360/H) degrees apart, at least one pair of co-located heads located at at least one of the H locations, the at least one pair of co-located heads including a first head of a first azimuth and a second head of a second azimuth, the one of the H locations located 180 degrees from the at least one pair of co-located heads containing a head of a second azimuth, the tape digital recorder rotating the headwheel at a preselected rotation rate and moving the tape at a preselected normal play tape speed when recording digital data at the first rate, the method of recording the reduced rate bit stream comprising the steps of: a) positioning the tape in close proximity to the headwheel; b) moving the tape around the headwheel at a speed of 2/xH the preselected normal play tape speed; c) rotating the headwheel at the preselected rotation rate, one of the head locations beginning a pass over the moving tape during each (360/H) degree rotation of the headwheel, each of the H head locations 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 the at least one pair of co-located heads over the tape for a first time by continuing to rotate the headwheel at the preselected rotation rate; e) controlling the first head of the first azimuth of the at least one pair of co-located heads to commence recording data on the tape as the first head begins to pass over the tape and to continue recording the data on the tape until the first head completes passing over the tape; f) continuing to rotate the headwheel at the preselected rotation rate to rotate the headwheel (360/H)(xH/2-1) degrees from the point recording was last commenced; g) controlling the record heads to inhibit recording of data by any of the record heads that begin to pass over the tape as the tape rotates the (360/H)(xH/2-1) degrees from the point recording was last commenced; h) continuing to rotate the headwheel at the preselected rotation rate to begin passing a next one of the head locations, located on the headwheel (360x/2) degrees from the one of the recording locations where the head last used to record data on the tape is located; i) controlling a next one of the heads located at the next one of the record head locations and having an azimuth differing from the azimuth of the last head used to record data on the tape, to commence recording data on the tape using the next one of the heads when the next one of the heads begins to pass over the tape and to continue recording the data on the tape until the next one of the heads completes the pass over the tape; j) repeating steps f through i.

Claim 17

A method of operating a digital tape recorder, capable of recording a full rate bit stream on a tape, to record on the tape a reduced rate bit stream having a data rate of 2/xH the data rate of the full rate bit stream, where x is a positive integer and H is an even positive integer greater than two, the digital tape recorder including a headwheel having heads of alternating azimuths uniformly distributed around the outer edge of the headwheel, at least one head being located at each one of H locations on the headwheel located (360/H) degrees apart, at least one pair of co-located heads located at at least one of the H locations, the at least one pair of co-located heads including a first head of a first azimuth and a second head of a second azimuth, the one of the H locations located 180 degrees from the at least one pair of co-located heads containing a head of a second azimuth, the tape digital recorder rotating the headwheel at a preselected rotation rate and moving the tape at a preselected normal play tape speed when recording the full rate bit stream, the method of recording the reduced rate bit stream comprising the steps of: a) positioning the tape in close proximity to the headwheel; b) moving the tape around the headwheel at a speed of 2/xH the preselected normal play tape speed; c) rotating the headwheel at the preselected rotation rate, one of the head locations beginning a pass over the moving tape during each (360/H) degree rotation of the headwheel, each of the H head locations 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 the at least one pair of co-located heads over the tape for a first time by continuing to rotate the headwheel at the preselected rotation rate; e) controlling the first head of the first azimuth of the at least one pair of co-located heads to commence recording data from the reduced rate bit stream on the tape as the first head begins to pass over the tape and to continue recording the data on the tape until the first head completes passing over the tape; f) continuing to rotate the headwheel at the preselected rotation rate to rotate the headwheel (360/H)(xH/2-1) degrees from the point recording was last commenced; g) controlling the record heads to inhibit recording of data by any of the record heads that begin to pass over the tape as the tape rotates the (360/H)(xH/2-1) degrees from the point recording was last commenced; h) continuing to rotate the headwheel at the preselected rotation rate to begin passing a next one of the head locations, located on the headwheel (360x/2) degrees from the one of the recording locations where the head last used to record data on the tape is located; i) controlling a next one of the heads located at the next one of the record head locations and having an azimuth differing from the azimuth of the last head used to record data on the tape, to commence recording data from the reduced rate bit stream on the tape using the next one of the heads when the next one of the heads begins to pass over the tape and to continue recording the data on the tape until the next one of the heads completes the pass over the tape; j) repeating steps f through i.

Claim 18

A method of operating a digital tape recorder, capable of recording a full rate bit stream on a tape, to record on the tape a reduced rate bit stream having a data rate of 2/xH the data rate of the full rate bit stream, where x is a positive integer and H is an even positive integer greater than two, the digital tape recorder including a headwheel having heads of alternating azimuths uniformly distributed around the outer edge of the headwheel, at least one head being located at each one of H locations on the headwheel located (360/H) degrees apart, at least one pair of co-located heads located at at least one of the H locations, the at least one pair of co-located heads including a first head of a first azimuth and a second head of a second azimuth, the one of the H locations located 180 degrees from the at least one pair of co-located heads containing a head of a second azimuth, the tape digital recorder rotating the headwheel at a preselected rotation rate and moving the tape at a preselected normal play tape speed when recording the full rate bit stream, the method of recording the reduced rate bit stream comprising the steps of: a) positioning the tape in close proximity to the headwheel; b) moving the tape around the headwheel at a speed of 2/xH the preselected normal play tape speed; c) rotating the headwheel at the preselected rotation rate, one of the head locations beginning a pass over the moving tape during each (360/H) degree rotation of the headwheel, each of the H head locations 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 the at least one pair of co-located heads over the tape for a first time by continuing to rotate the headwheel at the preselected rotation rate; e) controlling the first head of the first azimuth of the at least one pair of co-located heads to commence recording data from the reduced rate bit stream on the tape as the first head begins to pass over the tape and to continue recording the data on the tape until the first head completes passing over the tape; f) continuing to rotate the headwheel at the preselected rotation rate to rotate the headwheel (360/H)(xH/2-1) degrees from the point recording was last commenced; g) controlling the record heads to inhibit recording of data by any of the record heads that begin to pass over the tape as the tape rotates the (360/H)(xH/2-1) degrees from the point recording was last commenced; h) continuing to rotate the headwheel at the preselected rotation rate to begin passing a next one of the head locations, located on the headwheel (360x/2) degrees from the one of the recording locations where the head last used to record data on the tape is located; i) controlling a next one of the heads located at the next one of the record head locations and having an azimuth differing from the azimuth of the last head used to record data on the tape, to commence recording data from the reduced rate bit stream on the tape using the next one of the heads when the next one of the heads begins to pass over the tape and to continue recording the data on the tape until the next one of the heads completes the pass over the tape; j) repeating steps f through i.