Method and system of reproduction of magnetically recorded video signals at speeds differing from recording speed
AssigneeRobert Bosch GmbH
InventorJurgen Heitmann
Life of this patent
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Abstract
To provide for reproduction of video signals from a magnetic recording tape in which the video signals have been recorded at a speed different from the reproduction speed, so that, upon passage of the tape about a reproducing drum, in a spiral path, the recording angle of the inclined tracks differs from the reproducing scan track (compare tracks 3-7 and 11, 12 of FIG. 1b), a further magnetic head is provided and so positioned that the signals which are not scanned by one head are, effectively, scanned by another head; by use of a programmed memory, the signals can be stored in proper sequence for reproduction as essentially complete TV signals, for read-out in accordance with a desired TV scanning standard, in analog or digital signal form.
Claims11
Method of reproduction of video signals which are magnetically recorded on magnetic tape (1), looped about a head wheel (20), in which the speed of reproduction differs from a known recording speed,
- and in which, upon recording, data representing the video signals are recorded on tracks (3, 4, 5, 6, 7) which are inclined with respect to a longitudinal edge of the tape so that, upon reproduction at a different speed, the scanning tracks (11, 12;
- 15, 16) of a reproduction head (9, 14, 10, 21) on the head wheel (20) do not coincide with the recorded tracks (3, 4, 5, 6, 7)
- comprising the steps of
- temporarily storing the reproduced signals which are of a quality sufficient for reproduction;
- reading-out, at a predetermined television scanning standard, the temporarily stored signals subsequent to their having been stored;
- and further including the steps of
- providing at least two axially adjustable transducer heads (9, 14;
- 10, 21) on the head wheel (20);
- and controlling the relative axial position of the at least two transducer heads on the head wheel with respect to each other as a function of the relationship between recording speed and reproduction speed to place a maximum number of transducer heads (9, 14;
- 10, 21) in scanning transducing position over the previously recorded tracks (3, 4, 5, 6, 7).
System for reproduction of video signals which are magnetically recorded on the magnetic tape (1) looped about a rotating head wheel (20), at a reproduction spread which differs from recording speed,
- in which, upon recording, data representing video signals are recorded on tracks (3, 4, 5, 6, 7) which are inclined with respect to the longitudinal edge of the tape so that, upon reproduction, the scanning tracks (11, 12;
- 15, 16) of a reproduction transducer head (9, 14;
- 10, 21) do not coincide with the recorded tracks (3-7) and comprising
- a buffer memory coupled to the reproduction transducer head for temporarily storing the reproduced signals which are of a quality sufficient for reproduction;
- means for subsequent read-out of the buffer memory at a predetermined television scanning standard,
- at least two axially movable magnetic transducer heads (9, 14;
- 10, 21) spaced angularly from each other and positioned on the scanning head wheel supplying their signals to the buffer memory;
- means (68, 69, 70, 72) for determining the speed of the tape during reproduction in relation to a known speed of the tape during recording and for providing a speed relation control signal (72a)
- and means (22, 23) for controlling the axial positions of the heads as a function of the relationship between the recording speed and the reproduction speed of the tape to place a maximum number of magnetic heads, during reproduction in scanning transducing position over the previously recorded tracks (3-7),
- said position control means being connected to and responsive to the speed relation signals.
System according to 7, wherein four heads are provided and the angle of angular spacing of the transducer heads is about 90.degree. from each other.
Dependencies are inferred from the claim text.