Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the record
Patent
1990-04-04
1992-11-24
Heinz, A. J.
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the record
G11B 1552
Patent
active
051668416
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a tape transport apparatus for use in a video tape recorder, a digital audio tape recorder or the like.
BACKGROUND ART
Recently, in a recording reproducing apparatus using a tape medium, there is a growing demand for a recording apparatus which is long time-recordable and accomplishes a quick access. Regarding the high access, the increase of a tape transport speed and the reduction of acceleration and deceleration times are the technical problems to be solved.
Tape transport apparatuses are disclosed in, for example, Japanese Laid-Open Patent Publication No. 59-165260 and Japanese Laid-Open Patent Publication No. 59-165261.
An example of a conventional tape transport apparatus is described below.
A conventional tape transport apparatus comprises a winding reel, a supply reel, two rotation-number detectors for detecting the number of rotations of the two reels, two rectification smoothing devices for smoothing the outputs of the rotation-number detectors, an adder for adding the outputs of the two rectification smoothing devices, a comparator for comparing the output of a speed setting signal indicative of a tape speed with the output of the adder, an integrator, and a reel motor.
Regarding its operation, the rotation condition of the winding reel is detected by the first rotation-number detector and transmitted to the adder through the first rectification smoothing device. Similarly, the rotation condition of the supply reel is detected by the second rotation-number detector, transmitted to the adder through the second rectification smoothing device, and added to the output of the first rectification smoothing device. The comparator compares the speed setting signal with the output of the adder and the result is outputted to the integrator as a speed error signal. In order for the reel motor for driving the winding reel to receive the integrated speed error signal, the rotation of the winding reel is feedback-controlled.
However, according to the above-described construction, it is difficult, in particular, to control the torque applied to the winding reel when the tape speed is reduced. Desirably, a deceleration torque is applied to the winding reel in order to reduce the tape speed, but the tape is loosened if the deceleration torque is too large.
If the reduction torque is applied to the supply reel, the operation is a special processing to temporarily release the feedback control over the winding reel in the transient condition in which a high speed transport is switched to a low speed transport. Thus, the known tape transport apparatus has a problem that it has difficulty in controlling in detail, for example, the deceleration torque amount and deceleration time.
DISCLOSURE OF THE INVENTION
It is the object of the present invention to achieve stable acceleration and deceleration controls of a tape when the tape transports at steady, acceleration, and deceleration speeds through the same processing, and particularly, provide a tape transport apparatus capable of reducing a tape speed in a time shorter than conventional tape transport apparatuses do.
In order to achieve the above-described object, the present invention comprises: two reels for winding and feeding a tape; drive means for driving the two reels respectively; a tape speed detecting means for outputting the speed data on the tape; a desired value circuit for outputting the desired value of the tape speed; a tape speed error detecting means for outputting an error quantity between the output of the tape speed detecting means and the output of the desired value circuit; and a driving side determining circuit which receives the output of the tape speed error detecting means and, based on the error quantity of the speed, outputs a drive instruction to the drive means on the winding side when the tape speed is less than a desired value and to the drive means on the feeding side when the tape speed is more than the desired value.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram
REFERENCES:
patent: 4051415 (1977-09-01), Martin
patent: 4628375 (1986-12-01), Stadlmann
"Electrical Differential Tap Drive System"; IBM Technical Disclosure Bulletin; J. S. Weidenhammer, vol. 12 No. 11 Apr. 1970.
Ota Kiyoshi
Wakiyama Koji
Heinz A. J.
Matsushita Electric - Industrial Co., Ltd.
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