JP3530455B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a magnetic recording / reproducing apparatus, and more particularly to a magnetic recording apparatus which detects a tape position during rewinding or fast-forwarding a magnetic tape and controls tape running. It can be suitably used for a playback device. 2. Description of the Related Art There are the following conventional examples regarding control of FF and REW of a magnetic recording / reproducing apparatus. FIG. 1 shows a schematic diagram of a magnetic recording / reproducing apparatus.
The figure shows a state at the time of high-speed normal winding (hereinafter referred to as FF).
Using the capstan motor 1 as the driving force, the reel belt 2
The TU reel 8a rotates through the pulley 3, the pulley gear 4, the idler gear 5, the drive side (hereinafter referred to as TU) relay gear 6a, and the TU reel base 7a, and winds the magnetic tape 9 in the normal rotation direction. At the time of high-speed reverse winding (hereinafter referred to as REW), the idler gear 5 moves to the supply side (hereinafter referred to as SUP) relay gear 6b, and the SUP reel 8b similarly rotates to wind the magnetic tape 9 in the reverse direction. . During the FF and REW operations, the A / C head 10 transmits a control signal recorded on the magnetic tape 9 to the rotation speed detecting mechanism disposed on the capstan motor 1, the TU reel table 7a and the SUP reel table 7b. After reading, the drive reel (TU reel 8a, RE at FF)
The ratio (hereinafter referred to as a reel ratio) between the rotation cycle of the SUP reel 8b for W and the rotation cycle of the supply reel (SUP reel 8b for FF and the TU reel 8a for REW) and the supply reel. By calculating the amount of the magnetic tape 9 wound on the tape (hereinafter referred to as the remaining tape amount) as needed, a travel control such as a search for a destination on the tape and a stepwise switching of the tape speed is performed. In the magnetic recording / reproducing apparatus as described above,
During the FF and REW operations, a phenomenon that the magnetic tape slips in the winding direction in the magnetic tape wound on the reel (hereinafter, referred to as tape slip) may occur due to a load change on the magnetic tape. This is one of the causes of the fluttering of the reels during FF and REW, errors in calculating the reel ratio, and calculating the remaining amount of tape. In particular, when the FF and REW running are performed at a tape speed several hundred times that of the normal reproduction, these errors are a major factor that deteriorates the stability of the tape control. Here, an embodiment of the conventional means for detecting tape slippage will be described. FIG. 7 is a graph showing a temporal change of the reel ratio at the time of FF and REW. This time, the value of the reel ratio is calculated by (driving-side reel cycle) / (supply-side reel cycle). In the figure, a indicates the reel ratio at the time of normal operation, and a1 indicates the reel ratio at the time of tape slippage. When calculated by the above method, theoretically, the reel ratio gradually increases as time elapses as shown by a. However, when a tape slip occurs, the cycle of the supply-side reel becomes longer. Drops temporarily. FIG. 8 is an enlarged view of FIG. T1 and t2 in the figure
T3 is each reel ratio calculation point, and the reel ratio calculated at that time is r1, r2, r3. Tape slippage can be determined by comparing the reel ratio calculated at a certain reel ratio calculation point and the reel ratio calculation point immediately after it (for example, r1 and r2 at t1 and t2). However, if the reading error when reading the reel ratio is not taken into consideration, the tape is judged to be slipping even when the magnetic tape is not slipping (hereinafter referred to as erroneous judgment). Here, r 'indicates a reading error range of the reel ratio. Further, a 'is a virtual curve of a reading error range of the reel ratio when no slippage occurs, rm is a maximum reel ratio that is not erroneously determined at the reel ratio reading point t2, and b is a difference between r1 and rm. Here, if r2 <r1-b, it can be determined that the tape has slipped, and by repeating this determination at regular intervals during the FF and REW operations, the tape slip can be detected and the tape position can be detected. FIG. 6 is a block diagram showing a conventional tape slip detecting process. During the FF and REW running, the rotation cycle of the driving reel and the rotation cycle of the supply reel are input to the reel cycle ratio calculation unit to calculate the reel ratio at an arbitrary time. The reel ratio is calculated at regular intervals during FF and REW running, and only the largest value among the calculated reel ratios is sequentially updated as the maximum reel ratio value in the tape control circuit in the apparatus. Will be saved. Here, the value of the maximum reel ratio is FF and R
If there is a sudden load change during the EW running, the normal value may be detected far apart and erroneous determination may be made. Therefore, the determination of the past maximum reel ratio includes the reel ratio at a certain time and the past maximum reel ratio. A value obtained by adding a correction value to the larger value of the reel ratio in advance is used. The correction value is set in advance using a constant C as a predicted value. In the above processing, as shown in FIG. 6, the reel ratio at an arbitrary point in time and the corrected maximum reel ratio in the past are compared by the next-stage reel ratio / comparison section, and the tape slip detection is performed based on the output signal. And the tape running control taking the reading error into account was performed. However, in the above-described control method, particularly when the FF and REW operations are performed at a high speed, a load fluctuation exceeding a predicted value is likely to occur, and the reel ratio calculation result is determined to be large. After that, when the reel ratio returns to the normal ratio, the reel ratio temporarily decreases, so that a phenomenon similar to the above-described general tape slip phenomenon occurs. For this reason, an area that is not actually slipping is erroneously determined to be slipping, and an error in calculating the reel ratio is increased. Hereinafter, a description will be given of a phenomenon that becomes a problem when the reel ratio is large in the prior art. FIG.
6 is a graph showing a temporal change of a reel ratio at the time of REW. A dashed line c indicates a normal reel ratio, and a solid line d indicates a reel ratio when a large reel ratio calculation result is obtained. In the drawing, t1, t2, and t3 are reel ratio calculation points, respectively, and the calculated reel ratio is r1, r2, and r3.
It is. M0 to M3 are detected maximum reel ratios. In the prior art, for example, the reel ratio at time t3 is r3, and the comparison value at the time of performing the slip detection process is a past maximum value, and the value is M2. Where (r3-M
2) In the case of <S (S: threshold value), it can be determined that the vehicle is slipping, and F
The tape running is controlled by repeating this determination at regular time intervals during the F and REW operations. Here, the past maximum value M2 may be abnormally large when a sudden load change or the like occurs, and the discrimination accuracy at the time of switching the tape position or the tape speed during FF and REW running is deteriorated. There was a problem. For example, when performing high-speed FF and REW running at about several hundred times speed, unless the current tape position is accurately determined, problems such as a shift in tape speed switching timing and deterioration of the remaining tape precision occur. The present invention has been made in view of such a situation, and performs tape slip control without reducing the discrimination accuracy of the reel ratio even when the above-mentioned load fluctuation occurs. The present invention has the following configuration in order to solve such a problem. That is, the magnetic recording / reproducing apparatus according to the present invention comprises:
First cycle detection means for detecting the rotation cycle of the driving reel, second cycle detection means for detecting the rotation cycle of the supply reel, an output signal from the first cycle detection means and the second A reel cycle ratio calculating means for calculating a reel rotation cycle ratio based on an output signal from the cycle detecting means is provided. If the reel ratio at any time is smaller than the past maximum reel ratio, the reel ratio is determined to be the maximum reel ratio. A first calculating means for setting an output signal obtained by adding the predicted value of the constant A to the reel ratio at the arbitrary point in time as a past maximum reel ratio, and a case where the reel ratio at the arbitrary point is larger than the past maximum reel ratio A second calculating means for setting an output signal obtained by adding a predicted value of a constant B to an average value of the reel ratio at the arbitrary time and the past maximum reel ratio as a past maximum reel ratio; Out of the means Any one of a signal and an output signal from the second calculating means, a past maximum reel ratio determining means for determining a past maximum reel ratio, and an input signal from the reel cycle ratio calculating means. And a reel ratio / comparison means for comparing the magnitude of the input signal from the past maximum reel ratio determination means, and the tape slip control is performed based on the determination result of the comparison means. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a tape running control device according to the present invention will be described below with reference to FIGS. FIG. 2 is a block diagram showing a schematic configuration of the tape slip detection processing section of the present invention. 3 and 4 show an example of the configuration of an embodiment of the device according to the present invention. FIG.
Is a graph showing a time change at the time of FF and REW, and shows a case where the reel ratio increases with time. FIG. 4 is an enlarged view of a portion where the reel ratio is detected to be larger than usual in the graph of FIG. A broken line c in the figure indicates a normal reel ratio, and a solid line d indicates a reel ratio when a load fluctuation or the like occurs and the reel ratio calculation result is large. In the drawing, t1, t2, and t3 are the respective reel ratio calculation points, and the calculated reel ratios are r1 and r, respectively.
2 · r3. Further, m0 to m3 are the maximum reel ratios obtained by arithmetically operating the predicted values of the constants, respectively. Here, AVE1 to AVE3 are AVE1 = (r1 + m0)
÷ 2, AVE2 = (r2 + m1) ÷ 2, AVE3 = (r
3 + m2) ÷ 2, and the reel ratio at a certain point in time,
It shows the average value with the past calculated maximum reel ratio. Α, β, and γ in the figure are constants. At a certain point in time t3, according to the conventional method, as described above, the reel ratio r3 detected at time t3 is used.
And r2 detected only at time t2, which is the maximum reel ratio in the past with respect to the time point t3, so that, for example, the value of r2 suddenly changes due to load fluctuation or the like. Is determined as the largest reel ratio value in the past, and the tape slippage detection correction is performed, whereas in the present method, the detected reel ratio r3 at the time t3 and the maximum value in the past obtained by the arithmetic operation are calculated. Reel ratio m2 (m2 is the reel ratio r2 and m1 at time t2)
(Β is added to the average) and (r
3-m2) <S (S: threshold value) is unlikely to occur. That is, since an increase in the reel ratio due to a sudden load change is not determined as a normal tape slip, erroneous determination hardly occurs. At regular intervals during FF and REW operation,
By incorporating the conventional slip detection method into the detection method of the present invention and controlling the tape running based on the result of the determination, it is possible to improve the tape flutter, the reel ratio, or the error in calculating the remaining tape amount. According to the present invention described above, the following effects can be obtained. Since the magnetic recording / reproducing apparatus according to the present invention has the above-described configuration, the tape is FF and REW.
It is possible to improve a reel ratio calculation error generated based on a load change or the like during traveling, and to detect a tape slip with higher accuracy than before. Therefore, it is possible to improve the tape flutter and the reel ratio or the remaining tape ratio calculation error caused by one cause of the tape slippage, and to perform the tape running control with high accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram (FF) of a magnetic recording / reproducing apparatus according to the present invention.
Time). FIG. 2 is a block diagram of a tape slip detection process according to the present invention. FIG. 3 is a graph showing a temporal change of a reel ratio at the time of FF and REW (when the reel ratio increases) according to the present invention. FIG. 4 is an enlarged view of the vicinity of the graph in FIG. 3 where the reel ratio increases. FIG. 5 is a graph of a temporal change of a reel ratio at the time of FF and REW (when the reel ratio is increased) in the conventional processing. FIG. 6 is a block diagram of a conventional tape slip detection process. FIG. 7 is a graph showing a change with time of a reel ratio at the time of conventional FF and REW (when there is a normal tape slip). 8 is an enlarged view of the graph of FIG. 7 in the vicinity where the reel ratio decreases. [Description of Signs] 1 Capstan motor, 2 reel belt, 3 pulleys, 4 pulley gears, 5 idler gears, 6a TU
Relay gear, 6b SUP relay gear, 7a TU reel stand, 7b SUP reel stand, 8a TU reel, 8b
SUP reel, 9 magnetic tape, 10 A / C head, 1
1 cassette, 12 drums, 13 drive-side reel cycle measuring section, 14 supply-side reel cycle measuring section, 15 reel cycle ratio calculating section, 16 past maximum reel ratio determining section, 17
Reel ratio / comparison unit, 18 constant A (predicted value), 19 reel ratio average value calculating unit, 20 maximum reel ratio determining unit at any time, 21 constant B (predicted value), 22 tape running control unit, 23 maximum reel Ratio selection unit, 24 constant C (predicted value), a reel ratio in normal operation, a1 reel ratio when tape slippage occurs, a 'virtual ratio of reel error reading error range, t1, t2, t3 reel ratio calculation Points, r1, r2, r3, reel ratio calculated by t1, t2, t3, r 'reel ratio reading error range, rm t2
, The maximum reel ratio that does not make an erroneous determination, the difference between br1 and rm, c
Normal reel ratio, d Reel ratio when reel ratio is calculated to be large, m0, m1, m2, m3 Maximum reel ratio obtained by arithmetic operation at each time point, M0, M1, M2, M3
Maximum reel ratio detected at each time, AVE1 · AV
E2 · AVE3 Average value of the reel ratio at a certain point in time and the past maximum reel ratio obtained by arithmetic operation, α, β, and γ constants

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 27/10-27/34 G11B 15 / 46,15 / 093

Claims (1)

(57) [Claim 1] A first cycle detecting means for detecting a rotation cycle of a driving reel, a second cycle detecting means for detecting a rotation cycle of a supply reel, and A reel cycle ratio calculating means for calculating a reel rotation cycle ratio based on an output signal from one cycle detecting means and an output signal from the second cycle detecting means; A first calculating unit that sets an output signal obtained by adding a predicted value of the constant A to the reel ratio at the arbitrary point in time determined as the maximum reel ratio to be the past maximum reel ratio when the previous reel ratio is smaller than the past maximum reel ratio; If the reel ratio at the time is larger than the past maximum reel ratio, the output signal obtained by adding the predicted value of the constant B to the average value of the reel ratio at the arbitrary time and the past maximum reel ratio is used as the past maximum reel ratio. Second performance Means, and a past maximum reel ratio determining means for determining any one of the output signal from the first calculating means and the output signal from the second calculating means as a past maximum reel ratio. A reel ratio / comparison unit for comparing the input signal from the reel cycle ratio calculation unit with the magnitude of the input signal from the past maximum reel ratio determination unit, and performing tape slip control based on the determination result of the comparison unit. A magnetic recording / reproducing apparatus characterized by performing.