JPH0482041A - Tape driving controller - Google Patents

Abstract

PURPOSE:To control tape driving with a short fast-forwarding and rewinding time by detecting only a rotation ratio of reels from a running system and detecting the approach of the end of tape winding to issue a tape running decelerating command. CONSTITUTION:A winding ratio calculating means 114 takes present take-up reel rotational frequency NT' and supply reel rotational frequency NS' of the outputs of a take-up reel rotational frequency detecting means 108 and a supply reel rotational frequency detecting means 109 as the input and outputs a present winding diameter ratio rT'/rS' (=NS'/NT'). An DELTArT delay means holds this output rT'/rS' of the winding diameter ratio calculating means 114 and delays it by DELTArT (=fixed) to output it. A subtracting circuit 116 subtracts a winding diameter ratio rT/rS of DELTArT before as the output of the DELTArT delay means 115 from the output rT'/rS' of the winding diameter ratio calculating means 114 and outputs a resultant value DELTA(rT/rS). A comparator 117 sends the decelerating command in the case of DELTA(rT/rS)>DELTA(rT/rS)0, and reels are decelerated and rotated because of approach of the end. Thus, the fast-forwarding and rewinding time is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a running control device for a tape running system in a video signal recording/reproducing apparatus (VTR), a tape recorder, or the like.

BACKGROUND OF THE INVENTION In recent years, methods have been devised for tape drive devices such as tape recorders and VTRs to directly drive the reel and bring the tape running at a constant speed.

In addition, as a method for detecting the remaining amount of tape near its end, a method was devised to determine the winding diameter of the supply reel from the tape speed and the rotation ratio of the reel.

Furthermore, as described in Japanese Patent Application Laid-Open No. 55-89938, the ratio of the rotation speeds of the supply reel and the take-up reel is compared with either the ratio of the winding diameter of the entire length of the tape to the reel hub diameter or its reciprocal. A method for detecting near the end has been devised.

One of the purposes of these methods is to reduce the change in tape running speed due to the reel diameter during fast forwarding and rewinding of the tape, and on the other hand, to perform fast forwarding and rewinding of the tape at high speed in a short time, and This is to avoid sudden tension on the tape at the end by decelerating near the end.

Problems to be Solved by the Invention However, the above-mentioned method has the disadvantage of requiring a means for constantly contacting the tape to detect the tape speed or a means for detecting the total length of the tape, resulting in a complicated structure.

In addition, in a method that detects only the reel rotation ratio (tape winding diameter ratio) from the tape running system and compares it with a reference rotation ratio to determine when the end is near, large variations occur due to differences in the overall length of the tape. When the near-end determining means is used to determine the deceleration position during high-speed running, tapes with long tape lengths have the disadvantage that the tape decelerates well before the actual end, resulting in a long fast-forward and rewind time.

The present invention solves the above problems, and has a simple configuration in which only the reel rotation ratio is detected from the running system.The present invention has a simple configuration in which only the reel rotation ratio is detected from the running system, and there is little variation in judgment near the end depending on the tape length, and the tape drive has a short fast forward and rewind time. The purpose is to provide a control device.

Means for Solving the Problems In order to achieve the above object, the tape drive control device of the present invention includes a take-up reel rotation speed detection means, a supply reel rotation speed detection means, and a detection means for detecting the take-up reel rotation speed and the supply reel rotation speed. a winding diameter ratio calculating means for calculating a winding diameter ratio from the rotation speed; a differential value calculating means for calculating a value obtained by differentiating the winding diameter ratio by a winding reel radius or a supply reel radius; It is configured to include a deceleration command means that compares the differential value with a predetermined reference value near the end and outputs a deceleration command, and a reel control circuit that performs deceleration traveling control in accordance with the deceleration command.

Effect of the Invention With the above-described configuration, the present invention detects near the end of tape winding and issues a command to decelerate tape running by a simple means of detecting only the rotation ratio of the reel from the running system. It is possible to significantly improve the variation in closeness determination and realize tape drive control with short fast forward and rewind times.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a tape drive control device according to an embodiment of the present invention. A take-up reel 102 has a reel hub 104 with a radius rT)I, and a tape with a radius rT is wound thereon. 103
is a supply reel having a reel hub 105 of radius rSH and a tape wound with radius rs.

The take-up reel 102 and the supply reel 103 are directly connected to a take-up reel motor 106 driven by a take-up reel drive circuit 110 and a supply reel motor 107 driven by a supply reel drive circuit 111, respectively. 11
2 is a take-up reel control circuit, and 113 is a supply reel control circuit.

108 is a take-up reel rotation speed detection means, 109 is a supply reel rotation speed detection means, 114'' is a winding diameter ratio calculation means, 11
5 is a Δr7 delay means, 116 is a subtraction circuit, and 117 is a comparator.

In a tape drive control device consisting of the above-mentioned components, the following (near-end near the end of the tape) is detected,
The means for controlling the tape speed V by switching it will be explained.

The winding diameter ratio calculating means 114 is the winding reel rotation speed detecting means 1
08, the current take-up reel rotation speed NT which is the output from the supply reel rotation speed detection means 109, and the supply reel rotation speed Ns', and the current winding diameter ratio rr/rs'
(=NS'/NT') is output.

The Δr7 delay means holds the output r'/rs' of the winding diameter ratio calculation means 114, and outputs it with a delay of Δrr (constant). Note that Δr7 is detected when the take-up reel rotates by a certain amount.

A subtraction circuit 116 receives the output rr of the winding diameter ratio calculating means 114.
The value Δ(rT
/rs). Comparator 117 as deceleration command means
compares the output Δ(rT/rs) of the subtraction circuit 116 and the reference value Δ(rT/rs)o, and finds that Δ(rr/rs)>Δ(
rr/rs) If o, the deceleration command is taken up and the reel control circuit 1
12 and the supply reel control circuit 113, the reel is
It becomes a deceleration rotation near the end.

FIG. 2 illustrates a case where tapes of different tape lengths are used in the tape drive control device of the present invention.

201 has a long tape length, 202 has a medium tape length, 2
03 is the tape winding diameter ratio (rT/
rs) and the supply reel radius rs. Said curve 2
01, 202, 203 are represented by. h is the tape thickness, π
is pi, rl5 is the supply reel hub radius, rHT is the take-up reel hub radius, NT is the take-up reel rotation speed, and Ns is the supply reel rotation speed. 204 is the curve 201, 2
02°203 slope Δ(rr/rs), the discrimination criterion Δ(-> near the end of the tape, and the curve S with a small tape length
0 203 is a point rs"rl, and on the curve 201 with a large tape length is a point rg"r2. 205 is a conventional discrimination reference value (rr/rs)o near the end of the tape winding diameter ratio, and in the song 1203, it is r5-rl. Said curve 201
Above, rs=r3. In the tape drive control device of this embodiment, if the point of the deceleration position r5r1 immediately before the end is selected as the reference value Δ(rr/rs)o for a tape with a short tape length, then for a tape with a large tape length, The speed is also decelerated at the position of rs=r2, and it is possible to detect almost the end of the tape where L=small mustard=large. Especially for tapes with long tape lengths, the conventional standard value of the tape winding diameter ratio is 20.
Compared to the deceleration position rs=r3 determined in step 5, it is possible to detect a position much closer to the end. Based on the deceleration position, by switching to high speed rotation when rs>r2 and deceleration rotation when rSH≦rs≦r2, it is possible to significantly shorten the tape fast forwarding and rewinding time.

In the above description, it is assumed that the take-up reel is a reel that winds up the tape, and the supply reel is a reel that sends out the tape, and their roles change depending on the direction in which the tape runs.

Effects of the Invention As described above, the tape drive control device of the present invention includes a rotation speed detection means provided on the take-up reel and a supply reel, and a winding diameter ratio calculation means for calculating the winding diameter ratio from the rotation speed of both reels. and a differential calculation means for calculating a value obtained by differentiating the calculated winding diameter ratio with respect to the take-up or supply reel radius, and comparing the differential value of the winding diameter ratio with a reference value near the end and outputting a deceleration command. By using a deceleration command means and a reel control circuit that performs deceleration running control in accordance with the deceleration command, it is possible to greatly improve the dispersion in determination near the end due to the difference in tape length, and to decelerate near the end while winding at high speed. This has a great practical effect of realizing tape drive control with short fast-forwarding and rewinding times.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a tape drive control device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the relationship between the supply reel radius and the reel winding diameter ratio. 102... Take-up reel, 103 Old supply reel, 106... Take-up reel motor, 10
7... Supply reel motor, 108...
Take-up reel rotation speed detection means, 109... Supply reel rotation speed detection means, 110... Take-up reel drive circuit, 111... Supply reel drive circuit,
112...Take-up reel control circuit, 113...
. . . Supply reel control circuit, 114 . . . Winding diameter ratio calculation means, 115 . . . △r7 delay means, 11
6... Subtraction circuit, 117... Comparator. Agent's name: Patent attorney Shigetaka Awano 1 person

Claims (2)

[Claims] (1) A take-up reel rotation speed detection means, a supply reel rotation speed detection means, a winding diameter ratio calculation means for calculating a winding diameter ratio from the take-up reel rotation speed and the supply reel rotation speed, and the winding diameter a differential value calculating means for calculating a value obtained by differentiating the ratio with respect to the take-up reel radius or the supply reel radius; and a deceleration command that compares the differential value of the winding diameter ratio with a predetermined reference value near the end and outputs a deceleration command. and a reel control circuit that performs deceleration running control in accordance with the deceleration command. (2) The differential value calculation means for the winding diameter ratio includes a delay means for holding the winding diameter ratio while the winding reel rotates and the winding reel radius increases by a constant value, and a delay means for sequentially increasing the winding diameter ratio. 2. The tape drive control device according to claim 1, further comprising a subtraction circuit that subtracts the holding value of the winding diameter ratio from the current value.