JPS6329351A - Tape traveling controller - Google Patents

Abstract

PURPOSE:To freely set tape speed by providing a means to drive one side reel with the output signal of an adder and a period central value setting means setting a converting action point to an output value to the period of the input signal of a period detecting circuit. CONSTITUTION:The sum of the output of latches 14A and 14B is made by an adder 5, converted into an analog voltage by a D/A converter 8, inputted to a driving circuit 6 and the driving circuit 6 is constituted so as to conduct the current in proportion to the difference between the output voltage of the D/A converter 8 and the suitable reference voltage. Finally, for a feeding-back loop, the output of the adder 5 is stabilized to a certain constant value. At control circuit in which the sum of the period of a pulse outputted by FG3A and 3B provided at reels 2A and 2B is constant, a magnetic tape 1 is travelled approximately at constant speed. When the presetting value of counters 13A and 13B is changed by a period central value setting means 9, the number of the clock to count the counters 13A and 13B is changed and the speed of the magnetic tape 1 is changed in accordance with it. Thus, the tape speed when the data on the tape are read can be set in detail.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tape running control device that can freely set the tape running speed of a tape recorder or VTR that records data on a magnetic tape.

Conventional technology When a tape is run at high speed in a conventional tape recorder or VTR, in order to keep the tape running speed almost constant, the rotational speed of the reel is detected by sharing an axis with the two reel stands on which the tape is wound. A method has been adopted in which a reel FC is provided and the period sum of its output signal is made constant. (For example, Japanese Patent Application No. 60-309.34) Problems to be Solved by the Invention With such conventional techniques, although it is possible to achieve a fixed tape speed, it is possible to achieve a value that changes the tape speed little by little. It was extremely difficult to set the

The present invention has been made to eliminate such drawbacks, and an object of the present invention is to provide a tape running control device that can freely set the tape speed.

Means for Solving the Problems In order to eliminate the above-mentioned drawbacks, the present invention provides a magnetic tape, two reels on which the magnetic tape is wound, and two reel rotation speed detectors attached to the reels so as to share a shaft. two cycle detection circuits that detect the cycle of the signals output from each of the reel rotational speed detectors, and an adder that calculates the sum of the respective output values of the cycle detection circuits;
comprising driving means for driving one of the reels by the output signal of the adder, and period center value setting means for setting a conversion operating point to an output value for the period of the input signal of the period detection circuit, The magnetic tape running speed can be set by the cycle center value setting means.

Effect of the Invention With the above-described configuration, the present invention allows the running speed of the magnetic tape to be freely set to various values that change little by little using the cycle center value setting means.

Embodiment FIG. 1 is a block diagram showing an embodiment of the tape running control device of the present invention. In FIG. 1, 1 is a magnetic tape, 2A and 2B are a reel 28 and a reel 2B on which the magnetic tape 1 is wound, and 3A and 3B are reels provided so that the shafts are shared by the reel 2A and reel 2B, respectively. These are rotation speed detectors FG3A and FC3B. 4A and 4B are period detection circuits that operate in response to the outputs of FG3A and FG3B, respectively, and are composed of pulse generators 12A, 12B, counters 13A, 13B, and latches 14A, 14B, and detect the rotation of reels 2A, 2B. FG3A that occurs along with
, and works to output data corresponding to a period of 3B.

A clock oscillator 15 generates clocks for the counters 13A and 13B. The data output from the period detection circuits 4A and 4B is output as binary data corresponding to the number of stages (for example, eight) of the counters 13A and 13B. Further, 5 is an adder, which outputs the digital sum of the outputs of the period detection circuits 4A and 4B as its output. 8 is a D/A converter, which converts the digital data output from the adder 5 into an analog voltage. 6 is a drive circuit that supplies power to the motor 7 that drives the reel 2A using the output voltage of the D/A converter 8; Reference numeral 16 is a command generator composed of a microcomputer or the like, 18 is a data signal line that outputs a plurality of data, and 17 is a signal line that outputs a launch pulse. A latch 19 launches the data from the data signal line 18 with a latch pulse on the signal line 17 and outputs it. 11 is a ROM that provides fixed digital data; 10 is an adder circuit that adds the output of the latch 19 and the output of ROMII; its output is connected to counters 13A and 13B, and is connected to the reset pulse generated by pulse generators 12A and 12B; Counter 13A.

The precent value is 13B. The command generator 16 and latch 19 constitute a controller 9 that outputs control data, and the controller 9, ROM 11, and adder circuit 10 constitute period center value setting means.

Next, the operation of the embodiment shown in FIG. 1 will be explained. In FIG. 1, when the motor 7 rotates and the reel 2A rotates, the reel 2B also rotates as the tape 1 runs. At this time, FG3A, which is provided in common with the axis of reels 2A and 2B,
, 3B, a pulse signal related to the rotational speed of the reels 2A, 2B is generated. For example, when a pulse signal is output to FG3A, the pulse generator 12A outputs a latch pulse to the latch 14A to latch the output of the counter 13A, and then outputs a reset pulse to the counter 13A for addition. A counter 13A is preset to the output value of the circuit 10. The clock generated by the clock oscillator 15 is constant, and the output of the latch 14A is the preset value of the counter 13A and the clock within the pulse period generated by FG3A.
This is the sum of the number of clocks generated by the clock oscillator 15. F.C.
The same applies when 3B generates a pulse. latch 14
The sum of the outputs of A and 14B is created by the adder 5, converted into an analog voltage by the D/A converter 8, and inputted to the drive circuit 6. The feedback loop is configured to flow a current proportional to the difference between the basic YJ voltages, and eventually the output of the adder 5 settles down to a certain constant value.

That is, FG3A, 3 provided on reels 2A, 2B
The control circuit is such that the sum of the periods of the pulses output by B is constant, and the magnetic tape 1 runs at a substantially constant speed. Here, if the preset values of the counters 13A, 13B are changed by the cycle center value setting means 9, the number of clocks counted by the counters 13A, 13B changes accordingly, so that the speed of the magnetic tape 1 can be changed.

In FIG. 2, command data generated by the command generator 16 is 6
An example of operation has been shown in which both the BINT, ROM II, and the adder circuit 10 have an 8-bit configuration, and the stable value during control of the data after addition by the adder 5 is set to the center value, that is, 10,000,000.

In FIG. 2, reference numeral 21 indicates generated data generated by the command generator 16, and there are 64 types of data from oooooo to 111111.

When the fixed data in the ROM 11 is 00010100, the added data after the addition circuit 10 changes from 00010100 to 01010011 depending on the command data 21, as shown in FIG. 22. Data 2 after this addition
Since 2 is the preset value of the counters 13A and 13B, the counter 13A is set to the center value 10oooooo.
, 13B is the number of clocks counted up to the center value shown in FIG. 23 in binary notation, and is the number of clocks counted by 24 in FIG. 2 when expressed in decimal notation.

The counters 13A and 13B operate so that the addition result of the adder 5 becomes the center value 10000000 (therefore, the reel 2A is
, 2B, the control loop operates so that the periods of FGs 3A and 3B provided in FGs 3A and 3B are proportional, and as a result, the running speed of the magnetic tape 10 becomes proportional to the reciprocal of the value indicated by the clock number 24. As can be seen from the number shown in the clock number 24, the range of change in the running speed of the magnetic tape 1 is determined by the command data 2.
When 1 is ooooooo, when the command data 21 is 111111, it is 108/45 times - 2.4 times, so it is in the range of 1 to 2.4. Furthermore, it is clear from the above description that the range can be set in 64 steps.

The above explanation has been made assuming that the command data of the command generator 16 is 6 bits and the data after the adder circuit 10 is 8 bits, but the same effect can be obtained with any bit length regardless of the bit length of the data. Needless to say.

Effects of the Invention As described above, according to the present invention, it is possible to provide a tape running control device that can freely set the tape running speed in small steps with a simple configuration, and the tape speed when reading data on the tape can be set in detail. It has great utility value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a tape running control device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram for explaining the operation of the embodiment shown in FIG. 1... Magnetic tape, 2A, 2B... Reel, 3A, 3B... Reel rotation speed detector,
4A, 4B... Period detection circuit, 5...
Adder, 6.7... Drive means, 20...
・Period center value setting means.

Claims (2)

[Claims] (1) Magnetic tape and 2 where this magnetic tape is wound
two reels, two reel rotation speed detectors attached to the reels so as to share a shaft, two cycle detection circuits for detecting the cycles of signals output from each of the reel rotation speed detectors, and the cycle detection circuits. an adder that sums the respective output values of the circuit; a drive means that drives one of the reels by the output signal of the adder; and a conversion operating point of the period detection circuit to an output value with respect to the period of the input signal. What is claimed is: 1. A tape running control device comprising: a cycle center value setting means for setting a running speed of the magnetic tape; (2) The period detection circuit is configured to include a counter circuit that counts appropriate clocks, and the period center value setting means is a controller that outputs control data of digital data, and adds the control data output from the controller and fixed digital data. A tape running control device according to claim 1, characterized in that the tape running control device includes an adding circuit that performs the following steps.