JPS63281254A - Reel controller - Google Patents

Abstract

PURPOSE:To take up a tape at desired constant tape speed by comparing the output value of a calculating part and a value held at a latch part, and executing the control of a reel in accordance wit the output value. CONSTITUTION:The device is equipped with a clock generating part 3 to generate plural clocks, two counters 4 and 5 to count the period of the reel pulse of two reels with a clock from the clock generating part 3, a calculating part 6 to execute the prescribed operation based on the value of the counters 4 and 5, a latch part 7 to hold the output of the calculating part 6, a comparing part 8 to compare the output value of the calculating part 6 and the value held by the latch part 7 and a control part to execute the control of the reel in accordance with the output value of the comparing part 8. Thus, the clock generating part 3 is provided, a signal to control the reel is obtained with the clock and therefore, the tape can be wound at a desired constant tape speed regardless of the length of the tape, the tape thickness, the reel hub radius, etc., only by changing the frequency of the clock.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a reel control device.

[Summary of the Invention] The present invention includes a clock generation section that generates a plurality of clocks, two counters that count the periods of reel pulses of two reels using the clocks from the clock generation section, and a value of the counter. a calculation section that performs a predetermined operation based on the calculation section, a latch section that holds the output of this calculation section, a comparison section that compares the output value of the calculation section and the value held in the latch section, and an output of this comparison section. The tape is wound at a desired constant tape speed by simply changing the clock frequency.

[Prior Art] In a tape playback device using a rotating head, in order to read data recorded on the tape, the relative speed between the tape and the rotating head must be kept constant. If this is maintained, the speed of the rotating head can be easily controlled.

[Problems to be Solved by the Invention] In this case, in the past, it was difficult to always run the tape at a desired constant speed even if the tape length, tape thickness, and reel hub radius were different.

SUMMARY OF THE INVENTION An object of the present invention is to provide a reel control device that can always run a tape at a desired constant speed even if the tape length, tape thickness, and reel hub radius are different and can easily set the speed.

[Means for Solving the Problems] In order to achieve such an object, the present invention includes a clock generation unit that generates a plurality of clocks, and a clock generation unit that generates two reels using the clocks from this clock generation unit. There are two counters that count the period of the pulse, a calculation unit that performs a predetermined calculation based on the value of this counter, a latch unit that holds the output of this calculation unit, and a value that is held by the output value of the calculation unit and the latch unit. It is characterized in that it has a comparison section that compares the output value with the output value of the comparison section, and a control section that controls the reels according to the output value of the comparison section.

[Function] In the present invention, a clock generator that generates multiple clocks is provided, and the clock is used to obtain a signal to control the reel. Therefore, the length of the tape and the thickness of the tape can be adjusted simply by changing the frequency of the clock. Regardless of the reel hub radius etc.
The tape can be wound at a desired constant tape speed.

[Example] Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

The figure shows the configuration of an embodiment of the reel control device according to the present invention, in which 1 and 2 are reels, 3 is a clock generator, and 4 is a clock generator.
and 5 is a counter, and 6 is a calculation section.

7 is a latch section, 8 is a comparison section, and 9 is a D/A conversion section.

10 is a driving negative, and 11 is a switch. In addition, Ta and Tb are the reel pulse periods of reels 1 and 2, respectively, and f
l and f2 are clock frequencies, Ca and cb are output values of counters 4 and 5, respectively, S□ is an output value of latch section 7, and S! is the output value of the calculation unit 6, D is the output value of the comparison unit 8, V
d indicates the output voltage of the D/A converter 9.

Now, suppose that the radius of both reels 1 and 2 including the tape is ra and rb, respectively, and the tape speed is V.

This is because the tape speed V and the circumferential speeds of both reels 1 and 2 are equal.

Ta　　　　Tb This relationship holds true.

Also, if the tape length is Q, the tape thickness is W, and the reel hub radius is rh, then the area including the tape and tape hub of both reels is expressed using ra and rb as x ra"+
yc rb", and when expressed using Q, w, and rb, it becomes 2πrh"+fiw.1 Since both are equal, the following equation holds true.

πra”+ πrb”= 2 pc rh”+ Q w
・=(2) From equations (1) and (2), V and Ta,
The relationship between Tb is found as follows. Here, rh, Q, and w are tape-specific constants, so by keeping T'a''+'rb'' constant,
v2=constant, ie, the tape speed can be kept constant.

Hereinafter, a method for actually keeping T a''+T b'' constant will be explained in detail.

First, the tape is run at a constant speed V. for that,
For example, this can be achieved by using a capstan motor, as is also used in conventional cassette mechanisms. At this time, when the rotation periods Ta and Tb of both reels 1 and 2 are counted using the clock of frequency f from the clock generator 3, the rotation periods Ta and Tb of both reels are counted.
and the output value Cat'Cb of counters 4 and 5,
The following formula holds.

Ca=Ta-fl...(4)Cb
= Tb - f, (5) Using the output values Ca and cb of the counters 4 and 5, the calculation unit 6
Now, calculate the linear equation to obtain the output value S.

51=Ca"+Cb" ・=(6)
This calculation unit 6 can be realized using, for example, a ROM. Substituting equations (4) and (5) into equation (6), S□=Ta” ・fl”+Tb” ・fl”=(Ta”
+Tb”)・fl”...(7)

The latch unit 7 latches the value S1 obtained by the calculation unit 6.

Next, the pinch roller is released from the tape, the reel motor is switched to run the tape, and at the same time the sample clock frequency is changed from fl to f2. The output values Ca and Cb of counters 4 and 5 at this time are Ca = Ta-f, ・=(8
)cb=Tb-f2...(9)
Therefore, the output value S2 of the calculation unit 6 is S,=Ca''+
Cb''=(Ta''+Tb'')·f,''-(10). The comparison unit 8 outputs the difference between the output value S of the calculation unit 6 and the value S latched by the latch unit 7.

D=S, -81 (11) The D/A converter 9 amplifies the output of the comparator 8 and converts it into a D/A converter 9.
At the same time as performing A conversion, an appropriate bias value is added and a voltage Vd is output. This output voltage Vd is applied to the winding side rolling motor via the drive unit 1o and the switch 11.

When the tape speed is slow, the reel rotation periods Ta and T
Since b becomes larger, the voltage applied to the reel motor becomes higher and the tape speed becomes faster.

Conversely, when the tape speed is high, Ta and Tb.

Since both S, and D become smaller, the voltage applied to the reel motor becomes smaller and the tape speed becomes slower. Eventually, the tape speed settles down to a roaring speed of S,=S.

Eliminate Ta and Tb from equations (3) and (7), and let the tape speed at that time be vl. However, C=4 π"(2r h"+ -) = (12
)π Similarly, eliminate Ta and Tb from equations (3) and (8).

Let the tape speed at that time be v2.

As mentioned above, control is performed so that S□=82, so from equations (12) and (13), C, S, , S.

If you delete and organize it, you will get vl f engineering. Here, since V and f are constants, by keeping f constant, ■ can be kept constant. Also,
The desired tape speed can be easily changed by simply changing the clock frequency f.

Note that in a tape reproducing apparatus using a one-rotation head as in the above-described embodiment, since the tape speed is constant, a reel control device can be obtained in which the rotating drum can be easily controlled.

This reel control device can be used not only for tape playback devices using rotary heads, but also for fast forwarding and rewinding of conventionally used cassette tape recorders, data recorders, and the like.

[Effects of the Invention] As described above, according to the present invention, the tape can be wound at a desired constant tape speed by simply changing the clock frequency, regardless of the tape length, thickness, reel hub radius, etc. The desired speed can be easily changed by simply changing the clock frequency.

[Brief explanation of the drawing]

The figure is a configuration diagram showing an embodiment of a reel control device according to the present invention. 1.2... Reel, 3... Clock generation section, 4.5... Counter, 6... Calculation section, 7... Latch section, 8... Comparison section, 10... Drive Department.

Claims (1)

[Claims] a clock frequency generating section that generates first and second clock frequencies of different frequencies, and the first clock frequency and the second clock frequency are selectively applied, respectively corresponding to the two reels; first and second counter circuits that count the period of the reel pulse of each reel, a calculation circuit that performs a predetermined calculation based on the outputs of the first and second counter circuits, and a calculation value of the calculation circuit. , a comparison circuit that compares the calculated value in the calculation circuit with the calculation value held in the latch circuit, and a control circuit that controls the reels according to the output of the comparison circuit. A reel control device characterized by: