JPH0229966A - Tape speed controller for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To make a tape travel at a set speed regardless of the tape length by detecting a tape speed from the rotational period of a rotary drum at the time of a high speed tape travel and correcting reel servo data so that the tape speed meets the set speed. CONSTITUTION:The period of the rotary drum 1 is measured by a drum period measuring means 14 and its output is supplied to a comparator circuit 16. On the other hand, the reel servo data based on the tape speed information is supplied to a reel speed control means 9 by a reel servo setting means 8, and the data from the means 8 is supplied to a reference drum period setting means 15. Since a reference drum period is supplied by this means 15 to the circuit 16, the drum period and the reference drum period are compared by the circuit 16 and its output is fed to the means 8. The reel servo data to be controlled by the comparison output is corrected by the means 8. By this method, irrespective of the tape length, the tape can travel at the set high speed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing device that maintains a tape running speed at a constant speed during high-speed tape running, such as during high-speed searches, regardless of the length of the tape. TAPE SPEED CONTROL APPARATUS.

[Conventional technology]

A conventional tape speed control device of this type is shown in FIG.

In the figure, 1 is a rotating drum, 2 is a tape cassette, and a tape 2a pulled out from the tape cassette is wound around the rotating drum 1 at a desired angle. 3 is a supply reel, 4 is a take-up reel, and 3as4a is the supply reel 3
, a supply reel FG (frequency generator) that generates pulses when the take-up reel 4 rotates, and a take-up reel FG.

5.6 is a supply reel period measuring means and a take-up reel period measuring means for measuring the rotation period of the supply reel 3 and the take-up reel 4 based on the reels FG3a and 4a; 7 is the supply reel period measuring means 5, and the winding reel period measuring means 5; An adder 8 adds up the cycle from the reel cycle measuring means 6; 8 is a reel speed setting means for setting reel servo data to a control means 9, which will be described later, based on reel speed information from a microcomputer (not shown); 9 is the addition unit 8; This reel speed control means controls the reel speed so that the sum of both reel periods from the reel speed setting means 7 becomes the same as the reference period sum determined based on the reel servo data from the reel speed setting means 8.

10 is a low-pass filter that converts the speed control output from the reel speed control means 9 into a control voltage, and 11 is a reel drive circuit that drives the reel drive motor 12 based on the output from the low-pass filter 10.

Next, the operation of the conventional example described above will be explained. When a microcomputer (not shown) instructs the tape to run at high speed, the reel speed setting means 8 sets period sum data in the reel speed control means 9. On the other hand, reel FG
Reel period measuring means 5 from outputs generated from 3a and 4a
, 6, the reel period is measured. The measured reel periods are added in an adder 7, and the result is supplied to the reel speed control I1 means 9. Then, the reel speed control means 9 compares the reference period sum determined based on the reel servo data with the sum of both reel periods from the adder 7, outputs the comparison error as a pulse width modulation signal, and rotates both reels. A control voltage converted by a low-pass filter 10 is supplied to the reel drive motor 12 via a drive circuit 11 to control the reel drive motor 12 so that the sum of periods is constant.

Now, assuming that high-speed tape running is performed at a tape speed of 200 times, the reel speed setting means 8 sets period sum data that is 200 times as high for a tape length of 120 minutes in the reel speed control means 9, and increases the tape speed by 200 times. It will be run at.

[Problem to be solved by the invention]

By the way, since the conventional tape speed control device described above controls the reel rotation speed so that the sum of the rotation periods of both reels is constant, the maximum reel speed changes depending on the reel diameter. That is, the reel speed changes depending on the tape length.

For example, if you set reel servo data that increases the reel speed by 200 times for a 1-20 minute tape (a in Figure 3 (a)
(point a in Fig. 3(C)), the reel speed decreases by about 160 times with a 60-minute tape (point a in Fig. 3(C)). In other words, when reel servo data is set for a 120-minute tape, there is a problem in that the reel speed becomes slower than the set reel speed for tapes with short tape lengths.

[Purpose of the invention]

The present invention is intended to solve the above-mentioned problems, and its purpose is to provide a magnetic recording and reproducing apparatus with a tape speed that allows the tape to run at the same speed regardless of the tape length during high-speed tape running. Provides control equipment.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention detects the tape speed from the rotation period of the rotating drum in a reel servo using a constant sum of both loop period control method during high-speed tape running.
The gist is that the tape speed can be set to a preset tape speed regardless of the tape length.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. Note that the same reference numerals as in FIG. 2 above indicate the same circuits, and a description thereof will be omitted.

1a is a drum FG that generates a pulse signal when the rotary drum l rotates; 13 is a switch; 14 is a drum period measuring means that measures the rotation period of the rotary drum 1 based on the signal from the drum FG1a; 15 is not shown. A reference drum period setting means for setting reference drum data for a comparison circuit 16 to be described later based on drum speed information from a microcomputer; 16 is a drum period measuring means 14;
a comparison circuit for comparing the drum period measured by the reference drum period with the reference drum period from the reference drum period setting means 15;
7 is a head amplifier that amplifies the signal read by the rad lb for reproduction of the rotary head 1, and 18 is a PL that extracts a clock signal from the output of the head amplifier 17 and stabilizes it.
L circuit, 19 is drum speed control means for controlling the speed of the rotating drum 1 based on the clock signal from the PLL circuit 18, and 20 is a low-pass filter for converting the output from the drum speed control means 19 into a control voltage. , 21 is a drive circuit that drives the drum motor 22 based on the control voltage from the low-pass filter 20.

Next, the operation will be explained based on the above-mentioned configuration. When the rotary drum 1 rotates and a playback signal is output from the head lb, the playback signal is amplified by the head amplifier 17 and P
The clock signal is supplied to the LL circuit 18 and extracted.

The stable clock signal extracted by this PLL circuit 18 is supplied to drum speed control means 19. Here, the drum speed control means 19 compares the reference clock signal with the clock signal obtained from the PLL circuit 18, and outputs the speed error as a pulse width modulated signal.

The output from the drum speed control means 19 is converted into a control voltage via a low-pass filter 20 and supplied to a drum drive circuit 21. Therefore, the rotational speed of the drum motor 22 is controlled by the output from the drum drive circuit 21.

On the other hand, the reel servo reel speed setting means 8 supplies reel servo data to the reel speed control means 9 based on tape speed information from a microcomputer (not shown). Note that the reel servo data is period sum data in the reel servo. The reel speed control means 9 then compares the reference period sum determined based on the reel servo data with the sum of both reel periods from the adder 7, and outputs the comparison error as a pulse width modulation signal. The pulse width modulation signal from the reel speed control means 9 is converted into a control voltage by a low-pass filter 10, and is supplied to a reel drive motor 12 via a drive circuit 11 to control the rotational speed of the reel.

Further, the drum period measuring means 14 measures the period of the drum FC;la generated by the rotating drum 1, and its output is supplied to the comparison circuit 16. On the other hand, the reel servo setting means 8
The reel servo data based on tape speed information from a microcomputer (not shown) is supplied to the reel speed control means 9, and the reel servo data from the reel speed setting means 8 is supplied to the reference drum period setting means 15. Ru. The reference drum cycle setting means 15 supplies the reference drum cycle to the comparison circuit 16 based on the reel servo data, so the comparison circuit 16 compares the measured drum cycle and the reference drum cycle and outputs the comparison output. The reel servo is supplied to the reel speed setting means 8. This reel servo reel speed setting means 8 updates the reel servo data to be controlled based on the comparison output.

That is, assume that a 60-minute tape is running at a high speed of 200 times. At the start of high-speed tape running, tape speed information is supplied to the reel servo reel speed setting means 8, and reel servo data at point b in FIG. 3(b) is supplied to the reel speed control means 9. Then, when the tape speed rises and reaches the tape speed at point b, the switch 13 is switched to the state shown by the microcomputer (not shown), the drum FG1a and the drum period measuring means 14 are connected, and the drum period of the rotating drum 1 is measurement is started.

When the drum period is measured and output by the drum period measuring means 14, the measured drum period and the reference drum period from the reference drum period setting means 15 are compared by the comparing means, and a speed up signal is generated by the comparison. is supplied to the reel servo reel speed setting means 8, and reel servo data for increasing the tape speed is supplied to the reel speed detection means. Therefore, the tape speed gradually increases, and when the rotating drum 1 reaches the reference drum rotation, the switch 13 is switched from the state shown in the drawing by a microcomputer not shown, and the tape speed reaches 200 times the speed. Reel servo data 4 at this time is shown in Figure 3 (b
) becomes 0 points.

In the description of the embodiment described above, the explanation was given at the start of high-speed tape running, but even when the tape speed is reduced during high-speed tape running, the same operation as in the above embodiment is performed.

〔Effect of the invention〕

As described above, the present invention detects the tape speed from the rotation period of the rotating drum during high-speed tape running, and corrects the reel servo data to match the set tape speed. The tape can be run at a set high speed, and therefore even a tape with a short tape length can be searched at the same high speed as a tape with a long tape length.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a conventional example, and FIGS. 3(a) and 3(b) are characteristic diagrams showing tape speed versus tape length. DESCRIPTION OF SYMBOLS 1...Rotating drum, butt...Reel savore reel speed setting means, 9...Reel speed control means, 14...Drum cycle measuring means, 15...Reference drum cycle setting means, 1
6... Comparison circuit.

Claims (1)

[Claims] A drum servo that controls the relative speed of the tape and the rotating drum during high-speed tape running to match the relative speed during normal playback, and a reel that controls the reel rotational speed of the reel that runs the tape. A tape speed control device for a magnetic recording and reproducing device having a servo, a reel rotation speed setting means for setting reel speed data to the reel servo, a drum period measurement means for measuring a rotation period of a rotating drum, and a tape speed to be set. a reference drum period setting means for generating a reference drum rotation period corresponding to the reference drum rotation period; and a comparison circuit for comparing the periodic output of the rotating drum from the drum period measuring means and the reference drum period setting means. The drum rotation period is detected by the drum period measurement means, and the reel rotation speed data in the reel servo is corrected so that it becomes the same as the reference drum rotation period from the reference drum period setting means. A tape speed control device for a magnetic recording and reproducing device.