JPH0633558Y2 - Magnetic recording / reproducing device - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is a device for recording an audio PCM signal on a magnetic tape by a rotary head on one oblique track per unit time and reproducing the same. In particular, the present invention relates to a magnetic recording / reproducing apparatus suitable for controlling tape speed during high-speed search.

[Technical background of the device and its problems]

A device for recording and reproducing an audio signal on a magnetic tape by forming a diagonal track for each unit time by a helical scan type rotary head and reproducing the audio signal by converting it into PCM. As RD
Development of a magnetic recording / reproducing device called an AT (rotary head type digital audio tape recorder) is being promoted.

In this R-DAT, the running speed of the magnetic tape is normally recorded and reproduced in order to read the search information such as the program number of the music recorded on the magnetic tape, the cue signal of the music, and the absolute time in a short time. A high-speed search is performed in which the speed is set to 100 to 200 times the speed at the time, and the rotating drum equipped with the head is rotated at a speed matching the double speed of this magnetic tape.

And, at the time of this high-speed search, just like during normal playback,
To read the sub-coat data attached to each data to identify the data recorded on the magnetic tape,
The rotation speed of the rotating drum is controlled by the drum servo to make the frequency of the signal reproduced during the search the same as during normal reproduction, and the rotation of the reel that winds the tape is also controlled by the reel servo. Is kept at.

And, as a method to keep the tape speed constant during high speed running in FF or REW mode, there is a reel cycle detection method that controls by a value calculated from the rotation cycle of both the reel side on the supply side and the reel side. The method has a problem that the tape speed controlled by the tape length (30 minutes, 60 minutes, 90 minutes, 120 minutes, etc.) changes.

That is, in the reel cycle detection method, the sum of the rotation cycle of the supply-side reel and the rotation cycle of the winding-side reel is controlled to be constant, or the square of the rotation cycle of the supply-side reel and the rotation of the winding-side reel. There is a method of controlling the sum of the square of the cycle to be constant. For example, when the sum of the rotation cycle of the supply reel and the rotation cycle of the winding reel is controlled to be constant, the tape at that time is taken as an example. The speed V _t is However, T _S : rotation cycle of supply side reel T _T : rotation cycle of take-up reel d: tape thickness l: tape length r: reel hub diameter

Therefore, if the reel servo is applied so that the sum of the rotation cycles of the two reels (T _S + T _T ) becomes a constant value that gives the specified tape speed V _T (for example, 100 times speed, 200 times speed), High-speed search can be performed at double speed.

However, as is clear from the above equation, the tape speed V _T is not only the sum of the rotation cycles of the two reels (T _S + T _T ), but also the tape length l (30 minutes, 60 minutes, 90
Min., 120 min.), There is a problem in that the search speed V _t varies depending on the tape length of the loaded tape, and the search speed changes depending on the tape length.

[Purpose of device]

The present invention has been made to eliminate the above-mentioned conventional problems, and is controlled by a value calculated based on the sum of the cycle of the supply reel and the cycle of the take-up reel or the sum of the square of the cycle. Then, based on the data obtained by detecting the number of rotations of the drum when the tape speed becomes constant, the foot speed is applied to the reel servo so that the tape speed will be the actually required speed. It is an object of the present invention to provide a magnetic recording / reproducing apparatus capable of preventing the tape speed from changing depending on the tape length at times.

[Outline of device]

The present invention controls the tape speed by the reel servo so that the tape speed becomes constant according to the calculation result of the rotation cycle of the supply reel and the rotation cycle of the take-up reel, and when the tape speed becomes constant. The rotation cycle of the drum is compared with the reference rotation cycle of the drum corresponding to the set search speed, and the deviation is filtered back to the reel servo.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In the figure, 1 is, for example, 2 arranged at an angular interval of 180 °
A rotary drum equipped with three heads, P ₁ and PG ₂ are pulse generators that generate head switching pulses (SWP), 2 is a magnetic tape, 3 is a supply side reel stand, 4 is a winding side reel stand,
FG ₁ and FG ₂ are frequency generators that detect the rotations of the reel bases 3 and 4 on the supply side and the winding side, respectively.

Reference numeral 5 is a head amplifier that amplifies a signal read by the head, 6 is a PLL circuit that extracts a clock signal from the output of the head amplifier 5 and stabilizes it, and 7 is a drum motor 9 based on the clock signal from the PLL circuit 6. Is a drum motor speed control means for controlling the speed, and 8 is a drum motor driver for driving and controlling the drum motor 9 based on the speed control output from the drum motor speed control means 7. The head amplifier 5, the PLL circuit 6, the drum motor speed control means 7 and the drum motor driver 8 constitute a drum servo for controlling the rotation speed of the drum motor 9.

Reference numeral 10 is a drum cycle detecting means for detecting the rotation speed of the rotary drum 1 by the head switching pulse (SWP) from the pulse generator radars PG ₁ and PG ₂ , and 11 is the rotation of the supply side reel stand 3 by the output from the frequency generator PG _1. Supply-side reel cycle detecting means for detecting the cycle, 12 is winding-side reel cycle detecting means for detecting the rotation cycle of the take-up reel stand 4 based on the output from the frequency generator FG ₂ , 13 is supply-side reel cycle detecting means 11 An arithmetic unit for arithmetically operating the output of the reel motor 16 and the output of the winding side reel cycle detecting means 12, 14 controls the origin of the reel motor 16 by the output from the adder 13 and the control output from the latch circuit described later. Reel motor speed control means, 15 is a reel motor driver for driving and controlling the reel motor 16 based on the speed control output from the reel motor speed control means. Supply-side reel cycle detection means 1 described above
The reel servo for controlling the speed of the reel motor 16 is constituted by the take-up reel cycle detection means 12, the adder 13, the reel motor speed control means 14, and the reel motor driver 15.

17 is a set speed generating means for generating and outputting the rotation cycle of the drum corresponding to the set search speed as a reference signal,
Reference numerals 18 ₁ and 18 ₂ are comparators for comparing the rotational speed of the rotary drum 1 from the drum cycle detection means 10 with the set speed from the set speed generating means 17 during high speed traveling, and 19 ₁ and 19 ₂ are comparators 18 ₁ , 8
_A latch circuit for issuing a command for controlling the rotation speed of the reel base to the reel motor speed control means 14 for controlling the speed of the reel motor 16 at the time of high speed traveling based on the output of ₂ .

Next, the operation of the above configuration will be described.

The signal read from the magnetic tape 2 by the head mounted on the rotary drum 1 is amplified by the head amplifier 5,
The clock signal is supplied to the circuit 6 and the clock signal is extracted. This PL
The stable clock signal extracted by the L circuit 6 is supplied to the drum motor speed control means 7. The rotation speed of the drum motor 9 is controlled by controlling the drum motor driver 8 so that the cycle of the clock supplied from the drum motor speed control means 7 to the drum motor driver 8 becomes constant.

On the other hand, the rotation cycle of the supply-side reel obtained by the supply-side reel cycle detection means 11 by the output from the frequency generator FG ₁ and the winding-up obtained by the winding-side reel cycle detection means 12 by the output from the frequency generator FG _2. The arithmetic value with the rotation cycle of the side reel is obtained by the arithmetic unit 13, and the speed control signal from the reel motor speed control means 14 is supplied to the reel motor 16 through the reel motor driver 15 to rotate the reel motor 16. Is controlled.

The drum cycle detecting means 10 includes pulse generators PG ₁ and PG ₂
The head switching pulse (SWP) generated in step S1 is detected to detect the rotation speed of the rotary drum 1, and the output indicating the rotation speed obtained here is used as the + input terminal of the comparator 18 ₁ and the − of the comparator 18 ₂ . Supply to the input terminal. The set speed generating unit 17 generates and outputs a reference signal to provide a rotation period of the drum corresponding to the search speed set, the output indicating the reference rotational period comparator 18 ₁ - compared with the input terminal 18 ₁ Supply to the + input terminal of. These comparators 18 ₁ and 18 ₂ are means for comparing the rotational speed of the rotary drum 1 with the set speed corresponding to the tape length, and the respective comparison outputs are supplied to the latch circuits 19 ₁ and 19 ₂ . The outputs from the latch circuits 19 ₁ and 19 ₂ are supplied to the reel motor speed control means 14. The above latch circuit 19 ₁ ,
The output of the 19 _2, when the tape speed by the reel servo during high-speed traveling has become constant, based on the output obtained by detecting the rotational speed of the drum from the drum period detection unit 10, the tape speed is actually required The tape speed is fed back to the reel motor speed control means 14 so that the tape speed of the high speed search is achieved.

〔effect〕

According to the present invention described above, the tape speed is controlled by the reel servo so that the sum of the rotation cycle of the supply-side reel and the rotation cycle of the take-up reel becomes constant, and when the tape speed becomes constant. The rotation speed of the drum is compared with the reference rotation cycle of the drum corresponding to the set search speed, and the deviation is fed back to the reel servo. Can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment according to the present invention. 10 ... Drum cycle detecting means, 11 ... Supply side reel cycle detecting means, 12 ... Winding side reel cycle detecting means, 13 ... Arithmetic unit, 14 ...
Reel motor speed control means, 17 ... Set speed generation means, 18
₁ , 18 ₂ ... Comparator (comparison means).

Claims (1)

[Scope of utility model registration request] 1. A recording signal on a running tape is read by a head mounted on a rotary drum, and a clock signal is extracted from the read recording signal by a PLL circuit,
In a magnetic recording / reproducing apparatus configured to control the rotation speed of a drum motor to a predetermined speed based on this clock signal, supply reel cycle detection means for detecting a rotation cycle of a tape reel reel stand, The reel-side reel cycle detecting means for detecting the rotation cycle of the take-up reel stand, the arithmetic unit for adding the outputs from the supply side and winding-side reel cycle detecting means, and the tape speed by the output from the arithmetic unit Reel motor speed control means for controlling the rotation speed of the reel motor so that the rotation speed is constant, drum cycle detection means for detecting the rotation speed of the rotating drum, and a drum reference that gives the drum rotation speed corresponding to the set search speed. From the set speed generating means for generating and outputting the cycle signal and the drum cycle detecting means when the tape speed becomes constant during high speed search Of the reel motor speed control means so that the tape speed during high-speed search does not change depending on the tape length based on the comparison result. A magnetic recording / reproducing apparatus comprising: a comparing unit that corrects