JPH0722749Y2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a magnetic recording / reproducing apparatus, and more particularly to a magnetic recording / reproducing apparatus for stabilizing a tape feeding speed in a high-speed search for running a magnetic tape at a high speed.

(Prior Art) In a magnetic recording / reproducing apparatus such as a DAT, the feeding speed of a magnetic tape is controlled by controlling the rotation speed of a reel that is rotationally driven by a motor. In this control,
The reel rotation speed is controlled using FG information from an FG (frequency generator) provided on the reel side. At this time, since the tape feeding speed changes depending on the winding diameter of the tape, the reel rotation speed is set so that the recorded information on the tape can be read at the highest tape feeding speed.

(Problems to be solved by the invention) As described above, in the conventional magnetic recording / reproducing apparatus, the rotation speed of the reel is controlled by using the FG (frequency generator) information provided on the reel, and the highest tape feeding speed is achieved. Since the reel rotation speed is set so that information can be read at the same speed, there was a problem that the tape running speed would differ due to the difference in the tape winding diameter even if the tape was fed for the same recording time. .

On the other hand, using only the reel FG information, the sum of the reciprocals of the squares of the supply-side FG and the take-up-side FG is constant, that is, 1 / (FGs) ² + 1 / (FGs) ² It is also possible to make the tape feeding speed constant by controlling so that the values of and become constant, but there arises a problem that the control system for that purpose becomes complicated.

Therefore, an object of the present invention is to provide a magnetic recording / reproducing apparatus which can inexpensively and easily make the reel-based tape feeding speed constant.

(Means for Solving the Problems) In order to solve the above-mentioned problems, a magnetic recording / reproducing apparatus according to the present invention is a magnetic recording system in which the rotation of a reel that runs a recording medium and the rotation of a drum to which a magnetic head is attached are controlled. In the reproducing device, a drum control circuit for controlling the drum so that a clock frequency for reading generated from information recorded on a recording medium and a predetermined reference frequency are equal to each other, and a rotation speed of the drum. A comparison circuit that compares a proportional drum FG frequency with a reference frequency that determines the rotation speed of the drum and outputs a difference signal between the two frequencies, and controls the reel so that the difference signal obtained from the comparison circuit becomes zero. And a reel control circuit that keeps the drum FG frequency constant, and if the information recorded on the recording medium is not reproduced, The rotation control of the drum shifts to the mode for scanning the drum rotation speed, and the rotation control of the reel is
And a transfer control circuit that performs control to transfer to control based on reel FG information that is proportional to the rotation speed of the reel.

(Operation) In this invention, the drum control circuit controls the drum so that the clock frequency for reading generated from the information recorded on the recording medium is equal to the predetermined reference frequency, and the drum FG frequency is controlled. And the reference frequency that determines the rotation speed of the drum are obtained, the reel is controlled so that the obtained difference signal becomes zero, the drum FG frequency is kept constant, and the information recorded on the recording medium is When not reproduced, the drum rotation control is shifted to a mode in which the drum rotation speed is scanned, and the reel rotation control is shifted to control based on the reel FG information proportional to the rotation speed of the reel.

(Example) Next, this invention is demonstrated, referring drawings.

FIG. 1 is a block diagram showing an embodiment of a magnetic recording / reproducing apparatus according to the present invention.

The magnetic tape 5 has its travel position regulated by a tape guide including guide pins and guide rollers 4a to 4i so as to travel at a preset position, is sandwiched between the capstans 2, and travels via the pinch rollers 3. It

The capstan 2 is rotationally driven by a motor mounted coaxially. An FG (frequency generator) that changes according to the rotation speed is attached to this motor. The rotational driving force of the capstan 2 is transmitted to the supply reel 25 and the take-up reel 26 by the transmission mechanism.

The magnetic heads 1a and 1b are attached to the rotating drum at positions of 180 ° with each other, and have a relationship of inverse azimuth with each other, and reproduce the information signal recorded on the magnetic tape 5 and transfer the information signal to the tape. Make a record.

The equalizer amplifier 6 performs waveform equalization processing on the reproduction output from the magnetic heads 1a and 1b at the time of reproduction with a predetermined characteristic, and at the time of recording, the magnetic tape 5 is magnetized to a predetermined value. A recording current is applied to 1b.

The data strobe circuit 7 constitutes a PLL, receives an output signal of the equalizer amplifier 6 at the time of reproduction, generates a clock for reading the output signal, and converts it to reproduction output data in synchronization with the generated clock.

The ATF (automatic track following) error generation circuit 8 outputs a control error signal for the magnetic heads 1a and 1b to follow the recording track on the magnetic tape 5 during reproduction.
It is generated based on the reproduction signal from.

At the time of reproduction, the 8-10 conversion / timing generator circuit 9 decodes the reproduction data into 8-bit data based on the 8-10 conversion and at the same time generates a timing signal (for example, an ATF error) necessary for reproduction. It generates the necessary sampling signals and the reference signal for determining the rotation speed of the drum and capstan. Also, when recording,
The 8-bit data is encoded into a recording signal of 10-bit length based on 8-10 conversion, and a timing signal required for recording and an ATF signal are generated. Further, the 8-10 conversion / timing generator circuit 9 accesses the RAM 10, writes 8-bit data to the RAM 10 during reproduction, and reads 8-bit data from the RAM 10 during recording.

The ECC (error correction circuit), A / D, D / A, and digital I / O interface circuit 11 reads data from the RAM 10 during playback, performs de-interleaving and error correction processing, and records the recorded information signal. Is restored and sent to the D / A conversion circuit, digital I / O circuit, and sub code I / O circuit. Further, at the time of recording, the information signal to be recorded is received from the A / D conversion circuit, the digital I / O circuit, and the sub-code I / O circuit, the interleave and the correction code are added, and the information signal is written on the RAM 10.

The A / D conversion circuit in the A / D / D / A conversion circuit 12 converts an analog signal limited to a predetermined frequency band into a 16-bit digital signal, while the D / A conversion circuit uses a 16-bit digital signal. Converts data to analog signals.

The digital I / O circuit 13 receives a signal based on the digital audio interface format, decodes it, and outputs it to the circuit 11 as 16-bit data.
It receives 16-bit data from 11 and modulates it to a signal based on the digital audio interface format and outputs it.

The system control circuit 14 communicates with the mechanism control circuit 15 and the sub-code I / O circuit 11 according to the input from the key matrix 16, and operates the system according to a command from the user. .

The mechanism control circuit 15 communicates with the system control circuit 14, and the drum control circuit 18, the capstan control circuit 19, the reel control circuit 20, the mode motor.
It controls the operation of 21, 23, etc.

On the display 17, information to be notified to the user is displayed.

The drum control circuit 18 is a circuit for controlling the rotation of the drum to which the magnetic heads 1a and 1b are attached at a predetermined rotation speed and rotation phase, and a signal DF proportional to the rotation speed of the drum.
The G and the reference signal from the circuit 9 are compared to perform speed control, and the phase control is performed so that the contact start point of the head and the magnetic tape and the set phase position of the reference signal from the circuit 9 coincide with each other. When the recording information is read when the magnetic tape 5 is running at a speed other than the specified speed, the rotation speed of the drum is controlled so that the reading clock of the data strobe circuit 7 has a predetermined frequency. These operations are performed in response to commands from the mechanism control circuit 15.

The capstan control circuit 19 compares the signal CFG (capstan FG signal) proportional to the rotation speed of the capstan 2 with the reference signal from the circuit 9 and controls the rotation speed according to the comparison result. The rotation speed is set by the mechanism control circuit 15.

The reel control circuit 20 uses a signal RFG _s (reel FG signal) proportional to the rotation speed of the supply reel 25 and a signal RFG _t (reel FG signal) proportional to the rotation speed of the take-up reel 26 to rotate the reel. Generate a signal that controls a number. This signal is sent to the capstan control circuit 19 to control the rotational driving force of the capstan 2.

Of the mode motors 21 and 23, the motor 21 is a drive force transmission mechanism that determines whether or not to transmit the drive force of the capstan to the reel, and when transmitting, to the supply reel 25 or the take-up reel 26. Is a motor for operating the, and is controlled by the mechanism control circuit 15. The state of this mechanism is transmitted to the mechanism control circuit 15 by the logic of the rotary encoder 22.
Further, the motor 23 is a motor for pressing the pinch roller 3 onto the capstan 2 and for separating it, and is controlled by the mechanism control circuit 15. This state is transmitted to the mechanism control circuit 15 by the logic of the rotary encoder 24.

The supply reel 25 is coaxially provided with a means for generating an FG signal proportional to the rotation speed, applies back tension to the magnetic tape during reproduction, and runs the magnetic tape in the opposite direction to that during reproduction during RWD.

Take-up reel 26 is coaxially proportional to the rotation speed
A means for generating an FG signal is attached, and the magnetic tape sent from the capstan 2 is wound during playback,
At FF, the magnetic tape runs in the same direction as when playing.

The speed comparator 27 compares the drum FG frequency with the reference signal from the circuit 9 and sends an error signal to the reel control circuit so that the drum FG frequency becomes constant.

Next, the operation of this embodiment will be described.

The system control circuit 14 receives an instruction from the user through the operation of the key matrix 16.

When the system control circuit 14 determines that a high-speed search by reel is necessary, it outputs a reel high-speed search command to the mechanism control circuit 15.

In response to this, the mechanism control circuit 15 first drives the mode motors 21 and 23 to release the pressure of the pinch rollers and transmit the driving force of the capstan motor to the reel side required for tape running. Set.

Then, the drum control circuit 18 is instructed to start the drum. When the drum rotates and the reproduction output is detected from the magnetic heads 1a and 1b, the rotation speed of the drum is scanned, and the PLL of the data strobe 7 searches for the rotation speed of the locked drum. When the PLL locks, the drum control circuit 18 stops scanning the drum rotation speed and controls the drum rotation speed so that the read clock locked by the PLL has a specified frequency.

The mechanism control circuit 15 outputs a tape drive command by reel drive to the capstan control circuit 19 and the reel control circuit 20 to activate the reel. When the tape running is started and the reproduction output from the magnetic heads 1a and 1b is detected, the mechanism control circuit 15 instructs the reel control circuit 20 to control the error signal of the speed comparator 27 by the control based on the reel FG. Shift to control using.

In this way, by controlling the drum rotation speed to be constant while maintaining the read clock of the data strobe circuit 7 at the specified frequency, the tape traveling speed by reel drive can be maintained constant.

Further, when there is no reproduction output from the magnetic heads 1a and 1b and when there is no reproduction output, the drum control circuit enters a mode for scanning the drum rotation speed, and the reel control circuit 20 controls the reel rotation speed by the reel FG. Move to.

Again, if there is playback output from the magnetic heads 1a, 1b,
The control is performed such that the tape is moved to the previous state and the traveling speed of the tape becomes constant.

(Effect of the Invention) As described above, according to the present invention, since the tape traveling speed can be controlled to be constant with a simple configuration, the maximum tape feeding speed within the range where the recorded information on the tape can be read is maintained. Can be searched, and the search time can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a magnetic recording / reproducing apparatus according to the present invention. 1a, 1b, magnetic head, 2 capstan, 3 pinch rollers, 4a-4i tape guide, 5 magnetic tape, 6 equalizer amplifier, 7 data strobe, 8 ATF error generation circuit, 9 ... 8-10 conversion / timing generator, 10 ... RAM, 11 ... ECC / A / D / D
/ A interface, 12 …… A / D ・ D / A circuit, 13 …… Digital I / O, 14 …… System control circuit, 15 …… Mechanism control circuit, 16 …… Key matrix,
17 ... Display, 18 ... Drum control circuit, 19 ... Capstan control circuit, 20 ... Reel control circuit, 21,23 ...
… Mode motor, 22,24 …… Rotary encoder, 25
…… Supply reel, 26 …… Take up reel.

Claims (1)

[Scope of utility model registration request] 1. A clock for reading, which is generated from information recorded on a recording medium, in a magnetic recording / reproducing apparatus in which rotation of a reel for traveling a recording medium and rotation of a drum to which a magnetic head is attached are controlled. A drum control circuit that controls the drum so that the frequency and a predetermined reference frequency are equal to each other, and a drum FG frequency proportional to the rotation speed of the drum and a reference frequency that determines the rotation speed of the drum are compared. A comparison circuit that outputs a frequency difference signal; a reel control circuit that controls the reel so that the difference signal obtained from the comparison circuit becomes zero to keep the drum FG frequency constant; If the information that is being reproduced is not reproduced, the drum rotation control shifts to a mode in which the drum rotation speed is scanned, and the rotation of the reel is rotated. Control,
A magnetic recording / reproducing apparatus comprising: a transfer control circuit for performing a control for transferring to control based on reel FG information proportional to the rotation speed of the reel.