JPH11353738A - Magnetic recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform quick switching between a fast-forward mode and a fast- forward reproducing mode and between a rewinding mode and a rewinding reproducing mode so as to shorten a time until an image is outputted by controlling the rotational speed of a rotary cylinder similarly between in the tape fast-forward mode and in the fast-forward reproducing mode, and also similarly between in the tape rewinding mode and in the rewinding reproducing mode. SOLUTION: A cylinder motor speed control means 6 sets a target cycle and a target phase based on a command from a system controller 12 so that the rotational speeds of a rotary cylinder 2 are identical to each other between in a fast-forward mode and in a fast-forward reproducing mode. Similarly, the control means 6 sets the rotational speeds of the rotary cylinder 2 identical to each other between in a rewinding mode and in a rewinding reproducing mode. Thus, when switching is made from the fast-forward mode to the fast- forward reproducing mode or from the rewinding mode to the rewinding reproducing mode, a change occurs only in the speed of the capstan motor 4 of a light load without any changes in the rotational speed of the rotary cylinder 2 of a heavy load, and mode switching is quickly performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus capable of quickly switching between a fast-forward mode and a fast-forward playback mode, and a rewind mode and a rewind playback mode.

[0002]

2. Description of the Related Art In a conventional magnetic recording / reproducing apparatus, when a tape is fast-forwarded, a fast-forward command signal is sent from a system controller to a capstan control circuit, and simultaneously a fast-forward command signal is sent to a cylinder control circuit. The relative speed between the magnetic tape and the magnetic head was kept constant. When switching from the fast-forward mode to the fast-forward playback mode, control is performed to switch the capstan speed from the fast-forward speed to the fast-forward playback speed and to switch the cylinder rotation speed from the fast-forward speed to the fast-forward playback speed. I was

[0003] The same applies to the transition from the rewind mode to the rewind playback mode. In addition to the speed control of the capstan, the control for switching the cylinder rotation speed from the rewind speed to the rewind playback speed is performed. Was.

As described above, there is known a magnetic recording / reproducing apparatus of a control system in which both the capstan speed and the cylinder speed are switched at the time of selecting a fast-forward reproducing mode or the like (for example, Japanese Patent Application Laid-Open No. 9-128849). .

[0005]

However, in the above prior art, in mode switching, it is necessary to switch both the capstan speed (magnetic tape feed speed) and the cylinder rotation speed to the target speed, and the target speed is reached. There was a problem that it took time.

For example, the fast forward is 25 times the standard reproduction speed.
When the double speed and the fast forward reproduction are 19 times speed, it is necessary to change the capstan speed by 25/19 ≒ 1.3 times and to change the cylinder rotation speed by about 3%. Capstan speed control is light load (magnetic tape), so it has good follow-up performance. Cylinder speed control is heavy load (inertia mass of rotary cylinder), so it has poor followability, and its speed is stable even if the speed control width is small. It will take some time. Therefore,
There is a problem in that it takes time from the operation for switching to the fast-forward playback mode to outputting the fast-forward playback image. This is the same when switching from rewind to rewind playback mode.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording / reproducing apparatus capable of quickly switching between a fast-forward mode and a fast-forward playback mode, and a rewind mode and a rewind playback mode, and shortening the time required for outputting an image. is there.

[0008]

According to the present invention, there is provided a magnetic recording / reproducing apparatus comprising a capstan motor speed control means and a cylinder motor speed control means. Is characterized in that the rotating speed of the rotating cylinder in the tape fast-forward mode and the fast-forward reproducing mode is controlled to be the same, and the rotating speed of the rotating cylinder in the tape rewinding mode and the rewinding mode is controlled to be the same.

Further, in the present invention, in the tape fast-forward mode and the rewind mode, the signal reproduced by the magnetic head is masked by a mask circuit.

With the above configuration, when switching between the tape fast-forward mode and the fast-forward playback mode, and between the tape rewind mode and the rewind playback mode, only the speed of the capstan motor needs to be switched, so that speed control is stable in a short time. In addition, it is possible to reduce the time required to output a fast forward playback image or a rewind playback image.

Further, in the fast forward mode and the rewind mode, a reproduced signal is masked by a mask circuit since a reproduced screen is unnecessary. In this case, the relative speed between the magnetic tape and the magnetic head deviates from a predetermined value, but no problem occurs because no image is output.

[0012]

FIG. 1 is a block diagram showing the overall configuration of a magnetic recording / reproducing apparatus according to the present invention. In the magnetic recording / reproducing apparatus of this embodiment, an input signal is processed by a recording processing circuit 9 at the time of recording, and is recorded on a magnetic tape 1 as a recording medium by a magnetic head 3 mounted on a rotary cylinder 2. The data is reproduced by the head 3 and output through the reproduction signal processing circuit 10. The reproduced signal is output via the mask circuit 11 as necessary.

When a command for a fast-forward / rewind request comes, the system controller 12 commands the cylinder control circuit 6 and the capstan control circuit 8 to set a target speed. The cylinder control circuit 6 controls the rotation speed of the rotary cylinder 2 through the cylinder motor drive circuit 5, and the capstan control circuit 8
Controls the speed of the capstan motor 4 through the capstan motor drive circuit 7, that is, the running speed of the magnetic tape 1.

On the other hand, when a command for requesting fast-forward / rewind playback comes, the system controller 12 similarly commands a target speed to the cylinder control circuit 6 and the capstan control circuit 8, whereby the cylinder rotational speed and the magnetic tape running speed are determined. Control.

FIG. 2 is a block diagram showing a detailed configuration of the cylinder control circuit 6. As shown in FIG. The cylinder control circuit 6 includes a speed control system 29 and a phase control system 30.

In the speed control system 29, the timing of the rising edge of a DFG (Drum Frequency Generator) signal accompanying the rotation of the cylinder is latched by the latch circuit 13.
The latched value is read by the automatic counter 18 and the cycle measurement circuit 19 measures the cycle measurement value T1. On the other hand, the target cycle setter 14 sets a target cycle T2 according to a command from the system controller 12. The difference between the cycle measurement value T1 and the target cycle T2 is obtained and compensated by the control characteristic compensation circuit 15 to obtain a speed control signal.

In the phase control system 30, the DFG signal and D
A PG (Drum Phase Generator) signal is input, and the frequency division counter 21 divides the DFG signal at the input timing of the DPG signal. For example, if the DFG signal is 12 pulses / rotation, the frequency division counter 21 divides this by 1/12. The phase of the divided signal is set to MM (Monostable Multivibrator) 22
, And at the delayed timing, the latch circuit 23
Latches the automatic counter 18. This latched value and V.V. A phase difference from the SYNC input signal is obtained, and the phase difference is compared with a target phase 27, and compensated by a control characteristic compensation circuit 28 to obtain a phase control signal.

The speed control signal of the speed control system 29 and the phase control signal of the phase control system 30 are added by the adder 16, and
Modulated by a PWM (Pulse Width Modulation) circuit 17,
The speed control of the rotary cylinder 2 is performed by the cylinder motor drive circuit 5.

In the cylinder motor control means 6 according to the present embodiment, the target cycle and the target phase are set in accordance with a command from the system controller 12 so that the cylinder rotation speeds in the fast-forward mode and the fast-forward playback mode are the same. That is, the cylinder rotation speed at this time is set so that the relative speed between the magnetic tape and the magnetic head becomes a predetermined speed in the fast-forward playback mode. With this configuration, when switching from the fast-forward mode to the fast-forward playback mode, there is no change in the cylinder rotational speed and the heavy load (inertial mass) of the rotating cylinder
Not affected by In this case, since the speed of the lightly loaded capstan motor only changes, the response is fast, and the desired capstan speed (magnetic tape feed speed) can be instantaneously reached, so that the image is output in the fast forward playback mode. Time can be greatly reduced.

In this embodiment, the cylinder rotation speeds in the rewind mode and the rewind reproduction mode are set to the same speed, as described above. In this case, the cylinder rotation speed is set so that the relative speed between the magnetic tape and the magnetic head becomes a predetermined speed in the rewind playback mode, and is different from the set value in the fast-forward playback mode. As a result, when switching from the rewind mode to the rewind playback mode, the mode can be switched instantaneously.

In the present invention, in the fast-forward mode or the rewind mode, the reproduction signal is masked by the mask circuit 11 according to a command from the system controller 12. In this case, the relative speed between the magnetic tape and the magnetic head deviates from a predetermined value, but no problem occurs because no image is displayed.

[0022]

As described above, in the present invention, the speed control of the cylinder motor at the time of mode switching is made the same,
When switching between the fast-forward mode and the fast-forward playback mode, and switching between the rewind mode and the rewind playback mode, the time until a reproduced image is output can be greatly reduced.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a configuration of a cylinder control circuit in FIG. 1;

[Explanation of symbols]

 1: Magnetic tape 2: Rotating cylinder 3: Magnetic head 4: Capstan motor 6: Cylinder motor speed control means 8: Capstan motor speed control means 11: Mask circuit 12: System controller 29: Speed control system 30: Phase control system

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akifumi Mibe 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the multimedia system development headquarters, Hitachi, Ltd. (72) Inventor Yoshio Narita 1410 Inada, Hitachinaka-shi, Ibaraki Hitachi, Ltd. AV Division

Claims (2)

[Claims] 1. A magnetic tape is run by a capstan motor, and a rotary cylinder is rotated by a cylinder motor. The magnetic tape is run relatively to a magnetic head mounted on the rotary cylinder, and a signal is transmitted to the magnetic tape. A magnetic recording / reproducing apparatus for recording / reproducing, comprising: a speed control means of the capstan motor and a speed control means of the cylinder motor; wherein the speed control means of the cylinder motor is provided in the tape fast-forward mode and the fast-forward playback mode. A magnetic recording / reproducing apparatus, wherein the rotational speed of a rotary cylinder is controlled to be the same, and the rotational speed of the rotary cylinder is controlled to be the same in a tape rewind mode and a rewind / reproduce mode. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein a signal reproduced by the magnetic head is masked by a mask circuit in a tape fast-forward mode and a rewind mode.