JP3339084B2 - Magnetic recording / reproducing device - Google Patents

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.

[0002]

2. Description of the Related Art A conventional magnetic recording / reproducing apparatus will be described below with reference to the drawings.

FIG. 3 is a block diagram showing a configuration of a conventional magnetic recording / reproducing apparatus. In FIG. 3, a magnetic tape 1 is transferred by a capstan motor 2 and a pinch roller 3. The rotation speed of the capstan motor 2 is controlled by a frequency signal generator 5.
(Hereinafter referred to as FG) and applied to the speed control circuit 6 as an FG signal i. The speed control circuit 6 obtains the amount of deviation from a preset reference cycle and outputs it as a speed error signal g. The FG signal i is also applied to the frequency dividing circuit 8 and frequency-divided at the set frequency dividing ratio. At the time of reproduction, a CTL signal recorded on the magnetic tape 1 is detected by a control (hereinafter referred to as CTL) head 9 and applied to a reproduction circuit 12 via a switch 10 to output a reproduced CTL signal c. The frequency division timing of the frequency dividing circuit 8 is determined by the reproduced CTL signal c. The frequency-divided FG signal d and the reproduced CTL signal c are both applied to the switch 13, and the frequency-divided FG signal d is selected during recording, and the reproduced CTL signal c is selected during reproduction, and is applied to the phase control circuit 7. Further, a frame signal b generated from the input video signal is also applied to the phase control circuit 7, and outputs a phase error signal h corresponding to the phase difference between the two signals. The speed error signal g and the phase error signal h are mixed by the adder 17 and applied to the drive circuit 4 to control the speed and phase of the capstan motor 2. The CTL signal is recorded by the CTL head 9 via the recording circuit 11 and the switch 10 based on the frame signal b. Switches 10, 13
Is switched to the R side during recording and to the P side during reproduction by the mode selection signal a.

[0004]

In such a conventional magnetic recording / reproducing apparatus, since a frame signal is used as a reference for phase control in both recording and reproduction, an existing capstan motor is used to reduce the tape speed. When setting,
There is a problem that it can be set only by selecting the FG frequency division ratio, and cannot be set with high accuracy. Also, in order to set the tape speed with high accuracy, the number of FG signals generated per rotation of the capstan motor (the number of FG teeth) must be changed, and the shaft diameter of the tape feed portion must be changed. there were.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, there is provided a tape transfer means which rotates in contact with a magnetic tape, and a frequency which generates a signal having a frequency proportional to the rotation speed of the tape transfer means. A signal generator, a reference signal generator for generating a signal of a preset frequency, and a control signal from a control head during reproduction, and an output signal of the frequency signal generator during recording to select and output. First signal selecting means for resetting the reference signal generator at the rise or fall of the output signal of the frequency signal generator at the time of reproduction, and not resetting at the time of recording; A second signal selecting means for selecting a frame signal created from an input video signal, and selecting and outputting an output signal of the reference signal generator during recording; And phase control means for the phase difference between the output signal of the output signal and the second signal selecting means first signal selecting means controls the tape transport means to be constant,
Speed control means for inputting an output signal of the frequency signal generator and controlling the tape transfer means so that a cycle thereof is constant.

[0006]

By the above means, the reference signal for phase control is switched between recording and reproduction, and the timing of the recording phase control reference signal is previously determined by the FG signal during reproduction, so that the accuracy of the existing capstan motor can be improved. Not only can the tape speed be set well, but also stable editing can be realized without any servo disturbance during recording transition.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic recording / reproducing apparatus according to one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 1, a magnetic tape 1 is transferred by a capstan motor 2 and a pinch roller 3. The rotation speed of the capstan motor 2 is detected by the FG 5 and applied to the speed control circuit 6 as an FG signal i. The speed control circuit 6 obtains the amount of deviation from a preset reference cycle and outputs it as a speed error signal g. The FG signal i is also applied to the frequency dividing circuit 8 and frequency-divided at the set frequency dividing ratio. At the time of reproduction, the CTL signal recorded on the magnetic tape 1 is detected by the CTL head 9 and applied to the reproduction circuit 12 via the switch 10 to output the reproduced CTL signal c. The frequency-divided FG signal d and the reproduced CTL signal c are both applied to the switch 13, and the frequency-divided FG signal d is selected during recording, and the reproduced CTL signal c is selected during reproduction, and is applied to the phase control circuit 7. Also, a frame signal b created from the input video signal
And the internal reference signal e output from the reference signal generator 16 are applied to the switch 14, and during recording, the internal reference signal e
However, during reproduction, the frame signal b is selected and applied to the phase control circuit 7. The phase control circuit 7 outputs a phase error signal h corresponding to the phase difference between the output signal of the switch 13 and the output signal f of the switch 14. The speed error signal g and the phase error signal h are mixed by the adder 17 and applied to the drive circuit 4 to control the speed and phase of the capstan motor 2. During reproduction, the frequency-divided FG signal d is applied to the reference signal generator 16 via the switch 15, and the internal reference signal e is reset at the rise of the frequency-divided FG signal d. During recording, the switch 15 is set to the GND side and is not reset.

The NTSC / PAL selection signal j is a signal which becomes High level in the case of NTSC, and becomes a Low level in the case of PAL. The tape thickness selection signal k is High in the case of a thick tape.
This is a signal that is at the h level and at the low level for a thin tape. These two signals are applied to the reference signal generator 16 to switch the frequency of the internal reference signal e in four stages. As a result, the capstan motor 2 is set to each target four-stage rotation speed. {Tape speed = rotation speed of capstan motor 2 x (shaft diameter of capstan motor 2 + thickness of magnetic tape 1) x 3.14}
Therefore, even if the tape thickness is different, it is necessary to change the rotation speed in order to keep the tape speed constant.

The variable speed recording control signal 1 is a signal which becomes high level during variable speed recording and becomes low level during normal recording, and is applied to the reference signal generator 16. The variable speed recording is realized by switching the frequency of the internal reference signal e by this signal.

The CTL signal is recorded via a recording circuit 11 and a switch 10 based on the frame signal b.
More records. The switches 10, 13, 14, and 15 are set to the R side during recording and the P side during reproduction by the mode selection signal a.
Switch to the side.

FIG. 2 is a timing chart showing the operation of the magnetic recording / reproducing apparatus of the present invention. The FG signal i is a signal as shown in FIG. 2A, and a frequency-divided FG signal d obtained by dividing the frequency of the FG signal i is a signal as shown in FIG. 2B. The reproduced CTL signal c is a signal as shown in FIG. The frame signal b is a signal as shown in FIG. 2D and is a signal created from an input video signal (NTSC is 29.97H).
z and PAL are 25 Hz). The mode selection signal a is a signal that is at a high level in the playback mode and is at a low level in modes other than the playback mode. If the mode is changed from the playback mode to the recording mode at time t1, the mode selection signal a becomes as shown in FIG. The internal reference signal e is a signal as shown in FIG. 2 (F), which is reset at the rising edge of the frequency-divided FG signal d during reproduction, and thus has the same timing as the frequency-divided FG signal.
The phase reference signal f is a signal as shown in FIG. An operation is performed such that the frame signal b and the CTL signal c are locked in the reproduction mode, and the internal reference signal e and the frequency-divided FG signal d are locked in the recording mode. Although the output signal of the frequency dividing circuit 8 is supplied to the switches 13 and 15 in this embodiment, the present invention is also effective when the FG signal is supplied directly without passing through the frequency dividing circuit. .

[0013]

As described above, according to the present invention, since the internal reference signal and the FG signal are phase-locked at the time of recording, the frequency of the internal reference signal is set so that the target tape speed is achieved. The tape speed can be set accurately. Also, during normal playback or run-in playback, the frame signal and the playback CTL signal are phase-locked. At this time, the phase difference between the internal reference signal and the FG signal is made to be constant in advance, so that the servo disturbance also occurs during recording transition. And stable editing and splicing can be realized.

[Brief description of the drawings]

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

FIG. 2 is a timing chart showing the operation of the magnetic recording / reproducing apparatus according to one embodiment of the present invention;

FIG. 3 is a block diagram showing a configuration of a conventional magnetic recording / reproducing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic tape 2 Capstan motor 3 Pinch roller 4 Drive circuit 5 Frequency signal generator 6 Speed control circuit 7 Phase control circuit 8 Divider circuit 9 CTL head 10 Switch 11 Recording circuit 12 Reproduction circuit 13 Switch 14 Switch 15 Switch 16 Reference signal Generator 17 Adder a Mode selection signal b Frame signal j NTSC / PAL selection signal k Tape thickness selection signal l Variable speed recording control signal

Claims (5)

(57) [Claims] 1. A tape transfer means which rotates in contact with a magnetic tape, a frequency signal generator which generates a signal having a frequency proportional to a rotation speed of the tape transfer means, and a signal which generates a predetermined frequency. A reference signal generator, first signal selection means for selecting a control signal from a control head during reproduction, and selecting and outputting an output signal of the frequency signal generator during recording, and the frequency signal during reproduction. Reset control means for resetting the reference signal generator at the rise or fall of the output signal of the generator and not resetting during recording, and selecting a frame signal created from an input video signal during reproduction, and selecting Means for selecting and outputting an output signal of the reference signal generator, an output signal of the first signal selecting means, and a second signal selecting means Phase control means for controlling the tape transfer means so that the phase difference of the output signal of the constant,
A magnetic recording / reproducing apparatus comprising: a speed control unit that receives an output signal of the frequency signal generator and controls the tape transfer unit so that a cycle thereof is constant. 2. The magnetic recording / reproducing apparatus according to claim 1, further comprising means for detecting or setting the thickness of the magnetic tape, and switching the output frequency of the reference signal generator according to the output of the means for detecting or setting. apparatus. 3. The magnetic recording and reproducing apparatus according to claim 1, wherein the output frequency of the reference signal generator is switched according to the tape transfer speed of NTSC and the tape transfer speed of PAL. 4. The magnetic recording / reproducing apparatus according to claim 1, wherein variable speed recording is performed by switching an output frequency of a reference signal generator. 5. The method according to claim 1, wherein
A frequency divider for dividing an output signal of the frequency signal generator, wherein the output signal of the frequency signal generator is applied to first signal selecting means and a reference signal generator via the frequency divider; Magnetic recording and reproducing apparatus.