JPH08329660A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE: To provide a magnetic recording and reproducing device capable of minimizing the positional deviation of a vertical synchronizing signal of a video signal recorded before and after an editing point. CONSTITUTION: A phase difference between the vertical synchronizing signals of a reproducing signal and a video signal to be recorded is detected by a vertical synchronizing signal detection circuit 1, and the detected phase difference information is integrated by an integration circuit 2 at every sampling. Based on the integrated phase difference information and the video signal to be recorded, a phase reference signal generation circuit 3 generates a phase difference information, and based on this phase reference signal and a rotation information for a rotary cylinder, a rotary cylinder control circuit 4 controls the rotary cylinder.

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 having an image editing function, and more particularly to controlling a rotary cylinder.

[0002]

2. Description of the Related Art In recent years, magnetic recording / reproducing devices (hereinafter referred to as VTRs) have become widespread, and the chances of editing various source images to make a soft tape have increased. When editing with a VTR, unlike the 8mm or 16mm film used in movies, which is different from editing by cutting and connecting the film of the necessary scene,
By using TR and one or more VTRs for editing sources, video signals of necessary scenes are electrically connected to the magnetic tape contained in the editor VTR for editing. Most current V
The video track recorded on the magnetic tape by the helical scan system adopted in TR is very narrow, and in the analog VTR, the vertical sync signal or the horizontal sync signal of the video signal recorded in the video track is The output timing of the reproduced video signal differs depending on the recorded position. Therefore, if the position of the video signal recorded on the video track of the magnetic tape in the scanning direction of the magnetic head changes at the editing point, the continuity of the vertical sync signal or horizontal sync signal of the video signal will be impaired. Shake and skew occur.

Therefore, when editing with a VTR, the lower end of the magnetic tape of the video signal already recorded on the magnetic tape on the VTR side for the editing editor during the run up to the editing point, which is one of the editing operations. The automatic vertical synchronization signal alignment function is provided so that the vertical synchronization signal is recorded at the same position from the lower end on the magnetic tape even after the editing point.

FIG. 4 shows a video track pattern on a magnetic tape before and after an edit point in a conventional VTR.
FIG. 5A is a block diagram of the rotary cylinder control circuit at the time of recording in TR, and FIG. 5 is a timing chart of each signal.
FIG. 6A shows a block diagram of FIG. 6B when the automatic vertical synchronization signal alignment function is provided, and FIG. 6B shows a timing chart of each signal.

As shown in FIG. 4, an analog VTR of the helical scan type records a video track on a magnetic tape obliquely from the lower end to the upper end. At this time, since the vertical sync signal is determined by the format so as to be recorded at a position within a certain range from the lower end of the magnetic tape, the recorded position of the vertical sync signal on the magnetic tape by the recorded VTR is the format. Will vary within the range. Therefore, when a new image is edited on a magnetic tape that has already been recorded, the position on the magnetic tape of the vertical synchronization signal recorded before and after the editing point is displaced,
As a result, when the magnetic tape after editing is reproduced, vertical shaking or skew occurs at the editing point.

In FIG. 5 (a), S2 is a video signal to be recorded, 3 is a phase reference signal generation circuit for outputting the phase reference signal S5 to the rotary cylinder control circuit 4 (denoted as phase reference in the figure), and 5 is A rotary cylinder motor, 6 is a motor drive circuit, and 7 is an FG (Frequency Generat) that creates a frequency signal FG (S6) proportional to the rotation speed of the rotary cylinder motor 5.
or) section, 8 is a PG (Phase Generator) section for creating a signal PG (S7) representing the rotation phase of the rotary cylinder motor 5,
S9 is a rotary cylinder control signal output from the rotary cylinder control circuit 4 for controlling the motor drive circuit 6, 9 and 10 are video heads mounted on the rotary cylinder so as to face each other by 180 degrees, and 11 is output from the rotary cylinder control circuit 4. Image head switching signal HSW (S8)
Switch for switching 0 video heads, 12 for 9, 10
Is a video circuit for reproducing a signal reproduced by the video head and supplying a signal to be recorded to the video head. Further, in FIG. 6A, S1 is a reproduction video signal reproduced from the magnetic tape, 1 is a vertical synchronization signal phase difference for detecting the phase difference between the reproduction video signal S1 and the video signal S2 to be recorded. A detection circuit, S3, is a phase difference signal detected by the vertical synchronization signal phase difference detection circuit 1.

Next, the operation will be described. When the rotary cylinder rotates, the FG unit 7 generates n pulses (6 pulses in this case) of FG having a frequency proportional to the rotation speed. Further, in the PG unit 8, one pulse of PG is generated per rotation ahead of the video head 9.
Therefore, since the rotary cylinder control circuit 4 knows the positions of the video heads 9 and 10 from the FG of S6 and the PG of S7, it outputs the HSW of S8 for switching the video heads 9 and 10. The rotary cylinder control circuit 4 uses the video signal S to be recorded.
Based on the vertical synchronizing signal extracted from 2, the phase reference signal S5 output from the phase reference signal generation circuit 3 and HSW of the video heads 9, 10 or S8 have a constant phase relationship (edge of HSW and phase reference signal The motor drive circuit 6 is controlled by the rotary cylinder control signal S9 so as to maintain the time difference t) from the edge.
Control. The phase difference between the HSW of S8 and the phase reference signal of S5, that is, the video signal S2 to be recorded is the position from the tape lower end of the vertical synchronization signal recorded on the magnetic tape.

Further, when an automatic vertical synchronizing signal alignment function is added to this control block, the phase difference α of the vertical synchronizing signal between the reproduced video signal S1 and the video signal S2 to be recorded is detected. The circuit 1 detects and outputs the detection result to the phase reference signal generation circuit 3 as the phase difference signal S3. In the phase reference signal generation circuit 3, the video signal S2 to be recorded when there is no automatic vertical synchronization signal alignment function.
And the phase difference between the phase reference signal S5 and the phase difference between the reproduced video signal S1 and the video signal S2 to be recorded are added to generate the phase reference signal S5. In the rotary cylinder control circuit 4, if the phase difference between the HSWs of the phase reference signals S5 and S8 is controlled to the same t as in the case without the automatic vertical synchronization signal alignment function, the reproduced video signal S1 and the video signal S2 to be recorded are recorded. Therefore, the vertical sync signal of the video signal recorded on the magnetic tape to be edited and the vertical sync signal of the video signal to be edited can be recorded at the same position from the lower end of the magnetic tape. .

[0009]

However, in the above-described conventional configuration, when the reproduced video signal or the video signal to be recorded is fluctuated, the detected phase difference fluctuates, and the automatic vertical synchronization signal alignment function is not provided. Since the control is performed to eliminate the phase difference after one sampling at the earliest, the position of the vertical synchronizing signal of the actual video signal deviates from the target value to be controlled, and the vertical synchronizing signal of the reproduced video signal at the editing point There is a problem that a video signal to be recorded is recorded at a position deviated from the position.

The present invention solves the above problems, and minimizes the deviation between the reproduced video signal and the recorded video signal at the editing point even if there is fluctuation in the reproduced video signal or the video signal to be recorded. It is an object of the present invention to provide a magnetic recording / reproducing device that operates.

[0011]

In order to achieve this object, a magnetic recording / reproducing apparatus of the present invention detects a phase difference between a synchronizing signal between a reproduced video signal reproduced from a magnetic tape and a video signal to be recorded. Sync signal phase difference detection circuit, integration circuit that integrates the phase difference signal detected by the sync signal phase difference detection circuit, and phase that generates the phase reference signal based on the video signal to be recorded and the integrated phase difference signal A reference signal generation circuit,
A rotary cylinder control circuit is provided for controlling the rotary cylinder so that the phase reference signal and the video head attached to the rotary cylinder have a constant phase relationship based on the rotation information of the rotary cylinder and the phase reference signal.

[0012]

According to the present invention, the phase difference between the sync signal between the reproduced video signal reproduced from the magnetic tape and the video signal to be recorded is detected and the phase difference detection result for each detection is integrated. Therefore, even if there is fluctuation in the reproduced video signal or the video signal to be recorded, the shift in the recording position of the synchronization signal at the editing point can be minimized, and the discontinuity of the reproduced video signal after editing can be suppressed.

[0013]

Embodiments of the magnetic recording / reproducing apparatus of the present invention will be described below with reference to FIGS. The magnetic recording / reproducing apparatus in the embodiment of the present invention in which an integrating circuit is added in the automatic vertical synchronizing signal adjusting function of meeting the recording position of the video signal at the editing point is configured as shown in FIG.
Is a reproduced video signal, S2 is a video signal to be recorded, and 1 is S1.
Vertical sync signal phase difference detection circuit for detecting the phase difference between the vertical sync signal of the reproduced video signal of S1 and the video signal of S2 to be recorded, 2 is the phase difference signal S3 detected by the vertical sync signal phase difference detection circuit of 1. Integrating circuit 3 which integrates every half rotation of the rotary cylinder, 3 is a phase reference signal S based on the video signal S2 to be recorded and the phase difference signal S4 integrated by the integrating circuit 2
The phase reference signal generating circuit circuit for generating 5 and other parts have the same structure as the conventional magnetic recording / reproducing apparatus. 2 shows a block diagram of the integrating circuit 2 and FIG. 3 shows a reproduced video signal S1 input to the vertical synchronizing signal phase difference detecting circuit 1
, The video signal S2 to be recorded, the detected phase difference signal S3, and the phase difference signal S3 input to the integrating circuit of 2.
And the phase difference signal S4 integrated by the integrator circuit, and the video signal S2 to be recorded and the phase difference signal S4 after integration which are input to the phase reference signal generation circuit for 3 7 shows a timing chart of the output phase reference signal S5.

Next, the operation of this embodiment configured as described above will be described. The vertical sync signal phase difference detection circuit of 1 detects the phase difference between the vertical sync signal of the reproduced video signal S1 reproduced from the video signal already recorded up to the editing point of the magnetic tape to be edited and the video signal S2 to be recorded. , And outputs to the integrating circuit 2 as the phase difference detection signal S3. In the second integrating circuit, as shown in FIG. 2, the input phase difference signal S
A ^value obtained by multiplying the phase difference signal S3 (Z ⁻¹ ) before one sampling by a gain a is added to 3 and further multiplied by a gain b to form a phase difference signal S4 after integration. That is,

[0015]

[Equation 1]

The signal represented by is output to the phase reference signal generation circuit 3. For example, assume that the phase difference at a certain sampling time is α and the phase difference after integration is β. Three
The video signal S2 to be recorded by the phase reference signal generation circuit 3 of
On the other hand, the phase difference β represented by the integrated phase difference signal S4 input from the integrating circuit 2 is added, and the result is output to the rotary cylinder control circuit 4 as the phase reference signal S5.

In this way, by integrating the phase difference for each sampling with respect to the phase difference between the vertical synchronizing signal of the reproduced video signal S1 and the video signal S2 to be recorded up to the editing point,
This is the case where the reproduced video signal S1 or the video signal to be recorded has fluctuations, that is, the phase difference between the reproduced video signal S1 and the video signal S2 to be recorded varies for each sampling (every half rotation of the rotary cylinder). However, the fluctuation component is canceled and the deviation of the vertical synchronizing signal (including the horizontal synchronizing signal) recorded on the magnetic tape before and after the editing point can be minimized.

The drawings and the embodiments disclosed in this specification do not limit the present invention. Various changes, additions and substitutions can be made within the spirit and scope of the present invention. For example, the number of FGs per one rotation of the rotary cylinder is 2 or more and is an arbitrary integer, and the PG unit can be any means as long as it is determined 1: 1 with respect to the mounting position of the video head. In addition, the case where the phase difference signal of the vertical synchronizing signal between the reproduced video signal and the video signal to be recorded is in the plus direction or the minus direction with respect to the video signal to be recorded is expressed as addition. The means constituting the present invention can be easily realized by using a microprocessor.

[0019]

As described above, according to the present invention, the phase difference of the vertical synchronizing signal between the video signal reproduced from the video signal recorded up to the edit point of the magnetic tape to be edited and the video signal to be recorded from the edit point. A vertical sync signal phase difference detection circuit for detecting
An integration circuit that integrates up to the phase difference signal edit point detected by the vertical synchronization signal phase difference detection circuit, and a phase reference signal generation circuit that generates a phase reference signal from the video signal to be recorded and the integrated phase difference signal, Since the rotation cylinder is controlled based on the phase reference signal that cancels the fluctuation component when the phase difference between the playback video signal and the video signal to be recorded fluctuates at each sampling, there is fluctuation in the playback video signal or the video signal to be recorded. Even if there is such a position, it is possible to minimize the displacement of the position of the vertical synchronizing signal of the video signal recorded on the magnetic tape before and after the editing point.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an automatic vertical synchronization signal alignment function of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram of an integrating circuit in a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 3 is a time chart showing generation of a phase reference signal of the magnetic recording / reproducing apparatus in the embodiment of the present invention.

FIG. 4 is a diagram showing a video track pattern before and after an edit point of a conventional magnetic recording / reproducing apparatus.

5A is a block diagram of rotary cylinder control of a conventional magnetic recording / reproducing apparatus. FIG. 5B is a time chart of signals related to rotary cylinder control of a conventional magnetic recording / reproducing apparatus.

6A is a block diagram of a rotary cylinder control including an automatic vertical synchronization signal alignment function of a conventional magnetic recording / reproducing apparatus. FIG. 6B includes an automatic vertical synchronization signal alignment function of a conventional magnetic recording / reproducing apparatus. Time chart of signals related to rotary cylinder control

[Explanation of symbols]

 1 Vertical Sync Signal Phase Difference Detection Circuit 2 Integration Circuit 3 Phase Reference Signal Generation Circuit 4 Rotation Cylinder Control Circuit 5 Rotation Cylinder Motor 6 Motor Drive Circuit 7 FG Section 8 PG Section 9, 10 Video Head 11 Switch 12 Video Circuit S1 Reproduction Video Signal S2 Video signal to be recorded S3 Phase difference signal S4 Phase difference signal after integration S5 Phase reference signal S6 FG signal S7 PG signal S8 Video head switching (HSW) signal S9 Rotating cylinder control signal

Claims (1)

[Claims] 1. A synchronization signal phase difference detection circuit for detecting a phase difference between a reproduction video signal reproduced from a magnetic tape and a video signal to be recorded, and a position detected by the synchronization signal phase difference detection circuit. An integration circuit for integrating the phase difference signal, a phase reference signal generation circuit for generating a phase reference signal based on the phase difference signal integrated with the video signal to be recorded, and a rotation cylinder rotation information and the phase reference signal. A magnetic recording / reproducing apparatus further comprising a rotary cylinder control circuit for controlling the rotary cylinder so that the phase reference signal and a video head attached to the rotary cylinder have a constant phase relationship.