JPS61105757A - Rotating head type video signal reproduction device - Google Patents

Abstract

PURPOSE:To make it possible to retrieve the desired reproduction screen by providing a manual operation means which can be drived directly by hand without using driving power. CONSTITUTION:Reproduction of video signal is done by tracing the video track formed with a specific pitch on a magnetic tape 1 by rotating heads 2A, 2B. A capstan 10 together with pinch roller which is not illustrated in the figure transfers the tape 1 towards a long direction. The capstan 10 is rotated by a capstan moor 11. When a handle 36 is rotated by manual operation, a disc 34 is rotated through a shaft 35, and then a capstan flywheel is forced to rotate. When manual operation parts 34-36 are detected to be in operational position by a detecting pat 40, a capstan motor drive circuit prohibits the occurrence of drive of the moor 11. In such a way, the desired reproduction screen can be retrieved.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a rotating head type video signal reproducing device.

<Description of the Prior Art> Hereinafter, in this specification, a rotating two-head helical scan type VTR will be described as an example of this type of device. -1ift, in this type of VTR, when performing playback (so-called special playback) at an arbitrary recording medium transport speed that is different from that during recording, such as so-called high-speed playback, low-speed playback (including static playback), and reverse playback, - In order to prevent the occurrence of pars and to enable stable and clear image reproduction, it is necessary to ensure that the reproducing head accurately traces one recording track in each scanning field.

In order to perform such so-called noiseless special reproduction, various methods have been proposed and implemented in the past. For example, various considerations have been made regarding the regulation of the head width, the arrangement of the head, the drive of the recording medium, the rotational position of the head, and the like. For example, it is possible to make the two rotating heads have different widths, to perform reproduction using the two rotating heads with the same magnetization direction, to drive the recording medium intermittently, or even to change the head relative to the rotating surface due to the transport speed of the recording medium. Methods of displacing in orthogonal directions, or methods that combine these methods have been proposed and implemented.

In order to reproduce a static 1F screen on such a VTR, it is generally necessary to stop the recording medium. However, the track width is generally on the order of several tens of microns, and the tape must be stopped extremely precisely in order to reproduce the image. However, if this is to be achieved using an external switch, the timing of switch operation must be determined extremely accurately.

On the other hand, when searching for one frame of screen, the timing for stopping the tape from normal playback is 1/60.
It was impossible to achieve the desired static playback screen.

<Object of the Invention> The present invention has been made in view of the above problems, and an object thereof is to provide a rotary head type video signal reproducing device that can search for a desired reproduction screen with an extremely simple configuration.

<Explanation based on examples> The present invention will be explained below using examples.

FIG. 1 is a diagram showing a schematic configuration of a VTR as an embodiment of the present invention. In the figure, 1 is a magnetic tape as a recording medium, 2A and 2B are magnetic heads for reproduction, which are provided so as to have the same azimuth angle and face each other 180 degrees, and each has a bimorph element as a conversion means. The free ends of the electro-mechanical transducer elements 3A and 3B are covered. The conversion elements 3A and 3B are connected to a rotating member 4 at their tail ends, and the rotating member 4 is connected to a head rotating motor 5.
It is rotated as shown by the arrow in the figure. Although not shown in the figure, as is well known, the rads 2A and 2B are rotated while protruding from the slit between the pair of tape guide drums, and the tape guide drums 2A and 2B are 1 is wound diagonally over a range of 180 degrees or more. 6 is a rotational phase detector for detecting the rotational phase of the heads 2A and 2B, and the signal from this detector 6 is used as a head switching signal (hereinafter referred to as HSW signal) and is also attached to the head motor control circuit 7. given,
Based on the output of the detector 6, the control circuit 7 controls the head motor 5 through the head motor drive circuit 8 so as to rotate the heads 2A and 2B in a predetermined phase and at a predetermined rotational speed.

10 is a capstan which cooperates with a pinch roller (not shown) to constitute a transport means for transporting the tape l in the longitudinal direction; 11 is a capstan motor for rotating the capstan 10; 12 is a capstan; A frequency signal generator 13 generates a frequency signal (hereinafter referred to as a capstan FG signal) corresponding to the rotation of the stan lO, and a capstan FG signal is generated based on an ATF signal and a capstan FG signal from the frequency signal generator 12, which will be described later. This is a capstan motor control circuit that controls the capstan motor 11 through a capstan motor drive circuit 14 so as to rotate the capstan motor 10 in a predetermined phase and at a predetermined rotation speed.

In the VTR of this embodiment, the following method is used for tracking. That is, a plurality of types (for example, four types) of pylon signals having mutually different frequencies are superimposed one by one on the video signal of one field and recorded on a recording medium. This is then reproduced by a reproducing head to separate only the pilot signal component. Then, the levels of pilot signals obtained from the tracks on both sides (both adjacent tracks) of the track that the playback head is mainly tracing (main track) are compared to obtain track deviation information of the playback head, and this is used for tracking control. signal (ATF signal). That is, it is assumed that the well-known 4f method tracking is performed.

The functions of the fifth part will be briefly explained below.

The reproduction signals obtained from the reproduction heads 2A and 2B include a video signal and a tracking pilot signal as described above. This reproduction signal is amplified by a reproduction amplifier 21 and made into a continuous signal by the H3W signal, which is then supplied to a video signal reproduction processing circuit 22 and a tracking signal generation circuit 23. The video signal reproduction processing circuit 22 separates the video signal from the output signal of the reproduction amplifier 21, performs processing such as demodulation, and supplies the reproduced video signal in the original signal form to the output terminal 20. On the other hand, the tracking signal generation circuit 23 separates the pilot signal component from the output signal of the regenerative amplifier 21, compares the levels of the pilot signals obtained from both adjacent tracks, and performs well-known processing to obtain a tracking control signal. It is something.

24 is a system control circuit for controlling the operation of each part of the apparatus according to the operation mode of the apparatus. For example, the head motor control circuit 7, the capstan motor control circuit 13, the tracking signal generation circuit 23, the pattern signal generation circuit described later, etc. are connected to the recording section and during reproduction.
Furthermore, the operation differs depending on the specified tape speed, etc., and N control signals are generated so that the desired operation can be performed in each operation mode.

25 is a conversion element control circuit, which includes a pattern signal generation circuit 26, a low-pass filter (LPF) 27, and an addition circuit 2.
8, includes a DC component removal circuit 29 and a conversion element drive circuit. By the output of the conversion element control circuit 25, the electro-mechanical conversion elements 3A and 3B are respectively driven so that the reproducing heads 2A and 2B accurately trace one recording track in each scanning field.

Reference numerals 34 to 36 are manual operation units which will be explained in detail later, and when the knob 36 is rotated by manual operation, the disk 34 is rotated via the shaft 35, and the capstan flywheel 32 can be rotated in a strong ffJI manner. . These can be in a used position (indicated by a solid line in the figure) and an unused position (indicated by a dotted line in the figure), and this position is determined by the detection unit 40.
detected by.

Now, when the detection member 40 detects that the manual operation members 34 to 36 are in the use position, the capstan motor drive circuit 14 prohibits the capstan motor 11 from generating driving force.

''The detailed structure of the pattern signal generating circuit 26 in the two series structure is described in the patent application filed in 1973 by the same applicant as the present invention.
An example thereof is disclosed in No. 9-23998, so please refer to it. The outline of the operation of the pattern signal generation circuit 26 is to generate a pattern signal for each head 2A, 2B, the slope of which is determined using the capstan FG and whose level is shifted by the ATF signal. This allows the head 2 to move at any media transport speed and at any media position.
A and 2B are completely on-track to the video track to be played.

Next, an example of the manual operation member is shown in FIG. 2 and will be explained in detail.

In FIG. 2, 10 is a gear/pustan shaft for transporting the recording medium, and 32 is a flywheel for increasing the rotation accuracy of the capstan shaft 10.

It rotates together with the capstan shaft 10. 33 is a pinch roller that pinches a recording medium (not shown) together with the capstan shaft IO and transports it accurately; 34 is a rubber disc-shaped member fixed to the shaft 35; and 36 is the shaft 3
A knob 37 is fixed to the shaft 35 and is fixed to the shaft 35 and holds the front chassis (not shown) and the spring 38 between the knob 36 and the shaft 3.
5. Member for pushing out the disk 34 etc. in the direction of arrow a, 3
9 is a stopper that limits the amount of extrusion in the direction of the arrow a.

In such a configuration, normally (when not in use), the disk 34 is not in contact with the flywheel 32 (in a non-use position), and even if the knob 36 is manually rotated, the disk @34 rotates in conjunction with the flywheel 32. The rotation of the capstan shaft 10 is not affected. However, by pushing the knob 36 in the direction of the arrow and moving it to the position 36' indicated by the broken line (usage position), the disc 34 will be at the position 34' with the shaft 5 removed, and the flywheel 32 and disc 34' will be at the position 34'. If the knob 36' is rotated in the direction of arrow C, the circle a4'
also rotates in the direction of arrow d.

In accordance with this, the flywheel 32 is also configured to rotate in the direction of arrow e. In other words, by having the member shown in "-", it is possible to directly transfer the medium by manual force.

Moreover, by controlling the converting elements 3A and 3B with the integrated pattern signal generating circuit 26, the head 2A can select the video track to be reproduced no matter what state the recording medium (magnetic tape) is in.

Since 2B traces well, the above-described configuration makes it possible to quickly detect a desired still image without any noise appearing.

In the above-mentioned embodiments, the present invention is applied to a rotating two-head helical scan type VTR using a method of displacing the rotating head in a direction perpendicular to its rotating surface. It goes without saying that the present invention can be applied to any configuration in terms of the arrangement □1 width, displacement, etc.

Explanation of the effect> As explained below, according to the present invention, the r1t is extremely simple.
It is possible to create a rotary head type video signal reproducing device that can quickly search for a desired reproduction screen with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a VTR as an embodiment of the present invention, and FIG. 2 is a diagram showing an example of a manual operation member. (2) is a magnetic tape as a recording medium, 2A and 2B are heads, and 3A and 3B are electromechanical conversion elements. 10 is a capstan, 11 is a capstan motor included in the driving force generating means, 14 is a capstan motor drive circuit, 32 is a flywheel, 34 is a disc, 35 is a shaft, 36 is a manual knob, and 40 is a position detection It is a member.

Claims (2)

[Claims] (1) A device that reproduces a video signal by tracing video tracks formed at a predetermined pitch on a recording medium using a rotary head, which includes a transport means for transporting the recording medium, and a drive means for driving the transport means. 1. A rotating head type video signal reproducing device comprising: means for generating a driving force for moving the moving means; and manual operating means for directly driving the transporting means by manual operation without using the driving force. (2) The rotating head type video signal reproducing apparatus according to claim 1, wherein driving of the transfer means by the driving force is prohibited as the operating means is operated.