JPS5961381A - Helical scan type video tape recorder - Google Patents

Abstract

PURPOSE:To prevent the deterioration in picture quality by providing a means decreasing the part where a magnetic track recorded already is erased by overlapping the final magnetic tracks at the inserting edition and recording in a tracking servo circuit. CONSTITUTION:A movable contact (m) of a changeover switch SW1 is switched to a reproducing side fixed contact (p) at the inserting edition and recording and a movable contact (m) of a changeover switch SW2 is switched to a recording side fixed contact (r). Further, a control signal being at a high level during the insertion edition and recording is applied to an input terminal 11, a transistor 9 turns on and a capacitor 8 is connected in parallel with a capacitor 7. Thus, the amount of delay in a delay circuit 3 is different from that at normal recording and the recording position of the magnetic track at the insertion edition and recording is shifted as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an improvement of a helical scan type video tape recorder that enables insert editing recording.

BACKGROUND TECHNOLOGY AND PROBLEMS First, with reference to FIG. 1, a description will be given of a method of recording the gradual cooling of a conventional linear scan type video tape player. TP cuts the magnetic tape, 81, CT cuts the audio trunk and control trunk formed on the side edges of the magnetic tape I, respectively.CT
L is a control signal recorded in the control trunk CT corresponding to every other one of the oblique magnetic i-ranks. 1' to 1'14 indicate gradient magnetic tracks sequentially recorded one by one in each field of the video signal to be recorded on the magnetic tape P. Such magnetic track "T" 1
- T14 is recorded and formed alternately one by one by a pair of rotating magnetic heads having different operating gaps and arranged at an angle of 180 degrees. is stored in the tape guide drum.The tape guide drum consists of a fixed top drum and a rotating top drum.
The pair of rotating magnetic heads rotate together with the rotating upper tram.

In order to especially maintain the recording density of the magnetic tape TP, the magnetic tracks 1 to 14 are recorded so that their side edges overlap one another. If the width of the magnetically operating gap between a pair of rotating magnetic heads is a, and the width of the side edge of the adjacent magnetic rack Qi is C, then the magnetic tape T"
I) To each magnetic field 1 to Ranokugo 1 □ 'r14
The width of is a-c-b. That is, a certain magnetic track is scanned and recorded by the rotating magnetic head from 1 to upward in the figure, and then the adjacent (1-rank) track is first scanned and recorded by the other rotating magnetic head on the side of the magnetic trunk. When scanning is recorded from 1- to - in the figure so as to overlap the edges, the portion of width C that overlaps the magnetic trunk after the previous magnetic track is erased.

In this helical scan type pre-coater, the operation when recording inner editing is explained in the second section.
Explanation will be given with reference to the figure. For example, on the magnetic track 1゛5~TIo,I- in Figure 1, a new magnetic track 1゛5~TIo,I- is created based on the new video message.
Think about every time you insert an edit record (Ichine record). 9:4S2 and then remove the diagonal line (=jL) from the newly recorded magnetic track of the inner edit.゛1o is already recorded magnetic track 'l'
Since the magnetic track is 1 in 10, the magnetic track '1' is 1 in 4, and both sides of it are largely erased by the vehicle records of both R'r'lo and T12. Qi 1~Rank l"sr's actual value lJ, l (l is 2 b-
A and Naichi, 'CL mau.

For example, a is 33. +] If m and b are 19μIn, then d
Otherwise, it would be 5 μm.

For this reason, the final magnetic trunk of the inner editing record and 7
When reproducing the magnetic track T1+ which has already been recorded, the S/
Since N is extremely low, there is a risk that the image quality of the gravy screen will deteriorate and vertical synchronization will be disturbed.

1 of the Invention In view of the above, the present invention includes a pair of rotating magnetic heads provided with mutually different magnetically actuating gaps, and the phantom rotating magnetic head is capable of controlling adjacent magnetic tracks on a magnetic tape. Record the video so that the side edges are different from each other, and
Each time a new magnetic track is written on the previously recorded magnetic trunk of the magnetic tape, a pair of rotating magnetic heads is used to write a new magnetic track, thereby performing editing recording. The present invention proposes a meter recorder that can avoid deterioration of both sides of the LT raw and vertical synchronization disturbances.

Summary of the Invention The present invention is! 1. A pair of rotating magnetic heads with different magnetic working spaces 11 are used to record video signals on a pair of rotating magnetic beds so that the side edges of adjacent magnetic tracks on the magnetic tape are lT and yIY. At the same time, the inner In a helical scan video tape recorder that performs edit recording, the inserter [during edit recording, the recording position of at least the last magnetic trunk of a newly recorded magnetic track is set by 1 with respect to the already recorded magnetic trunk. Accordingly, the tracking servo circuit is provided with means for reducing the erased portion of the already recorded magnetic track by changing the final magnetic rack.

! According to the present invention, it is possible to avoid deterioration of the image quality of the reproduced screen and disturbance of vertical synchronization.

Example An embodiment of the present invention will be described below with reference to FIG.

In this embodiment, in a helical scan type video tape recorder in which the above-mentioned inner editing recording is enabled, the entire recording mass of the magnetic 1-rack to be newly recorded is transferred to the already recorded magnetic track when recording the inner editing. In contrast, the trasoking servo circuit is provided with means for reducing the portion of the recording trunk that is already erased by each movement of the final magnetic track.

In the embodiment shown in FIG. 3, the bus tanzabo is rotated during the operation of the video tape recorder. First, the cabstan servo circuit cs will be explained. S
Wl, SW2 are recording/playback selector switches 'Otsu each 0J
Moving contact m, recording side fixed contact r, i'f":,' J +
Ii! rl constant contact p constant contact center. During insert editing recording, the i-'I contact m of the changeover switch SW1 is switched to the playback side fixed contact p side, and the i+J moving contact m of the changeover switch SW2 is switched to the recording side fixed contact r side. Can be switched.

Hc is a fixed magnetic head for recording and reproducing the control signal CTL (see FIG. 4) recorded on the magnetic tape TP, and its coil is connected to the movable contact zn4 of the switching switch switch. The recording side fixed contact r of the changeover switch SW is connected to the :I control input terminal (14). A fixed contact p on the playback side of the changeover switch S W l is connected to a phase comparator circuit (2).

The recording side fixed contact r of the changeover switch S W 2 is connected to an input terminal (1) to which a vertical synchronizing signal separated from the video signal to be recorded is supplied. Changeover switch SW
The portrait side movable contact p of 2 is the internal oscillator ○SC of 3011z
connected to. 11 moving contacts r of changeover switch S W 2
n is connected to the I7 phase comparison circuit (2) through a tracking control delay circuit (3). (4) is its input terminal. The output side of the phase comparison circuit II!f4+21 is connected to the capsun motor CM via an amplifier (5).

The control circuit (15) described above is connected to the input terminal (4) of the delay circuit (3) for I/Laso kink control. The power supply →-8 is connected to ground through a resistor (6) and a capacitor (7). The midpoint of the connection between the resistor (6) and the Ndenza (7) is connected to the collector of the switching river transistor (9) through the NDC (8) and its emitter is grounded. 1-Ran resistor (9)
is connected to an input terminal (11) to which an insert edit recording control signal is supplied through a resistor α0).

DS is a drum servo circuit, in which the movable contact m of the changeover switch SW2 is supplied to the phase comparator circuit (12), and in response to the rotation of the pair of rotating magnetic heads (
7FI to the magnetism that makes up the light body's Balssee Lake
The output of 30112 from i p is the phase comparator circuit (12)
supplied to The output of this phase comparator circuit is connected via an amplifier (13) to a drum morph DM for rotating the throat of a pair of rotating magnets together with the upper drum of the tape guide tram.

Note that in the cap servo circuit cs and the drum servo circuit DS, only the phase servo system is shown, and the speed servo system is not shown.

Next, the operation of the circuit shown in FIG. 3 will be explained with reference to FIG. 4 as well. At the time of insert editing recording, the movable contact m of the changeover switch sw1 is reswitched to the fixed contact p on the 4j side, and the movable contact rn of the changeover switch SW2
is switched to the recording side fixed contact r.

Furthermore, the input terminal (11) is supplied with a control signal in which °C is at a high level during that period during insert editing recording, so the transistor (9) is turned on during that period, and the capacitor (8) is connected to the capacitor - +J. - (connected in parallel to 71. Due to this, the delay amount R& (:) is different from the delay amount during normal recording, and as shown in No. 4821, the delay amount R & (:) is connected in parallel to the magnetic The recording positions of tracks 'r'5 to '7'' +o are recorded shifted to the right in FIG. The effective width d of the track T l'l is
becomes an IJ dog that is Δd from 2b-a. This Δd is, for example, 3.5 ttr, and then d is 5 μm.
It spreads from 8.5 μm. In this case, the magnetic trunk]
゛The level of the reproduction signal (high frequency signal) of 11 is approximately 60%.''
Increase by 1. Therefore, the S/N of the vertical synchronization signal is improved.
/N also goes.

Next, delay amount 118 + 3) 4 connected circuits (15
) Nyo-(The amount of delay compared to normal recording is set to 0.)
．． The high frequency signal levels at 1.2 and 3 steps/sec are 65 mV, 80 mV, 95 mV, and 11
It was 0 mV.

In addition, in the above embodiment, f to be recorded by insert editing
a In the case where the entire magnetic trunk is kept in place,
Insert editing It is also possible to perform HJ recording by shifting a predetermined amount from a magnetic track before or before the final magnetic track to be recorded to the final magnetic trunk. In that case, it is necessary to confirm the position of the final nitrate 1-rack that should be edited and recorded.

In the above-mentioned embodiment, the means for reducing the erased portion of the magnetic trunk is provided in the skewer 1 stand 9-bo circuit, but the 1Q6J may be used.

Jυf Karu Helical S Toyan Type Video Testo Ray
According to the data, the erased portion of the already recorded 62 magnetic track that overlaps with the final magnetic track of the newly recorded magnetic track during Inser J-editing recording is reduced, and due to dirt, the IIf Since the S/N of the signal '3- (+l'II frequency signal J+) is adjusted to the same level, image deterioration and vertical synchronization disturbance on the internal screen can be avoided.

The features of the present invention described above are 11. A pair of rotating magnetic heads with very different magnetically actuated air gaps is used in a row of rotating (
A video head is used to record video signals on the magnetic tape so that the side edges of adjacent magnetic tracks are flush with each other, and a pair of rotating magnetic heads is used to record video onto the already recorded magnetic tracks on the magnetic tape. In a helical scan type video tape recorder that performs insert recording by writing a new magnetic track, the last one of the already recorded magnetic trunks during insertion recording. Since the portion erased by the magnetic track 1 is reduced and the S/N of the 6 raw signal of that magnetic track is improved, the 411. It is possible to avoid half-screen image quality deterioration and vertical synchronization disturbance.

[Brief explanation of the drawing]

Figures 1 and 2 show the recording patterns of a magnetic recording tape during normal recording and insert editing recording in a conventional helical scan type video tape recorder, and Figure 3 shows a helical scan type video tape recorder according to the present invention. A block diagram showing the main parts of an embodiment of a scan type video table recorder,
FIG. 4 is a pattern diagram showing a recording pattern of a magnetic tape to provide an explanation thereof. TP is a magnetic tape, T1 to T1.4 are already recorded saws, T'5 to T'l, o
is the inserter 1 (newly recorded at the time of editing recording). This magnetic track is CT I. is controll'' - small signal, C3 is 1~ranking the 1st time M& as main stand servo [j! I 17&,
(No. 3 is a delay circuit for track control, and (15) is a control circuit for changing the delay. 452

Claims (1)

[Claims] A pair of rotating magnets with different magnetically actuated gaps.
The pair of rotating magnetic heads record the video signal on the magnetic tape so that the side edges of the adjacent magnetic 1-ranks overlap (I), and record the video signal on the magnetic tape that has already been recorded. Each time a new magnetic track is recorded on a pair of rotating magnetic heads on a magnetic rack, a new magnetic track is recorded on the magnetic rack. In the video tape recorder, when editing and recording, the recording position of at least the final magnetic trunk of the newly recorded magnetic track is shifted by ζ with respect to the already recorded magnetic track,
The last magnetic track is a helical scan characterized in that the tracking number-pole circuit is provided with means for reducing the erased portion of the already recorded magnetic l-rank. type video tape recorder.