JPH0481179A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To reduce the time till the REC mode is set by providing plural field memories and a circuit controlling a delay and matching momentarily a color framing of a digital picture signal to be recorded with a color framing on a tape through the use of the memory. CONSTITUTION:A color framing detection circuit 11 receiving an input signal outputs a color framing signal (15Hz) 12 and a framing signal (30Hz) 13. Then a field number comparator circuit 14 receiving the said signal 12 and a field number on a tape reproduced by using a control signal (CTL) head detects the coincidence of the color framing. As a result, when the color framing is coincident, a multiplexer 3 selects a digital signal 3 and when one frame is deviated, the multiplexer 6 selects a digital signal 5 delayed by two fields. Thus, the field number of the input signal momentarily is matched with the field number recorded on the tape, and the effect of the inertia of the motor can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a digital image signal recording method suitable for recording an image signal converted into a digital signal onto a magnetic tape using a rotating magnetic head.

BACKGROUND OF THE INVENTION In recent years, VTRs that digitally record and play back composite signals have almost no deterioration in image quality during dubbing, but in order to record high-density image data on tape, the synchronization signal waveform This portion is not recorded, and instead color framing information is superimposed on a control signal (hereinafter abbreviated as CTL signal). Therefore, the portab used in the field /l/
At 9 o'clock, the motor is controlled and recorded so that the color framing of the CTL signal is continuous.

A conventional VTR that performs digital recording and playback will be described below with reference to the drawings.

FIG. 4 is a block diagram showing a conventional splicing device, and FIG. 3 shows the timing of a CTL signal of an NTSC composite digital VTR and a field number of an input signal. A conventional continuous shooting device will be described below with reference to FIGS. 3 and 4.

When digitizing image signals and recording them on magnetic tape,
Since it becomes difficult to record one field of image data on one track, it is recorded on multiple tracks. Therefore, as shown in FIG.
When rotating at rpm, the CTL signal is recorded at 90H7 cycles, and color framing information is recorded by changing the duty of the CTL signal. In FIG. 3, when the duty ratio continues to be 6.4, it indicates the start of field I, and when the duty ratio continues to increase to 4.6, it indicates the start of field (2).

Next, to explain the continuous shooting process of a portable VTR, when entering the REC pause from the RKC state, the tape is rewound by the amount of time the motor servo pulls in to stably enter the next RXC state (hereinafter referred to as auto pack). There is a need.

NTSC composite digital) Approximately 40 frames for vVTR, approximately 8 frames for PAL composite digital VTR
0 frame autoback.

The CTL signal read from the CTL head 25 in FIG. 4 is amplified by the amplifier 23, and a CTL signal as shown in FIG. 3 is obtained. This CTL signal is doubled by a doubler 21, and by means such as a microcomputer, the duty is determined 19 and the field number is detected.

Doubling the multiplied and separated CTL signal above is a convenient means of detecting only the rising edge of the pulse.

On the other hand, color framing information is detected from the input composite signal 11, phase comparison is performed with the field number on the tape by a phase comparator 27, and error information is sent to a motor drive circuit 31 by a means 29 such as pulse width modulation. ,
The phase of the capstan motor 33 is controlled to match the color framing of the input signal.

Problems to be Solved by the Invention However, in the above conventional configuration, due to the inertia of the capstan motor, the NTSC composite VTR
So 4o frame, PAL composite digital 7vVT
In R, you have to autobank 80 frames. Therefore, after the REC command comes, I discharge 1 in NTSC.
．． It has the disadvantage that it enters the RKC state in 33 seconds, while in PAL it takes 3.2 seconds, which is too slow for a field portaple.

The present invention solves the above-mentioned conventional problems, and aims to shorten the time from issuing an RXG command to entering the RRG state as much as possible.

Means for Solving the Problems In order to achieve this object, the magnetic recording/reproducing apparatus of the present invention has a configuration consisting of a plurality of field memories and a circuit for controlling the amount of delay.

Function: This configuration uses memory to instantly match the color framing of the digital image signal to be recorded to the color framing on the tape, rather than adjusting the servo to the input signal, reducing the time it takes to enter the R11 state. can do.

Embodiment Below, a magnetic recording and reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1C is a configuration diagram showing input signal delay control of an NTSC composite digital VTR as a first embodiment of the present invention. In FIG. 1, a two-field delay memory 4
, a multiplexer 6, and a field number comparison circuit 14 are added to the conventional configuration.

The operation of the first embodiment as an NTSC composite digital VTR constructed as described above will be explained.

The input signal color-7 framing detection circuit 11 outputs a color framing signal (15 Hz) 12 and a framing signal (30 Hz) 1''.

After receiving the RIG command, the capstan servo system operates in accordance with the framing signal (30H2) 13.

The auto-pack time required to lock the capstan motor to the framing signal (3oH2) 13 is only 20 frames, which is half of the conventional 40 frames. However, at this time, field I and field (2) may coincide with each other, and the color framing relationships do not necessarily match. Therefore, the input color framing signal 12 and the field number on the tape reproduced from the CTL head are detected by the field number comparing circuit 14 to detect whether or not the color framing matches, and the multiplexer 6 is switched to the switching signal 15 and I~. send. As a result of comparing the field numbers, if they match, digital signal 3 is selected, and if they are shifted by one frame (two fields), digital signal 5 delayed by two fields is selected by multiplexer 6.

As described above, by instantly matching the field number of the input signal to the field number recorded on the tape, the influence of the inertia of the motor can be minimized.

Next, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing input signal delay control of a PAL composite/digital VTR as a second embodiment of the present invention. One-color framing in the PAL system is an 8-field sequence, so the framing signal (25
H2) When locking the servo with 13, field numbers r, m, and v.

If you don't know which one to lock, add two 2-field delay memories 34 and 36, and use multiplexer 40.
Also change. And input signal 3 or delay memory lJ4,3
4. Select one of the outputs in 36. With the above additional changes, the autopack time that conventionally required 80 frames can now be reduced to 2° frames.

Also, 1st. In both embodiments, it is desirable that the input signal delay control circuit be located as close as possible to the recording head and after the digital audio signal has been mixed.

Effects of the Invention As described above, the magnetic recording/reproducing apparatus of the present invention is equipped with a plurality of field memories and a circuit for controlling the amount of delay, thereby significantly shortening the 9 time required for servo start-up during continuous shooting as a portable VTR. I can do it.

2 for NTSG composite digital/L/VTR
This has a great practical effect of reducing the servo start-up time to 1/4 of that in PAL composite digital VTRs.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a magnetic recording/reproducing apparatus according to a first embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment,
FIG. 3 is a timing diagram of the CTL signal and field numbers in the first embodiment of the present invention, and FIG. 4 is a block diagram of the conventional example. 4...2 field delay memory, 6...
-Multiplexer, 14...Field number comparator. Name of agent: Patent attorney Shigetaka Awano and 1 other person Ward 1

Claims (2)

[Claims] (1) It has a plurality of field memories and a delay amount control means, and the input signal is delayed by the delay amount control means so as to maintain continuity with the field number detected from the control signal on the tape during the run-up for splicing. A magnetic recording and reproducing device configured to perform control. (2) The magnetic recording and reproducing apparatus according to claim 1, wherein the field memory has two fields as one unit.