JPH03265383A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the picture quality by reproducing one preceding recording track with one head pair in combination heads and recording a recording signal whose time axis is varied in response to the time axis variation of the reproduced signal by other head pair. CONSTITUTION:First and second head pairs 10a, 10b and 11a, 11b are provided with a prescribed step difference and arranged on a rotating body while being parted by a distance being an integral number of multiple of a horizontal scanning period, and when recording by the head 11a is implemented, the head 10a reproduces one preceding track recorded by the head 11b and at the recording of the head 11b, the head 10b reproduces one preceding track recorded by the head 11a. Then the time axis variation of the reproduction signal is detected and the time axis variation equivalent to the time axis variation of the reproducing signal is given to the recording signal based on the output. Thus, the picture quality of the reproduced video signal is improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a time recording/reproducing device, and particularly to a time recording/reproducing device including a combination head in which a plurality of pairs of heads are arranged adjacently in a predetermined relationship. The present invention relates to magnetic recording and reproducing devices such as video tape recorders (VTRs).

(Prior Art) In general, home VTRs are configured so that a standard recording/playback mode (SP mode) and a long-duration recording/playback mode (EP mode) with a slower tape running speed can be set. For each mode, two recording/reproducing heads are placed on a rotating cylinder at an angle of 180 degrees with the rotating shaft sandwiched between them.Using these recording/reproducing heads, one field of video signals is generated in one stream by half a rotation of the rotating cylinder. It is configured to record and reproduce information on a magnetic tape so as to form a track, and to record and reproduce one frame of video signals in one revolution. Therefore, the rotating cylinder rotates 30 times per second, and its rotation is controlled by the servo system. However, the rotating cylinder itself has uneven rotation that cannot be controlled by the servo system, and the rotation is unique to the mechanical parts of the tape transport system. 10 because it is affected by vibration, uneven rotation, changes in tape tension, etc.
The video signal will be recorded while containing jitter in the frequency band around 0 Hz. This jitter has no correlation between adjacent fields and is random, so
On the tape pattern, there are random time axis fluctuations between adjacent tracks, and the positions of the horizontal synchronization signals are aligned, so-called "
Even if recording is performed in an H-aligned manner, the actual recording state is a poor H-aligned recording state, and especially when played back with a head that is wider than the track width, color flicker, edge noise, etc. occur in the reproduced signal, resulting in deterioration of image quality. The problem of inviting occurs. Furthermore, when the head crosses the track during high-speed playback of cue reviews, skew distortion occurs, resulting in a deterioration in image quality.

(Problems to be Solved by the Invention) As described above, in conventional VTRs, because the "H alignment" between adjacent trays is not sufficient, color flicker, edge noise, skew distortion, etc. occur in the reproduced signal.
This had the problem of causing image quality deterioration.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a magnetic recording and reproducing device that has a simple configuration and is capable of improving the image quality of reproduced video signals.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a first and second head pair that has a predetermined height and is arranged on a rotating body at a distance that is an integral multiple of the horizontal scanning period. and a combination head configured to record signals on the magnetic tape so that the first pair of heads sequentially forms tracks, while the second pair of heads records signals from a previously recorded track different from the track currently being recorded. means for reproducing a signal; time axis variation detecting means for comparing a synchronization signal of the recording signal with a synchronization signal of the reproduction signal to detect a time axis variation of the reproduction signal; and an output of the time axis variation detection means. A magnetic recording and reproducing apparatus is constructed by comprising a time axis control means for controlling the time axis of the recording signal based on the magnetic recording signal and giving a time axis variation to the recording signal corresponding to a time axis variation of the reproduction signal.

(Function) According to the above configuration, the combination head reproduces the previous recording track by one track using the second pair of heads, and generates a recording signal whose time axis is varied in accordance with the time axis variation of the reproduced signal. Operation difference, so as to record with the first pair of heads
As a result, it is possible to improve the accuracy of the "H arrangement" between adjacent tracks on the tape, thereby reducing color flicker in the playback signal.
The occurrence of edge noise and skinny distortion can be reduced, and image quality can be improved as much as possible.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a recording system of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, and is designated by 10a in the figure.

Reference numeral 10b denotes a first recording/reproducing head for standard recording/reproducing mode (SP mode), which has different azimuth angles. For the first recording and reproducing heads 10a and 10b, a pair of recording and reproducing heads 11a and llb for long-time recording and reproducing mode (EP mode) are connected to each other at an integer multiple of one horizontal scanning period (IH), for example, 2H. First and second combination heads 12a and 12b are formed by being spaced apart from each other by a corresponding distance and are combined, and as shown in FIG.
It is mounted against the 0 degree position.

Heads lla and llb have the same azimuth angle as heads 10a and 10b, respectively, and head 10a.

The head width is narrower than that of the head 10b, and the head 10b is attached to the rotating cylinder 9 so that its reference surface is stepped by a distance d from the reference surface of the heads 10a and 10bk. This interval d is 19.3/2 (
It is desirable to set it to a value greater than (μm). As a result, the first
As shown in FIG.
゜Draw T5, the head 11b is T2,
Draw T 4. When recording is performed by the head 11a, at the same time, the head IC 1a traces the previous track recorded by the head 11b and reproduces the track. The head 10b reproduces the previous track recorded by the head 11a.

to the first and second combinations 12a;
Each head 10a, 10b of 12b is connected to a fixed contact a of a changeover switch 14 via a preamplifier 13a, 13b, respectively.
and b. This changeover switch 14 has a movable contact C connected to a signal processing circuit 16 via an FM demodulation circuit 15.
The output end of this signal processing circuit 16 is connected to a first horizontal synchronization (hereinafter referred to as HD) signal separation circuit 17 . This first HD signal separation circuit 17 includes a composite synchronization signal separation circuit 17a, an equivalent pulse removal circuit 17b, and an HDD signal separation circuit 17a.
It consists of a pulse forming circuit 17c, which separates a horizontal synchronizing signal from the input signal and outputs it to one input end of the phase comparator circuit 18. This phase comparison circuit 18 has a second horizontal synchronization (hereinafter referred to as HD) signal separation circuit 1 at the other input terminal.
A voltage controlled oscillation circuit (VCO) 20 is connected to the output terminal via an integrating circuit 21.

The second HD signal separation circuit 19 includes a composite synchronization signal separation circuit 19a1, an equivalent pulse removal circuit 19b, and an HD pulse generation/interrogation circuit 19C.

Further, numeral 22 in the figure is a recording video signal input terminal, to which a luminance/color (hereinafter referred to as Y/C) separation circuit 24 is connected via an automatic gain control (AGC) circuit 23. This Y/C separation circuit 24 controls its luminance (hereinafter, Y
The second horizontal synchronizing signal separation circuit 19a and the variable delay circuit 25 are connected to the signal output terminal. This variable delay circuit 25 has the clock signal input terminal connected to the VCO2.
0 is connected, and one input end of a mixer 28 is connected to the output end via a Y signal processing circuit 26 and an FM modulation circuit 27.

The other input terminal of mixer 28 is connected to the output terminal of variable delay circuit 29 . These two variable delay circuits have their clock signal input terminals connected to the output terminals of the VCO 20, and their input terminals are connected to the color of the Y/C separation circuit 24 (hereinafter referred to as , C) signal output ends are connected. The output end of the mixer 28 is provided with the first and second combination heads 12a, 12.
Each head lla, llb of b is connected.

In the above configuration, when recording a video signal in the long-time recording mode, first, the first and second combination heads 12g and 12b write the magnetic tape T to each of the heads 10a and 10b using the respective heads lla and llb. Truck Tr
, T3, T5 and T2. One track before T4 is reproduced, and the reproduced signal is output to fixed contacts a and b of the changeover switch 14 via preamplifiers 13a and 13b. At this time, the changeover switch 14 is controlled to switch in response to a control signal corresponding to the rotation of the rotary cylinder 9, and selectively switches between the first and second combination heads 12a.

The reproduction output of the first recording/reproducing head 10a, 10b of 12b is output to the FM demodulator 15. The FM demodulation circuit 15 performs FM demodulation on the input reproduction signal, and the signal is guided to a signal processing circuit 16 for signal processing, and then guided to a first HD signal separation circuit 17 . The first HD signal separation circuit 17 separates the HD signal from the manually generated signal and outputs it to the phase comparison circuit 18. This phase comparator circuit 18 has a recording video signal input terminal 2.
The synchronization signal of the video signal supplied to the AGC circuit 23,
The signal is supplied via the Y/C separation circuit 24 and the second HD signal separation circuit 29, and the phases of the input HD signals are compared and a phase comparison signal is output to the integration circuit 21. The integrating circuit 21 determines the time axis fluctuation from the input phase comparison signal, and outputs a phase error signal corresponding to this time axis fluctuation to the VCO 20.
Output to. The VCO 20 outputs a clock (CLK) signal having an oscillation frequency corresponding to the input phase error signal to the variable delay circuits 25 and 29 to control the variable delay circuits 25 and 29.

Of these, the variable delay circuit 25 controls the time axis of the Y signal input from the Y/C separation circuit 24 in accordance with the clock signal, and outputs it to the FM modulation circuit 27. The FM modulation circuit 27 performs FM modulation on the manually generated Y signal, and then outputs it to one input terminal of the mixer 28 . The other two variable delay circuits are Y
The recording C signal from the /C separation circuit 24 is sent to the low frequency conversion circuit 3.
After being low-frequency converted at 0, the recorded low-frequency converted C signal that is guided and manually input is outputted to the other input terminal of the mixer 28 with its time axis controlled in accordance with a clock signal. mixer 2
Reference numeral 8 denotes a second recording/reproducing head 11a of the first and second combination heads 12a, 12b, which mixes the inputted recording Y signal and recording low frequency conversion C signal to produce a video signal for recording.

11b. Here, the recorded video signal input terminal 22
The video signal supplied to the second recording/reproducing head 11a corresponds to the time axis one track before.

T+, Ti, Ts and T2 . of the magnetic tape T through 11b. Recorded in T4.

In this way, the magnetic recording and reproducing apparatus described above includes each head 10 of the first and second combination heads 12a and 12b.
A and 10b reproduce the previous track, and each head 11a receives a recorded video signal whose time axis is controlled in accordance with the time axis fluctuation of the reproduced signal.

11b was configured to record on the magnetic tape T.

According to this, it is possible to align the HD signals on the magnetic tape T with high precision in the long-time recording/reproduction mode, and the prevention of crosstalk fluctuations from adjacent tracks is facilitated, resulting in color flicker, edge noise, and skew. Since distortion can be reliably prevented, the highest possible image quality can be achieved.

It goes without saying that the present invention is not limited to the above embodiments, and that various modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As described in detail above, according to the second invention, it is possible to provide a magnetic recording and reproducing device that has a simple configuration and can improve image quality in long-time recording and reproducing mode.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIGS. 2 and 3 are diagrams showing the arrangement of the recording/reproducing head shown in FIG. 1, and FIG. 4 is a diagram showing the arrangement of the recording/reproducing head shown in FIG. FIG. 3 is a diagram shown for explaining the recording/reproducing head and the tape pattern of the magnetic tape. 9... Rotating cinder, 10 g + 10 b...
One pair of recording and reproducing heads, l1g, llb... The other pair of recording and reproducing heads, 12m, 12b... First and second combination heads, 13g, 13b...
Preamplifier, 14... changeover switch, 15... FM
Demodulation circuit, 16... Signal processing circuit, 17.18...
First and second HD signal separation circuits, one...phase comparison circuit, 20...VCo, 21...integrator circuit, 22...
...recorded video signal input terminal, 23...AGC circuit, 2
4...Y/C separation circuit, 25.29...Variable delay circuit, 26...Y signal processing circuit, 27...FM modulation circuit, 28...Mixer, 30...Low frequency conversion circuit.

Claims (1)

[Claims] A combination head configured by having a first and second head pair arranged on a rotating body with a predetermined step height and spaced apart by an integral multiple of a horizontal scanning period; means for reproducing a signal from a previously recorded track different from the track currently being recorded by the second pair of heads while recording the signal to form a track; a time axis variation detection means for comparing synchronization signals and detecting a time axis variation of the reproduced signal; and controlling the time axis of the recording signal based on the output of the time axis variation detection means;
1. A magnetic recording and reproducing apparatus comprising: time axis control means for giving the recorded signal a time axis variation corresponding to the time axis variation of the reproduced signal.