JPH0799668A - Video signal recording device and video signal reproducing device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of color slurring in the vertical direction due to the timing deviation between reproduced luminance signal and color signal even in the case of the variance in the attaching position of a recording magnetic head on a rotating cylinder by adding vertical synchronizing information generated from a vertical synchronizing signal to the color signal to record it. CONSTITUTION:A vertical synchronizing signal separating circuit 5 separates the vertical synchronizing signal from the luminance signal inputted to a luminance signal input terminal 3. A vertical synchronizing information generating circuit 6 generates vertical synchronizing information from the vertical synchronizing signal. Vertical synchronizing information is added to an inputted color difference signal R-Y by an adder 7. A color difference signal synthesizing circuit 8 synthesizes two color difference signals R-Y and B-Y into one synthesized color difference signal, and horizontal synchronizing information is added to this signal by an adder 11, and it is recorded on a magnetic tape 14 through a color signal processing circuit 12, a recording, amplifier 13, and a magnetic head 15. Consequently, vertical synchronizing information of color difference signals is detected at the time of reproducing, and the phase is matched to that of the vertical synchronizing signal of the reproduced luminance signal to eliminate the deviation between these signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal recording apparatus and a reproducing apparatus for recording and reproducing a high quality color video signal on a magnetic tape or the like.

[0002]

2. Description of the Related Art Conventionally, the VHS system has been widely used in homes as a video tape recorder for recording color video signals. About 250 million VHS video tape recorders have spread all over the world,
It has become one of the necessities in ordinary households.

The following systems have been proposed as high-quality recording systems which are compatible with the recording systems of the above video tape recorders. First, the input composite video signal is separated into a luminance signal, a carrier color signal, and two color difference signals, the luminance signal is frequency-modulated, and the carrier color signal is converted into a low frequency band, as in the VHS system. The frequency-modulated luminance signal and the low-frequency-converted carrier color signal are mixed and recorded on a track on a magnetic tape by a magnetic head. The two color difference signals are combined into one as a composite color difference signal by time axis compression, and then horizontal synchronization information is added. Then, frequency modulation is performed with a carrier having a frequency higher than the frequency-modulated luminance signal band, and different magnetic heads perform overwriting on a part of the recorded track of the magnetic tape from above. This high image quality recording method is described in "Japanese Patent Application No. 4-314814" filed by the present applicant.

The above conventional technique will be described with reference to the block diagram of the conventional video signal recording apparatus shown in FIG. In FIG. 5, reference numerals 1 and 2 are color difference signal input terminals, and B-
Y and R-Y signals are input. 3 is a luminance signal input terminal,
4 is a carrier color signal input terminal, 8 is a color difference signal synthesizing circuit that compresses the time axes of the two input color difference signals and adds them in time series to form one synthetic color difference signal, and 9 is a horizontal synchronizing signal from the luminance signal. A horizontal sync separation circuit for separating the horizontal sync information, a horizontal sync information generation circuit for generating horizontal sync information from the horizontal sync signal output from the horizontal sync separation circuit, an adder 11,
Reference numeral 12 is a color signal processing circuit for performing FM modulation for converting an input signal into a signal suitable for recording on a magnetic tape, and 13
Is a recording amplifier for amplifying the output signal of the color signal processing circuit 12, 14 is a magnetic tape, 15 is a magnetic head for recording the output signal of the recording amplifier 13 on the magnetic tape 14, 16
Is a luminance signal processing circuit for performing FM modulation for converting an input signal into a signal suitable for recording on a magnetic tape, 17 is a low frequency conversion circuit for converting a carrier color signal to a low frequency, 18
Is an adder, 19 is a recording amplifier for amplifying the output signal of the adder 18, and 20 is a magnetic head for recording the output signal of the recording amplifier 19 on the magnetic tape 14.

The operation of the conventional video signal recording apparatus configured as described above will be described below.

The horizontal sync separation circuit 9 extracts a horizontal sync signal from the brightness signal input to the brightness signal input terminal 3.
Then, the horizontal synchronization information generation circuit 10 generates horizontal synchronization information to be added to the composite color difference signal from the extracted horizontal synchronization signal. The color difference signals input to the color difference signal input terminals 1 and 2 are compressed in the time axis of the two color difference signals by the color difference signal combining circuit 8 and added in time series to form one combined color difference signal. Then, the horizontal synchronization information is added to the composite color difference signal by the adder 11. Further, the color signal processing circuit 12
The data is recorded on the magnetic tape 14 by the recording amplifier 13 and the magnetic head 15.

On the other hand, the luminance signal is converted by the luminance signal processing circuit 16 into an FM signal suitable for recording on a magnetic tape. Then, the adder 18 adds the carrier color signal converted into the low frequency by the low frequency conversion circuit 17 to form a mixed video signal, which is recorded on the magnetic tape 14 by the recording amplifier 19 and the magnetic head 20. It

[0008]

In the above-mentioned conventional high image quality recording system, since the vertical sync signal is not added to the composite color difference signal, the reproduction timing of the composite color signal cannot be specified during reproduction. There was such a problem.
That is, the mounting positions of the magnetic head for recording the mixed video signal and the magnetic head for recording the composite color difference signal are arranged considerably apart on the rotating cylinder. Due to the phase fluctuation (jitter) of, the timing of the luminance signal reproduced by one magnetic head and the color difference signal reproduced by the other magnetic head is shifted in units of horizontal scanning lines. Misalignment occurs. Therefore, it is difficult to maintain high quality image.

In view of the above problems, the present invention provides a reproduced luminance signal and color signal even when the mounting position of the magnetic head for recording varies on the rotating cylinder or when the phase of cylinder rotation fluctuates. The present invention provides a video signal recording device and a reproducing device in which vertical color misregistration due to the timing misregistration does not occur.

[0010]

In order to solve the above problems, (1) a video signal recording apparatus according to the present invention comprises a vertical sync separation circuit for separating a vertical sync signal of an input video signal, and a vertical sync signal from the vertical sync signal. A vertical synchronization information generation circuit that generates vertical synchronization information and an addition circuit that adds the vertical synchronization information to a color signal are provided. (Corresponding to claim 1) (2) The video signal reproducing apparatus of the present invention controls so that the phase of the vertical synchronizing information of the reproduced chrominance signal with respect to the vertical synchronizing signal of the reproduced luminance signal has a predetermined relationship. It is provided with a phase control means. (Corresponding to claim 11) (3) The video signal reproducing apparatus of the present invention comprises a gate signal generating circuit for generating a gate signal in a range including the vertical synchronization information of the reproduced color signal. (Corresponding to claim 14)

[0011]

According to the present invention, the vertical synchronization information generated from the vertical synchronization signal is added to the color signal and recorded, so that the vertical synchronization information of the luminance signal and the vertical synchronization information of the color signal are reproduced. Since the timing can be adjusted, vertical color misregistration does not occur.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a video signal recording apparatus according to an embodiment of the present invention.

In FIG. 1, 1-4 and 8-20 are shown in FIG.
The same constituent elements as those in FIG. Reference numeral 5 is a vertical sync separation circuit for separating the vertical sync signal from the luminance signal, 6 is a vertical sync information generation circuit for generating vertical sync information from the vertical sync signal output from the vertical sync separation circuit 5, and 7 is an adder.

The operation of the video signal recording apparatus of this embodiment constructed as described above will be described below.

The vertical sync separation circuit 5 separates the vertical sync signal from the brightness signal input to the brightness signal input terminal 3.
Then, the vertical synchronization information generation circuit 6 generates vertical synchronization information from the vertical synchronization signal. The vertical synchronization information is added to the RY signal of the input color difference signal by the adder 7.

FIG. 2 shows the waveforms of the input signal and the output signal of the vertical sync separation circuit 5 and the waveform of the vertical sync signal generated by the vertical sync information generation circuit 6. In FIG. 2, ()
The numeral in () means the number of the horizontal synchronization period, and the vertical synchronization information is added to the 14th horizontal synchronization period in this case.

As in the conventional example shown in FIG. 5, the color difference signals are compressed by the color difference signal synthesizing circuit 8 on the time axis of the two color difference signals within the horizontal synchronizing period, and added in time series to be combined into one. It becomes a color difference signal. Then, horizontal synchronization information is added to the composite color difference signal by the adder 11, and further, by the color signal processing circuit 12, the recording amplifier 13, and the magnetic head 15.
It is recorded on the magnetic tape 14.

On the other hand, the luminance signal is converted by the luminance signal processing circuit 16 into an FM signal suitable for recording on a magnetic tape. Then, in the adder 18, the carrier color signal converted into the low frequency is added. Further, it is recorded on the magnetic tape 14 by the recording amplifier 19 and the magnetic head 20.

On the magnetic tape 14, the color difference signal recording tracks are formed between the luminance signal recording tracks.

As described above, according to this embodiment, at the time of recording, the vertical synchronizing information is generated by utilizing the vertical synchronizing signal of the luminance signal, and the information is added to the color difference signal and recorded, so that at the time of reproduction, It is possible to detect the vertical synchronization information of the color difference signal, and by adjusting the phase of the vertical synchronization signal of the reproduced luminance signal and the vertical synchronization signal of the reproduced color difference signal, the deviation between the luminance signal and the color difference signal is eliminated. Disappeared
Therefore, the color shift in the vertical direction does not occur.

The time-axis expansion of the color difference signal which has been time-axis compressed on the recording side is performed on the reproducing side. The time-axis expansion is performed by using a memory and changing the writing and reading speeds. The above-mentioned phase matching can be realized by changing the read timing of the memory.

By the way, the vertical synchronization information added to the color difference signal has a polarity opposite to that of the horizontal synchronization information when added in a direction in which the pulse direction becomes the white level, and therefore it is easy to distinguish from the horizontal synchronization information. There are advantages. In addition, if the pulse directions are such that the black level is reached, the FM
When modulated, the pulse portion goes to the side where the frequency shift is low, so there is an advantage that the so-called blurring phenomenon does not easily occur.

In this embodiment, the vertical synchronizing signal is separated from the input luminance signal. However, when the composite video signal (composite signal) is input, the vertical synchronizing signal is separated from the composite video signal. You may.

In this embodiment, the vertical synchronization information is added to the RY signal of the color difference signal, but it may be added to the BY signal of the color difference signal.

Further, by adding vertical synchronization information to the RY signal in the 14th horizontal synchronization period and to the BY signal in the 15th horizontal synchronization period, for example,
Even if one of the horizontal sync periods cannot be played back due to dropout or the like, the vertical sync information of the other horizontal sync period can be used. In this case, when it is added to the RY signal and when it is B
Since the position of the vertical synchronization information is different from that when it is added to the -Y signal, which horizontal synchronization period of the vertical synchronization information can be distinguished at the time of reproduction, and correct phase matching can be performed.

In this embodiment, the color difference signal synthesizing circuit 8 is also used.
I added vertical sync information to the color difference signal before input to
It may be added to the output signal of the color difference signal synthesis circuit 8.

Next, another embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a block diagram of a video signal reproducing apparatus according to another embodiment of the present invention. Figure 3
In 35, 35 is a rotating cylinder, 38 is its rotating direction, 36 is a magnetic tape, and 37 is its running direction. Also, 31 and 32, 33 and 34
Are magnetic head pairs, respectively. The magnetic tape 36 is wound around the rotating cylinder 35 by about 180 degrees or more,
Each of the four magnetic heads constitutes a so-called helical scan type video tape recorder that obliquely scans the magnetic tape 36.

Reference numeral 40 is a head amplifier for amplifying the signals reproduced by the magnetic heads 31 and 32, and 41
Is a bandpass filter (BPF) for extracting a specific band from the output of the head amplifier 40, 42 is an FM demodulation circuit for demodulating the output signal of the bandpass filter 41, and 43 is an output signal of the FM demodulation circuit 42. Is a variable delay circuit for variably delaying the signal, 44 is a reproduced luminance signal which is an output thereof, 45 is a head amplifier for amplifying a signal reproduced by the magnetic heads 3, 4, and 46
Is a band pass filter (BPF) for extracting a specific band from the output of the head amplifier 45, 47 is an FM demodulation circuit for demodulating a reproduction color signal 48 from the output signal of the band pass filter 46, and 49 is a reproduction luminance. A vertical sync separation circuit for extracting the vertical sync signal 50 from the signal 44, and 51 is a gate signal generation circuit for generating a timing gate signal 52 with the vertical sync signal 50 as a reference.
Reference numeral 3 is a vertical sync detection circuit for detecting a V pulse (vertical sync information) 54 from the reproduced color signal 48 by using the timing gate signal 52, and 55 is a phase of the vertical sync signal 50 and a phase of the V pulse 54. Is a phase control circuit that controls the delay amount of the variable delay circuit 43 so that and have a predetermined relationship.

The operation of this embodiment configured as described above will be described with reference to FIG. 3 and FIG. 4 showing the signal waveforms of the respective parts.

The outputs of the magnetic heads 31 and 32 are guided to a head amplifier 40 through a well-known rotary transformer and amplified, and thereafter, an unnecessary band is removed by a band pass filter 41, and an FM demodulation circuit 42. Is reproduced by the variable delay circuit 43 and delayed by the reproduction luminance signal 44.
Becomes This reproduced luminance signal contains a luminance signal component and a vertical synchronization signal component as shown by a waveform 44 in FIG.
The vertical sync separation circuit 49 extracts the vertical sync signal 50 contained in the luminance signal, guides it to the gate signal generation circuit 51, and produces the timing gate signal shown by the waveform 52 in FIG.

The outputs of the magnetic heads 33 and 34 are also guided to a head amplifier 45 through a well-known rotary transformer and amplified, and then an unnecessary band is removed by a bandpass filter 46, and an FM demodulation circuit 47. Is demodulated to produce a reproduced color signal 48, which is guided to the vertical sync detection circuit 53. This reproduced color signal has a composite color difference signal component and an H pulse (horizontal synchronization information) as shown by a waveform 48 in FIG.
And 1 in advance for one specified line within the vertical blanking period.
The V pulse is included in which the / 2H period has a level higher than the pedestal potential.

As shown by the waveform 52, the timing gate signal mainly includes a certain line of the V pulse included in the reproduced color signal, and the fluctuation due to the jitter between the timing gate signal and the reproduced composite color difference signal is expected. Around 1
It has a waveform that covers the range of 3 lines including each line. In the vertical synchronization detection circuit 53, by operating so as to detect a potential higher than the pedestal potential in the reproduction color signal 48 only during the period of the timing gate signal 52, the V signal can be detected without erroneous detection by the video signal component of the reproduction color signal.
The pulse 54 is detected.

In the phase control circuit 55, the vertical sync signal separated from the reproduction luminance signal and the V detected from the reproduction color signal are detected.
By controlling the pulse and the pulse so as to have a predetermined phase relationship, the phase difference between the reproduction luminance signal and the reproduction color signal is eliminated, and as a result, the color deviation is eliminated.

As described above, in this embodiment, by using the timing gate signal, the vertical synchronization information can be surely obtained from the reproduction color signal, and the reproduction phase of the color signal can be obtained based on the vertical synchronization information. It can be adjusted to the playback phase.

In the above embodiment, the gate signal generating circuit 51 obtains the timing gate signal 52 with reference to the vertical synchronizing signal 50 of the reproduction luminance signal 44. The timing gate signal is the reproduction color signal. Since it only needs to occur within the range of the vertical blanking period that includes the specific line including the V pulse, the head switch signal for switching the head may be used as a reference.

The period of the timing gate signal is 3 lines in the case of FIG. 4, but if it is too narrow, it will not be able to absorb variations due to head mounting variations and jitter, and if it is too wide, reproduction will occur. The video signal component of the color signal facilitates erroneous detection. Therefore, it is appropriate that the period of the timing gate signal is 20 lines or less, which is close to the vertical blanking period.

[0037]

As described above, according to the present invention, by adding the vertical synchronization information to the color signal and recording the same, the timing of the vertical synchronization information of the luminance signal and the vertical synchronization information of the color signal is reproduced at the time of reproduction. Therefore, it is possible to obtain an excellent effect that the color shift in the vertical direction due to the phase fluctuation of the cylinder rotation and the variation of the mounting position is eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram of a video signal recording device according to an embodiment of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the video signal recording device in the embodiment of the present invention.

FIG. 3 is a block diagram of a video signal reproducing device according to another embodiment of the present invention.

FIG. 4 is a waveform diagram for explaining the operation of a video signal reproducing device according to another embodiment of the present invention.

FIG. 5 is a block diagram of a conventional video signal recording device.

[Explanation of symbols]

 1, 2 Color difference signal input terminal 3 Luminance signal input terminal 4 Carrier color signal input terminal 5 Vertical sync separation circuit 6 Vertical sync information generation circuit 7 Adder 8 Color difference signal synthesis circuit 9 Horizontal sync separation circuit 10 Horizontal sync information generation circuit 11 Addition 12 Color difference signal processing circuit 13 Recording amplifier 14 Magnetic tape 15 Magnetic head 16 Luminance signal processing circuit 17 Low frequency conversion circuit 18 Adder 19 Recording amplifier 20 Magnetic head 31, 32, 33, 43 Magnetic head 35 Rotating cylinder 36 Magnetic tape 40 Head amplifier 42 FM demodulation circuit 43 Variable delay circuit 44 Playback luminance signal 45 Head amplifier 47 FM demodulation circuit 48 Playback color signal 49 Vertical sync separation circuit 50 Vertical sync signal 51 Gate signal generation circuit 52 Timing gate signal 53 Vertical sync detection circuit 54 V Pulse 55 phase control circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display H04N 9/87 Z

Claims (17)

[Claims] 1. A video signal recording device for recording the brightness signal and the color signal of an input video signal including a brightness signal, a color signal, and a vertical synchronizing signal by different heads, respectively. A vertical sync separation circuit that separates a sync signal, a vertical sync information generation circuit that generates vertical sync information from an output signal of the vertical sync separation circuit, and an adder circuit that adds the vertical sync information to the color signal. A video signal recording device characterized by the above. 2. The video signal recording apparatus according to claim 1, wherein the vertical synchronizing signal is included in the luminance signal, and the vertical synchronizing separation circuit separates the vertical synchronizing signal from the luminance signal. 3. The video signal recording device according to claim 1, wherein the vertical synchronization information generation circuit generates the vertical synchronization information within a vertical blanking period of the color signal. 4. The vertical synchronization information is formed by pulses, and the adder circuit adds the pulses so that the direction of the pulses is in the white level direction. Video signal recording device. 5. The vertical synchronization information is formed by pulses, and the adding circuit adds the pulses so that the direction of the pulses is in the black level direction. Video signal recording device. 6. The color signal includes two color difference signals, and an adder circuit adds vertical synchronization information to at least one of the two color difference signals. The video signal recording device according to. 7. The color difference signal combining circuit according to claim 6, further comprising a color difference signal combining circuit that compresses the time axes of the two color difference signals included in the output of the adding circuit and adds them in time series to form one signal. The described video signal recording device. 8. A color difference signal synthesizing circuit for compressing the time axis of two input color difference signals and adding them in time series to form one signal, wherein the adding circuit is perpendicular to the output of the color difference signal synthesizing circuit. 7. The video signal recording device according to claim 6, wherein the synchronization information is added. 9. The video signal recording apparatus according to claim 1, wherein the vertical synchronization information generation circuit generates vertical synchronization information within one horizontal period. 10. A vertical synchronization information generation circuit generates two vertical synchronization information, and an addition circuit adds the two vertical synchronization information to different horizontal periods of two color difference signals. The video signal recording device according to any one of claims 6 to 8. 11. A video signal reproducing apparatus for reproducing a luminance signal having a vertical synchronizing signal and a color signal having vertical synchronizing information recorded on different tracks, respectively.
Vertical sync information detecting means for detecting vertical sync information from the reproduced color signal, and the phase of the detected vertical sync information having a predetermined relationship with the phase of the reproduced vertical sync signal of the luminance signal. A video signal reproducing apparatus comprising a phase control means for controlling. 12. A video signal reproducing apparatus for reproducing a luminance signal having a vertical synchronizing signal and a time-axis-compressed color difference signal having vertical synchronizing information recorded on different tracks, respectively. 12. The video signal reproducing apparatus according to claim 11, further comprising a time axis expansion means using a memory for expanding the time axis of the color difference signal, wherein the phase control means controls a read timing of the memory. . 13. A luminance signal having a vertical synchronizing signal and a color signal which is added in time series after vertical synchronizing information is added to different horizontal periods of two color difference signals and recorded on different tracks. 12. A video signal reproducing apparatus for reproducing, wherein the phase control means sets and controls a predetermined relationship according to the position within the horizontal period of the vertical synchronization information of the reproduced color signal. Item 13. The video signal reproducing device according to any one of Items 12. 14. A video signal reproducing apparatus for reproducing a luminance signal having a vertical synchronizing signal and a color signal having vertical synchronizing information recorded on different tracks, respectively.
A gate signal generation circuit that generates a gate signal in a range including the vertical synchronization information of the reproduced color signal, and a vertical synchronization information detection unit that detects the vertical synchronization information from the reproduced color signal within the period of the gate signal. And phase control means for controlling the phase of the detected vertical synchronization information so as to have a predetermined relationship with the phase of the reproduced vertical synchronization signal of the luminance signal. The video signal reproducing device according to claim 13. 15. The video signal reproducing apparatus according to claim 14, wherein the gate signal generating circuit generates a gate signal based on the vertical synchronizing signal of the reproduced luminance signal. 16. The video signal reproducing apparatus according to claim 14, wherein the gate signal generating circuit generates a gate signal based on a head switch signal for switching heads. 17. The video signal reproducing apparatus according to claim 14, wherein the gate signal generating circuit generates a gate signal within a range of 20 horizontal periods or less.