JPH06121339A - Video signal recording and/or reproducing device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of a picture quality by specifying the period of a discrimination signal based on the synchronizing signal of an input video signal so as not to record the discrimination signal in this period. CONSTITUTION:An RDTV signal (aa) is supplied to a clamp circuit 1, vertical synchronizing signal separator circuit 2, and horizontal synchronizing signal separator circuit 3. A signal from the clamp circuit 1 is inputted to one input of a switch circuit 5. On the other hand, vertical and horizontal synchronizing signals 2a and 3a respectively separated by the separator circuits 2 and 3 are supplied through a counter circuit 4 to a switch circuit 5 as a control signal 4a. The switch circuit 5 selects the output of the clamp circuit 1 and the voltage of a voltage source V1, and supplies the EDTV signal from which a discrimination signal (bb) is removed to an Y/C separator circuit 6. Thus, a modulated recording signal related with the EDTV signal (aa) from which the discrimination signal (bb) is removed can be recorded in a magnetic tape T.

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 device, a video signal reproducing device, or a video signal recording and / or reproducing device which is a video signal recording / reproducing device.

[0002]

2. Description of the Related Art FIG. 5 is a diagram for explaining an image of a letter box system, and FIG. 6 is a diagram for explaining an EDTV signal. A conventional technique will be described below with reference to the drawings.

In recent years, a method of transmitting a high quality landscape image having an aspect ratio of 16: 9 compatible with a conventional television receiver having an aspect ratio of 4: 3 has been studied. As one of them, when displaying on a conventional television receiver, black portions are formed in the upper and lower portions of the screen as shown in FIG.
There is a letterbox method to display an image with an aspect ratio of 6: 9, and corresponds to this black part so that a high quality image can be obtained when displayed on a monitor having an aspect ratio of 16: 9. It has been proposed to insert vertical and horizontal high-frequency components as auxiliary signals during the period.
Hereinafter, this signal will be referred to as an EDTV signal.
This is illustrated in (A).

Then, in order to make it possible to determine whether or not it is the EDTV signal, a determination signal bb is inserted in a predetermined line within the vertical blanking period as shown in FIG.

When the above-mentioned EDTV signal is recorded / reproduced by a video signal recording / reproducing apparatus such as a VTR, a comb filter using a predetermined line correlation for separating a luminance signal and a chrominance signal related to the video signal is used to obtain the above-mentioned line correlation. Auxiliary signal is of high quality because deterioration of auxiliary signal does not occur, fluctuations in the time axis direction occur due to jitter and head switching points, and further deterioration of frequency characteristics and group delay characteristics accompanying recording and reproduction occurs. In the decoder for obtaining the image, the signal could not be decoded properly.

[0006]

In such a case, if the discrimination signal remains in the reproduction output signal of the video signal recording / reproducing apparatus, the EDTV is used in the television receiver having an aspect ratio of 16: 9 corresponding to the EDTV signal. Since the image is displayed after being discriminated as a signal, there is a problem that the image quality is rather deteriorated.

Therefore, the present invention has been made to solve the above problems.

[0008]

The present invention provides the following constitution in order to solve the above problems.

A video signal recording or recording / reproducing apparatus for recording an input video signal having a discrimination signal indicating a type in a vertical blanking period, wherein the period of the discrimination signal is specified based on a synchronization signal of the input video signal. A video signal recording or recording / reproducing device characterized in that the discrimination signal is not recorded during this period.

A video signal reproducing or recording / reproducing apparatus for reproducing an output video signal having a discrimination signal indicating a type in a vertical blanking period, wherein the period of the discrimination signal is specified based on a synchronizing signal of the output video signal. A video signal reproducing or recording / reproducing apparatus characterized in that the discrimination signal is not reproduced and outputted during this period.

[0011]

1 is a block diagram for explaining the main part of a recording system according to an embodiment of a video signal recording or recording / reproducing apparatus of the present invention, and FIG. 2 is a video signal reproducing or recording / reproducing apparatus of the present invention. FIG. 3 is a block diagram for explaining a main part of a reproducing system according to an embodiment, and FIG. 3 is a block diagram for explaining a main part of a reproducing system according to another embodiment of a video signal reproducing or recording / reproducing apparatus of the present invention. FIG. 4 is a timing chart for explaining FIGS. 1, 2 and 3. Embodiments will be described below with reference to the drawings.

(First Embodiment) The first embodiment is a recording system for ED.
The present invention relates to a video signal reproducing or recording / reproducing apparatus for removing a discrimination signal from a TV signal.

In FIG. 1, the EDT is connected from a transmission line (not shown).
V signal aa is clamp circuit 1 and vertical sync signal separation circuit 2
And the horizontal synchronizing signal separation circuit 3 respectively. Then, after the EDTV signal aa is clamped by a well-known clamp such as a pedestal clamp in the clamp circuit 1, this signal is supplied to one input of the switch circuit 5.

On the other hand, vertical and horizontal sync signal separation circuits 2 and 3
At the EDTV signal aa, the vertical and horizontal synchronizing signals are separated and the waveform is shaped, and the vertical and horizontal synchronizing signals 2a are obtained.
3a is supplied to the reset input and the clock input of the counter circuit 4, respectively.

The operation of the counter circuit 4 will be described with reference to FIG. 4. The vertical synchronizing signal 2 shown in FIG. 7B separated and shaped from the EDTV signal aa shown in FIG.
The counter circuit 4 is reset during the high level period of a,
After this signal falls from the high level to the low level, counting is started using the horizontal sync signal 3a shown in FIG. 6C, which is similarly separated and shaped, as a clock pulse,
After carrying out 17 counts, a carry output (not shown) is obtained, and a counter circuit output signal 4a which is delayed for a certain period from this signal and maintains a high level during the rising discrimination signal period and then falls is obtained.

The counter circuit output signal 4a is supplied to the control input of the switch circuit 5 described above, and the switch circuit 5 selects the output of the clamp circuit while the signal is at the low level (state shown in FIG. 1). On the other hand, during the high level period, the voltage of the voltage source V1 which is the other input is selected and the EDTV signal from which the determination signal bb is removed is supplied to the Y / C separation circuit 6.

The recording luminance signal 6a and the recording color signal 6b separated by the Y / C separation circuit 6 are supplied to the luminance and color signal recording processing circuits 7 and 8, respectively, and subjected to known processing and output. The modulated output signals of both circuits are added by the adder circuit 9. Then, the output of the adder circuit 9 is supplied to the recording amplifier 10 and subjected to predetermined amplification, and then supplied to the magnetic head 11 via a rotary transformer (not shown), and the discrimination signal bb is removed from the EDTV signal aa. The modulated recording signal is recorded on the magnetic tape T.

In this way, according to the video signal recording or recording / reproducing apparatus in the first embodiment, it is possible to provide the magnetic tape T on which the modulated recording signal related to the EDTV signal aa from which the discrimination signal bb is removed is recorded. You can

(Second Embodiment) In the first embodiment, the recording system E
The discrimination signal bb in the DTV signal aa has been removed.

However, when the magnetic tape T recorded by the video signal recording or recording / reproducing apparatus having no such function is reproduced by the video signal reproducing or recording / reproducing apparatus, the EDTV signal aa having the discrimination signal bb is reproduced. When this is displayed on a television receiver having a conventional aspect ratio of 4: 3 as an EDTV signal and displayed,
On the contrary, there is a problem that the image quality is deteriorated.

Then, in order to solve such a problem, the second
The embodiment provides a video signal reproducing or recording / reproducing apparatus capable of removing the discrimination signal bb from the EDTV signal aa in the reproducing system.

In FIG. 2, the modulated reproduction signal relating to the EDTV signal aa having the discrimination signal bb from the magnetic tape T is reproduced by the magnetic head 11 and is supplied to the reproduction preamplifier 12 via the rotary transformer (not shown). After predetermined amplification, modulated reproduction luminance having high-frequency and low-frequency components, luminance and color signal reproduction through high-pass and low-pass filters 13 and 14 (HPF, LPF) for separating color signals, respectively. The signals are supplied to the processing circuits 15 and 16 and are subjected to well-known demodulation here, and reproduction luminance and color signals 1
5a and 16a are obtained.

Then, the reproduction luminance signal 15a is supplied to the clamp circuit 1 and the vertical and horizontal synchronizing signal separating circuits 2 and 3, respectively, and the counter circuit 4 uses the respective output signals as in the first embodiment. The first and second switch circuits 18,
19 control signals are obtained.

The reproduced luminance signal 15a from the clamp circuit 1 is sent to the first switch circuit 18 and reproduced color signal 1
6a is supplied to the second switch circuit 19, and the voltage supplied from the voltage sources V1 and V2 in the determination signal period is the same as in the switch circuit 5 described above. 16a are respectively selected and output, and an output luminance signal 18a and an output color signal 19a having no discrimination signal are output.
And is output to a transmission line (not shown).

The output luminance signal 18a and the output color signal 1
9a is supplied to the adder circuit 20, and the output EDTV signal 2 from which the determination signal bb obtained by the addition here is removed.
0a is supplied to a television receiver or the like.

In this way, E having the discrimination signal bb
It is possible to provide a video signal reproducing or recording / reproducing apparatus which outputs the output EDTV signal 20a from which the discrimination signal bb is removed even if the magnetic tape T on which the modulated recording signal related to the DTV signal aa is recorded is reproduced.

Now, with reference to FIG. 3, a video signal reproducing or recording / reproducing apparatus which serves as both the dropout compensating circuit and the circuit for removing the discrimination signal bb will be described.

Conventionally, in order to compensate for dropout, the envelope of the reproduction modulation signal is detected, and when the output level is below a predetermined value, it is considered that dropout has occurred, and the current reproduction modulation signal is reproduced 1H before. There is known a dropout compensation circuit that is used by replacing it with a modulation signal.

Therefore, the discrimination signal bb is decided to be removed by using the reproduction modulation signal of 1H before which does not have the discrimination signal bb even in the discrimination signal period.

The difference between FIG. 3 and FIG. 2 is that the output of the dropout detection circuit 21 and the counter circuit 4 is provided between the reproduction preamplifier 12 and the high-pass filter 13 and the OR circuit 22 and the third switch circuit 23. And 1H delay circuit 24
Is provided and the first and second switch circuits 18 and 19 are removed. The difference will be mainly described below.

The reproduction modulation signal is supplied to the dropout detection circuit 21 through the reproduction preamplifier 12, where a dropout detection signal which becomes high level only during the dropout period is obtained and is supplied to one input of the logical sum circuit 22. Supply. Further, the other input of the OR circuit 22 is supplied with the output signal of the counter circuit 4 which is at the high level only during the discrimination signal period, and the control signal which can be ORed here is supplied to the third switch circuit 23. .

The third switch circuit 23 supplies the reproduced modulation signal to the high-pass filter 13 and the low-pass filter 14 without delay in the illustrated state when the control signal is at the low level. On the other hand, when the control signal is at the high level, the movable modulation piece is switched and connected from the state shown in the figure, and the reproduction modulation signal obtained by delaying 1H via the 1H delay circuit 24 is obtained by the highpass filter 13 and the lowpass filter 14.
And supply to.

Since the reproduction modulation signal output from the third switch circuit 23 does not have a signal corresponding to the discrimination signal bb during the discrimination signal period, the reproduction luminance signal 15a obtained by demodulating the reproduction luminance signal 15a is obtained. , Reproduction color signal 16a, output ED
The TV signal 20a has the discrimination signal bb removed.

In this way, E having the discrimination signal bb
It is possible to provide a video signal reproducing or recording / reproducing apparatus which outputs the output EDTV signal 20a from which the discrimination signal bb is removed even if the magnetic tape T on which the modulated recording signal related to the DTV signal aa is recorded is reproduced.

In the first and second embodiments described above,
The auxiliary signal period shown in FIG.
a, a first auxiliary control signal cc which is at a high level only during the auxiliary signal period shown in FIG. 1B is generated by using a counter circuit or the like based on the synchronizing signal of the output video signal such as the output EDTV signal 20a, Only the horizontal synchronization obtained from this signal and the output video signals such as the EDTV signal aa and the output EDTV signal 20a is at the low level, and the other periods are at the high level.
Of the auxiliary control signal dd (not shown)
Of the output signal of the counter circuit 4 instead of the output signal of the counter circuit 4 and the third auxiliary control signal ee (not shown) which can obtain the logical product of the auxiliary control signals cc and dd It goes without saying that the auxiliary signal period may be supplied to the first and second switch circuits 18 and 19 to replace the auxiliary signal period with a black level signal or the like for recording or reproduction.

In the above-described second embodiment, in the video signal reproducing or recording / reproducing apparatus which superimposes the information of the discrimination signal on the color output signal and outputs it, the information of the discrimination signal is transmitted and output without superimposing. Of course, it is also good.

[0037]

As described above, according to the configuration of the present invention,
Since the period of the discrimination signal is specified based on the synchronization signal of the input video signal and the discrimination signal is not recorded during this period, it is possible to provide a recording medium on which a modulated recording signal having no discrimination signal is recorded. For example, even when this recording medium is reproduced by a conventional video signal reproducing or recording / reproducing apparatus in which the discrimination signal is not reproduced and is not reproduced, it is possible to obtain the output video signal from which the discrimination signal is removed, and the image quality is deteriorated. The effect is that it can be prevented.

Further, as described above, according to the configuration of the present invention, the period of the discrimination signal is specified based on the synchronizing signal of the output video signal, and the discrimination signal is not reproduced and output during this period. Even if the recording medium on which the modulated recording signal having the above is recorded is reproduced, there is an effect that the output video signal having no discrimination signal can be reproduced and outputted, and the image quality deterioration can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining a main part of a recording system according to an embodiment of a video signal recording or recording / reproducing apparatus of the present invention.

FIG. 2 is a block diagram for explaining a main part of a reproducing system according to an embodiment of a video signal reproducing or recording / reproducing apparatus of the present invention.

FIG. 3 is a block diagram for explaining a main part of a reproducing system according to another embodiment of the video signal reproducing or recording / reproducing apparatus of the present invention.

FIG. 4 is a timing chart for explaining FIGS. 1, 2, and 3.

[Explanation of symbols]

 aa EDTV signal (input video signal) bb discrimination signal 15a reproduction luminance signal (output video signal)

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[Procedure amendment]

[Submission date] September 27, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 5

[Correction method] Added

[Correction content]

FIG. 5 is a diagram for explaining a letterbox type image.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 6

[Correction method] Added

[Correction content]

FIG. 6 is a diagram for explaining an EDTV signal.

Claims (2)

[Claims] 1. A video signal recording or recording / reproducing apparatus for recording an input video signal having a discrimination signal indicating a type in a vertical blanking period, wherein the period of the discrimination signal is determined based on a synchronization signal of the input video signal. A video signal recording or recording / reproducing apparatus characterized in that the discriminating signal is specified and not recorded during this period. 2. A video signal reproducing or recording / reproducing apparatus for reproducing an output video signal having a discrimination signal indicating a type in a vertical blanking period, the period of the discrimination signal being based on a synchronizing signal of the output video signal. A video signal reproducing or recording / reproducing apparatus characterized in that the discriminating signal is specified and not outputted during this period.