JPH0346636Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] This invention compresses the time axis of a pair of component color signals and time-division multiplexed them, for example, to a track different from the luminance signal and simultaneously transmits the luminance signal. The present invention relates to a recording device for recording, and particularly to a recording device with an automatic discrimination function that can automatically discriminate between a standard video signal with no time axis variation and a video signal with time axis variation.

[Conventional technology]

A recording and reproducing method has been proposed in which a color video signal is divided into a luminance signal and a pair of component color signals and recorded on separate tracks for recording devices such as camera body video and other recording and reproducing devices (VTR). (Japanese Unexamined Patent Publication No. 134891/1989, etc.). In this recording and reproducing method, a pair of component color signals, for example a pair of color difference signals R-Y and B-
As shown in FIG. 7B, the time axis of Y is compressed to 1/2 and time division multiplexed, and this compressed time division multiplexed color signal (hereinafter referred to as compressed color difference signal) is used as the recording track of the luminance signal Y. recorded adjacent to each other.

FIG. 8 shows an example of a recording apparatus 10 showing a specific example for realizing such a recording method.

In the recording device 10, the video signal S _V supplied to the terminal 1 is converted into a horizontal synchronizing pulse P _H by the Y/C separator 2.
a luminance signal Y (FIG. 7A) including a chroma signal C
The luminance signal Y is combined with a first synchronizing signal (pulse) P _Y , which is used for time alignment between channels, etc., in an adder 3. As shown in FIG. 7A, the synchronizing pulse P _Y is inserted and added to, for example, the latter half of the horizontal synchronizing pulse P _H with a polarity opposite to that of the pulse P _H.

The reason for inserting the positive polarity pulse P _Y is to facilitate the synchronization separation of this pulse P _Y and to prevent the generation of moiré by preventing spurious to the low frequency components of the luminance signal Y due to this pulse P _Y. It's for a reason.

W _H is the pulse width of the pulse P _H , and in this example, the pulse width of the synchronization pulse P _Y is selected to be 1/2W _H.

The luminance signal S _Y into which the synchronization pulse P _Y has been inserted is subjected to FM modulation by an FM modulator 4 and then recorded on a recording medium, for example, a tape 5.

On the other hand, the chroma signal C is supplied to the decoder 6 and converted into red and blue color difference signals R-Y, B-Y. The compressed color difference signals (R-Y) and (B-Y) are divided and multiplexed, and a second synchronization signal (pulse) P _C is inserted into the compressed color difference signals (R-Y) and (B-Y) in the adder 8, resulting in compressed color difference signals as shown in FIG. A signal S _C is formed.

The second synchronization pulse P _C is inserted at the same time position where the first synchronization pulse P _Y is inserted in order to provide time alignment between channels. Note that in this example, the second synchronization pulse P _C is inserted in a negative polarity state.

The compressed color difference signal S _C is FM modulated by an FM modulator 9 and then recorded on the tape 5 . In this case, the recording track for the compressed color difference signal is formed adjacent to the recording track for the luminance signal S _Y. Ha and Hb indicate recording and reproducing heads.

By the way, when the chroma signal C is converted into a pair of color difference signals (R-Y), (B-Y) by the decoder 6 as described above, the converted color difference signals (R-Y), (B-
As is clear from FIG. 7B, the burst signal indicating the phase information of the chroma signal C is missing in Y).

Therefore, a pair of color difference signals (RY), (B-
Color framing information, which is phase information of the chroma signal C, that is, an identification signal is superimposed on one of the signals Y). In FIG. 8, 12 is a circuit for forming this identification signal, in which the luminance signal Y is supplied to the synchronization separation circuit 13 and the horizontal and vertical synchronization pulses P _H ,
P _V is separated, and these synchronizing pulses P _H and P _V are supplied to the identification signal forming section 14 together with the burst signal output from the decoder 6 to form an identification signal ID.

To give an example of an NTSC video signal, in this example, as shown in FIG. 9, an identification signal ID is formed in which the first and second fields are "H" and the third and fourth fields are "L". Ru.

The synchronizing pulses P _H and P _V are further supplied to the gate pulse forming circuit 15, and at a predetermined number of horizontal scanning lines, in this example, a gate pulse for one horizontal period is generated.
_PG is formed, and the gate circuit 16 is turned on. In this example, for an NTSC video signal
A gate pulse _PG is generated at the 15th H, and in the case of a PAL video signal, a gate pulse _PG is generated at the 12th H.

The gated identification signal ID is sent via a switch 18, which will be described later, to a blue color difference signal (B-) in this example.
The 15th color difference signal (B-Y) of each field is supplied to the adder 19 provided in the transmission system of Y).
An identification signal ID, which is phase information corresponding to that field, is superimposed on the field.

In the reproduction system, it is encoded into a chroma signal C based on this identification signal ID.

FIG. 10 shows an example of a reproducing device 20 provided in a recording/reproducing device, in which terminals 21 and 22 are supplied with a luminance signal S _Y ′ and a compressed color difference signal S _C ′ reproduced from heads Ha and Hb. , these are supplied to the reproduction signal processing circuit 23. In other words, the compressed color difference signal
After S _C ' is FM demodulated by the demodulator 24, it is supplied to the time axis expander 25 and converted into a pair of color difference signals (R-Y) and (B-Y) whose time axis has been expanded twice. The pair of color difference signals (RY) and (B-Y) output from the reproduced signal processing circuit 23 are supplied to the encoder 26 and converted into a chroma signal C having color phase information.

Therefore, the blue color difference signal (B-Y) is further supplied to the identification signal ID detection circuit 27, and the identification signal ID obtained from this determines that the phase of the subcarrier in the encoder 26 is the reference phase for each field. controlled by.

On the other hand, the luminance signal Y which is FM demodulated by the demodulator 28
is supplied to the synthesizer 29 together with the chroma signal C, from which a video signal S _V in a standard signal format is output.

By the way, the video signal S _V to be recorded by the recording device 10 shown in FIG. There is a non-standard video signal (hereinafter referred to as a non-standard signal) in which the In the case of the standard signal, since the interleaving or color framing relationship between the luminance signal Y and the chroma signal C is the same, the identification signal ID output from the forming section 14
becomes regular phase information.

On the other hand, in the case of a non-standard signal with time axis fluctuations, that is, jitter, the luminance signal Y
The interleave or color framing relationship between the chroma signal C and the chroma signal C is originally not correct, and therefore the identification signal ID obtained from the forming section 14 is also not regular phase information.

For this reason, switch 1 shown in FIG.
8, identification signal ID only for standard signals
is recorded superimposed on the blue color difference signal (B-Y), and is not superimposed when it is a non-standard signal. Playback device 2 for non-standard signals
0, a pair of color difference signals (RY) and (B-Y) are modulated and converted into a chroma signal C based on a standard subcarrier.

[Problem that the invention attempts to solve]

Now, conventionally, the above-mentioned switch 18 is manually operated. In other words, the user using the recording device 10 judges the presence or absence of jitter in the video signal input to the recording device 10, turns on the switch 18 when a standard signal is supplied, and turns on the switch 18 when a non-standard signal is supplied. , the switch 18 is manually operated to turn off.

Therefore, if the presence or absence of jitter in a video signal is incorrectly determined, even if it is a non-standard signal with jitter, it may be determined to be a standard signal, increasing the probability of erroneous operation.

Furthermore, when manually operating the switch 18, the knob of the switch 18 must be placed on the operation panel surface of the recording device 10, which increases the number of switches. This would be inconvenient to provide the above-mentioned functions.

Therefore, this invention solves these conventional problems by automatically distinguishing between standard signals and non-standard signals and automatically switching the above-mentioned switch. The present invention proposes a recording device with an automatic discrimination function for standard video signals, which avoids erroneous operations and eliminates the need for knobs.

[Means for solving problems]

In order to solve the above-mentioned problems, in this invention, as shown in FIG. 1, a detection circuit 30 for detecting fluctuations in the time axis of the video signal is provided, and the switch 18 is controlled by the output _PS of the detection circuit 30.

As shown in FIG. 2, the detection circuit 30 includes a circuit 31 for forming an error voltage V _E corresponding to a time axis error;
It is comprised of a discrimination circuit 50 that discriminates between a standard video signal without time axis variation and a video signal with time axis variation by determining the magnitude of error voltage _VE .

[Effect]

According to this configuration, the error voltage V _E increases or decreases in response to the time axis error. In other words, when the time axis error is small, the voltage V _O when there is no time axis fluctuation is the center and fluctuates over a small range, whereas when the time axis error is large, the center voltage
An error voltage V _E that deviates significantly from V _O is output. Therefore, by distinguishing the magnitude of this error voltage, it is possible to easily and accurately determine whether the signal is a standard signal or a non-standard signal. The switch 18 is controlled to be turned on by the detection output P _S which is the discrimination output obtained when the standard signal is supplied.
Therefore, when the signal is a non-standard signal, the switch 18 is turned off and no identification signal is recorded.

〔Example〕

FIG. 1 is a system diagram showing an example of a recording apparatus 10 according to the present invention, and parts corresponding to those in FIG. 8 are given the same reference numerals, and their explanation will be omitted.

In this invention, as shown in FIG. 1, a time axis variation detection circuit 30 is provided, and the switch 18 is automatically controlled by its output _PS .

FIG. 2 shows an example of this detection circuit 30, and the error voltage forming circuit 31 is an AFC circuit composed of a PLL.

32 is a VCO, and the oscillation output (its frequency is, for example, 4sc (sc is a subcarrier frequency)) outputted from this VCO is supplied to a synchronization signal generator 33 to form a subcarrier, and a horizontal frequency signal P _H (the subcarrier frequency). 3A is shown as a horizontal synchronization signal for convenience of explanation) is formed. The horizontal synchronization signal P _H is outputted to the first monomulti 34 to form the monomulti output _MM1 shown in FIG. 3B, which is supplied to the boot strap circuit 35 to form the sawtooth signal PT shown in FIG. This is supplied to the sampling hold circuit 36.

On the other hand, a video signal S _V is supplied to the terminal 40,
This is supplied to a sync separation circuit 41 to separate a horizontal sync pulse P _H , which is then supplied to a half H killer circuit 42 to remove the 0.5H period horizontal sync pulse. This output is supplied to the second monomulti 43 to form the monomulti output MM ₂ shown in E of the figure, which is further supplied to the third monomulti 44 to generate a predetermined pulse width shown in D of the figure. A mono multi-output MM ₃ is formed with. The sawtooth signal PT is sampled at this mono multi-output MM ₃ .

The sampling hold output is supplied to the low-pass filter 38 via the amplifier 37, thereby generating an error voltage corresponding to the time axis error, that is, the amount of jitter, of the video signal S _V supplied to the terminal 40, that is, the horizontal synchronization pulse _PH . V _E is obtained.

The error voltage V _E is supplied to the VCO32, and
The signal is supplied to the discrimination circuit 50.

The discrimination circuit 50 has a window comparator 51, and the above-mentioned error voltage V _E is commonly supplied to the + terminals of a pair of comparators 52 and 53 forming the window comparator 51. One terminal of one comparator 52 is supplied with a reference voltage V _H shown in FIG. 4 that determines the upper limit of the window comparator, and one terminal of the other comparator 53 is supplied with a reference voltage V V _L is supplied.

The pair of comparison outputs W _H and W _L are supplied to an OR circuit 54 . However, the terminal to which the comparison output _WL is input is an inverted input terminal. The OR output is supplied to the retriggerable monomulti 55 as a trigger pulse.

Therefore, if the standard signal is now supplied to the terminal 40, there will be almost no jitter, so the error voltage V _E will be near the center voltage V _O shown in FIG.
As a result, the error voltage V _E is within the reference voltages V _H to _{V L} . Therefore, the comparison output W _H is “L”, and the comparison output
_WL becomes "H" and the OR output remains "L" and does not change. Therefore, the detection output P _S which is the discrimination output obtained at the output terminal 56 is "L", and in this example, the switch 18 is turned on by this detection output P _S .

When the switch 18 is turned on, the identification signal ID is superimposed on the blue color difference signal (RY).

On the other hand, the non-standard signal is at terminal 40.
In this case, there is a large amount of jitter, so if the horizontal frequency is higher than the reference horizontal frequency, the error voltage V _E will also increase with the amount of fluctuation, so one comparison output W _H will be “ “L” to “H”
, the OR output is inverted to "H", and the mono multi 55 is triggered. As a result, the detection output
P _S is inverted from "L" to "H", and the switch 18 is controlled to be off at this time.

Here, if the time constant of the monomulti 55 is set to a time of about 15H, the time axis will fluctuate over a period of 15H or more when the non-standard signal is present, so the monomulti 55 will continue to output or Continues to be triggered by output. As a result, the detection output P _S
remains “H” as long as a non-standard signal with a large amount of jitter continues to be supplied, and switch 1
8 maintains an off state, during which the identification signal ID is prohibited and is not superimposed on the color difference signal (B-Y).

Contrary to the above, if jitter occurs below the standard horizontal frequency, the error voltage V _E
becomes lower than the lower limit reference voltage V _L , so at this time, the comparison output W _L of the other comparator 53 is inverted from "L" to "H", and based on the OR output obtained accordingly, the monomulti 55 is “L” as above
The signal is reversed from "H" to turn off the switch 18.

For this reason, a pair of reference voltages V _H , V _L
By setting in advance a value close to the center voltage V _O ,
Standard signals and other non-standard signals can be reliably discriminated.

As in the conventional case, such an identification signal ID is detected by a detector 27 shown in FIG. 10 and used for encoding processing.

By the way, in the recording device 10 described above, when the Y/C separator 2 separates the luminance signal Y and the chroma signal C, a part of the chroma signal C remains in the luminance signal Y. When a luminance signal Y containing C is recorded and reproduced, the chroma signal C and the luminance signal Y are synthesized in the synthesizer 29 shown in FIG. The phase of the subcarrier of the residual chroma signal included in the luminance signal Y does not match the phase of the subcarrier of the residual chroma signal.

Therefore, a beat occurs between the subcarrier of the chroma signal C and the residual subcarrier, which significantly deteriorates the reproduced image quality. Cross colors also occur.

In order to improve image quality deterioration, it is sufficient to limit the luminance signal Y to a band that does not include residual chroma signals.

FIGS. 5 and 6 show an example of a recording device 10 that can also solve such problems.

In the example shown in FIG. 5, the band of the luminance signal Y is limited before recording on the tape 5, and the luminance signal Y separated by the Y/C separator 2 is sent to the low-pass filter 61. and the signal band containing the residual chroma signal is removed.

The luminance signal Y _L that has been band-limited by the low-pass filter 61 and the luminance signal Y that has not been band-limited are supplied to a switching circuit 62, which is controlled by the detection output P _S obtained from the time axis fluctuation detection circuit 30. Ru.

In other words, when it is a standard signal,
Since the switching circuit 62 is switched as shown, the luminance signal Y which is not band-limited is selected. On the other hand, when the signal is a non-standard signal, the band-limited luminance signal Y _L is selected and recorded. In the reproducing device 20, this luminance signal _YL is supplied to the synthesizer 29, so even when it is synthesized with the chroma signal C, subcarrier beats, cross colors, etc. do not occur. Therefore, the reproduced image quality does not deteriorate.

Note that 60 in the figure indicates the recording signal processing circuit of FIG.

FIG. 6 shows an example in which the band of the luminance signal Y is limited in the reproduction system.

In this example, in order to identify a non-standard signal on the playback device 20 side, an identification signal ID' is added on the recording device 10 side. Therefore, an identification signal ID' forming circuit 64 is provided on the recording device 10 side.

Identification signal ID′ is an identification signal for standard signals.
Although a signal unrelated to the ID is used, it is preferable in terms of signal processing that the superimposition timing and the like be the same as the identification signal ID, so this forming circuit 64 is configured similarly to the forming circuit 12 described above.

However, in a signal forming section (not shown) corresponding to the signal forming section 14 provided in the forming circuit 12, an identification signal unrelated to the phase information from the decoder 6 is generated.
To form ID', no subcarrier supply from the decoder 6 is required.

Identification signal ID formed by forming circuits 12 and 64,
ID' is selected by switch 18. That is, based on the detection output P _S , when the signal is a standard signal, the identification signal ID is selected, and when it is a non-standard signal, the identification signal ID' is selected and superimposed on the blue color difference signal (B-Y).

On the other hand, on the reproduction device 20 side, a low-pass filter 65 having frequency characteristics similar to that shown in _FIG . A switching circuit 66 that selects a luminance signal Y that is not subject to band limitations.
is provided, and this switching circuit 66 is switched and controlled by an identification signal ID'.

Therefore, in addition to the detection circuit 27 for the identification signal ID, a detection circuit 67 for the identification signal ID' is provided, and only when the identification signal ID' is detected, the switching circuit 66 is switched as shown in the figure to switch the band. The limited luminance signal Y _L and chroma signal C are combined.

When configured as shown in Figures 5 and 6,
Even in the case of a non-standard signal, since no residual chroma signal is included in the luminance signal Y, image quality deterioration due to subcarrier beats and cross colors does not occur.

[Effect of idea]

As explained above, according to the configuration of this invention, it is possible to accurately discriminate whether the video signal supplied to the recording device 10 is a standard signal or a non-standard signal, and therefore the switch 18 is activated based on the detection output _PS . If controlled, the identification signal can be reliably recorded in a superimposed manner when the standard signal is used.
On the contrary, when the signal is a non-standard signal, superimposition of the identification signal ID can be reliably prohibited.
Therefore, according to this invention, it is possible to form a chroma signal C with correct phase information.

According to this configuration, since switching of the switch 18 can be automatically controlled, there is no need to arrange a knob for controlling the switch on the panel surface, and therefore, this invention is suitable for application to a portable recording device. .

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of a recording device according to this invention, FIG. 2 is a system diagram showing an example of a time axis fluctuation detection circuit, FIG. 3 is a waveform diagram for explaining its operation, and FIG. 5 and 6 are system diagrams showing other examples of this invention, FIG. 7 is a waveform diagram of a video signal to explain this invention, and FIG. 8 is an explanatory diagram for explaining the operation of the discriminator circuit. FIG. 9 is a system diagram showing an example of a recording device for recording the video signal of FIG.
The figure is a waveform diagram of an identification signal, and FIG. 10 is a system diagram showing an example of a video signal reproducing apparatus. 10 is a recording device, 20 is a playback device, 12 is an identification signal ID forming circuit, 30 is a time axis variation detection circuit, 18 is a switch, 31 is an error voltage V _E forming circuit, 50 is a discrimination circuit, and 51 is a window. A do comparator, 55 is a retriggerable monomulti, and P _S is a detection output.

Claims (1)

[Scope of utility model registration request] In a recording device that compresses the time axis of at least one pair of component color signals out of a video signal consisting of a luminance signal and a pair of component color signals and records them on a tape, the color to be superimposed on one of the component color signals. A circuit for forming a framing identification signal is provided, as well as a detection circuit for detecting the presence or absence of a time axis fluctuation in the video signal, and this detection circuit includes a circuit for forming an error voltage corresponding to a time axis error, and a circuit for forming an error voltage corresponding to a time axis error. and a discrimination circuit that discriminates between a reference video signal with no time axis variation and a video signal with time axis variation by determining the magnitude of A recording device with an automatic discrimination function for standard video signals, in which an identification signal is superimposed on the component color signal.