JPS60236392A - Recording and reproducing device of carrier chrominance signal - Google Patents

Abstract

PURPOSE:To improve S/N of a reproduction carrier chrominance signal by executing the de-emphasis only with respect to a carrier chrominance signal for a period except a color burst signal transmission period. CONSTITUTION:An adder circuit 42 outputs a signal obtained by adding a reproduction carrier chrominance signal from a terminal 40 to that from a phase adjuster 48 to a switch circuit 49. On the other hand, a coefficient circuit 43 supplies an output carrier chrominance signal to the circuit 49. A reproduction horizontal synchronizing signal separated from a reproduction luminance signal arrives at a terminal 50, and is supplied to a burst gate pulse generator circuit 51. From a common terminal of the circuit 49 to an output terminal 25, the carrier chrominance signal from the circuit 42, to which a de-emphasis characteristic is given with respect to the reproduction carrier chrominance signal except a color burst signal input period of an input reproduction carrier chrominance signal, is fetched. For the color burst signal period, a reproduction color burst signal can be fetched from the circuit 43 to which the de-emphasis characteristic is not given.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a recording and reproducing device for a carrier color signal, and in particular, it pre-emphasizes the carrier color signal and records it on a magnetic recording medium, and when reproducing the reproduced carrier color signal, it is recorded on a magnetic recording medium. The present invention relates to a carrier color signal recording and reproducing apparatus that restores the original reproduced carrier color signal whose noise has been reduced through emphasis.

Conventional technology In a recording and reproducing device such as a VTR, a luminance signal and a carrier color signal are separated from a color video signal to be recorded and reproduced, each is subjected to predetermined signal processing, and then both signals are multiplexed for recording and reproduction. Conventionally, when carrying color signals,
Similar to the wi degree signal, line correlation has been used to reduce noise. In other words, since the reproduced carrier color signal usually has line correlation, but most of the noise mixed in the reproduced carrier color signal has no line correlation, the input/output reproduced carrier color of the 1H delay circuit Mix the signals and extract noise without line correlation,
By mixing this noise with the reproduced carrier color signal through a limiter, it is possible to extract a reduced reproduced carrier color signal in which the noise is canceled out.

However, in the conventional recording/reproducing apparatus having the above-mentioned noise reduction circuit, for a reproduced carrier color signal having no line correlation, signal components having no line correlation are also subtracted from the input reproduced carrier color signal along with the noise. Therefore, there was a problem in that the spatial frequency characteristics in the vertical direction (vertical resolution) deteriorated.

Therefore, the present applicant previously proposed a recording and reproducing apparatus for carrier color signals as shown in FIG. 8 in Japanese Patent Application No. 58-138872. In the figure, a color video signal of a standard television system (<NTSC system or PAL system) inputted to an input terminal 1 is supplied to a low-pass filter 2, where the luminance signal is separated, and then to a bandpass filter 3. The carrier color signals are separated and passed. The luminance signal is supplied to a recording luminance signal processing circuit 4, where it undergoes predetermined signal processing such as frequency modulation (FM). On the other hand, the carrier color signal is supplied to a pre-emphasis circuit 5, where, as will be described later, pre-emphasis is performed for each signal component appearing vertically on the screen at intervals of one horizontal scanning period (one day). After being given a pre-emphasis characteristic in which the high spatial frequency components are relatively enhanced in level compared to the low frequency components, they are supplied to the recording/carrying color signal processing circuit 6, where they are frequency converted to, for example, low frequencies. The signal is converted into a predetermined signal format suitable for magnetic recording and reproduction. The luminance signal and the carrier chrominance signal which are respectively converted into predetermined signal formats and taken out by the recording luminance signal processing circuit 4 and the recording carrier chrominance signal processing circuit 6 are supplied to the recording amplifier 7, where they are mixed and amplified, respectively. Thereafter, the data is recorded on the magnetic tape 9 by the recording rotary head 8.

On the other hand, during reproduction, the green signal recorded on the magnetic tape 9 is reproduced by the reproducing rotary head 10, and the reproduced signal is passed through a preamplifier 11 to a high-pass filter 12 and a low-pass filter 13.
supplied to For example, by using the high-pass filter 12, FMle
The i degree signal is divided into signal waves and demodulated into a luminance signal of the original band by the reproduced luminance signal processing circuit 14. On the other hand, the carrier color signal that has been low-pass converted and recorded by the low-pass filter 13 is separated from the reproduced signal, and this carrier color signal is supplied to the reproduced carrier color signal processing circuit 15, where it is also The signal is returned to the signal form and becomes a reproduced carrier color signal. The reproduced carrier color signal is supplied to a de-emphasis circuit 16;
Here, the high-frequency component of the vertical spatial frequency is relatively attenuated in level compared to the low-frequency component, and a characteristic complementary to the vertical spatial frequency versus level characteristic of the pre-emphasis circuit 5 is imparted. be done. Therefore, from the de-emphasis circuit 16, the pre-emphasized reproduced carrier color signal is returned to its original waveform before being pre-emphasized and is taken out and supplied to the mixing circuit 17, where it is sent to the reproduced luminance signal processing circuit 14. It is mixed with the reproduced luminance signal. As a result, a reproduced color video signal with lower noise components is outputted from the mixing circuit 17 to the output terminal 18.

Here, since the spatial frequency versus level characteristic in the vertical direction of the screen is de-emphasized by the de-emphasis circuit 16, the S/N ratio of the reproduced carrier color signal can be improved, and the de-emphasis circuit 16 also Since the vertical spatial frequency versus level characteristics are emphasized and recorded by the pre-emphasis circuit 5 provided in the recording system in advance, the S/N ratio is improved and the vertical spatial frequency characteristics are recorded at the output terminal 18. A reproduced color video signal without deterioration in spatial frequency versus level characteristics is extracted.

Next, the pre-emphasis circuit 5 will be explained.

FIG. 9 shows a block diagram of an example of the pre-emphasis circuit 5. In the figure, for example, N
The carrier color signal separated from the TSC color video signal is supplied to subtraction circuits 21 and 22, respectively. Subtraction circuit 21
The output carrier color signal is supplied to a one-day delay circuit 23, where it is delayed by one horizontal scanning period, and then multiplied by a coefficient of 1 (for example, 0.76) by a coefficient circuit 24 and sent to a phase adjuster 2.
5. The phase adjuster 25 is an unnecessary circuit if an accurate delay time of 1H can be obtained by the one-day delay circuit 23. However, the delay time actually obtained by the 1HN delay circuit 23 is not exactly one day, and in this case, the output signal of the coefficient circuit 24 is supplied to the subtraction circuit 21 without performing phase adjustment, and the output signal is subtracted from the input carrier color signal. When this operation is performed, the coefficient + is equivalently reduced, so that the required pre-emphasis characteristic cannot be obtained.

Therefore, by adjusting the phase of the output signal of the coefficient circuit 24 using the phase adjuster 25 so that it becomes the same as the phase of the carrier color signal delayed by one day, the desired pre-emphasis characteristic can be obtained. .

The subtraction circuit 21 performs a subtraction operation of subtracting the output signal of the phase adjuster 25 from the carrier color signal from the input terminal 20. Here, as is well known, the color subcarrier frequency of the carrier color signal in the NTSC system is 227.5 times the horizontal scanning frequency, and is 0.
．． Due to the fraction of 5, the phase of the color subcarrier at the beginning and end of 1H differs by 0.5 period, that is, 180°.

Therefore, if the carrier color signal extracted from the phase adjuster 25 is accurately delayed by one day and has a line correlation with the input carrier color signal from the input terminal 20, the carrier color signal is in an opposite phase relationship, and the subtraction circuit From 21, a carrier color signal that is substantially added to the carrier color signal 1H before is taken out. The output carrier color signal of this subtraction circuit 21 is supplied to a one-day delay circuit 23, and is also supplied to a coefficient circuit 26, where the coefficient is multiplied by 2 (for example, 0.14), and then the phase adjuster 2
7 to the subtraction circuit 22.

The subtraction circuit 22 performs a subtraction operation to subtract the output carrier color signal of the phase adjuster 27 from the input carrier color signal, and outputs the obtained signal to the output terminal 28 as a pre-emphasized carrier color signal. Here, the phase adjuster 27 is provided to accurately adjust the phase of the two-manually conveyed color signal in the subtraction circuit 22.

Further, the output signal of the output terminal 28 is: A carrier color signal to which a pre-emphasis characteristic is added in which the level of the high-frequency component of the spatial frequency in the vertical direction of the screen of the input carrier color signal is relatively enhanced compared to the low-frequency component. and is output as an output signal (preemphasized carrier color signal) of the pre-emphasis circuit 5.

Problems to be Solved by the Invention Here, the carrier color signal shown in FIG. 10(A) is supplied to the input terminal 20, and the carrier color signal has a strong H correlation of 1.
If a carrier color signal having the waveform shown in FIG. 10(A) is supplied to the input terminal 210 during any horizontal scanning period in the field, the output terminal 28 will receive the signal shown in FIG. 10(A) near the center of the screen, for example. A carrier color signal having the same waveform as the carrier color signal is extracted. However, even in the case of a carrier color signal input having a strong H correlation, the frequency characteristics of the one-day delay circuit 23 are not comparable to the frequency band of the input carrier color signal. If the delay time is narrow and it is not possible to provide a predetermined one-day delay characteristic, distortion such as smear will occur in the output of the one-day delay circuit 23, and the output terminal of the delatitude circuit 21 will have a distortion as shown in FIG. 10 (B). As shown in FIG. 10(C), a carrier color signal with a signal waveform with deteriorated transient characteristics appears, and furthermore, a carrier color signal with distortions such as overshoot and ringing is output from the subtraction circuit 22 to the output terminal 28 as shown in FIG. 10(C). In particular, this distortion becomes larger as the coefficient of the coefficient circuit 24 is increased in order to improve the signal-to-noise ratio (S/N ratio).
This contradicts the improvement in the degree of improvement in the N ratio. In particular, Figure 10 (A) ~
The distortion in the color burst signal shown as CB in (C) is
This poses a problem in that it interferes with the operation of a carrier color signal processing circuit (for example, an APC circuit, an ACC circuit) based on the amplitude and phase of a color burst signal, and deteriorates the quality of a reproduced image.

Further, if the input carrier color signal of the pre-emphasis circuit 5 is schematically illustrated for one field, it is as shown in FIG. 11(A), for example. Here, □ and FIG. 11 (A> indicate carrier color signals with the same saturation level for convenience of illustration, and the color burst signals during the period in which only the color burst signal is transmitted within the vertical blanking period are shown in the same figure. 29 in (A), and as is well known, the carrier color signals are the color burst signal and the carrier color signal in the video period (for convenience of explanation, this will be referred to as the "modulated color signal") except for the vertical blanking period. ) are synthesized alternately in time series, but in the same figure (A), for convenience of illustration, 30
As shown in (only the waveform of the modulated color signal is shown continuously, and the color burst signal waveform is omitted from the diagram.In reality, the modulated color signal is transmitted intermittently,
When observed with a small time axis on an oscilloscope, the first
As shown by 30 in FIG. 1(A), it appears to be continuous.

When the carrier color signal shown in FIG. 11(A) is passed through the pre-emphasis circuit 5, the color burst signal 29 of the first several H periods has a carrier color signal non-transmission period immediately before it, and the line correlation is As a result, the amplitude becomes larger than that of the subsequent color burst signal near the center of the screen, for example, as shown in FIG. 2B. This amplitude increase is suppressed together with the modulated color signal by the ACC circuit in the recording/carrying color signal processing circuit 6, as shown in FIG. 11(C), and then transmitted.
6, the color burst signal and the modulated color signal of several H periods at the beginning of the field of the reproduced carrier color signal lose the complementarity of emphasis, and the amplitude becomes lower than that at the time of recording as shown in FIG. 11(D). There was a problem in that the color at the top of the screen became lighter as a result.

SUMMARY OF THE INVENTION Therefore, the present invention provides a carrier color signal recording and reproducing apparatus that solves the above problems by substantially stopping the operation of the pre-emphasis circuit and de-emphasis circuit during the color burst signal transmission period. The purpose is to provide.

Means and Effects for Solving the Problems The present invention provides a recording system in which a carrier color signal is supplied, and the high frequency component of the vertical spatial frequency is compared to the low frequency component during a period excluding the color burst signal input period. A pre-emphasis circuit is provided to output the color burst signal with a relatively enhanced level, and to substantially stop the operation of the color burst signal. A color signal is supplied, and its color burst signal input agent r
The period excluding 1 has a characteristic of attenuating the level of the high-frequency component of the vertical spatial frequency relative to the low-frequency component, and provides a characteristic complementary to the characteristic of the pre-emphasis circuit, as well as the color burst. A de-emphasis circuit that can substantially stop the operation of the signal is provided, and pre-emphasis and de-emphasis are not performed on the color burst signal. This will be explained with reference to FIGS. 7 to 7.

Embodiment FIG. 1 is a block diagram of a first embodiment of the pre-emphasis circuit provided in the recording system of the apparatus of the present invention, and FIG. 3 is a block diagram of the first embodiment of the de-emphasis circuit provided in the reproduction system of the apparatus of the present invention. A block diagram is shown. The device of the present invention has a configuration similar to that shown in FIG. 8, but the configurations of the pre-emphasis circuit 5 and the de-emphasis circuit 16 are different from those of the recording/reproducing device proposed by the applicant. . In FIG. 1, the same components as those in FIG. 9 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 1, the carrier color signal entering the input terminal 20 is subtracted by
2, respectively, and the coefficient circuit 31.

For example, when a carrier color signal as shown in FIG. 2(A) is input, the coefficient circuit 31 selects one of the carrier color signals having a waveform as shown in FIG. 2(C) taken out from the subtraction circuit 22. It is provided to adjust the amplitude to be the same as the amplitude of a portion where distortion such as overshoot or ringing does not occur (that is, a waveform portion where no distortion due to transient response is observed) and output it. Therefore, the amplitude of the waveform portion of the output carrier chrominance signal of the subtraction circuit 22 in which no distortion due to the transient response is observed and the amplitude of the output carrier chrominance signal of the coefficient circuit 31 at the same time are approximately at the same level.

The carrier color signal to be pre-emphasized extracted from the subtraction circuit 22 is supplied to the terminal 32a of the switch circuit 32, while the carrier color signal extracted from the coefficient circuit 31 is simply level-adjusted without being given any pre-emphasis characteristics. The signal is supplied to terminal 32b of switch circuit 32. On the other hand, the horizontal synchronizing signal separated from the luminance signal to be recorded is supplied to the burst gate pulse generation circuit 34 via the input terminal 33, where it is connected to the input terminal 2 by known means.
Continuously during the same period of the color burst signal transmission period T1 in the input carrier color signal as shown in FIG. The period is low level, as shown in Figure 2 (B
) generates a burst gate pulse as shown in FIG. This burst gate pulse is applied to the switch circuit 32 as a switching pulse, and during its high level period (T+10T2), the input carrier color signal of the terminal 32b is selectively outputted.
During the low level period, the input carrier color signal as shown in FIG. 2(C) is selectively output from the terminal 32a.

As a result, from the common terminal of the switch circuit 32 to the output terminal 35, high spatial frequencies in the vertical direction are transmitted to the carrier color signal (modulated color signal) excluding the color burst signal input period of the input carrier color signal. A pre-emphasis characteristic that relatively enhances the level of the component compared to the low-frequency component is imparted, and the above-mentioned pre-emphasis characteristic is imparted to the color burst signal (indicated by CB in FIG. 2 (A>)). A conveyed color signal as shown in FIG. 2(D) consisting of a color burst signal that is not
CB indicates a color burst signal corresponding to the color burst signal in the input carrier color signal shown in FIG. 2(A). Furthermore, the burst gate pulse shown in FIG. It can be seen from FIGS. 2C and 2D that the distortion component present at the output terminal of the arithmetic circuit 22 can be removed by maintaining the high level for a certain period T2 after the end of the calculation.

According to this embodiment, since there is no distortion component due to pre-emphasis in the color burst signal at all, it is possible to solve the problems that occurred in the above-mentioned recording and reproducing apparatus for carrier color signals proposed by the present applicant. I can do it.

Next, a first embodiment of the de-emphasis circuit will be described with reference to FIG. In FIG. 3, a reproduced carrier color signal returned to the original band is input to a terminal 40, and this reproduced carrier color signal is transmitted to a subtracter circuit 41. Addition circuit 42 and coefficient circuit 43
are supplied respectively.

The output signal of the subtraction circuit 41 is fed back to the subtraction circuit 41 through a 44° coefficient circuit 45 and a phase adjuster 46 of the 1H delay circuit, while a coefficient circuit 47 and a phase adjuster 48
are supplied to the adder circuit 42 through the respective channels. Phase adjuster 46
Similarly to the phase adjuster 25, the coefficient LI of the coefficient circuit 45 is 0.87, and the coefficient 12 of the coefficient circuit 47 is 15'l. For example, it is 0.18.

The adder circuit 42 adds the reproduced carrier color signal from the input terminal 40 and the reproduced carrier color signal from the phase adjuster 48 and outputs the resulting signal to the terminal 49a of the switch circuit 49.

This output signal is a reproduced carrier color signal (de-emphasized (reproduction transport color signal).

Further, this de-emphasis characteristic is once complementary to the pre-emphasis characteristic in which the level is attenuated by the amount of level enhancement of the pre-emphasis characteristic.

On the other hand, the coefficient circuit 43 is provided for the same purpose as the coefficient circuit 31 and supplies its output carrier color signal to the terminal 49b of the switch circuit 49. Further, a reproduced horizontal synchronizing signal separated from the reproduced luminance signal enters the input terminal 50 and is supplied to the burst gate pulse generating circuit 51. The burst gate pulse generation circuit 51 has a circuit configuration similar to that of the burst gate pulse generation circuit 34, and is, for example, at a high level during the color burst signal transmission period in the reproduced carrier color signal and for a certain period immediately thereafter. During the other periods, a low-level burst gate pulse is generated and applied as a switching pulse to the switch circuit 49. During the high-level period, it is connected to the terminal 49b, and during the low-level period, it is connected to the terminal 49a.

As a result, from the common terminal of the switch circuit 49 to the output terminal 52, the addition circuit 42 is provided with the above-described de-emphasis characteristic for the reproduced carrier color signal excluding the color burst signal input period of the input reproduced carrier color signal. During the color burst signal transmission period, a reproduced color burst signal from the coefficient circuit 43 to which no de-emphasis characteristic is applied is extracted.

Next, a second embodiment of the apparatus of the present invention related to the invention set forth in claim 2 will be described. FIG. 4 is a block diagram of a pre-emphasis circuit of the recording system of the second embodiment of the apparatus of the present invention; FIG. 6 shows a block system diagram of a reproduction system de-emphasis circuit of a second embodiment of the apparatus of the present invention. Fourth
Figure, in Figure 6.

Components that are the same as those in FIGS. 1 and 3 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 4, a coefficient circuit 55 corresponds to the coefficient circuit 24, and its coefficient M1 is, for example, about 0.
76 were selected. Similarly, the coefficient circuit 56 is a circuit corresponding to the coefficient circuit 26, and its coefficient M2 is, for example, approximately 0.2.
4 has been selected.

The carrier color signal taken out from the subtraction circuit 22 is supplied to a non-linear circuit 57. The non-linear circuit 57 is, for example, an amplitude limiter that limits the amplitude of an input signal to a constant value, and is configured so that input signals having an amplitude smaller than this constant value are passed through and output as they are without amplitude limiting. ing. The carrier color signal taken out from the non-linear circuit 57 is multiplied by a coefficient M3 (for example, about 1.3) by a coefficient circuit 58, and then passed through a switch circuit 59, added to an adder circuit 60, and then outputted to an output terminal 61. Ru. This output terminal 61
The output signal is output as a carrier color signal to which a non-linear pre-emphasis characteristic is applied depending on the amplitude of the carrier color signal.

Here, when a carrier color signal as shown in FIG. 5(A) is input to the input terminal 20, the output terminal of the subtraction circuit 21 is
A signal No. 1 as shown in B) appears, and a signal as shown in FIG. 1C, which is the difference between the two signals shown in FIG. Delay circuit 23
When the frequency characteristics of the signal are insufficient, transient response distortion remains in this signal as well. The switching circuit 59 is controlled by the burst gate pulse from the burst gate pulse generating circuit 34, and is opened only during the color burst signal transmission period and a certain period immediately thereafter, and is closed during other periods. Therefore, a signal as shown in FIG. 5(D) is taken out from the switch circuit 59 and added to the adder circuit 6.
0.

As a result, the adder circuit 60 outputs a color burst ←
In the darkness of the #118 dark α column, a carrier color signal to which a non-linear pre-emphasis characteristic has been imparted is extracted, and in the color burst signal period, the color burst signal in the carrier color signal from the input terminal 20 is pre-emphasized. It is taken out as is without being exposed.

Next, to explain the second embodiment of the de-emphasis circuit shown in FIG. 6, coefficient circuits 65 and 66° correspond to coefficient circuits 45 and 47 in FIG. 3, respectively, and the coefficients N+ and N2 are For example, 0.87. It is selected as 0.13. The reproduced carrier color signal taken out from the subtraction circuit 42 is supplied to a coefficient circuit 68 through a non-linear circuit 67 having the same configuration as the non-linear circuit 57, where it is multiplied by a coefficient N3 (for example, 0.57) and then sent to a switch circuit. 69 to the subtraction circuit 55. The switch circuit 69 is opened by the gate pulse from the burst gate pulse generation circuit 51 only for a predetermined fixed period within the color burst signal transmission period of the reproduced carrier color signal and the period immediately after which the carrier color signal is not present. The transmission of the output signal of the coefficient circuit 68 to the subtraction circuit 70 is blocked, and the output signal of the coefficient circuit 68 is supplied to the subtraction circuit 70 by being closed during periods other than the above.

The subtraction circuit 70 performs a subtraction operation of subtracting the reproduced carrier color signal output from the switch circuit 69 from the reproduced carrier color signal from the input terminal 40 during periods other than the color burst signal transmission period and the fixed period immediately thereafter. A reproduced carrier color signal with a non-linear de-emphasis characteristic complementary to the pre-emphasis characteristic is generated, and this is sent to the output terminal 7.
Output to 1. Further, during the color burst signal transmission period, the subtraction circuit 70 outputs the color burst signal in the reproduced carrier color signal from the input terminal 40 as it is to the output terminal 71.

FIG. 7 shows a block system diagram of an embodiment of a circuit in which a pre-emphasis circuit and a de-emphasis circuit are each constructed using a common circuit. First, to explain the operation during playback, during playback, switches 76, 78, 92 and 93
are respectively switched and connected to the contact P side. As a result, the reproduced carrier color signal input to the input terminal 75 is transferred to the switch 76, the subtraction circuit 79, the IH delay circuit 80. The signal is supplied to a subtraction circuit 79 through a coefficient circuit 81 and a phase adjuster 82, where it is subtracted from the reproduced carrier color signal after 1H from the switch 76. The output signal of the subtraction circuit 79 is supplied to a one-day delay circuit 80, and is also supplied to a subtraction circuit 85 through a coefficient circuit 83 and a phase adjuster 84, where it is subtracted from the reproduced carrier color signal from the switch 76. After that, the nonlinear circuit 86
and is supplied to the switch circuit 88 through the coefficient circuit 87.

On the other hand, the reproduced horizontal synchronizing signal that has entered the input terminal 89 is supplied to the burst gate pulse generation circuit 90, where it is converted into a burst gate pulse similar to that of the burst gate pulse generation circuit 51, and then sent to the switch circuit 88 as a switching pulse. applied. As a result, the switch circuit 8
Reference numeral 8 performs opening/closing control similar to that of the switch circuit 69. Therefore, only the signals in transmission periods other than the color burst signal transmission period pass through the switch circuit 88 and pass through the subtraction circuit 91.
The signal is then subtracted from the reproduced carrier color signal from switch 76. Therefore, during periods other than the color burst signal transmission period, the subtraction circuit 91 extracts a reproduced carrier color signal with non-linear de-emphasis characteristics, similar to the output signal of the subtraction circuit 70 shown in FIG. , are output to the output terminal 94 through the switch 93. According to this embodiment, by providing the non-linear circuit 86, it is possible to reduce the rate at which the de-emphasis circuit cannot restore the original waveform (for example, if the gain of the differential amplifier 77 is G, then 1/G ).

On the other hand, during recording, the switches 76, 78, 92 and 93 are connected to the contact R side, respectively. As a result, the input terminal 75
The carrier color signal inputted to the switch 76 and the differential amplifier 7
7. Switch 78. Subtraction circuit 79, IH delay circuit 80.
The signal is supplied to a subtraction circuit 79 through a coefficient circuit 81 and a phase adjuster 82, respectively. The carrier color signal taken out from the subtraction circuit 79 is supplied to a one-day delay circuit 80, and is also supplied to a subtraction circuit 85 through a coefficient circuit 831 and a phase adjuster 84, where the carrier color signal from the switch 78 is After being subtracted, the signal is supplied to the non-linear circuit 86.

The non-linear circuit 86 has the same configuration as the non-linear circuits 57 and 67, and the output carrier color signal of the subtraction circuit 85 is extracted with the amplitude of a portion larger than a constant value being limited in amplitude, and further passed through the coefficient circuit 87 to the switch circuit. 88. on the other hand,
A horizontal synchronizing signal to be recorded is separated and input to the input terminal 89 and supplied to the burst gate pulse generating circuit 90 .

During recording, the burst gate pulse generation circuit 90 generates the same pulse as the burst gate pulse from the burst gate pulse generation circuit 34, and supplies this to the switch circuit 88 as a switching pulse. Therefore, the switch circuit 87 passes only the output signal of the coefficient circuit 87 during the period other than the color burst signal transmission period and supplies it to the subtraction circuit 91, where it is subtracted from the carrier color signal from the switch 78.

The output signal of subtraction circuit 91 is supplied to the inverting input terminal of differential amplifier 77 through switch 92. This circuit obtains a pre-emphasis characteristic which is the opposite characteristic by inserting a de-emphasis circuit during reproduction into the feedback loop of the differential amplifier 77. Therefore, the signal outputted from the differential amplifier 77 to the output terminal 94 through the switch 93 becomes a non-linear pre-emphasized carrier color signal during periods other than the color burst signal transmission period, as in FIG.
During the color burst signal transmission period, the color burst signal is non-linearly pre-emphasized. In addition, each coefficient 0+, 02 and 03 of coefficient circuit 81.83 and 87
are each, for example, 0.87.

0.13 and 0.57.

In the above embodiment, the de-emphasis circuit having the configuration shown in FIG. 6 is put into the feedback loop of the differential amplifier 77 to obtain the pre-emphasis characteristic, but the pre-emphasis circuit having the configuration shown in FIG. The differential amplifier 77
The de-emphasis characteristic may be obtained by putting the signal into a feedback loop.

Note that the present invention is not limited to the above-described embodiments; for example, although the phase adjuster is provided on the output side of the coefficient circuit in all the embodiments, it may be provided on the input side of the coefficient circuit.

Furthermore, although the above embodiments have been described with respect to the case where the carrier color signal of the NTSC system is pre-emphasized and de-emphasized, the present invention can also be applied to the carrier color signal of the PAL system. However, in this case, in the carrier color signal of the PAL system, the phase of the color subcarrier of one of the two color difference signals is inverted every day, so the delay circuits 23°44.80 are It is configured to have a delay time that is a natural number times 2H. Also, non-linear circuit 57°67.
86 is not limited to an amplitude limiter.

Effects of the Invention As described above, according to the present invention, pre-emphasis and de-emphasis are performed on the spatial frequency in the vertical direction only for the carrier color signal in the period excluding the color burst signal transmission period. Similar to the device proposed by the present applicant, it is possible to improve the S/N ratio of the reproduced carrier color signal by improving the vertical direction by de-emphasis, as in the conventional noise reduction circuit using line correlation. Even if a delay circuit is used that does not reduce the spatial frequency characteristics (vertical resolution) of the color burst, and its frequency characteristics are such that it can transmit the carrier color signal without distortion, color burst Since the above-mentioned pre-emphasis and de-emphasis are not performed on the signal, the color burst signal does not suffer from distortion due to deterioration of transient characteristics, and therefore the carrier color signal based on the amplitude and phase of the color burst signal without causing any hindrance to the operation of processing circuits (APC circuits, ACC circuits, etc.).
It is possible to prevent deterioration of the reproduced image quality, and since the amplitude of the color burst signal is the same as that in other periods even during the first number HJllff of the t field, the operation of the ACC circuit is It does not have any influence, and therefore the complementarity of emphasis can be improved. Furthermore, in a recording and reproducing apparatus equipped with only one of a nonlinear pre-emphasis circuit and a non-linear de-emphasis circuit, the amplitude of the carrier color signal is not so emphasized when recorded or reproduced. It is possible to reproduce the carrier color signal reproduced from a magnetic tape into the original signal waveform without any practical problem even if it passes through a non-linear de-emphasis circuit. It has the advantage that it can be reproduced into the original carrier color signal waveform with almost no practical problems, and can therefore be reproduced compatible with current VTRs.

[Brief explanation of the drawing]

1 and 3 are block system diagrams showing the main parts of the recording system and reproduction system of the first embodiment of the apparatus of the present invention, respectively, and FIG. 2 is a signal waveform diagram for explaining the operation of the block system shown in FIG. 1. , 4th
6 and 6 are block system diagrams respectively showing the main parts of the recording system and reproducing system of the second embodiment of the apparatus of the present invention, and FIG.
7 is a signal waveform diagram for explaining the operation of the illustrated block system. FIG. 7 is a block system diagram of the main part of the third embodiment of the device of the present invention.
The figure is a block system diagram showing an example of a carrier color signal recording/reproducing device previously proposed by the applicant, and FIG. 9 is a block system diagram showing an example of the main part of the recording system of the device proposed by the applicant. , FIG. 10 is a signal waveform diagram for explaining the operation of the block system shown in FIG. 1, and FIG. 11 is a signal waveform diagram for explaining the operation of the block system shown in FIGS. 8 and 9. DESCRIPTION OF SYMBOLS 1... Color video signal input terminal, 2... Low-pass filter for luminance signal separation, 3... Bandpass filter for carrier color signal separation, 5... Pre-emphasis circuit, 6... Recording carrier color signal Processing circuit, 9... Magnetic tape, 16... De-emphasis circuit, 18... Reproduction color video signal output terminal, 20... Transport color signal input terminal, 21.22°41.70.79,85 .91...Subtraction circuit, 23°44.80...1 day delay circuit, 24,26.31°4
3.45, 47.55.56, 58.65°66.68
．． 81.83.87...Coefficient circuit, 25°27.46
, 48, 82.84... Phase adjuster, 28.35.6
1...Pre-emphasis carrier color signal output terminal, 32
．． 49,59.69,76°78.8B,92.93・
...Switch circuit, 33゜89...Horizontal synchronization signal input terminal, 34.51.90...Burst gate pulse generation circuit, 40...Reproduction carrier color signal input terminal, 42.6
0...Addition circuit, 50...Reproduction horizontal synchronization signal input,
Terminal, 52.71...De-emphasized carrier color signal output terminal, 57.6786...Non-linear circuit, 77...
・Differential amplifier. Figure 1 Figure 9 Figure 10 → Kanoaki

Claims (1)

[Claims] (1) The carrier color signal separated from the color video signal is converted into a predetermined signal format and recorded on a recording medium, and during playback, the reproduced carrier color signal in the original signal format is reproduced from the reproduced signal reproduced from the recording medium. In a recording/reproduction device for a carrier color signal, the recording system is supplied with the carrier color signal, and the carrier color signal in a period other than the color burst signal input period has a high-frequency component of spatial frequency in the vertical direction. a pre-emphasis circuit that outputs the color burst signal with its level enhanced relatively compared to the low frequency component, and substantially stops its operation for the color burst signal and outputs the color burst signal without imparting the level enhancement characteristic. The reproduced carrier color signal restored to the original signal form is supplied to the reproduction system, and the reproduced carrier color signal in the period excluding the color burst signal period has a high spatial frequency in the vertical direction. A characteristic for relatively attenuating the level of high-frequency components compared to low-frequency components, which imparts characteristics complementary to the characteristics of the pre-emphasis circuit, and to the color burst signal in the reproduced carrier color signal. A recording and reproducing device for a carrier color signal, characterized in that it is provided with a de-emphasis circuit which substantially stops its operation and outputs the signal without imparting the level attenuation characteristic. ■ Converting the carrier color signal separated from the color video signal into a predetermined signal format and recording it on a recording medium, and upon reproduction, obtaining a reproduced carrier color signal in the original signal format from the reproduced signal reproduced from the recording medium. In a carrier color signal recording/reproducing device, the above-mentioned carrier color signal is supplied to the recording system, and the high-frequency components of the spatial frequency in the vertical direction are reduced for the carrier color signal in a period excluding the color burst signal input period. The level is relatively enhanced and outputted according to the amplitude of the carrier color signal compared to the color burst signal, and the operation is substantially stopped for the color burst signal to perform the non-linear level enhancement. A pre-emphasis circuit is provided to output the signal without imparting characteristics, and the reproduction system is supplied with the reproduced carrier color signal returned to the original signal form, and the reproduced carrier color signal for the period excluding the color burst signal period is supplied to the reproduction system. is a characteristic in which the high frequency component of the vertical spatial frequency is compared with the low frequency component, and the level is relatively attenuated according to the amplitude of the reproduced carrier color signal, which is complementary to the characteristic of the pre-emphasis circuit. imparting non-linear characteristics, and
The invention is characterized in that a de-emphasis circuit is provided which substantially stops the operation of the color burst signal in the reproduced carrier color signal and outputs the color burst signal without imparting the non-linear level attenuation characteristic. Recording and reproducing device for carrier color signals.