JPH0347037B2 - - Google Patents

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 de-emphasizes the reproduced carrier color signal during reproduction. The present invention relates to a carrier color signal recording and reproducing apparatus for restoring the original reproduced carrier color signal with reduced noise.

BACKGROUND TECHNOLOGY In a recording and reproducing apparatus 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 and recorded. In the case of reproduction, noise has conventionally been reduced using line correlation for the carrier color signal in the same way as for the luminance signal. 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 By mixing the signals to extract noise that has no line correlation and 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 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. 6 in Japanese Patent Application No. 138872/1982. In the figure, the standard television system (NTSC system or PAL system) input to input terminal 1
The color video signal is supplied to a low-pass filter 2 to separate the luminance signal, and is supplied to a bandpass filter 3 to separate the carrier color signal. 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 the pre-emphasis circuit 5, where it appears in the vertical direction on the screen for one horizontal scanning period (1H), as will be described later.
Pre-emphasis is performed for each signal component at intervals, and after being given a pre-emphasis characteristic in which the level of the high-frequency component in the vertical direction is relatively enhanced compared to the low-frequency component, the recording conveyance color signal processing circuit 6 is given pre-emphasis characteristics. Here, it is converted into a predetermined signal form suitable for magnetic recording and reproduction, such as frequency conversion to a low frequency band. 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 rotary recording head 8.

On the other hand, during reproduction, the already recorded signal on the magnetic tape 9 is reproduced by the rotary reproduction head 10, and the reproduced signal is passed through the preamplifier 11 to the high-frequency filter 1.
2, supplied to the low-pass filter 13; For example, an FM luminance signal is separated by a high-pass filter 12 and demodulated into a luminance signal of the original band by a reproduced luminance signal processing circuit 14. On the other hand, the low-pass filter 13
For example, the carrier color signal that has been low-pass converted and recorded 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 returned to its original signal form. This becomes the reproduced transport color signal. The reproduced carrier color signal is supplied to the de-emphasis circuit 16, where the high-frequency component of the vertical spatial frequency has a characteristic that the level is relatively attenuated compared to the low-frequency component.
is given a characteristic that is complementary to the vertical spatial frequency versus level characteristic of . Therefore, from the de-emphasis circuit 16, the reproduced carrier color signal which has been pre-emphasized is restored to its original waveform before being pre-emphasized and is taken out and supplied to the mixing circuit 17 where it is extracted from the reproduced luminance signal processing circuit 14. Mixed with the reproduced luminance signal. As a result, mixing circuit 1
7 to an output terminal 18, a reproduced color video signal with noise components reduced in frequency is taken out.

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 can improve the S/N ratio. Since the spatial frequency versus level characteristic in the vertical direction is emphasized and recorded by the pre-emphasis circuit 5 provided in advance in the recording system, the S/N ratio is improved and the spatial frequency in the vertical direction is output to the output terminal 18. A reproduced color video signal with no deterioration in level characteristics is extracted.

Next, the pre-emphasis circuit 5 will be explained. FIG. 7 shows a block diagram of an example of the pre-emphasis circuit 5. In the figure, a carrier color signal separated from, for example, an NTSC color video signal input to an input terminal 20 is supplied to subtraction circuits 21 and 22, respectively. The output carrier color signal of the subtraction circuit 21 is supplied to a 1H delay circuit 23, where it is delayed by one horizontal scanning period, and then the coefficient circuit 24 outputs a coefficient.
The signal is multiplied by K ₁ (for example, 0.76) and supplied to the phase adjuster 25 . The phase adjuster 25 is a 1H delay circuit 23
This circuit is unnecessary if a delay time of 1H can be obtained accurately. However, the delay time actually obtained by the 1H delay circuit 23 is not exactly 1H, and in this case, the delay time obtained by the subtraction circuit 23 without performing phase adjustment.
If the output signal of the coefficient circuit 24 is supplied to the input carrier color signal and a subtraction operation is performed on the input carrier color signal, the coefficient _K1 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 1H, 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 due to the fraction of 0.5, the color subcarrier has a phase of 0.5 period at the beginning and end of 1H. In other words, they differ by 180°. Therefore, if the carrier color signal extracted by the phase adjuster 25 after being delayed by 1H is line-correlated with the input carrier color signal from the input terminal 20, the carrier color signal is in an opposite phase relationship, and the carrier color signal is outputted from 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 1H
The signal is supplied to the delay circuit 23, and also to the coefficient circuit 26, where it is multiplied by a coefficient K ₂ (for example, 0.14) and then supplied to the subtraction circuit 22 through the phase adjuster 27.

The subtraction circuit 22 performs a subtraction operation of subtracting 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-input carrier color signal in the subtraction circuit 22.
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. , is output as an output signal (pre-emphasized carrier color signal) of the pre-emphasis circuit 5.

Problems to be Solved by the Invention Here, the carrier color signal supplied to the input terminal 20 has a waveform as shown in FIG. 8A. In the figure, the period
a ₁ is a vertical blanking period, period a ₂ is a portion of the vertical blanking period where a vertical synchronizing pulse and an equivalent pulse exist, and period a ₃ is a portion where a color burst signal exists. Further, period _a4 is a vertical scanning period in which a color burst signal and a carrier color signal are present. The carrier color signal shown in FIG. 8A has a waveform as shown in FIG. 8B by amplifying the level of the high frequency component of the vertical spatial frequency compared to the low frequency component in the pre-emphasis circuit shown in FIG. 7. is output from the terminal 28. In the case of a rotating two-head type video tape recorder, the carrier color signal shown in _FIG . The phase of the reproduced carrier color signal is discontinuous before and after. Here, if the vertical time constant and level enhancement degree of the pre-emphasis circuit are set to values that can sufficiently reduce noise, the signal of the previous field becomes the signal of the vertical scanning period of the next field following the switching point. This affects even the beginning of the playback screen, causing hue and amplitude disturbances at the top of the playback screen.
Another problem was that the horizontal period also varied due to ski distortion.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a recording/reproducing circuit for carrier color signals which solves the above-mentioned problems by making the operations of the pre-emphasis circuit and de-emphasis circuit different between the vertical scanning period and the vertical blanking period. shall be.

Means and Effects for Solving the Problems The present invention provides a recording system in which one or both of a vertical time constant and a level enhancement degree for a predetermined period including at least a vertical blanking period is different from that for a period other than the predetermined period. A pre-emphasis circuit is provided, which is smaller than the time constant and the degree of level enhancement, and outputs the high-frequency component of the vertical spatial frequency of the supplied carrier color signal with a relatively level-enhanced level compared to the low-frequency component. The reproduction system has characteristics complementary to the characteristics of the pre-emphasis circuit for each period in the predetermined period and other periods, and the reproduction system has characteristics that are complementary to the characteristics for each period of the pre-emphasis circuit, and the reproduction system has characteristics that are complementary to the characteristics of the pre-emphasis circuit for each period. This embodiment is provided with a de-emphasis circuit that outputs a high-frequency component at a level relatively attenuated compared to a low-frequency component, and each embodiment will be explained with reference to FIG. 1 and the following.

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. 2 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. Show the diagram. The apparatus of the present invention has the same configuration as that shown in FIG. 6, but the configurations of the pre-emphasis circuit 5 and the de-emphasis circuit 16 are different from those of the recording/reproducing apparatus proposed by the applicant. In FIG. 1, the same components as those in FIG. 7 are denoted by the same reference numerals, and their explanations will be omitted. 1st
In the figure, the carrier color signal delayed by 1H in the 1H delay circuit 23 is supplied to the terminal 30a of the switch circuit 30. This carrier color signal is taken out from the terminal 30b or 30c of the switch circuit 30. terminal 30
The signal extracted from b is sent to the coefficient circuit 24 as a coefficient.
The signal is multiplied by K ₁ (for example, 0.76), and the signal taken out from the terminal 30c is multiplied by a coefficient K ₃ (for example, 0.56) in the coefficient circuit 31 and then supplied to the phase adjuster 25.

Further, the output carrier color signal of the subtraction circuit 21 is supplied to the No. 1 delay circuit, while the coefficient circuit 26 outputs a coefficient
Switch circuit 3 after being multiplied by K ₂ (for example 0.14)
The signal is supplied to the terminal 32b of the switch circuit 32, multiplied by a coefficient _K4 (for example, 0.69) in the coefficient circuit 33, and then supplied to the terminal 32c of the switch circuit 32. The switch circuit 32 takes out a signal from either the terminal 32b or 32c from the terminal 32a and supplies it to the phase adjuster 27.

Further, a switching pulse as shown in FIG. 8D with a frequency of 30 Hz and a duty ratio of 50%, for example, generated from the rotation detection signal of the rotating drum is input to the terminal 34, and is supplied to the pulse generating circuit 35. The pulse generating circuit 35 detects the rising and falling edges of the switching pulse, generates a vertical blanking pulse as shown in FIG. . Each of the switch circuits 30 and 32 connects the terminal 3 during the L level period of the vertical blanking pulse.
0a and 30b, 32a and 32b are connected, and terminals 30a and 30c, 32a and 32c are connected during the H level period.

Therefore, in the vertical period, the coefficient circuits 24, 2
6, and the vertical time constant and level enhancement of the pre-emphasis circuit are the same as the circuit shown in FIG. Furthermore, during the vertical blanking period, the coefficient circuits 31 and 3
3, and the vertical time constant and level enhancement degree of the pre-emphasis circuit at this time are about half of those of the circuit shown in FIG. As a result, the carrier color signal outputted from the terminal 28 shown in the first diagram has a waveform as shown in FIG. 8C. Even in the carrier color signal shown in FIG. 8C, the phase before and after the switching point is discontinuous, but the signal of the previous field does not affect the beginning of the signal of the vertical scanning period of the next field.

Next, a first embodiment of the de-emphasis circuit will be described with reference to FIG. In FIG. 2, a reproduced carrier color signal restored to its original band is inputted to a terminal 40, and this reproduced carrier color signal is supplied to a subtraction circuit 41 and an addition circuit 42, respectively. The output signal of the subtraction circuit 41 is passed through the 1H delay circuit 43 to the switch circuit 4.
The signal is supplied to the terminal 44a of the switch circuit 44, and taken out from the terminal 44b or 44c of the switch circuit 44. terminal 4
The signals taken out from 4b and 44c pass through coefficient circuits 45 and 46, respectively, and further pass through a phase adjuster 47 and are fed back into a subtraction circuit 47. Further, the output signal of the subtraction circuit 41 is passed through the coefficient circuits 48 and 49 to the terminals 50b and 50c of the switch circuit 50.
terminal 50b of the switch circuit 50.
or 50c is taken out from the terminal 50a and passed through the phase adjuster 51 to the adder circuit 4.
2. The coefficients L ₁ and L ₃ of the coefficient circuits 45 and 46 are, for example, 0.87 and 0.74, and the coefficients L ₂ and L ₄ of the coefficient circuits 48 and 49 are, for example, 0.13 and 0.74, respectively.
It is said to be 0.26.

Also, the switching pulse entering terminal 52 is supplied to a pulse generator 53, where the switching pulse in FIG.
Vertical blanking pulses similar to those shown in FIG. 1 are generated and supplied to switch circuits 44 and 50, respectively. Switch circuits 44 and 50 are connected to terminals 44a and 44b, 50a and 50b, respectively, during the L level period of the pulse.
and connect terminals 44a and 44c during the H level period.
Connect 50a and 50c.

Therefore, the reproduced carrier color signal is weighted by coefficient circuits 45 and 48 during the vertical scanning period. During the vertical blanking period, weighting is performed by coefficient circuits 46 and 49, and the time constant and level enhancement degree in the vertical direction at this time are about half of those when coefficient circuits 45 and 48 are used.

The adder circuit 42 adds the reproduced carrier color signal from the input terminal 40 and the signal from the phase adjuster 51, and outputs the resulting signal from the terminal 54. This output signal is a reproduced carrier color signal (de-emphasized reproduced carrier) to which a de-emphasis characteristic is applied, in which the high-frequency component of the spatial frequency in the vertical direction of the screen of the input reproduced carrier color signal is relatively attenuated in level compared to the low-frequency component. color signal). Furthermore, this de-emphasis characteristic when coefficient circuits 45 and 48 are used is exactly complementary to the pre-emphasis characteristic when coefficient circuits 24 and 26 are used in the circuit shown in FIG. Coefficient circuit 3 when using
This characteristic is exactly complementary to the pre-emphasis characteristic when using 1,33.

As a result, from the terminal 54, during the vertical scanning period,
A carrier color signal to which a de-emphasis characteristic complementary to the pre-emphasis characteristic is applied is extracted during each vertical blanking period.

Next, a second embodiment of the inventive apparatus according to the invention set forth in claim 2 will be described. FIG. 3 is a block diagram of a pre-emphasis circuit of the recording system of the second embodiment of the inventive apparatus. FIG. 4 shows a block system diagram of a regenerated yarn de-emphasis circuit according to a second embodiment of the apparatus of the present invention. In FIGS. 3 and 4, the same parts as in FIGS. 1 and 2 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 3, coefficient circuits 55 and 56 correspond to the coefficient circuit 24, and the coefficient M ₁ is, for example, about 0.76, and the coefficient M ₃ is, for example,
0.31 respectively. Similarly, coefficient circuit 5
7 and 58 are circuits corresponding to the coefficient circuits 26 and 33, respectively, and the coefficient M ₂ is selected to be approximately 0.24, and the coefficient M ₄ is selected to be approximately 0.69, respectively.

The carrier color signal taken out from the subtraction circuit 22 is
It is supplied to non-linear circuits 59 and 60, respectively. The non-linear circuits 59 and 60 are, for example, vibration limiters that limit the amplitude of an input signal to a constant value, and input signals with an amplitude smaller than this constant value are passed through and output as they are without amplitude limiting. It is configured like this. The fixed value limited by the non-linear circuit 59 is set to a level smaller than the fixed value limited by the non-linear circuit 60. The carrier color signals taken out from the nonlinear circuits 59 and 60 are multiplied by coefficients M ₅ (for example, 1.3) and M ₆ (for example, 1.6) by the coefficient circuits 61 and 62, respectively, and then sent to the terminals 63b and 63 of the switch circuit 63.
c. The switch circuit 63 connects the terminals 63a and 63b during the L level period of the vertical blanking pulse supplied from the pulse generating circuit 35, and connects the terminals 63a and 63c during the H level period. The carrier color signal taken out from the terminal 63a of the switch circuit 63 is supplied to the adder circuit 64, where it is added to the carrier color signal from the input terminal 20, and then output from the output terminal 65.

Therefore, the carrier color signal outputted from the output terminal 65 is transmitted to the coefficient circuits 55 and 5 during the vertical scanning period.
7, 61 and the non-linear circuit 59 provide a non-linear pre-emphasis characteristic according to the amplitude, and the vertical time constant and level enhancement degree of this non-linear pre-emphasis characteristic are set to values sufficient for noise reduction. Also, during the vertical blanking period, a non-linear pre-emphasis characteristic is provided by the coefficient circuits 56, 58, 62 and the non-linear circuit 60, and the vertical time constant and level enhancement degree of this non-linear pre-emphasis characteristic are equal to 1 in the vertical period. It is said to be around /2. Therefore, the signal of the previous field does not affect the signal of the next field in the vertical scanning period.

Next, the second de-emphasis circuit shown in FIG.
To explain the embodiment, the coefficient circuits 66, 6
7, 68, and 69 are coefficient circuits 45 and 4 in FIG. 2, respectively.
In the coefficient circuit corresponding to 6, 48, 49, the coefficient
N ₁ , N ₂ , N ₃ , N ₄ are, for example, 0.87, 0.55, 0.13, respectively.
It is selected as 0.45. The reproduced carrier color signal taken out from the subtraction circuit 77 is sent to non-linear circuits 59 and 60.
They are supplied to coefficient circuits 72 and 73 through nonlinear circuits 70 and 71 having the same configuration, respectively, and are multiplied by coefficients N ₅ (for example, 0.57) and N ₆ (for example, 0.60), and then supplied to terminal 74b of switch circuit 74. ,74c
supplied to each. The switch circuit 74 connects the terminals 74a and 74b during the L level period of the vertical blanking pulse supplied from the pulse generating circuit 53, and connects the terminals 74a and 74c during the H level period, and the carrier color signal taken out from the terminal 74a. is supplied to the subtraction circuit 75. The subtraction circuit 75 receives the carrier color signal through the coefficient circuits 66, 68, 72 and the non-linear circuit 70 during the vertical scanning period, and the carrier color signal through the coefficient circuits 67, 69, 73 and the non-linear circuit 71 during the vertical blanking period. Input terminal 4 respectively
By performing a subtraction operation from the reproduced conveyance color signal starting from 0, the reproduced conveyance is given a nonlinear de-emphasis characteristic that is complementary to the nonlinear pre-emphasis characteristic of the vertical scanning period and the vertical blanking period of the circuit shown in the third diagram. A color signal is generated and output from the output terminal 76.

FIG. 5 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. To explain the operation during reproduction, during reproduction, the switch circuits 81, 83, 103, and 104 are respectively switched and connected to the contact P side. As a result, the reproduced carrier color signal that has entered the input terminal 80 is supplied to the terminal 86a of the switch circuit 86 through the switch circuit 81, the subtraction circuit 84, and the 1H delay circuit 85, and is taken out from the terminals 86b and 86c of the switch circuit 86, respectively. It will be done. The signals taken out from terminals 86b and 86c, respectively, pass through coefficient circuits 87 and 88, respectively, and are fed back to subtraction circuit 84 through phase adjuster 89. The output signal of the subtraction circuit 84 is sent to the coefficient circuits 90, 9.
1 through each terminal 92b of the switch circuit 92,
92c, and the signal from either terminal 92b or 92c of switch circuit 92 is supplied to terminal 92c.
2a, and is supplied to a subtraction circuit 94 through a phase adjuster 93, where it is subtracted from the reproduced carrier color signal from the switch circuit 81. The output signal of the subtraction circuit 94 is supplied to the terminals 99b, 99c of the switch circuit 99 from the nonlinear circuits 95, 96 through the coefficient circuits 97, 98, respectively, and the signal taken out from the terminal 99a of the switch circuit 99 is supplied to the subtraction circuit 10.
0.

On the other hand, the pulse generation circuit 102
Vertical blanking pulses similar to those shown in FIG. 8E are generated from the incoming switching pulses and supplied to switch circuits 86, 92, and 99, respectively. As a result, during the vertical scanning period, the terminals 86a, 86b, 9 of the switch circuits 86, 92, 99, respectively.
2a and 92b, 99a and 99b are connected, and during the vertical blanking period, terminals 86a, 86c, 9
2a and 92c, and 9a and 99c are connected, respectively. In this way, during the vertical scanning period, the non-linear circuit 9
5. The signals passed through the coefficient circuit 97 and the signals passed through the non-linear circuit 96 and the coefficient circuit 98 during the vertical blanking period are subtracted from the reproduced carrier color signal from the switch circuit 81. Therefore, from the subtraction circuit 100, a reproduced conveyance color signal to which different non-linear de-emphasis characteristics are applied during the vertical scanning period and the vertical blanking period is taken out, similar to the output signal of the subtraction circuit 75 shown in FIG. The signal is then output from the output terminal 105.

On the other hand, during recording, switch circuits 81, 83, 1
03 and 104 are respectively connected to the contact R side. As a result, the carrier color signal input to the input terminal 80 is
Switch 81, differential amplifier 82, switch circuit 8
3. Subtraction circuit 84, 1H delay circuit 85, switch circuit 86, coefficient circuit 87 or 88, phase adjuster 8
9 and are supplied to the subtracting circuit 84. The carrier color signal taken out from this subtraction circuit 84 is 1H.
is supplied to the delay circuit 85, while the coefficient circuits 90,
91 respectively, and this coefficient circuit 90 or 91
The passed signal is supplied from the switch circuit 92 via the phase adjuster 93 to the subtraction circuit 94, where it is subtracted from the carrier color signal from the switch 81 and then supplied to non-linear circuits 95 and 96, respectively.

The nonlinear circuits 95 and 96 are nonlinear circuits 59 and 96, respectively.
60, and the amplitude-limited signal taken out here is further passed through a coefficient circuit 9.
The signals are supplied to the switch circuit 99 through the signals 7 and 98, respectively. Therefore, the switch circuit 99 extracts the signal from the coefficient circuit 97 during the vertical scanning period and the signal from the coefficient circuit 98 during the vertical blanking period, and supplies them to the subtraction circuit 100, where they are combined with the carrier color signal from the switch circuit 83. Subtract. The output signal of the subtraction circuit 100 is passed through a switch 104 to a differential amplifier 82.
is supplied to the inverting input terminal of In this circuit, a de-emphasis circuit during reproduction is placed in the feedback loop of the differential amplifier 82, thereby obtaining a pre-emphasis characteristic that is the opposite of the de-emphasis circuit. Therefore, the signal output from the differential amplifier 82 to the output terminal 105 through the switch 104 is a carrier color signal that has been non-linearly pre-emphasized with different characteristics during the vertical scanning period and the vertical blanking period, as in FIG. Become. Note that the coefficient circuits 87, 88, 90,
Each coefficient of 91, 97, 98 0 ₁ , 0 ₃ , 0 ₂ , 0 ₄ ,
0 ₅ and 0 ₆ are, for example, 0.87, 0.55, 0.13, 0.45, respectively.
0.57, 0.60 are selected.

According to this embodiment, by including the non-linear circuits 95 and 96, 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 82 is G, (The deviation is only 1/G).

In the above embodiment, the de-emphasis circuit having the configuration shown in FIG. 4 is placed in the feedback loop of the differential amplifier 82 to obtain the pre-emphasis characteristic, but the pre-emphasis circuit having the configuration shown in FIG. It may also be inserted into the feedback loop of the differential amplifier 82 to obtain de-emphasis characteristics.

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 NTSC carrier color signals are pre-emphasized and de-emphasized, the present invention can also be applied to PAL carrier color signals. 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 1H, so the delay circuits 23 and 4
3 and 85 are each configured to have a delay time that is a natural number times 2H. Also, non-linear circuits 59, 6
0, 70, 71, 95, and 96 are not limited to amplitude limiters.

Effects of the Invention As described above, the recording system of the present invention has a recording system in which one or both of the vertical time constant and level enhancement degree for a predetermined period including at least the vertical blanking period are vertical time constants for periods other than the predetermined period. a pre-emphasis circuit which is set to be smaller than a constant and a degree of level enhancement, and outputs a high-frequency component of a vertical spatial frequency of the supplied carrier color signal with a relatively level-enhanced level compared to a low-frequency component; The reproduction system has characteristics complementary to the characteristics of the pre-emphasis circuit for each period in the above-mentioned predetermined period and other periods, and the vertical direction of the reproduction carrier color signal returned to the original signal form is Since a de-emphasis circuit is provided that outputs the high-frequency components at a level that is relatively attenuated compared to the low-frequency components, it is possible to improve the S/N ratio of the reproduced carrier color signal, similar to the device proposed by the applicant mentioned above. In addition, unlike conventional noise reduction circuits that use line correlation, the vertical spatial frequency characteristics (vertical resolution) due to de-emphasis are not degraded, and the signal of the previous field is not affected by the signal of the next field. It is possible to prevent hue disturbances and amplitude disturbances from occurring in the upper part of the reproduced screen without affecting the beginning of the vertical scanning period, and also to prevent fluctuations in the horizontal period due to skew distortion. Furthermore, in a recording/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 during recording and reproduction.
The carrier color signal reproduced from a magnetic tape recorded by a VTR can be reproduced into the original signal waveform without any practical problem even if it is passed through a non-linear de-emphasis circuit. The original carrier color signal waveform can be reproduced using a VTR with almost no practical problems.
Therefore, it has features such as being compatible with current VTRs.

[Brief explanation of drawings]

1 and 2 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 FIGS.
FIG. 5 is a block system diagram showing the main parts of the recording system and playback system of the embodiment, FIG. 5 is a block system diagram of the main parts of the third embodiment of the apparatus of the present invention, and FIG. FIG. 7 is a block system diagram showing an example of a recording/reproducing device for a carrier color signal; FIG.
FIG. 8 is a signal waveform diagram for explaining the operation of the block systems shown in FIGS. 1 and 7. 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
...Record transport color signal processing circuit, 9...Magnetic tape, 16...De-emphasis circuit, 18...Reproduction color video signal output terminal, 20...Carrier color signal input terminal, 21, 22, 41, 75, 77, 8
4,94,100...subtraction circuit, 23,43,8
5...1H delay circuit, 24, 26, 33, 45,
46, 48, 49, 55-58, 61, 62, 6
6-69, 72, 73, 87, 88, 90, 9
1,97,98...coefficient circuit, 25,27,4
7, 51, 89, 93...phase adjuster, 28, 6
5...Pre-emphasized carrier color signal output terminal,
30, 32, 44, 50, 81, 83, 86, 9
2,99,104...Switch circuit, 34,5
2,101...Switching pulse input terminal, 3
5, 53, 102...Pulse generation circuit, 40...
Reproduction carrier color signal input terminal, 42, 64... Addition circuit, 54, 76... De-emphasized carrier color signal output terminal, 59, 60, 70, 71, 95, 9
6...Nonlinear circuit, 82...Differential amplifier.

Claims (1)

[Claims] 1. A carrier color signal separated from a color video signal is converted into a predetermined signal format and recorded on a recording medium, and when reproduced, the reproduced signal reproduced from the recording medium is converted into the original signal format. In a recording/reproducing apparatus for a carrier color signal that can be reproduced as a reproduction carrier color signal, the recording system has a time constant in the vertical direction and/or a degree of level enhancement for a predetermined period including at least a vertical blanking period. Pre-emphasis is smaller than the time constant and level enhancement in the vertical direction, and outputs the high frequency component of the vertical spatial frequency of the supplied carrier color signal with the level enhanced relative to the low frequency component. A circuit is provided in the reproduction system, and the reproduction system has characteristics complementary to the characteristics of the pre-emphasis circuit for each period in the predetermined period and other periods, and reproduces the reproduction carrier color returned to the original signal form. 1. A recording/reproducing device for a carrier color signal, comprising a de-emphasis circuit that outputs a high-frequency component in the vertical direction with a level attenuated relative to a reduced component. 2 converting the carrier color signal separated by the color video signal into a predetermined signal format and recording it on a recording medium;
In a carrier color signal recording and reproducing apparatus that obtains a reproduced carrier color signal in the original signal form from the reproduced signal reproduced from the recording medium during reproduction, the recording system includes at least a vertical direction for a predetermined period including a vertical blanking period. One or both of the time constant and level enhancement degree are smaller than the vertical time constant and level enhancement degree for periods other than the predetermined period, and the high frequency range of the vertical spatial frequency of the supplied carrier color signal A non-linear pre-emphasis circuit is provided to relatively enhance the level of the carrier color signal in accordance with the amplitude of the carrier color signal compared to the low-frequency component and output the signal. The characteristics are complementary to the characteristics for each period of the pre-emphasis circuit, and the high frequency component in the vertical direction of the reproduced carrier color signal restored to the original signal form is compared with the low frequency component to determine the reproduced carrier color. 1. A recording/reproducing device for a carrier color signal, characterized in that a non-linear de-emphasis circuit is provided which outputs a signal after relatively attenuating its level according to the amplitude of the signal.