JPS6090491A - Reproducing device of color video signal - Google Patents

Abstract

PURPOSE:To simplify circuit constitution, to decrease the cost and to reduce noise by time-base-compressing so that only one out of two kinds of color difference signals in a narrow band will be transfered in a horizontal blanking period of a luminance signal. CONSTITUTION:An NTSC color video signal entering an input terminal 1 is supplied for a low-pass filter and a band filter 3, and a luminance signal and a carrier chrominance component are separated and filtered. The carrier chrominance component from the band filter 3 is demodulated into an I signal EI and a Q signal EQ by a decoder 4. The former is added to a synthesis circuit 7 through a burst removal circuit 5, and the latter is added to the same synthesis circuit 7 through a 1/5 time base compressing circuit 6. Taking consideration of minimizing quality deterioration of a reproduced picture in case of a color video signal having little line correlation, said circuit 6 time-base-compresses an effective horizontal scanning period of the Q signal EQ and a burst level transfer period to one-fifth, and outputs them so that they will be multified in a horizontal blanking period of a luminance signal and transfered.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to the recording and reproduction of color video signals, and in particular to the recording and reproduction of color video signals.
Among the different types of color difference signals, a specific negative color difference signal is time-axis compressed, time-division multiplexed with the other color difference signal, and multiplexed with the luminance signal. This multiplexed signal is recorded on a recording medium, and when played back, it is time-axis compressed. The present invention relates to a recording and reproducing apparatus that expands the time axis of a color difference signal (-) and returns it to the original time axis, and then generates a reproduced color video signal together with other color difference signals and luminance signals that are simultaneously transmitted.

Prior Art Current color video signal recording and reproducing devices (for example, V T
The mainstream type of recording/reproducing device is the standard method (N
A luminance signal and a carrier chrominance signal are separated from a composite color video signal of 8017 type, AL method or SECAM method, and the luminance signal is frequency modulated and the carrier chrominance signal is frequency modulated. converts the frequency to the low frequency range and transmits the low frequency conversion (
! After 22 months, the frequency-modulated wave is frequency-division multiplexed and recorded, and even if signal processing is performed in the opposite direction to that during recording, a 14-color composite color video signal compliant with any standard system can be obtained during playback. It is a recording and reproducing device using a range conversion recording and reproducing method (there is C as η1 in one cycle.) A recording and reproducing device using such a low frequency converting recording and reproducing method cannot select the band of the luminance signal arbitrarily; It is particularly suitable for application to consumer VTR, which has a relatively narrow band.
Demodulated color signal 8 is affected by VTR playback time axis fluctuation1
], ■Only the luminance signal passes through the FM modulation and demodulation system, and no pilot signal is recorded or reproduced to remove time axis fluctuations of the reproduced low-frequency conversion carrier chrominance signal, so there is little beat interference, and ■ The frequency-modulated luminance signal acts like a high-frequency bias, and has the advantage that the C carrier color signal can be recorded with good linearity.

However, on the other hand, the above-mentioned low-frequency conversion recording/reproducing type recording/reproducing device frequency-division multiplexes the frequency-modulated luminance signal and the low-frequency conversion carrier chrominance signal and records and reproduces it on a C nonlinear transmission system magnetic tape. ■Since the recording and playback band is limited, the band of the low-frequency conversion carrier color signal [
The band of the frequency-modulated luminance signal (in other words, the band of the luminance signal) must be narrowed; The I (ffi number) band of the signal is limited by -C due to low frequency conversion, ■Low II!! conversion carrier color signal lN RSC system or PAL system color video signal recording aid is a balanced modulation wave. Since it is bias recorded by the frequency-modulated luminance signal, the AM of the lj raw low-frequency conversion carrier color signal is caused by uneven contact between the j-p and the head.
Noise occurs and the S/N (signal-to-noise ratio) deteriorates, resulting in a history of ■
A recording i1j/recording system to which the so-called azimuth recording/reproducing method is applied, in which two heads that record and reproduce adjacent bidet sub-tracks are set at different azimuth angles to record and form a bidet 71-1-rack without a guard band. :At JX Sooka,
Since the azimuth loss effect is not 1-min for the low-frequency range, the adjacent low-band converted carrier color signal [1-stroke component] is injected into the reproduction Ci F3. , during recording and reproduction, the phase of the color subcarrier frequency of the low-pass conversion carrier color signal of the Nl SC system or PAL system is set to 1.
Horizontal scanning period (11-1>) by approximately 90° transition (
For example, Publication No. 14 Publication No. Sho 55 C1-9073,
-32273e Publication), or it is necessary to take countermeasures against cross 1 hake, such as inverting the phase of only the -h low frequency conversion carrier color signal of adjacent video tracks every 11-1. Ta.

Furthermore, when recording and reproducing SIE CA fvl lj type color video single signals using the above-mentioned azimuth recording and reproducing type recording and reproducing apparatus, since the carrier color signal is a frequency modulated wave, Although it is not possible to apply countermeasures against this, it is necessary to check the recording position of the horizontal synchronizing signal in the direction perpendicular to the longitudinal direction of the adjacent bidet racks (track width direction). If we record the ゛ space as W4 and IJ (so-called 1'' alignment recording), and also include the sideband acid content, we get 2M1 (carrier color which is a broadband frequency modulated wave of z or higher (counting down ij). In the case where the modulation signal components of the obtained low-pass converted carrier color signals are approximately the same, that is, the same type of color difference signal components are recorded and reproduced (for example, in the case of 26875, etc.), the frequencies reproduced as crosstalk from adjacent tracks of the above-mentioned low frequency conversion carrier color signal have a correlation with the color video signal components at one field interval. , Moreover, since the modulation signal components with almost the same modulation signal components are recorded side by side, the frequency will be approximately the same as the frequency of the low-frequency conversion carrier color signal of the reproduction track, and the frequency will be Since it is close to zero, the influence of the cross alone can be almost eliminated.

However, when reproducing a magnetic tape of a track pattern that is not recorded in the "I" arrangement, the tracks are adjacent to each other. l-Rack S E
Because the carrier frequencies of the low frequency conversion carrier color signals of the CAM;l'> formula are different, the beat frequency due to crosstalk from adjacent tracks extends to the high frequency range, causing noise on the reproduced television screen. Therefore, there was a problem in that the azimuth recording and reproducing method could not be applied.

On the other hand, due to recent dramatic advances in semiconductor technology, precision processing technology, and small parts technology, it has become possible to improve the image quality of recording and reproducing devices by H% and to make the devices smaller and lighter. Sata. In order to reduce the size and weight of the device, the cullet rise and the reduction of the drum diameter have a great influence, and in order to secure the necessary recording time for the small cullet I-, it is necessary to slow down the running speed of the j-pu. In order to obtain high image quality in such a compact and lightweight recording and reproducing apparatus, a new recording and reproducing method other than the above-mentioned low frequency conversion recording and replaying method has been required.

Various recording and reproducing methods have been proposed to meet the above requirements, but one of them is
M demodulates the two types of color difference signals to C4!1, compresses the time axis, and also compresses the luminance signal, time-division multiplexes these signals, and frequency-modulates this time-division multiplexed signal to transfer it to the recording medium. During recording and playback, signal processing is performed in the opposite manner to that during recording.
There was a recording and reproducing device that had a configuration that reproduced the original standard color video signal by 1q (for example, Japanese Patent Laid-Open No. 53-5
(See Publication No. 926). This recording/reproducing device takes into account the difference between the bands of the luminance signal and the color difference signal, and is designed so that the color difference signal, which is a signal with a narrower band, can be transmitted within the horizontal blanking period. The time axis of the color difference signal transmitted within the period is compressed to about 20% of the 1H period, and in order to be advantageous from the viewpoint of bandwidth utilization, the luminance signal is compressed to the same degree as the time axis compressed color difference signal. The time axis is compressed and transmitted during approximately 80% of the 11-1 period so as to occupy a band of , this signal is supplied to an FM modulator, the output signal of this FM modulator is recorded on a magnetic tape, etc., and during playback, signal processing is performed in the opposite direction to that during recording to obtain a playback color video signal. (Hereinafter, this will be referred to as the "timeplex" method).

FIG. 1 shows an example of the 1@ signal waveform of the time division multiplexed signal shown in -. For example, field frequency 501-12. As is well known, in a PAL system or SECAM system composite color video signal with 625 scanning lines, 11-1 is 64 μs, the horizontal blanking period is 12 μs, and the luminance intensity is reduced during the remaining 52 μs video period. The carrier color signal is transmitted (excluding the color burst signal), of which the luminance signal is compressed on the time axis in about 80% of the period of 64 μS, and the carrier color signal is demodulated to generate two types of color signals. The time axis compressed luminance signal and the time axis compressed color difference signal are time-division multiplexed as shown in Figure 1, and the time axis compressed color difference signals are Signals are transmitted line sequentially. In addition, as shown in Fig. 1, the compression signal number between both lines is transmitted at about 504zs to 60μS, but the 1 (-1 period is 64μS''''', and the remaining period (
Blanking period) Wed/Sat 1r41 light signal +1.5YN
c and the reference level of the color signal are transmitted.

If you use the time-plex method for transmitting such time-division multiplexed signals, the turtle signal and color signal code will be the same.
Since there is no period transmitted in y, N T S C
7' To prevent phase n interference and moiré between the luminance signal and color difference signal that may occur when the luminance signal and the carrier color signal are band-sharing multiplexed and transmitted, such as in the J-type or PAL color video signal. It will not happen, and it will not happen.
In the case of C, PAL, and SECAM color video signals, even if they are recorded and played back on racks that are not lined up by a recording and playback device using the azimuth recording and playback system, adjacent tracks are not time-shared. Since the multiplexed signal is recorded in the form of a frequency-modulated wave signal obtained by frequency modulating a high-frequency carrier wave in which the azimuth loss effect is limited, almost no crosstalk occurs due to the azimuth loss effect, and as described above. Crosstalk countermeasures are no longer required, and high-quality playback images can be obtained.

Furthermore, the above-mentioned time-axis compressed luminance signal and time-axis compressed luminance signal according to the time plex method have an energy distribution in which the energy is high in the low frequency band and the energy is small in the high frequency band. Since it is a signal format suitable for frequency modulation, it has a large modulation index, which can greatly improve the S/N ratio, and almost completely eliminates playback time axis fluctuations when extending the time axis. From the above, the reproduced image quality can be greatly improved compared to that of the low frequency conversion recording T1 raw method.

However, the above-mentioned time brex method uses a luminance signal that has a considerably wider band than the color difference signal, and the time axis is compressed and transmitted in the same way as the color difference signal. There is a problem in that a complex and sophisticated luminance signal time-base compression circuit using a lean-bring frequency is required, and the circuit 414 of the entire device is IM and expensive. In addition, the above-mentioned time-plex method requires processing to divide the horizontal synchronization number 5 from the luminance number 15, insert it at a predetermined position, and send it 1 time.
Handling of horizontal synchronization signal is relatively ffi ff1ll”
If there is a C signal and the I signal and Q signal 8 are sent as color difference signals, the open/open axis compression ratio is 161- for both signals (・,
There is a problem in that the wideband I signal is band-limited to the level of the Q signal.

Therefore, the present invention provides a method for transmitting only one color difference signal, which has a narrow band or the same degree or band as the band of the other color difference signal, within the horizontal blanking period of the luminance signal, in addition to the two unique color signals. The signal obtained by compressing the time axis so as to be transmitted is time-division multiplexed within the horizontal blanking period of the other color difference signal, and
A time-division multiplexed signal whose phase is inverted every horizontal scanning period (11-1) is generated, the signal is multiplexed with a luminance signal without time axis compression and recorded, and a comb filter is used during reproduction. The luminance signal and time-division multiplexed signal are separated from the signal, and the time-axis compressed chrominance signal is time-axis expanded to return to the original time axis. This solves all of the above problems. The purpose of the present invention is to provide a recording and reproducing apparatus for color video signals.

Means for Solving the Problems The present invention provides a second color difference signal whose band is equal to or less than the band of the first color difference signal, at least for an effective horizontal scanning period of the second color difference signal. A time-base compression circuit compresses the signal part and the signal part of the burst level transmission period in the period 1il within the horizontal blanking period of the luminance signal, and a time-base compressed color difference signal of the time-base compression circuit J. a time-division multiplexed signal generating path IIq for obtaining a time-division multiplexed signal which is time-division multiplexed within an interval corresponding to the horizontal blanking period of the first color difference signal and whose phase is inverted in one horizontal scanning period f; , the time division multiplexed signal and the time axis compression are not 1
a first mixing circuit for superimposing a large signal with the i degree signal, and a means for recording the output multiplexed signal of the first mixing circuit on a recording medium and reproducing it; a comb-shaped filter that separates and outputs the signal and the luminance signal separately; Based on the switching signal generated during the horizontal scanning period, the reproduced signal of the first color difference signal from which the phase inversion for each horizontal scanning period has been removed and the second color difference signal whose time axis has been compressed are separated and output. (1) from the switch circuit means, the second color difference signal compressed in the 1 axis is expanded in the 1 axis, and the second color difference signal is restored to the original time axis. a time axis expansion circuit for obtaining a signal; a circuit for generating a carrier color signal compliant with a desired standard television system from reproduced signals of the first and second color difference signals; and a circuit for generating a carrier color signal based on the carrier color signal and the comb filter. The second mixing circuit multiplexes the reproduced luminance signals and combines the multiplexed signals with the reproduced color video signals, and an embodiment thereof will be described below with reference to FIG. 2 and the subsequent drawings. .

Embodiment FIG. 2 shows a block system diagram of a recording system of an embodiment of the apparatus of the present invention. This embodiment is an example applied to a helical scan type VTR of the NTSC standard. In the figure, the NTSC color video signal input to the input terminal 1 is supplied to a low-pass filter 2 and a band-pass filter 3, respectively. The low-pass filter 2 separates the luminance signal, and the bandpass filter 3 separates the carrier chrominance signal. be waved. Here, for convenience of explanation, as an input NTSC color video signal,
When a color par signal as shown in FIG. 3(A) is input, a luminance signal Ey having a waveform as shown in FIG. 3(B) is extracted from the low-pass filter 2. A
), CB+, CB2, and CB3 accept color burst signals.

The carrier color signal taken out from the bandpass filter 3 consists of two types of color difference signals: the ■ signal and the Q signal (No. 4), and the color subcarrier frequency is 3.
．． 57954! i M LI Z /! : A modulated wave obtained by carrier suppression quadrature two-phase amplitude modulation, which is supplied to the decoder 4 and demodulated into one signal E+ and Q signal [Q. Here, the brightness decay signal Ey and the color difference signals E+ and Ea are expressed by the following equations, as is well known.

In the above formula, [R, Ea and Ea are each red.

Gamma-corrected green and blue primary color signals are shown.

” The above color difference (#-j + shi (-1 is approximately 1.!IMII
There is a baseband signal that occupies the Z band, and the color par signal input section has a waveform as shown in Figure 3 (C).
The above color difference signal [Q occupies a band of approximately 0.5 MHz
When a color par signal is input, it becomes a signal with a waveform as shown in the figure (<]).

In addition, in FIG. 3(C), 01 and C2 indicate the burst level which is a DC level serving as the color reference of the color difference signal E+,
Also, in the same figure (D>, dl and C2 indicate the burst level of the color difference signal Eo. The burst level is white. 100% is 1.
Then, cl and C2 are respectively 0.11, d,
and C2 are −0 and 17, respectively.

As will be explained later, this embodiment aims to minimize the quality deterioration of the reproduced image in the case of a color video signal in which the similarity of video information in the vertical direction of the screen, that is, the correlation in the vertical direction (or line correlation) is small. In consideration of
15, the time axis is compressed. That is, among the output color difference signals E+ and Eo of the decoder 4, the color difference signal Eo is supplied to the 115 time axis compression circuit 6, and here, the period -1-1 of the color difference signal Eo shown in FIG. The time axis of the signal part of the signal part of the period child 2 before and after the period including the burst level transmission period is reduced to 115 LF.The above period -
1-1 is 1H (= 63.5'555μS) minus horizontal blanking JIl'J (hereinafter referred to as "1-1 blanking") C, which is 10.5μS to 11.4μS. 1/11 53,055571s-52,15
55 μS, equal to the effective horizontal scanning period.

In addition, the time axis L "condensed circuit 6 is λ7-di coupled
It can be constructed from a digital circuit including a charge transfer element such as a device (COD), a random access memory (1RAM) such as an AD converter, and a DA converter.

In this way, 1/511. The T axis compression circuit 6 compresses the signal portion of the sum of 114 intervals 2 including the effective horizontal scanning period T1 and the burst level transmission period of the color difference signal EQ to 1/1). A time axis compressed color difference signal r3Q' consisting of It is time-division multiplexed into J sections corresponding to the line erasure period. The burst removal circuit 5 is
If there are burst levels C+ and C2 during the horizontal blanking period of the color difference signal [E I, they will overlap with the time axis compressed signal Eo and will not be reproduced by the reproduction system described later. This is a circuit for removing c2.

Here, the color difference signal IE1. lEo's above 19JJ
The signal level during the period excluding l-+ and T2 is at a constant level, and the signal portion of the color difference signal Eo during the period excluding period T++T2 is not output from the 115 time axis compression circuit 5. As shown in FIG. 3(E), the output signal of the combining circuit 7 is the color difference signal E within one period.
+I effect Horizontal scanning period signal and time axis compressed color difference signal E
o' becomes a time division multiplexed signal which is synthesized in time series. In addition, in the above time-axis compressed color difference signal EQ', the color difference signal 13o of 0.5 MH2 in band is 115, and the time-axis pressure 1i
1 signal, the band is approximately 2.5MHz
(= 0.5M1-IZ÷(115)). Therefore, the band of the output time division multiplexed signal of the combining circuit 7 is approximately 2. '
5M1-1z, which is a band that can be transmitted with sufficient S/N even in a general home VTR that has a relatively narrow recording/playback band, so the frequency of the color difference signal is Ifi bamboo does not deteriorate. But 11! The color difference signal [I in the T-division multiplex signal is not limited in any way to the original band 1.
5M1-IZ allows you to read within the recording.

In this way, the time division multiplexed signal as shown in FIG. 3 (13) synthesized and extracted by the synthesis circuit 7 is supplied to the terminal 8a of the switch circuit 8, while
) to J, the phase is inverted, and then the terminal 8 of the switch circuit 8
b.

On the other hand, the luminance signal EY described above is the horizontal periodic signal #! 1 circuit 10, where the horizontal synchronizing signal is separated and extracted and then supplied to a 1/2 frequency divider 11.

As a result, the phase of the 1/2 frequency divider '11 is synchronized with the horizontal synchronizing signal. A symmetrical rectangular wave with 211 periods is extracted,
This 7Jj shaped wave is applied to the switch circuit 8 as a switching signal, and during the one day period that constitutes the switch circuit 288, the terminal 8a is in the human power (C'i selection output) j state, and the next 11
During one period, switching control is performed to alternately switch and connect I Ll fQ such that the input signal of the terminal 8b is connected to the selected output state.

Therefore, the output signal of the switch circuit 8 is as shown in FIG.
As shown in J, the time-division multiplexed signal obtained by alternately inverting the phase of the time-division multiplexed signal shown in FIG. 114 periods synthesized in time series, color difference signal E+, time axis compressed color difference signal [o' phase inversion signal 10■ and Eo
' are synthesized in time series, resulting in a time division multiplexed signal in which the 7j IH periods appear alternately. This switch circuit 8
The 'TJ time-division multiple signal 1 signal shown in FIG.
), the luminance signal without time axis compression [Y] is mixed and converted into a multiplexed signal as shown in (G) of the same figure, and then supplied as a recording signal to the recording signal processing circuit 14 . Note that the one-day delay circuit 12 generates a delay of at least 11] due to the time axis compression circuit 6, so the stage c is added to compensate for this delay.

The recording signal processing circuit 14 is a circuit that performs signal processing suitable for magnetic recording and reproduction on input multiplexed signals, and has a circuit configuration in which a pre-emphasis circuit, a small solenoid 1, a dark clip circuit 2, a frequency modulator, etc. are connected in cascade. has been done. Predetermined signal processing is performed by the recording signal processing circuit 14 -C1
For example, the FM signal obtained by frequency modulating the multiplexed signal C carrier wave shown in FIG. recorded.

Next, the reproduction system will be explained. Figure 4 shows a block system diagram of the +LF reproduction system of an embodiment of the apparatus of the present invention.1 In the same figure, a magnetic tape is wound by a rotary head at the terminal 16. A reproduced FM signal extracted from the source (not shown) is supplied to the reproduced signal processing circuit 17, where it is FM demodulated and given a de-emphasis characteristic, as shown in FIG. The reproduced multiplexed signal as shown in G) is extracted. This reproduced multiplex signal is sent to the tightening circuit 18. are supplied to the delay circuit 19 and 11-1, respectively, and further 1l-1il! Delayed WiI 20 k: cl; Re11-IN Delay'i:sh /j The regenerated multiplexed signal is supplied to the subtraction circuit 19, and on the other hand, it is supplied to the addition circuit 18 through the switch circuit 21.

The above circuits 18, 19, 20 and 21 constitute a comb filter, and the luminance signal in the reproduced multiplexed signal is extracted from the adder circuit 18, and the luminance signal from the subtractor circuit 19 is extracted every 1H as shown in FIG. 3(F). A phase-inverted time division multiplexed signal is extracted.

This will be explained in more detail. Now A.

There are two signals called B, and one signal B is 1! ], the above signal A is added to the signal transmitted in the order of B, 100, B, B, etc., and 1 = signal is A + B on the nth line (horizontal scanning line), A+B on the n+1st line, A+8 on the n+2nd line. n+3
In the th line, A+E3. It is transmitted as follows. When this addition signal is passed through a 1H delay circuit, the output signal is A+B on the n+1st line and A100 on the 11+2nd line.

On the n+3rd line, A+8. ... are taken out in this order. Therefore, the comb filter consisting of the above-mentioned 11-1 delay circuit and the adder 9* circuit that tightens the input addition signal and the output delay signal, respectively, extracts the signal 5shi2Δ from all lines. Also, from the comb filter 1, which consists of a subtraction circuit that subtracts the output delayed signal from the input signal of the 111 delay circuit described above, n + 1 ? r
2nd stitch on the tth line, 213 on the 11+2nd 1st line
, ++ -+-3rd line r20°... is transmitted in the following order (+'3, that is, signal 2B is 11
The phase is inverted every -1 and the signal is taken out.

Therefore, the signal A in this embodiment is a luminance signal]3Y, and the signal A shown in FIG. 3(E) is
It is a time division multiplexed signal in which the phase of 1-11E is inverted (without the phase inversion).Therefore, the luminance signal EY is taken out from the -c1 addition circuit 18, and the subtraction circuit 19 converts the above time division multiplexed signal into 11-l 1U. The phase is inverted (i.e., Fig. 3).
]:) is extracted with the waveform shown in ).

However, the above explanation is based on the ideal case where there is perfect vertical correlation between the bright signal and the time division multiplexed signal, but in reality, perfect vertical correlation cannot be expected. At that time, a time division multiplexed signal is added to the luminance signal, that is, a vertical differential component of the color difference signal (for example, the sum of the time division multiplexed signal of the n-th line and the phase inverted signal of the time division multiplexed signal of the n-1 line row). signal, the phase inverted signal of the time division multiplexed signal on the n+1th line, the sum signal with the time division multiplexed signal on the 11th line, etc.), and conversely, the color difference signal (time division multiplexed signal) contains the luminance signal. A vertical differential component of the signal EY (for example, a signal of the difference between the luminance signals of the 11th line and the n-1 line, a signal of the difference between the luminance signals of the n+1 line and the n line) is mixed in.

Furthermore, unlike the present invention, two types of time-axis compressed color difference signals are time-division multiplexed within a 1H period, and a time-division multiplexed signal whose phase is inverted every 1H is multiplexed onto a luminance signal and recorded. When recording on a medium and reproducing it, there is no correlation between the time axis compressed color difference signal and the luminance signal multiplexed within the 111 period, so the luminance signal and the color difference number 15 are The influence of the vertical differential component mixed in from one force to the other force may become more noticeable.

To explain this further on the screen, the color difference signals p constituting a color video signal that displays, for example, a circular color image 38 on the horizontally wide playback screen 37 in FIG.
Of i, IEI, and [Q, Ey is compressed in time to 3/4, and 〇 is compressed in time to 1/4, and both signals are
time division multiplexing within a period and record this time division multiplexed signal,
If you play it as is without further extending the time axis,
As shown in FIG. 5, for example, the width of the left side of the playback screen 37 [
Color image 3 with color difference signal E O in the screen area of /4
9 is displayed, and the color image 40 corresponding to the color difference signal F+ is displayed in the remaining screen portion having a width of 3 L/4.

In addition, the luminance signal is added to the above time division multiplexed signal by time axis compression J
Fact 4 = <When recording and reproducing multiplexed images, the reproduced image based on the luminance signal has the same shape and size as the circular color image, as shown at 41 in Fig. It becomes an image. Therefore, the phase of the above time division multiplex No. 15 is inverted to ill, and the luminance signal is multiplied and recorded.
During playback, a comb-shaped filter is used to separate and extract the luminance signal and time division multiplexed signal from the playback signal, and the two types of time-axis compressed color difference signals are returned to their original time axis after time-axis expansion. Reproduction of a recording and reproducing apparatus configured to generate a carrier color signal from the two types of reproduced color difference signals obtained as a result and mix it with a reproduced luminance signal to obtain a reproduced color video signal] Reproduction to display a J color image As shown at 42 in FIG. 5, the screen displays, in addition to a color image 43 having the same shape and hue as the original color image 38, dashed lines 44 and 45 formed by the mixed component of the vertical differential component of the color difference signal into the luminance signal. A linear image as shown in the figure and a linear image as shown in dashed-dotted lines 46 and 47 due to the mixed component of the vertical differential component of the i-degree signal into the color difference signal appear.

Here, the above image /1.4.45 is the color image 3
9.40 appears as an oval ring with different brightness, and image 46.47 appears as colored lines, and areas with no vertical correlation (upper and lower parts of the image) appear thicker. . One of the objects of the present invention is to
7 to be significantly reduced. In addition, the image 46 is the outline of the image part displayed in the width of 3L/4 on the right side of the screen of the color image 38, and is the outline of the image part that has been expanded along the axis between 4/3 (l + ¥), and the other image 47 (more The image part displayed in the L/4 width on the left side of the screen of color image 38 is
8 is the outline of the image portion that has been expanded on the time axis.

Returning again to FIG. After the phase is inverted, the signal is supplied to the terminal 2211 of the switch circuit 22.

On the other hand, the reproduced luminance signal taken out from the adding circuit 18 is
The horizontal synchronization signal is supplied to the horizontal synchronization signal separation circuit 24, where the horizontal synchronization signal is separated and extracted, and then the switching pulse generation circuit 2
5. The switching pulse generation circuit 25 is
The above reproduced horizontal synchronization signal will be described later.J5/111. '
A signal [Q
Detects the burst level described above in the reproduced color difference signal [(), and detects the polarity such that it can be obtained at the normal value (approximately -0.17, assuming 100% white as 1 as described above). And, ?lj, ': Then, generate a symmetrical rectangular wave with a period of 2H phase-synchronized with the horizontal synchronizing signal, and use this symmetrical rectangular wave as a switching pulse -C switch circuit 2
Output to 2. In this case, the switch circuit 22 is 11
-1 is alternately connected to the terminals 22a and 22b, and from its output terminal, the reproduced time division multiplexed signal from which the phase inversion every 11'' has been removed, as shown in FIG. 3 ([), is taken out. The signal is supplied to the next stage signal separation circuit 26.

The switch circuit 26 generates an l-1 blanking pulse that is at a predetermined level only during a period corresponding to the horizontal blanking period of the reproduced luminance signal based on the reproduced horizontal interval lv] signal.
The output pulse of the blanking pulse generation circuit 27 is supplied as a switching pulse, and switching control is performed so that it is connected to the terminal 26a during the period corresponding to the horizontal blanking period, and connected to the terminal 2C311 during the other periods. . As a result, the switch circuit 26 outputs the raw signal of the color difference signal [l] from the terminal 26a and supplies it to the encoder 29 through the IHiE expansion circuit 30, and the time axis compressed color difference signal Eo' from the terminal 26b. 571 and is supplied to the time axis expansion circuit 28. .

The 5l1 time axis extension circuit 28 extends the time axis of the human horn signal Eo' by a factor of 1 to return it to the original time axis.
C color difference signal 1-(Outputs the reproduced signal.

Since this reproduced color difference signal includes a burst level in 0, it is supplied to a switching pulse generation circuit 25 where the burst level is detected, and is also supplied to an encoder 29. The two encoders output the reproduced color difference signal “1”.
and 13. are supplied respectively, from which, for example, N T S
The mixing circuit 34 generates a carrier color signal based on the C method.
Go out into the world. Note that since the burst level has been removed from the reproduced color difference signal [g] during recording, the can-burst signal g is generated by an oscillator or the like in the encoder 29. In addition, the 11-1 delay circuit 30 outputs the 11J color difference signal E from the time axis compression circuit 28J.
This is a circuit for synchronizing time with o.

By the way, the switch circuit 21 is a circuit that passes or blocks an input signal, and allows the reproduced horizontal synchronization signal to pass through the vertical synchronization signal pre-circuit 31 and the V blanking pulse generation circuit 32 in order to generate a vertical return signal of C1q. Line erasure period (V
A V blanking pulse of a predetermined level is applied as a switching pulse for a period corresponding to the blanking period). As a result, the switch circuit 21 is turned off during the vertical blanking period and 11-! The transmission of the output signal of the delay circuit 20 to the adder circuit 18 is cut off, and is turned on during periods other than the vertical blanking period to avoid passing the above-mentioned incoming signal.

Here, the switch circuit 21 is installed.As is well known, the phase of the vertical synchronizing signal is shifted by []/2 between odd and even fields due to interlaced scanning. I] of this vertical synchronization signal by a comb filter
This is to prevent the vertical synchronization signal of the reproduced luminance signal Ey taken out from the adder circuit 18 from being disturbed due to the phase shift of /2. Therefore, adder circuit 18. The luminance signal comb filter made up of the IH delay circuit 20 and the switch circuit 21 is inoperative during the vertical blanking period, and during this period, the adder circuit 18 outputs the reproduced multiplexed signal from the reproduced signal processing circuit 17. is output as is. Note that in the reproduced multiplexed signal, no color difference signal originally exists during the vertical blanking period (since it is an IC, a burst level exists after the equalization pulse after the vertical synchronization signal).

The reproduced luminance signal taken out from the adder circuit 18 is 1l-
After being delayed by 11-1 to the if delay circuit 23, it is supplied to the mixing circuit 34. The 111 delay circuit 33 delays the reproduced color difference signals Ea and I by 111 times by the time axis extension circuit 2E3 and the 111i1ffi delay circuit 3o, so the 1. : It's stepped up. Mixing circuit 34
multiplexes the Tlj raw luminance signal and the reproduced carrier color signal to generate a reproduced color video signal of 18 II" it L/in accordance with the NlSCb) formula, and outputs this signal to the output terminal 35.

If this J is applied to this embodiment, then I (H No. E+ and Q signals [Q] can be recorded in a narrow band without band-limiting? In a band that can be sufficiently transmitted even when Since both Ey and Ey are not compressed on the time axis, there is a correlation. Therefore, even if there is little correlation in the vertical direction in the image, one power of the luminance signal EY and color difference signal E1 causes the other Ji and the other The vertical differential component that mixes from one side to the other is not so noticeable.

Furthermore, the time axis compressed color difference No. 15 Eo' is multiplexed within the horizontal blanking period, but since the horizontal synchronization signal has perfect vertical correlation, the luminance signal EY is converted to the color difference signal Eo'.
No leakage of the vertical differential component to o' occurs. On the other hand, leakage of the vertical differential component from the color difference signal Eo' to the luminance signal Ey occurs, but since the color difference signal Eo' is multiplexed within the horizontal blanking period, the above leakage occurs. Since the noise also occurs during the horizontal blanking period, the noise does not appear on the playback screen. Note that a part of the color difference signal Eo' may be slightly multiplexed in the video period, but even in that case, noise due to leakage of the vertical differential component from the signal Eo' to Ey may occur in the horizontal corners of the playback screen. It is not noticeable because it only appears slightly on the surface.

Application Example J3: The present invention is not limited to the above-mentioned embodiment, and various other application examples are possible. For example, in the recording system, after time-division multiplexing the time-axis compressed color difference signal Eo to the color difference signal [E+, the phase is inverted every 11''.
The time-axis compressed color difference signal Eo and the color difference signal 8[1] are phase-inverted every 11-1 for each person, then both signals are combined, and the signals are inverted every 11'' by f1/l. 11
．． 1b) A comparatively high signal may be obtained. Similarly,
In the ilT 4.1-system, the signals [Q' and [l, etc.] may be separated, and then the phase inversion of the 1l-If signal may be removed.

In addition, the present invention provides that if only the N 1' S C:/j formula = 1
It can also be applied to other standard television systems such as the PAL system and the SECAM system.

In this case, 1) two types of color difference signals Eu, Lv and SL, which constitute the carrier color signal of the AL system; The signals may be converted into color difference signals El and IEQ using a delay circuit, a switching switch, etc., and then processed. Furthermore, it is also possible to apply the present invention directly by time-base compressing one of the color difference signals Eu and l'Ev, or DR and DB, each having a band of about 1.3 MH2. However, in terms of transmission band, it is more effective to apply the present invention after converting into El and Eo.

Furthermore, the present invention is not limited to application to VTRs, but can also be applied to devices that record signals on a recording medium such as a disc-shaped magnetic sheet or a disk and reproduce the same.

Effects As described above, according to the present invention, during recording, only one of the two types of color difference signals, which has a band narrower than the band of the other color difference signal or has a similar band, is used as the luminance signal. The signal obtained by compressing the time axis so as to be transmitted within the horizontal blanking period is time-division multiplexed within the horizontal blanking period of the external color difference signal, and one water ηI scanning period (I Ll
), generate a time-division multiplexed signal whose phase is inverted for each signal, and multiplex the signal with a luminance signal without time axis compression and record it in C.
During playback, a comb filter is used to separate the luminance signal and time division multiplexing (Li) from the raw signal, and the time axis is compressed. From this endogenous color difference signal and one other reproduced color difference signal, the desired target TV-J revision system (CNTSC system, PAL7'j system, SEC8 ~ system) is compliant!
Since the two-color transmission and polarization signals are J:, it is possible to solve all the problems of the low-frequency conversion recording and reproducing method described above. On the other hand, there is no time axis compression and expansion processing (2), so the circuit configuration can be simpler and cheaper than the conventional timeplex method, and the horizontal synchronization signal is transmitted as is. Since the horizontal synchronization signal is inserted at a predetermined position, it is easy to handle the horizontal synchronization signal.
Of the signals, only the narrowband Q signal is compressed by the h-axis JLE [Water 'l'! Since it is transmitted within the 1li line erasure period, the L signal band is not limited as in the conventional time-plex method, and the L signal and Q signal can be almost completely transmitted even in a narrow recording/reproduction band. I can do it. Moreover, in the present invention, since the luminance signal and the color difference signal behind the two types of color difference signals (for example, the l signal) are not compressed on the time axis, a correlation exists, and a correlation exists in the vertical direction in the C image. If the LE compression difference signal is small, the vertical differential component of the -1 signal mixed between the luminance signal and the non-time axis compressed color difference signal should be made less noticeable. Since it is multiplexed within the erasing period, the vertical differential component of the time-axis compressed color difference signal may leak into the luminance signal, but this noise does not appear on the playback screen, so there is no problem. Since the horizontal synchronization signal has a perfect correlation in the heavy oil direction, the vertical differential component of the luminance signal will not be mixed into the time-axis compressed color difference signal.
From the above, even if there is no vertical correlation in the image, the noise caused by it can be significantly reduced and become less noticeable. In addition, since only the - color difference signal (for example, Q bind-off) is used for time axis compression and time axis expansion, only one 114@1f - compression circuit and 2 time axis expansion circuits are required, which simplifies the circuit configuration. , and furthermore, since the comb filter is kept stationary during the vertical blanking period of the reproduced luminance signal,
It is possible to prevent the phase of the vertical synchronization signal, which has a phase difference of 4/2 between the odd field and the even field, from being disturbed, and furthermore, it is possible to prevent the phase of the vertical synchronization signal from being disturbed. It has a number of features such as being able to record in the common signal format 1-7 in the i"j revision system.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a time division multiplexed signal waveform recorded by the conventional time plex method, and FIG. 2 is a diagram showing an example of the recording system of the apparatus of the present invention.
Figures (△) to (G) are respectively shown in Figure 2.
1 is an explanatory time chart, FIG. 4 is a block system diagram showing an embodiment of the reproduction system of the apparatus of the present invention, and FIG. There is a diagram illustrating a reproduced image when there is no vertical correlation in the image when a signal obtained by multiplexing a luminance signal with the signal is recorded. 1...NTSC color video signal input terminal,
4... Decoder, 5... Burst removal circuit, 6...
・115 Time axis compression circuit, 7...Synthesis circuit, 8.21
, 22゜26...Switch circuit, 10.24...Horizontal synchronization signal separation circuit, 12.20.30.33...1
day delay circuit, 13.34...mixing circuit, 16...reproduction signal input terminal, 18...addition circuit, 19...subtraction circuit, 25...switching pulse generation circuit, 28...
...5/1 time axis expansion circuit, 29...: [encoder,
35... Reproduction color video signal output terminal.

Claims (1)

[Scope of Claims] (1) First color difference IrU'; B and at least one of the second color difference signals whose bandwidth is less than or equal to the band of the first color difference Ih; Ij Effect - The time required to compress the signal part of the IL scanning period and the signal part of the burst level transmission period into the period within the horizontal blanking period of the luminance signal is 1t (1
1 compression circuit, and time axis Ui color reduction If from the time axis compression circuit (1:, the bow is time-division multiplexed within an interval corresponding to the horizontal blanking period of the first color difference signal, and one horizontal scanning A 110-division multi-vehicle signal generation circuit that receives a time-division multiplexed signal whose phase is inverted in one period, and the time-division multiplexed signal 11iff.
G! a first mixing circuit that multiplexes I 'I'llll 1 to a large extent with an uncondensed luminance signal; a means for recording the output multiplexed signal of the first mixing circuit on a recording medium;
Reproduction of the multiplexed signal recorded on the line recording medium/JE-J
the reproducing means, and the reproducing multiplexing (items ii to 11.) minutes υ
A comb filter that separately separates and outputs the j-multi-Φ signal and the luminance signal, and a reproduced music division multiplexed signal from the comb filter from the horizontal synchronization signal in the reproduced luminance signal from the comb filter. Based on the generated switching signal, the first
switch circuit means for separating and outputting a reproduced signal of the color difference signal and the time-axis compressed second color difference signal, respectively; A time axis expansion circuit that obtains a reproduction signal of the second color difference signal returned to any time axis even if the axis is expanded, and a time axis expansion circuit that obtains a reproduction signal of the second color difference signal returned to any time axis, and a time base expansion circuit that obtains a reproduction signal of the first and second color difference signals based on a desired standard television system. a second mixing circuit that multiplexes the carrier color signal and the reproduced luminance signal from the comb filter and outputs the multiplexed signal as a reproduced color video signal. A color video signal recording and reproducing device characterized by the following. ■ The comb filter is inactive during the vertical blanking period of the luminance signal and reproduces the regenerated multiplex signal Fl+
Q'b is characterized by outputting the signal exactly as it is.
H1' A color video signal recording and reproducing apparatus according to claim 1. (2) The switch circuit means detects the DC level or the Li burst level of the color reference of the color difference signal of the A process 2 > 3 from the time axis expansion circuit, and applies J, The phase phase φl of the time-division multiplexed signal for each horizontal scanning period is removed based on the switching signal of the polarity determined.
Koma r [
A color video signal recording and reproducing apparatus according to claim 1 or 2. (4) The first color difference signal 'l-L is l (jj signal,
The second color difference signal is)
The time axis compression circuit is characterized in that the effective water 31' scanning period of the Q(g) is compressed into a time axis layer of 115.
[Claim 1: 11d recording and reproducing apparatus for color video signals as set forth in one of the first to third claims. (5) The first color difference signal 8 is I (May), the second color difference signal is the Q signal, and the time division multiplexed signal generation circuit Any one of claims 1 to 3 is characterized in that it has a circuit that adjusts the horizontal blanking period equivalent interval to a certain level and time-division multiplexes it on the time-base compressed color difference signal. A recording and reproducing device for the color video IΔ.