JPS6096091A - Reproducing device - Google Patents

Abstract

PURPOSE:To remove the output level difference between the chrominance signals of a pair of components following the time base expanding and to share a comb-shaped filter device by reproducing the signal in which a pair of the component chrominance signal and luminance signal are simultaneously and separately recorded to the adjoining track respectively. CONSTITUTION:A comb-shaped filter device 20 is installed between the steps of a time base expander 3 and an encoder 4. Thus, even when the output level of a pair of the color difference signal R-Y and B-Y is dislocated by the time base expander 3, it is made equal by the comb-shaped filter device 20. For this reason, the output level difference is suppressed. Since the color difference signals R-Y and B-Y before they are modulated are supplied to the comb-shaped filter device 20, the comb-shaped filter device 20 can be commonly used even when the signal to be recorded to a magnetic tape 1 is an NTSC system or a PAL system. Namely, the 1H delay element is only installed to the comb-shaped filter device 20. In this way, the deterioration of the vertical resolution can also be improved. Further, since the signal to be processed with the comb-shaped filter device 20 is the color signal of the base band component, the pass band is narrow and for this reason, the frequency characteristics are good.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention reproduces a pair of component color signals and luminance signals A and I, respectively, which are separately recorded simultaneously on adjacent trunks. The present invention relates to a playback device that performs conversion.

A pair of component color signals, for example a pair of color difference signals R
-Y, B-Y are compressed on the time axis to ten times, and these compressed color difference signals are arranged in a variable force within one horizontal period, and the composite compressed color difference signal and luminance signal are simultaneously recorded separately on adjacent tracks. , and a recording/reproducing device designed to play back the music.
During reproduction, signal processing as shown in FIG. 1 is performed.

Figure 1 shows an example of a reproduction device for color signals, in which a composite compressed color difference signal recorded on a magnetic tape (11) is reproduced by a head Hc, and the reproduced composite compressed color difference signal is FM demodulated. The time axis expander (3) consists of a CCD, etc. which also serves as time axis correction.
A pair of color difference signals R-Y and B-Y whose time axes have been expanded are output together with correction of the time axes.

This pair of color difference signals R-Y, B-Y is sent to the encoder (4)
The signal is converted into a carrier color signal using, for example, 3.58M1lz as a subcarrier, and this is supplied to a subsequent comb filter device (20) to remove noise components contained in the carrier color signal. The output is combined with a reproduced luminance signal Y in an adder (21) to form a well-known video signal Sv.

Now, if the playback devices w and a are configured in this way, the time axis expander (3) will be required for two channels, the R-Y system and the B-, Y system, but in this case, the human output level of each channel will be The characteristics generally do not match, and therefore a level difference occurs between a pair of color difference signals after time axis expansion.

In addition, a comb filter device (20
), the passing frequency is high and the frequency characteristics become a problem, and when this playback device αO) is applied not only to the NTSC system but also to different television standard systems such as the PAL system, for example, a PLL system self-generating device When used as a comb filter device (20), the comb filter device (20)
A delay element for the horizontal period (■1) must be prepared,
Therefore, it is not possible to share the device.

Moreover, by providing a 2H delay element, the vertical resolution is significantly degraded.

On the other hand, if the comb filter device (20) is installed between the FM demodulator (2) and the time axis expander (3) as shown in FIG. 20)
Although the drawbacks caused by providing the signal at the final stage are eliminated, the inconsistency in output levels caused by passing through the time base expander (3) is unavoidable.

OBJECTS OF THE INVENTION Accordingly, the present invention eliminates the output level difference between a pair of components (color signals) associated with time axis expansion processing, and makes it possible to share a comb filter device.

Summary of the Invention In this invention, a luminance signal and a composite compressed color signal consisting of a pair of time-axis compressed component color signals are recorded separately and simultaneously in adjacent l-ranks. When reproducing the signal, the composite compressed color signal is demodulated, and the demodulated composite compressed color signal is supplied to a time axis expander to expand the time axis of the pair of color signals, and these are passed through a comb filter. The color signal is supplied to the apparatus, noise components contained in the color signal are removed, and the signal is fed to the encoder to form a "C carrier color signal."

EXAMPLE Next, an example of the present invention will be explained with reference to FIG. 3 and the following. However, in the example below, a pair of component colors (i
This is a case where a pair of color difference signals R-Y and B-Y are used as the signals.

In this invention, as shown in FIG. 3, the time bending axis stretcher (3)
A comb filter device i' is provided between the stage and the encoder (4).
j (20).

With this shift, the output levels of the pair of ζ color difference signals R-Y and B7Y are shifted by the time axis expander (3), and °ζ is also averaged by the comb filter device (20) in the subsequent stage, resulting in an output level difference. can be suppressed.

Furthermore, since the color difference signals R-Y and B-Y before being modulated are supplied to the comb filter device (20), the signal to be recorded on the magnetic tape
The comb filter device 1f (20) can be used in common with the L method as well. Zunawaji, this comb filter device (20)
It is only necessary to provide an IH delay element.

This also makes it possible to improve vertical resolution deterioration4.Furthermore, since the signal to be processed by the comb filter device (20) is a color signal of the baseband component, the passband is narrow and the frequency characteristic is is good.

By the way, a special filter device is used as the comb filter device' (20) used in the above-mentioned reproducing device αω. That is, in a conventional comb filter device consisting of an IH delay element, an adder, and a subtracter, the color level is low at the leading edge (the front edge of the image) of the input color difference signal, and the color level is low at the trailing edge (the front edge of the image).
+! ! It is well known that color shift occurs at the rear edge of the II image.

The comb filter device (20) used in the present invention improves the color level drop and color shift at the leading and trailing edges of the input color difference signal to the extent that they are not visually detectable at all, and also has line correlation. In some parts, the S
The configuration is such that the effect of improving /N can be sufficiently obtained.

FIG. 4 is a basic block diagram of this comb filter device (20), and FIG. 5 is a schematic waveform diagram showing the operation of FIG. 4.

As shown in FIG. 4, this comb filter device (20)
Then, the human input signal (R-Y or B-Y color difference signal) (fifth
A) is applied to a comb filter consisting of an IH delay line (21) and a subtractor (22), and the S
A human signal Sc with improved /N is obtained. This signal is given to a correlator (27) and correlated with the input signal sA. This correlator (27) has an AND function, and its output becomes the signal SD (=SAXSC) as shown in the fifth figure. Therefore, the human input signal sA is obtained from the output of the °ζ correlator (27).
Since there is no output, no extra signal appears at the trailing edge xB of the human-powered Iha, as is the case in the fifth diagram. As a result, color blur in the vertical direction of the screen can be eliminated.

Furthermore, in this embodiment, the correlator (27) is constructed so as to improve the principle shown in FIG. 4 and correct the low color level at the leading edge XF of the input signal shown in FIG. ing. In other words, as shown in the waveform diagram of Fig. 6, at the leading edge Xp, the output Ss of the IH delay line (11 (Fig. 6B) is For those without one (5AI in the figure), the output SD of the correlator (27) (
It is output as is as shown in Fig. 6D). Also sB for S8
For a signal with a line correlation, °ζ is taken out as the output of a comb filter (SD=SC). Further, in the trailing edge portion xB of the signal, as described above, what is not present in the input sA but is present in the delayed output sB is not outputted (So = sAXSc). As a result, a signal train is obtained which is substantially the same as the human input signal SA, but whose S/H has been improved by the comb filter.

Next, FIG. 7 is a block diagram of a noise removal circuit showing an embodiment of the present invention, and FIG. 8 is a waveform diagram showing its operation.

First, to explain ′ according to Fig. 8, as in Fig. 6, the IH delay signal Sc, (Fig. 8B) is subtracted from the human input SA (in this example, the signal 5b delayed by τ) (Fig. 8A). By doing so, the comb filter signal Sc becomes 7. I get fucked. At this time, noise components or distortion components without line correlation (indicated by circles in FIG. 8) included in the input signal S8 are attenuated.

It should be noted that the human power signal S^ is distorted in one direction of the oscillation width -■ by the non-linear portion of the electromagnetic conversion thread of the magnetic tape (l)/magnetic head 11c.

If the input signal is recorded in IH alternating inversion, distortion components appear in opposite phases in alternating lines.

Therefore, the distortion components of the signal processed by the ζ comb filter are canceled by averaging.

Next, XSC is applied to the logical product S of the human power sb and the comb filter output Sc, and a signal that does not cause color shift at the trailing edge is formed as shown in the eighth diagram. In addition, the swing width of human-powered SA is Sc
If it is set to a state larger than ζ, the output of the comb filter is taken out as is except at the trailing edge. Also, at the leading edge, a human input signal S8□ appears with a level of + (-6 dB) and whose distortion components are sufficiently attenuated.

Next, the logical sum (SA+SR) of S8 and Ss is taken, and a signal without line correlation and distortion or noise without line correlation are extracted as shown in FIG. 8E. Furthermore, this signal SI
! and the human signal S (XSg to S) is taken,
As shown in FIG. 8F, the first line signal to the input signal S and distortion or noise components without line correlation are extracted. Further, the signal is removed without causing any color shift at the trailing edge of the input signal SA.

As a final process, the logical sum (SD+Sp) with the signal St)'(!:5IIF) is taken, and the level correction at the leading edge is performed to obtain the output signal sG of FIG. 8G.

Comparing the output signal sG and the input signal S8, the first line of the input signal shows the human power itself, the middle part shows the output after noise removal processing using a comb filter, and the next line where the input signal ends Then no extra signal will be generated.

Therefore, the problems of color level loss at the vertical leading edge of the image and color blurring at the trailing edge, which are drawbacks of conventional comb filter devices, are both eliminated.

Next, a block circuit diagram of the embodiment shown in FIG. 7 will be explained. Note that in FIG. 7, the symbol 5A7Sa corresponds to the waveform diagram in FIG. The minute delay time is human power Sa and each delay line (31),
The outputs Sb and Sc of (32) are used for phase distortion removal. The output Sb of the delay line (31) is treated as a main line output and processed by a comb filter consisting of an IH delay line (31), a subtracter (32) and an adder (23). Comb filter output SC+sF! and the above human signal Sa”S
c is processed by correlators (35) to (42), and the calculations (product and sum) explained in FIG. 8 are performed.

Since each correlator performs calculations on only one of the upper half and tenth half of the waveform of the human input signal to be processed, two systems of correlators are provided for processing the -F half and the lower half of the waveform.

9A and 10A show each correlator (35) to (42)
Figure 9B and Figure 10B show the basic circuit of ゛4.
The operating waveforms that occur are omitted. As shown in FIGS. 9A and 10A, the correlator is constructed by connecting the emitters and collectors of a pair of NPN or PNP transistors in common, and the output S
z is taken from the common emitter resistor RE.

When configured with NPN transistors as shown in Figure 9A,
Since the portion where the level of the input S x + S y is high becomes the output level, the upper half of the waveform yields the logical sum Sχ+Sy, and the lower half yields the output S'z of the logical product Sx XSy.

In addition, when configured with PNP transistors as shown in Figure 10A, the part where the level of human power Sx;SV is small becomes the output level, so as shown in Figure 10B, the upper half of the waveform is the AND SxX'Sy, An output Sz of the logical sum Sx +Sy is obtained.

Each of the correlators (35) to (42) shown in FIG. 7 is constructed by combining the basic circuits shown in FIG. 9A or FIG. 10A. In FIG. 7, the correlators (37) and (3B) are connected to the human power Sa and the outputs Sb and S of the τ delay circuits (31) and (32).
c is given, and logical sums Sa+Sb+Sc are formed in the upper half and upper half of the signal, respectively. This processing is performed as a preprocessing to remove phase distortion, but in this explanation, the sum S, a+Sb→Sc or the product 5a-3b'S
c is treated as being substantially equivalent to the human input signal in FIG. 8A. The outputs SΔ of the correlators (37) and (3B) are the correlators (41), respectively.

(42) 5. is ANDed with the comb filter output Sc (FIG. 8C) obtained from the subtractor (22) to form an output of So = sA xsc <FIG. 8D).

On the other hand, the output (9th IB) of the comb filter IH delay line (21) and the main line signal 5b (=SA) are connected to the adder (23
) to form a blur signal in FIG. 8E. Signal S! ! and said signal S a r S b .

Sc is given to the correlators (35) and (36), and the half and q half of the signal are respectively ζSa −3b
・Sc xS Bi, Zunawachi SA x31! A logical AND operation is performed to form a signal sF shown in FIG. 8F.

This signal Sp and the output sD of the correlators (41) and (42)
are obtained by the correlators (39) and (40), respectively, and the logical sum operation of S'0+Sp is performed in the upper half and lower half of the signal, respectively, and the output sG is formed as shown in FIG. 8G. be done.

The processed signal passes through the ) side slice circuit (43) and the upper side slice circuit (44), respectively, and is sent to the adder (45).
and is extracted via a low-pass filter (46) for removing harmonic wave components.

When using the above-described comb filter device (20), a pair of transistors can be used by first configuring it as shown in FIGS. 9A and 10A. As a result, the balance between the base and emitter voltages of the transistor is improved, making it possible to eliminate the need for manual adjustment. Furthermore, since the pair of color difference signals has a horizontal blanking period, by pedestally clamping this horizontal blanking level, the DC level of the signal input to the correlator is stabilized. In this case, although not shown, a clamp circuit may be provided before the correlators (35) to (38).

Note that the video signals that can be handled by this playback device (1 (+1) may be of the SECAM format in addition to those described above.

Effects of the Invention As explained above, according to the present invention, since the comb processing can be performed in the low frequency region by -9, the frequency characteristics of the comb filter device (20) are improved, and its configuration (clock system, bit In addition, it is possible to eliminate the level difference between a pair of color difference signals caused by time axis expansion processing, and the configuration can be simplified because the comb filter device jif can be shared. I can figure it out. Further, since the comb filter device uses an IH delay element as shown in FIG. 7, there is no deterioration in vertical resolution.

Since the adder (23) can be used for simple addition, it can also be configured as a 4-resistance addition type (using the same resistance). In this case, the output level after addition is the output level of the subtracter (22). , so both ilf+l fM become unnecessary.

[Brief explanation of drawings]

Figures 1 and 2 are system diagrams of conventional playback equipment;
4 is a system diagram showing an example of a regenerator according to the present invention, FIG. 4 is a comb filter diagram showing the principle of the comb filter device, FIGS. 5 and 6 are bot waveform diagrams illustrating the operation of FIG. 4, and FIG. A block diagram showing an embodiment of the filter device, FIG. 8 is a neo waveform diagram showing the operation of FIG. 7, FIGS. 9A and 10A are circuit diagrams showing the basic configuration of the correlator used in FIG. 7, respectively.
FIGS. 9B and 10B are waveform diagrams illustrating the operations of FIGS. 9A and 10A, respectively. aψ is a regenerator, (20) is a comb filter device, (2
) is an FM demodulator, (3) is a time axis expander, and (4) is an encoder. The same Hidemori Matsukuma, j, j, j・4ノ1ν Taku'ko: Pa Figure 1 ■ Figure 2 Figure 4 Shigeru Figure 5 Figure 6 Figure 8 Figure 9A Figure 9B Lower cow number = βX to issue

Claims (1)

[Claims] When a luminance signal and a composite compressed color signal consisting of a pair of time-axis compressed component color signals are recorded separately and simultaneously on adjacent tracks, the composite compressed color signal is At the same time as being demodulated, the demodulated composite compressed color signal is supplied to a time axis expander to expand the time axis of the pair of color signals. A reproduction device in which noise components contained therein are removed and the signal is supplied to an encoder to form a carrier color signal.