JPH03224389A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent generation of a lead color signal and a lag color signal by generating a burst gate pulse to a position to be located substantially and using the pulse so as to extract a chroma signal and synchronizing the burst signal of the extracted chroma signal timewise with respect to a luminance signal. CONSTITUTION:When a lead color signal or lag color signal takes place in a burst signal B of a chroma signal S2 with respect to a horizontal synchronizing signal, the burst signal B of the chroma signal S2 is extracted in a timing of a burst gate pulse Bg. The signal is integrated by a capacitor 54 to obtain an integrated voltage of Vmax. The integrated DC voltage V is inputted to an A/D converter terminal 55a of a microcomputer 55 and a 2nd DELAY 50 is controlled by a DC voltage V1 outputted from a CONT terminal 55b of the microcomputer 55. Thus, it is possible to match the burst signal B and the horizontal synchronizing signal Hsync to an optimum location. Thus, generation of a lead color signal or a lag color signal is prevented on a reproduced pattern.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a video tape recorder, for example, in which a problem occurs due to a difference in processing time in the respective processing steps of a luminance signal and a chroma signal separated during playback mode. The present invention relates to a magnetic recording/reproducing device configured to correct a time difference between both signals.

[Prior Art] Fig. 9 is a block diagram showing the configuration of a reproducing system in a VTR, which is an example of a conventional magnetic recording/reproducing device. Pick up recorded information. (3) is a head amplifier that amplifies the picked up information.

(30) is a luminance signal processing circuit, and (31) is a chroma signal processing circuit, which separates the output signal from the head amplifier (3) into a luminance signal and a chroma signal and processes the respective signals. (12) is a mixing circuit (hereinafter referred to as MIX),
A video signal obtained by combining the luminance signal and chroma signal output from the image processing circuits (30) and (31) is sent to the terminal (
26).

The luminance signal processing circuit (30) includes an FM automatic gain control circuit (hereinafter referred to as FM AGC) (4),
FM equalizer (hereinafter referred to as FMEQ) (5)
, double limiter (hereinafter referred to as double LIM) (8
), demodulation circuit (hereinafter referred to as DEM) (7), de-emphasis (8), low-pass filter (hereinafter referred to as LP)
F) (9), noise canceller circuit (hereinafter referred to as NC) (10), and image quality adjustment circuit (11)
It is made up of.

The chroma signal processing circuit (31) is f129 KHz
L P F (20), Funheta (21), 3.5
It consists of an 8 MHz band pass filter (hereinafter referred to as BPF) (22) and a comb filter (23).

Next, the operation of the above configuration will be explained.

Information picked up from the magnetic tape (1) by the magnetic hand (2) is amplified and separated by the head amplifier (3), and then sent to the luminance signal processing circuit (30), ? -; respectively input to the chroma signal processing circuit (31).

The information input to the luminance signal processing circuit (30) is FMAG
C (4), FM EQ (5), double LIM (8)
, DEM (7) to become an FM luminance video signal, and unnecessary carrier leakage and high-frequency noise are cut by de-emphasis (8) and LPF (9). When passing this L P F (9), - 50 for boat fishing
It has l with a delay time of about 0 to 800 n5ec.

Subsequently, the S/N is improved by the NC (10), and the frequency characteristics during reproduction are corrected by the image quality adjustment circuit (11), and then the signal is input to one of the MIX (12).

On the other hand, the information input to the chroma signal processing circuit (31) is input to the LPF (20) and is processed at 629 during recording.
The low frequency chroma signal, which has been converted to a low frequency range of KHz±500 K)Iz, is separated from the luminance FM signal and extracted. The delay time 2 at this time is approximately 300 n5ec.

The signal is then converted into a 3.58 MHz chroma signal by a converter (21), and then input to a BPF (22) where unnecessary carriers and noise are removed. The delay time 3 accompanying this passage through B P F (22) is approximately 500 n5ec.

Subsequently, after the comb filter (23) removes the wolfberry stalk, it is input to the other MIX (12),
In this M I
are combined to form a predetermined video signal S3, which is sent to terminal (2
6) is output.

In the above reproduction processing operation, the delay time in the luminance signal processing circuit (30) is approximately τ1+α1 (α1: delay time of the entire circuit)! ago n5ec, and the delay time in the chroma signal processing circuit (31) is 3+ at τ2+.
α2 (α2: delay time of the entire circuit) is approximately 900 n
5ec, and as long as the luminance signal and chroma signal are recorded properly, the processing circuits (30) and (31) for both signals
The delay times in the video signal S3 are almost the same, and there is no color shift such as color delay or color advance in the video signal S3. If there is, the processing time of the reproduction system is fixed, so the time difference between the luminance signal and chroma signal will cause color advance or color lag on the reproduced screen. As shown in Figure 10, as a means of compensating for the time difference between
A time correction circuit (
32) is known. In the same figure,
The luminance signal amplified and separated by the head amplifier (3) is passed through the bypass filter (33) (hereinafter referred to as ][]) to the luminance (τ) processing circuit (30), while the chroma signal is input to the L P +? After (20), Kuromai, ζ
The 111 power transmission y+ from the black 713 processing circuit (31) is manually inputted to the No. 713 processing circuit (31), and the 111 power transmission y+ from the black No. 713 processing circuit (31) is inputted to the luminance signal and the luminance signal. The sleeve IF is designed to compensate for the misalignment of the M I
The video signal S3 synthesized at
■) We are trying to make this happen.

In a circuit having such a time sleeve 1)-circuit (32), the time sleeve positive circuit (32) has a reference voltage (VB), a transistor (Q) as shown in FIG. ,
Reactor (L), capacitor (C), resistor (Re, R,
It is configured to measure the time shift of the input chroma signal and fixedly set the correction time according to the measured shift, so that the amount of correction for the time shift is always constant. belongs to.

[Problems to be Solved by the Invention] Since the conventional magnetic recording and reproducing device is configured as described above, the recording system and the reproducing system in the same device are as follows.
Since the delay time of the filter and the entire circuit is set so that there is no time difference between luminance signal processing and chroma signal processing, color shift problems such as color advance and color delay do not occur. However, for example, when playing back a tape recorded on another device, the conventional example shown in FIG.
There is a problem in that color advance or color lag occurs on the playback screen due to time lag in the recording system.

Furthermore, in the conventional example shown in FIG. 10, due to the presence of the time correction circuit (32), only when the time difference between the luminance signal and the chroma signal is constant, the difference can be corrected and the two signals can be synchronized. However, if the time lag fluctuates, it is not possible to accurately correct the time lag.

This invention was made to solve the above-mentioned problems, and even when playing back a tape in which the luminance signal and chroma signal are recorded with a time lag, the time lag will be corrected. To provide a magnetic recording and reproducing device capable of reliably and accurately correcting color, preventing the occurrence of color advance and color delay, and reproducing images faithful to the original picture.

[Means for Solving the Problems] A magnetic recording and reproducing device according to the invention according to claim 1 creates a burst gate pulse at a position where a burst signal of a chroma signal should originally be located from a horizontal synchronization signal of a reproduction luminance signal,
A chroma signal is extracted by the burst gate pulse, and the chroma signal is temporally controlled so that the burst signal of the extracted chroma signal is temporally synchronized with the luminance signal. .

Further, the i-Q recording and reproducing apparatus according to the invention as set forth in claim 2 is characterized in that the correction time by the means for correcting the temporal deviation between the luminance signal and the chroma signal that are separated from each other is manually variable. shall be.

[Function] According to the invention described in claim 1, a burst gate pulse is created at the position where the burst signal of the chroma signal should originally be from the horizontal synchronization signal of the reproduced luminance signal, and the burst gate pulse of the chroma signal is created at the position of the burst gate pulse. By controlling the chroma signal temporally so that the burst signals are temporally synchronized, it is possible to correct the temporal deviation between the luminance signal and chroma signal during recording during playback, and this allows for color advancement. It is possible to eliminate the occurrence of color lag.

Further, according to the second aspect of the invention, by manually varying the correction time for the time shift of the input chroma signal,
Regardless of the magnitude of the time difference between the luminance signal and the chroma signal, it is possible to accurately synchronize the two signals and reproduce an image that is faithful to the original image.

[Embodiment of the Invention] An embodiment of the present invention will be described above based on the drawings.

FIG. 1 is a block diagram showing the configuration of an amphibonic system in a magnetic recording/reproducing apparatus according to an embodiment of the present invention.
) and (31) are the same as those in the conventional example shown in FIG. 9, so the corresponding parts are given the same reference numerals and detailed explanation thereof will be omitted.

In FIG. 1, (5b) is a synchronization signal separation circuit (hereinafter referred to as
5YNCSEP) extracts the horizontal synchronization signal (?) from the brightness video signal St output from the image quality adjustment circuit (11).
ELAY), a burst gate pulse is created at the position where the burst signal of the chroma signal should originally be from the extracted horizontal synchronizing signal.

(52) is a switch circuit, (53) is an amplifier, (54)
is an integrating capacitor, which connects the chroma signal S2 output from the chroma signal processing circuit (31) to the switch circuit (52).
At the same time, it is extracted at the timing of creating the burst gate pulse, and integrated by the capacitor (50) via the amplifier (53). (55) is a microcomputer, and the DC voltage integrated by the capacitor (50) is output to the A/D conversion terminal (50).
5a).

(50) is a second delay circuit (hereinafter referred to as second DELAY), which is used for L P in the chroma signal processing circuit (31).
It is inserted after the F (20) and the microcomputer (55)
), the burst signal of the chroma signal S2 is changed to the luminance signal S1 by the DC voltage output from the C0NT terminal (55b) of the
It is controlled to be temporally synchronized with the horizontal synchronization signal.

Figure 2 shows the above-mentioned amplifier (53) and the second D E
A detailed configuration example of L A Y (50) is shown, and the amplifier (53) amplifies the burst signal of the chroma signal S2 input via the switch circuit (52) using the first stage transistor (Ql). At the same time, the second stage transistor (Q2) sets the bias level near the ground potential, current amplifies only the portion above half of the burst signal, rectifies it with the capacitor (54), and outputs the DC voltage V. .

On the other hand, the second DELAY (50) is an all-pass filter composed of a transistor (Q4), and has delay characteristics as shown in FIG.

That is, the delay time Td of the chroma signal low-frequency converted to 829 KHz is - boat fishing, where ω = 2 πf, f = fi29 K
It is Hz. Here, the FET transistor (Q3) corresponding to R is connected to the C0NT terminal (
55b), the transistor (Q5) is turned on and off to achieve Td.
control.

Next, the operation of the above configuration will be explained. Note that the operations for reproducing the information picked up from the tape (1) by the magnetic head (2) in the luminance signal processing circuit (30) and the chroma signal processing circuit (31) are exactly the same as in the conventional example, so these A detailed explanation will be omitted, and only the operation of the added portion will be explained.

FIG. 4(^) shows a case where the luminance signal S1 output from the luminance signal processing circuit (30) and the chroma signal S2 output from the chroma signal processing circuit (31) are not temporally shifted. Luminance signal S1 to 5YNCS E r) (56
The burst gate pulse Bg and this burst gate are input to the horizontal synchronization port (sync is the first DEI, AY f51) extracted by There is a predetermined positional relationship in time with the burst signal B of Kuromai No. 8 S2 extracted by pulse Bg.

In this case, by rectifying the burst signal B extracted at the timing of the burst gate pulse Bg via the capacitor (54), the integrated voltage V is as shown in FIG. 5(A).
It becomes the maximum as shown by V max of .

FIG. 4 (Bl shows the case where the burst signal [3 of the chroma signal S2 is shifted forward in time with respect to the predetermined position, that is, the horizontal synchronization A8 and 11sync, that is, the case of color advance; this is This corresponds to the position of Vs in FIG. 5(A).

Moreover, FIG. 4(C) shows the burst signal B of the chroma signal S2.
This shows a case where the signal is temporally shifted later than the horizontal synchronizing signal, that is, there is a color delay, and this corresponds to the position of Vs in FIG. 5(B).

In the case of FIG. 4(B) or FIG. 4(C) above, the burst signal B of the chroma signal S2 is extracted at the timing of the burst gate pulse Bg, and this is integrated by the capacitor (50) to integrate V wax. A voltage is obtained. Input this integrated DC voltage ■ to the A/D conversion terminal (55a) of the microcomputer (55), and input it to the C0NT of the microcomputer (55).
The second voltage Vl output from the terminal (55b)
By controlling DELAY (50), it is possible to align the burst signal B and the horizontal synchronization signal Hsmanc to the optimal position, and even when reproducing information that has shifted in color during the recording process, it is possible to By correcting the time difference between the luminance signal and the chroma signal, it is possible to prevent color advance or color delay from occurring on the playback screen.

FIG. 6 is a flowchart showing the details of the operation of the microcomputer (55), and a case will be described in which there is a color advance at the initial setting stage.

First, initialize the 8 voltage values N (step 71).
) with the second I) r': l A Y (50
[・Hi: 1゛First addition to transistor (q3)! tll standard electric IEVO, L I″F C20+ and the second I) l:LAY (Set to 1 ft) so that the total delay time due to 501 matches the delay time during playback of the regular recording deso. There is.

The initial reference voltage VO is input from the CON T terminal (55b) to the register 72), and the input to the A/D conversion terminal 155a) is input to the register A (7°).
At the same time as the step 73), the color advance degree M is initialized (step 74).

Next, step 75) decrements the above N.
From the above J, l;
Step 76). Along with this, △/1 conversion terminal (5
5a) is switched to register B (step 77).
), which allows the FET of the second DELAY (50)
) The gate voltage of transistor (Q3) decreases slightly,
As Td becomes smaller, the color progresses in the direction of -layer color advance.Therefore, in order to initially determine whether or not the color advance is occurring, the contents of registers A and B are compared (step 78).

Here, since there is also a DC fluctuation, the above-mentioned M is incremented in step 79), and the above-described steps 75 to 80 are repeated until M=IO.

If the contents of register B are small until M=10, it is determined that the color is advancing (step 80), N is incremented (step 81), and the above FET transistor (Q3)
The gate voltage of is gradually increased to gradually increase Td, and when it passes the starting point Vs in FIG. 5(A), step 78
In step 82, it is determined that A<B and that there is an initial color advance.

In the case of initial color progression, M = 10, so
N is further incremented (step 87), Td is gradually increased (steps 87, 88, 89), passing through the maximum point V Ila of FIG. =H position is reached (step 90), where the maximum point VIIlax is equal to the starting point Vs
Since the voltage is between the reference voltage VO and the turning point Vc, a voltage obtained by multiplying the reference voltage VO by (1/2) 8 is added to the reference voltage
Output to the NT terminal (55b) (step 91).

Through the above steps, the voltage obtained by integrating the burst signal B becomes the maximum point Vl1ax, and the temporal positions of the luminance signal and the chroma signal are matched.

Further, if there is a color delay in the initial stage, the contents of register A will gradually lower Td in steps 75 and 76, and the contents of register B to be fetched next will increase, so that in step 78, A<B,
Due to the initial color lag, in step 82 M
=O.

Therefore, N is decremented (step 83),
For a given A=
The position B is reached (steps 84, 85, 86), where, as mentioned above, the maximum point 7 ax is the starting point V
s and the turning point Vc, the reference voltage vO
Subtract the voltage obtained by multiplying (1/2) by 8 from the reference voltage vO to obtain C
It is output to the 0NT terminal (55b) (step 91).

Through each of the above steps, the temporal positions of the luminance signal and the chroma signal are matched, as in the case of color advance described above.

FIG. 7 is a block diagram showing the configuration of a reproducing system in a magnetic recording/reproducing apparatus according to another embodiment of the present invention.
30) to (35) are the same as those of the conventional example shown in FIG. io, so the same reference numerals are given to the island portions, and detailed explanation thereof will be omitted.

7, the difference from the conventional example shown in FIG. 10 is that a correction time adjustment section (36) is added for manually varying the length of correction time in the time correction circuit (32). As a specific example of the configuration of this correction time adjustment section (3B), as shown in FIG. 8, a variable resistor (VR) is provided to vary and adjust the correction time.

According to the embodiments shown in FIGS. 7 and 8, the time difference between the luminance signal and chroma signal during playback can be adjusted while checking on the monitor (35), so simulations, etc. There is no need to go through the hassle of determining specification values, and time shifts can be corrected accurately in real time.

Although FIG. 8 shows the correction time adjustment section (3B) provided with a variable resistor (VR), the same effect can be obtained even if a variable capacitance, variable coil, etc. are provided.

[Effects of the Invention] As described above, according to the invention set forth in claim 1, even when playing back a tape in which the luminance signal and the chroma signal are recorded with a time lag, the Since the time difference between the two signals can be automatically corrected, it is possible to prevent color advance or color delay from appearing on the playback screen.

Further, according to the second aspect of the invention, when correcting the time difference between the luminance signal and the chroma signal, the correction time can be manually varied, regardless of the size of the one-hour difference. By accurately synchronizing both signals, it is possible to easily reproduce images that are faithful to the original image.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a reproducing system in a magnetic recording and reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a detailed configuration diagram of the main parts in FIG. 1, and FIG. 3 is a delay characteristic of an all-pass filter. 4 is an explanatory diagram showing the positional relationship between the burst signal and the horizontal synchronization signal, FIG. 5 is a diagram to explain the operation, FIG. 6 is a flowchart showing details of the operation of the microcomputer, and FIG. 8 is a block diagram showing the configuration of a reproducing system in a magnetic recording/reproducing apparatus according to another embodiment of the present invention, FIG. 8 is a configuration diagram of main parts, and FIG. 9 is a block diagram showing the configuration of a reproducing system in a conventional magnetic recording/reproducing apparatus. Block diagram, Fig. 1θ is a block diagram showing the configuration of another conventional example, Fig. 11 is a block diagram showing the configuration of another conventional example.
FIG. 2 is a configuration diagram of the main parts of FIG. (30)... Luminance signal processing circuit, (31)... Chroma signal processing circuit, (32)... Time correction circuit, (36)...
)...Correction time adjustment section, (50)...Second DEL
AY, (51)...first DELAY, (52)...
・Switch circuit, (53)...An7', (54
)...integral condenser? , (55)...Microcomputer. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (2)

[Claims] (1) Means for creating a burst gate pulse at the position where the burst signal of the chroma signal should originally be based on the horizontal synchronization signal of the reproduced luminance signal, means for extracting the chroma signal at the creation timing of the burst gate pulse, and the extracted chroma signal. 1. A magnetic recording and reproducing apparatus comprising: means for temporally controlling a chroma signal so that a burst signal of the signal is temporally synchronized with a luminance signal. (2) It is characterized by comprising means for correcting the time difference between the luminance signal and chroma signal separated during reproduction of the video signal, and means for manually varying the correction time for the time difference. magnetic recording and reproducing device.