JPS62271586A - Magnetic picture recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent the picture deterioration due to color fade-out by stopping the occurrence of a signal for compensating color fade-out or blocking the propagation of said signal during an intermittent drive period that the drive and stop of a magnetic recording medium are alternately repeated. CONSTITUTION:During a still picture reproducing period being the period of stopping the drive of a tape, a track jump pulse TJP signal for compensating color fade-out and a signal delay amount switching signal DLC are inputted to a video signal processing circuit 109. Thus continuity in the circuit 109 is restored to prevent the occurrence of color fade-out. During the intermittent drive period that the drive and stop of the tape are alternately repeated, a reproduction signal is almost the same as in normal reproduction, and no discontinuity of a chiromance component occurs. Consequently, the occurrence or propagation of the signal for compensating color fade-out is blocked. In such a way, the continuity of the chrominance signal can be secured even in the middle of the intermittent drive and reproduction, and color fade-out never occurs, whereby a picture is not deteriorated.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing device, and more specifically, a device compatible with the European Television System that performs variable speed playback by intermittent magnetic tape drive. The present invention relates to a magnetic recording and reproducing device.

[Conventional technology]

In a rotating head helical scan type magnetic recording/reproducing device (hereinafter abbreviated as VTR), in addition to normal playback, in which the magnetic tape is run at the same constant speed as when recording,
For example, as seen in Japanese Unexamined Patent Publication No. 59-116950, magnetic tape is driven intermittently, that is, stops and drives are repeated alternately, and still image playback when stopped and normal playback when driven. It has an intermittent drive playback function that alternately repeats the above operations, thereby realizing noiseless slow motion.

On the other hand, in addition to the NTSC system used in Japan and the United States, television systems include the NTSC system used in Japan and the United States, as well as the book by Yokoyama et al. As described, P belonging to the European Television System (CCIR system)
There are AL method and SECAM method.

In this CCTR system, "8mm Video Color Signal Processing Circuit" by Kanryu et al., Technical Report Vol. 1 of the Society of Television Engineers.
8. Na24. VH25-8, p, 41-p, 4
6 (October 1984), in a variable speed playback mode such as still playback, the color signal becomes discontinuous, and the monitor's color killer circuit operates, causing color fading.

In order to compensate for color fading, a track jump pulse (Track Jump Pulse) representing the point in time when the head crosses a track (track jump) is used.

It is necessary to generate a signal (hereinafter abbreviated as TJP) and to switch the amount of signal delay.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, no consideration is given to compensation for color fading during the intermittent drive playback operation in a VTR compatible with the CCIR system, which is the European television system.
When performing intermittent playback with the CCIR compatible VTR,
There is a problem in that the color signal of the reproduced image during the intermittent drive period becomes discontinuous, resulting in color fading.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording and reproducing device equipped with an improved video signal processing control circuit that prevents color fading during intermittent playback in a helical scan VTR compatible with the CCrR television system. It is in.

[Means to solve the problem]

The above-mentioned object includes a detecting means for detecting a discontinuous point in a reproduced color signal, and a correcting means for correcting the discontinuous point in the color signal using a discontinuous point detection signal detected by the detecting means. In a magnetic recording and reproducing apparatus compatible with the television system, during a period of still reproduction performed when the drive of the magnetic recording medium is stopped, the discontinuity detection signal detected by the detecting means is used to adjust the color by the correcting means. Although signal discontinuity is corrected, when the magnetic recording medium is driven intermittently, in which driving and stopping are repeated alternately, means for disabling the function of the detection means for detecting discontinuities in the reproduced color signal is provided. This is achieved by disabling the discontinuous point detection signal.

[Effect]

During the still playback period, which is the period when the tape drive is stopped, the video signal processing circuit receives the TJP signal for color fading compensation,
A signal delay amount switching signal is input manually to restore continuity of color signals within the video signal processing circuit and prevent color fading from occurring.

On the other hand, during the intermittent drive period in which the tape is alternately driven and stopped, the playback signal is generally the same as normal playback, and no discontinuity occurs in the color signal, so the intermittent drive control signal The generation of the signal for erasure compensation is stopped or the propagation of the signal is cut off.

By doing the above, the continuity of color signals is ensured even during intermittent drive reproduction, so that color fading and image deterioration do not occur.

〔Example〕

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a system block diagram showing an example of the overall configuration of a rotating head helical scan type VTR as an embodiment of the present invention.

Here, for convenience of explanation, a 4-frequency pilot signal as seen in Japanese Patent Publication No. 53-116120 is superimposed on a video signal and recorded on a video track, and during playback, these pilot signals are used for tracking control. In a VTR that performs this, an intermittent drive control method, as seen in Japanese Patent Laid-Open No. 59-116950, is adopted in which the number of pulses from the frequency detector of the magnetic tape drive motor is counted to determine the amount of magnetic tape feed. This will be explained using an example.

First, a head helical scan type VTR system according to the present invention will be briefly described with reference to FIG.

In FIG. 1, 101 is a magnetic tape, 102 is a capstan, 103 is a capstan motor, 104 is a cylinder, 105, 406, 133 are video heads, 107 is a cylinder motor, 108 is a video signal input terminal, 109 is a video signal a processing circuit, 110 a pilot signal generation circuit;
111, 120, 124 are adders, 112 is a recording amplifier, 113 is a low retransistor, 114, 122
are frequency detectors, 115 and 123 are frequency discriminators, 116 is a tack head, 117 is a head phase adjustment circuit, 118 is a reference signal input terminal, 119 is a phase comparator, 121 and 125 are motor drive circuits, 1
26 is a preamplifier, 127 is a video signal output terminal, 128
, 130 are low-pass filters (hereinafter abbreviated as LPF), 129Ll is an ATF circuit, 131 is a system control circuit, and 132 is an intermittent drive control circuit.

First, during recording, the magnetic tape 101 is connected to the capstan 102.
It is driven by and runs in the direction of the arrow. This capstan 102 is rotationally driven in the direction of the solid line arrow by a capstan motor 103.

On the other hand, video heads 105 and 106 attached to the cylinder 104 at a distance of 180 degrees from each other are connected to the cylinder motor 1.
07 and rotates in the direction of the dashed arrow.

This cylinder 104 is attached to a rotating shaft that is inclined with respect to the longitudinal direction of the tape 101, and is driven to rotate at a frequency that is twice the vertical synchronizing signal frequency of the recorded video signal.

On the other hand, the video signal VD applied to the video signal input terminal 10B and signal-processed by the video signal processing circuit 109 and the recording pilot signal RECPLT generated by the pilot signal generation circuit 110 are added by an adder 111 and recorded. The signal is amplified by an amplifier 112 to form a recording signal R3, which is supplied to video heads 105 and 106 via a rotary transformer 113 and recorded on a video track on the tape 101.

Next, the operation during playback will be explained.

In FIG. 1, the rotational speed of the cylinder motor 107 is detected by a frequency detector 114, and this detection signal DFG is sent to a frequency discriminator 115 to convert it into a speed control voltage SDD according to the rotational speed. adder 120,
Cylinder motor l'07 via motor drive circuit 121
is supplied to rotate the cylinder 104 at around a predetermined rotational speed.

Next, the rotational phase of the video heads 105 and 106 is detected by the tack head 116, and this detection signal TP is sent to the phase adjustment circuit 117, which outputs a head phase detection signal SW.
and the reference signal REF at the terminal 118 to the phase comparator 119.
, and the phase error signal is sent to an adder 120 . By returning to the cylinder motor 07 via the motor drive circuit 121, the video heads 105, 106, 133 are rotated in phase synchronization with the reference signal REF.

On the other hand, the rotational speed of the capstan motor 03 is detected by the frequency detector 122, and this detection signal CFG is sent to the frequency discriminator 123, which outputs a speed control voltage SD corresponding to the rotational speed.
C, and this voltage SDC is sent to an adder 124. By supplying the capstan motor 03 via the motor drive circuit 125, the capstan 102 is rotated at a predetermined rotational speed.
drive the rotation.

Further, the signal PS reproduced from the tape 101 by the video heads 105 and 106 is sent to the preamplifier 126 via the rotary transformer 113 and amplified. The amplified playback signal RF is sent to the video signal circuit 109 to become a playback video signal, and is output to the video output terminal 127.
The regenerated pilot signal PBPL is transmitted through the LPF 128 of
T and is sent to the ATF circuit 129.

The method of forming the tracking error signal AFTSIG from the reproduced pilot signal PB PLT is described, for example, in
3-116120, and will not be described in detail here.

Tracking error signal ATFS from ATF circuit 129
After the IG is sufficiently smoothed by the second LPF 130, it is sent to the motor drive circuit 125 via the adder 124, and the capstan motor 103 is rotationally driven at a predetermined rotation speed and phase.

FIG. 2 is an explanatory assembly diagram showing a specific example of the configuration of the rotating cylinder 104 in FIG. 1. FIG.

Figure 3 is National Technical Report V, a magazine published by Matsushita Electric Industrial Co., Ltd. 1.2811h3 (1982
) is an explanatory diagram showing an example of a video trunk on a magnetic tape (indicated by a broken line) and a head scanning trajectory (indicated by a solid line) during intermittent drive playback, according to the trunk pattern coordinate method described in Indicates a noiseless state. The hatched area in the figure shows the area where video output can be obtained by head scanning, and the horizontal axis shows time, and the divisions show the time at which the head phase detection signal SW changes, that is, the video head switching point. The vertical axis shows the amount of tape travel.

FIG. 4 is a diagram of signal waveforms at various parts in the circuit of FIG. 1 when the magnetic tape is driven intermittently as shown in FIG. 3.

Hereinafter, with reference to FIGS. 1 to 4, an overview will be given of the operation when a magnetic tape is driven intermittently to perform intermittent playback.

Here, as described above, a case will be explained assuming that the tape feeding amount by intermittent driving is defined by the count value of the number of pulses from the frequency detector 122 attached to the capstan motor 103.

The intermittent drive command signal SC from the system control circuit 131 is sent to the pilot signal generation circuit 110.degree. intermittent drive control circuit 132, and transitions to the intermittent drive regeneration state.

In this intermittent drive playback state, the pilot/two signal generating circuit 110 generates the ATF circuit 129 when the head scanning position is in a noiseless state during the tape running stop period.
The tracking error signal ATFSIG, which is the output of
5 and, as shown in FIG.
The same azimuth angle as the CH-1 head 105 installed at 2.5H (H: distance corresponding to 1 horizontal opening signal period) behind the head (in Fig. 2, the case of ■ azimuth is shown)
The scanning video head during the intermittent drive period is the CH-1 head 105 and the CH-2 head 106 having an azimuth angle different from that of the CH-1 head 105, as in normal playback. Suppose that

The intermittent drive control circuit 132 outputs capstan motor control signals C, C0NT [4th
Figure C)] starts the capstan motor 103.

After starting the capstan motor 103, as described above, the head switching signal H3W [FIG. 4b] is sent to the video signal processing circuit 109 via the preamplifier 126 to switch the scanning video head to the CH-1 head 105 and CH-2 head 1
06 (in Fig. 4, the head phase detection signal SW
is "L", CH-1 head 105. C when “H”
The H-2 head 106 or the CH-3 head 133 becomes the scanning head, and when the head switching signal H3W is "L", the CH-2 head 106. (The figure shows the case where the CH-3 head 133 becomes the scanning head when the signal is H'').

Output signal CFG of frequency detector 122 obtained according to rotation of capstan motor 103 [Fig. 4 d), e)
] When the number of pulses reaches a predetermined count value N, the intermittent drive control circuit 132 outputs a reverse rotation command signal REV [FIG. 4f)] to the capstan motor drive circuit 125, and the capstan motor 103 generates reverse torque,
Reverse braking is performed to stop the rotation of the capstan motor 103.

During the stop period, the level of the tracking error signal ATF SIG created from the reproduced pilot signal PBPTL is set to be the same as the average level during normal reproduction in the noiseless state, as described above. A deviation from the position can be detected as a deviation from the average level, and the next tape feed amount is controlled by increasing or decreasing the count value N of the number of pulses of the CFG signal according to the amount of deviation.

Next, using Fig. 5, Fig. 6, Fig. 7, and Fig. 8,
V compatible with European Television System (CCIR system)
The TJP signal and signal delay amount switching, which are essential for variable speed reproduction in TR, will be explained.

Here, for convenience of explanation, an example will be described in which the head scanning position during the tape running stop period is at the field still position shown in FIG. 2.

FIG. 5 to FIG. 7 are tape pattern diagrams (partial) in a rotating head helical scan type VTR according to the present invention.
FIG. 5 shows an example of the standard mode (Standard mode).
d Play (hereinafter abbreviated as SP mode), αH (
The tape pattern diagram when the scanning line recording position deviation between adjacent trunks determined by the tape feed speed is 2.0 H, and Figure 6 shows the long-time mode (1, on Play,
(hereinafter abbreviated as LP mode), α.

is 1. FIG. 7 is a tape pattern diagram in the case of OH, and is a tape pattern diagram in the extended mode (Extended Play, hereinafter abbreviated as SP mode) when α□ is 0.5H.

In Figures 5 to 7, the numbers inside the video trunk (shown with solid lines) are horizontal scanning line numbers, and the speed ratio of SP mode, LP mode, and SP mode is 1:'A:W. do.

FIG. 8 is an explanatory diagram showing an example of the horizontal scanning area scanned by the video head when performing field still in a CCIR compatible VTR, in which a) is in SP mode, b)
shows the case of LP mode, and c) shows the case of SP mode.

In the field still playback shown in FIG. 8, the number of playback horizontal synchronization signal sections scanned by the video head (hereinafter referred to as the playback H number) is 312 for one field period in the CCIR system.
．． 5H and αH (SP mode 1, OH, LP mode: 1
．． OH, SP mode: 0°5H). Also,
As mentioned above, the CH-3 head 133, which serves as the scanning video head during still playback, is installed 2.5H behind the CH-2 head 106, which serves as the scanning video head during normal playback. As shown, the scanning position of CH-3 head 133 is 2.5 mm from CH-1 head 105.
The position is shifted to the left by H minutes.

In FIG. 8a), the CH-1 head 105 scans from IH to 314.5H (-312,5H+2.OH) (CH-2 head 106 also scans the same position).

On the other hand, CH-3 Herad 133 is from 622,5H,
Scan up to 312H. Here, CH-3 head 13
At the point in time when the scanning of No. 3 is completed and the RAD 105 starts scanning to CH-1, the switching of the color signal every horizontal period, which is a feature of the CCIR method, is performed in the same way as in normal reproduction (in Fig. 8, -) to (+).The (+) and (-) signs indicate that the subcarrier phase is switched every horizontal period in the PAL system, and that the color difference signal is switched in the SECAM system. (shown). Therefore, no breakdown occurs in the color signal.

Meanwhile, the scanning of the CH-1 head 106 has been completed, and the CH-3 head 106 has finished scanning.
At the time when the head 133 starts scanning, the color signal changes from (+) to (-) during one horizontal period, causing a breakdown in the color signal.

Therefore, at the end of scanning of the CH-1 head 106, that is, at the rising phase of the head phase detection signal SW,
A TJP signal is required for color fading compensation (indicated by a broken line in the figure).

Compensation for color fading using the TJP signal is also described in "Color Signal Processing Circuit for 8mm Video" written by Kanyanagi et al., and since it has little to do with the present invention, it will not be described in detail here.

FIG. 8b) shows the case of LP mode, but α.

is 1. This is the same as the case in Figure 8a), except that it is OH and the TJP signal is required at the falling phase of the head phase detection signal SW, and can be easily inferred. The explanation will be omitted.

Figure 8C) is for the SP mode, but Figure 8A),
The difference from the SP mode and LP mode shown in b) is that α is 0.58, so the CH-1 head 105
The scanning start and end points are the beginning and end points of the horizontal scanning section (312.5H+0.5H=313H).

Therefore, since the scanning position of the CH-3 head 133 at the start and end of scanning is in the middle of the horizontal scanning section, not only the color signal but also the luminance signal is corrupted.

In order to prevent this video signal from failing, the playback signal from the CH-1 head 105 or CH-3 head 133 is set to 0.
．． 5) A method of delaying by one equivalent period of time is used (No. 8).
The figure shows a case where the reproduced signal from the CH-1 head 105 is delayed).

According to this method, as shown in the figure, the failure of the luminance signal and color signal can be resolved at the same time, and the TJP signal required in the above-mentioned SP mode or LP mode is not required.

Next, embodiments of the present invention will be specifically described with reference to FIGS. 9 to 16.

The feature of the embodiment of the present invention is that the intermittent drive playback is an alternating repetition of still playback and normal playback, so the TJP signal or signal delay amount switching signal necessary for color fading compensation during the still playback period is The objective is to prevent deterioration of the reproduced image due to unnecessary compensation by prohibiting the occurrence of achromatic compensation or blocking the signal during the normal reproduction period, that is, the intermittent drive period, when achromatic compensation is unnecessary.

FIG. 9 is a block diagram showing a specific example of the preamplifier 126 and the video signal processing circuit 109 in FIG. 1.

In FIG. 9, 200 is a CH-1 head reproduction code amplifier, 201 is a CH-2 head reproduction code amplifier, 202 is a CH-3 head reproduction code amplifier, 203 is a first switch, and 204 is a second switch. 205 is a video signal output amplifier, 206 is a luminance signal processing circuit, 207 is a color signal processing circuit, 208 is a 0.5H delay circuit, 209 is a third switch, 210 is a TJP signal processing circuit, 211 is a mixer It is.

FIG. 10 shows the video signal control circuit in the intermittent drive control circuit 132 in FIG. FIG. 2 is a circuit diagram showing an example of the configuration of a processing circuit.

In FIG. 10, 212 is a video signal control circuit;
．． 301, 304, 306, 307, 311.312 are AND gates, 302.320 are inverters, 303, 305 are OR gates, 308
, 313 are respectively centric flip-flops (
(hereinafter abbreviated as R3-FF), 309, 310, and 317 are edge detectors, 314 and 318 are signal delay circuits, 315 is an intermittent drive circuit, and 316 is a NAND gate.

11, 13, and 15 show the video track on the magnetic tape (indicated by broken lines) and the head scanning locus during intermittent playback (indicated by solid lines), respectively, based on the trunk pattern coordinate method as shown in FIG. 3. ) is an explanatory diagram showing an example of
Each in SP mode.

Shows the case of LP mode and LP mode (however, the tape travel amount on the vertical axis is normalized by trunk pitch)
. 12, 14, and 16 are signal waveform diagrams of each part in the video signal control circuit 212 configured as shown in FIG. 10, and correspond to FIGS. 11, 13, and 15, respectively. , SP mode.

This is the case of LP mode.

First, the operation in the SP mode will be described with reference to FIGS. 9, 10, 11, and 12.

During the still playback period during intermittent drive playback, the video head that obtains the playback signal is connected to the CH-1 head 105 and the CH-1 head 105.
Since there are three heads 133, the second switch 204 in the preamplifier 126 in FIG. 9 is switched to the terminal 1 side.

In FIGS. 9 and 12, the reproduced signal PS from the low retransformer 113 is sent to the preamplifier 126, and C)(
-1 head reproduction code amplifier 200°CH-2 head reproduction code amplifier 201. CH-3 head reproduction code amplifier 20
It is amplified by 2. The amplified playback signal is sent to the first switch 203 according to the (No. 8 level) of the head phase detection signal SW.
．． The signal is sent to the second switch 204. During the still playback period, as described above, since the second switch 204 is switched to the terminal 1 side, the CI-1-3 head playback symbol is transferred to the first switch 203 via the second switch 204. Sent. (At this time, the head switching signal H3W is "H" as explained in Fig. 4) [Fig. 12 a), e)
reference].

As described in the explanation of FIG. 4, the first switch 203 is switched to the terminal 0 side when the signal level of the head phase detection signal SW is "L", and the CH-1 head reproduction symbol is When the head phase detection signal SW is "H", it is switched to the terminal 1 side, selects the CH-3 head reproduction symbol, and sends it to the video signal output amplifier 205.

The reproduced signal RF further amplified by the video signal output amplifier 205 is inputted separately to a luminance signal processing circuit 2061 and a color signal processing circuit 207 in the video signal processing circuit 109 and processed therein. The output of the color signal processing circuit 207 is
However, as explained using FIG. 8, in the case of the SP mode described here, a 0.5H signal delay is not required, so the third The switch 209 is switched to the terminal 0 side by the signal delay amount switching signal DLC (when the level of the signal delay amount switching signal is "H", it is switched to the terminal 1, and when it is "L", it is switched to the terminal O side). Figure 12g)].

The output of the third switch 209 is the TJP signal processing circuit 2
In the case of the SP mode, discontinuity in the color signal is canceled in response to the TJP signal [FIG. 12 f)] of the rising phase of the head phase detection signal SW. TJP signal processing circuit 21
0, the continuous color signal is sent to the mixer 211, mixed with the luminance signal from the luminance signal processing circuit 206, and output as a regular video signal (the TJP signal processing circuit 210 signal processing is not performed if is not input).

Next, referring to FIG. 9, FIG. 1O, and FIG. 12, the operation during the intermittent drive period of the intermittent drive regeneration in the SP mode will be explained.

In Figures 10 and 12, system control 1
．． 1 frame sending signal F of the control signal SC from 31
ADV causes an intermittent drive period.

■The frame sending signal FADV is the first R3-FF30
8 [Fig. 12b)] and the AND gate 311
is in a conductive state. On the other hand, the head phase detection signal SW is
Inverter 302, 320, AND gate 30h NA
It is input to an ND gate 316 and edge detectors 309 and 310. The falling edge signal of the head phase detection signal SW from the edge detector 309 is input to the reset terminal R1 of the first R3-FF 30B via the AND gate 311, and resets the first R3-FF 308. 1
Figure 2 b > 1. By blocking the AND gate 1-311 and preventing the subsequent propagation of the falling edge signal of the head phase detection signal SW, the intermittent drive is prevented from overlapping and malfunctioning. is sent to the set terminal S2 of R3-FF313 to set the second R3-FF313 [first
At the same time, the signal is sent to the intermittent drive circuit 315 via the first signal delay circuit 314 to start intermittent driving of the magnetic tape [FIG. 12C)].

The output of the second R3-FF313 [Fig. 12 d)] is O
The signal is inverted through the R gate 305, delayed through the second signal delay circuit 318, and outputted through the fourth switch 319 to the AN signal.
is input to the D gate 306 (here, in the case of SP mode, it is assumed that the fourth switch 319 is switched to the SP side, and the signal delay amount of the second signal delay circuit 318 is such that the intermittent drive operation starts. (assumed to be greater than or equal to the pulse width of the TJP signal generated at the falling phase of the head phase detection signal),
AND gate 306 is shut off.

On the other hand, the AND gate 306 includes inverters 302, A
ND Gate 300. The opposite phase signal of the head phase detection signal SW is inputted through the OR gate 303, but as mentioned above, the AND gate 306 is cut off, so the signal is not propagated to the edge detector 317. , the TJP signal is not output until the second R3-FF 313 is in the cent state [FIG. 12f), the broken line indicates the TJP signal whose output is prohibited].

Further, the Q output of the second R3-FF 313 is input to the NAND gate 316, and the output of the NAND gate 316 indicates that the head phase detection signal SW during the intermittent drive period is “H”. ”2 in Figure 9 during the period
This becomes a head switching signal H3W that switches the switch 204 to the terminal O side.

When the intermittent drive ends [FIG. 12C], the capstan motor control signals C and C, which are the outputs of the intermittent drive circuit 315,
The AND gate 312 becomes conductive due to the negative phase signal of 0NT.

The rising edge signal of the head phase detection signal is inputted to the AND gate 312 from the edge detector 310.
The AND gate 312 detects the rising phase of the head phase detection signal immediately after the intermittent drive ends, and the second R3-FF31
3 [Fig. 12 d)].

When the second R3-FF313 is reset, the NAND
The head switching signal H3W, which is the output of the gate 316, is H”
Also, the OR gate 305, the second signal delay circuit 318 . AND gate 3 via fourth switch 319
The signal input to the inverter 302 . AND
K) 300, the negative phase signal of the head phase detection signal SW via the OR gate 303 is inputted to the edge detection circuit 317 through the AND gate 306, and starts outputting the TJP signal again [FIG. 12 f )], video signal processing is performed using the still replay amount.

Next, regarding the LP mode, the difference from the previously described SP mode is that the TJP signal is generated at the rising phase of the head phase detection signal SW.

Therefore, in the LP mode, since the TJP signal is not generated at the time when the intermittent drive operation starts, the signal delay by the second signal delay circuit 318 is not necessary. Therefore, the fourth switch 319 is switched to the LP side in the LP mode.

The other points are exactly the same as the operation in SP mode, and the 9th
10, FIG. 13, FIG. 14, and the explanation for the SP mode, the operation in the LP mode can be easily inferred, so the explanation will be omitted.

Next, the case of SP mode will be explained using FIG. 9, FIG. 10, FIG. 15, and FIG. 16.

Here, only the points that are different from the SP mode, r mode, and p mode will be mentioned.

The difference between SP mode, SP mode, and LP mode is that, as mentioned in the explanation of FIG. 8, in SP mode,
The signal for compensating for color fading is not the TJP signal but the signal delay amount switching signal DLC.

9, FIG. 10, and FIG. 16, the head phase detection signal SW is transmitted to the inverter 320. The signal is input to AND gate 307 via AND gate 304 . The reverse phase output of the output of the second R3-FF3]3 is input to the AND gate 307, and is in a conductive state during the still reproduction period as described in the explanation of the SP mode. For this reason, AND
The output of the gate 307, the signal delay amount switching signal DLC, becomes "L" when the head phase detection signal SW is "H".
In the case of "L", it becomes "H" [Fig. 16g)].

In FIG. 9, the output of the color signal processing circuit 207 is input to the third switch 209 via the third switch 209 or the 0.5H delay circuit 208, and the third switch 209 switches the amount of signal delay. By switching to the terminal 1 side when the signal level of the signal DLC is "H" and to the terminal 0 side when it is "L", the reproduced signal during the period when the head phase detection signal SW is "L", that is, the CH-1 head The reproduced signal of 105 can be delayed by 0.5 H, and color fading can be prevented.

Next, in the intermittent drive period, the output of the second R3-FF 313 [Fig. 16 d)] is determined at the rising edge of the head phase detection signal SW, which starts the intermittent drive operation, as explained in the case of the sp mode. In the period from the falling phase to the rising phase of the head phase detection signal SW immediately after the end of intermittent driving, it becomes "H" and the output of the OR gate) 305 becomes "L", so the AN
T) Game I-307 is cut off and the signal delay amount switching signal D
The waveform shown by the broken line in FIG. 16g) of the LC is not output.

Next, another embodiment of the present invention will be described using FIGS. 17 and 18. Features of other embodiments of the present invention include generation of a TJP signal or signal delay amount switching signal for achromatic loss compensation;
The purpose is to use a microcomputer to prohibit generation or cut off signals during intermittent drive regeneration.

FIG. 17 shows another specific example of the intermittent drive control circuit 132 in FIG. FIG. 18 is a flowchart showing the processing procedure in the intermittent drive control circuit configured as shown in FIG. 17.

In FIG. 17, 400 is an input/output port, 401 is a logical operation unit (hereinafter abbreviated as ALU), 402 is a random access memory (hereinafter abbreviated as RAM), 403 is a read-only memory (hereinafter abbreviated as ROM), and 404 is a program A counter (hereinafter abbreviated as PC), 405 an instruction decoder (hereinafter abbreviated as ID), and 406 an edge detector.

Hereinafter, the operation of another embodiment of the video signal control of the intermittent drive control circuit according to the present invention will be explained using FIGS. 17 and 18 and according to the flowchart of FIG. However, the detailed operation inside the microcomputer is well known and has no direct relation to the present invention, so a description thereof will be omitted.

Intermittent drive command S from system control circuit 131
At C, the intermittent drive control circuit 132 starts intermittent drive regeneration.

In FIG. 17, the head phase detection signal SW from the head phase adjustment circuit 117 is input to the edge detector 406 via the human output port 400.

Edge detector 406 detects the rising phase and falling phase of head phase detection signal SW and outputs interrupt request signal IRQ to A Lu2O3.

In response to this interrupt request signal IRQ, the program flow transitions from the intermittent drive control program 500 to the video signal control program in the RAM 402 or ROM 403 as shown in FIG. 18 (501 in FIG. 18).

In the video signal control program, the recording tape speed (
(SP mode, LP mode, BP mode), intermittent drive status (capstan motor control signal C9CONT, reverse rotation command signal REV, head phase detection signal SW, etc.)
Fig. 18 502). After that, it is determined whether the color signal of the video signal is discontinuous at a trunk jump point (503 in FIG. 18), and if it is not a track jump point, a scanning head selection determination is performed (507 in FIG. 18). ), and in the case of a trunk jump point, the recording tape speed judgment (first
8 (Fig. 8, 504).

Recording tape speed judgment is based on the recording tape speed.
This is because the processing is different as explained in FIGS.

When the recording tape speed is in SP mode or LP mode, the process goes through the TJP signal generation routine (505 in Figure 18) to determine the scanning head selection (507 in Figure 18), and in the case of EP mode, the signal delay amount switching is performed. Signal generation routine (first
The process branches to scanning head selection determination (507 in FIG. 18) via step 506 in FIG. Since the forms of the TJP signal and the signal delay amount switching signal have already been explained in the previous embodiment, they will not be specifically mentioned here.

In the scanning head selection determination (507 in FIG. 18), it is determined whether the scanning head is the CH-2 head 106 or the CH-3 head 133 according to the intermittent drive situation,
When selecting the CH-2 head 106, the processing of the video signal control program is finished, and when selecting the CH-3 head 133, after branching to the head switching signal generation routine (508 in FIG. 18), the video signal is The processing of the control program ends (509 in FIG. 18).

During the intermittent driving period, in the determination of the track jump point (503 in FIG. 18), since there is no color signal discontinuity point during driving as described above, the scanning head selection determination (503 in FIG. 18) is immediately performed. 507),
TJP signal or signal delay amount switching signal D for color fading compensation
LC is not output.

The effect of stopping the generation of the achromatic compensation signal or blocking the signal propagation during the intermittent drive period is the same as in the previous embodiment, so
The explanation will be omitted.

In the above embodiments, the edge detection circuit of the head phase detection signal SW is performed using an edge detection circuit as an example. The present invention is also effective even when a method is used in which the head phase detection signal is frequently referred to and the time point at which the level changes is used.

By doing the above, when performing intermittent drive playback in a helical scan VTR compatible with the European television system, it is possible to stop the generation of a color fading compensation signal or interrupt signal propagation during the intermittent drive period. Therefore, the continuity of color signals is ensured even during intermittent drive reproduction, and it is possible to prevent image deterioration due to color fading.

In the above embodiment, a VTR configured to perform tracking control using a 4-frequency pilot signal has been described as an example, but the present invention is not limited to this, and tracking control may be performed using other methods. It is also applicable and effective for VTRs.

In the above embodiment, the CH-3 head is installed at a position 2.5H behind the CH-2 head, and αH is set at 2.5H in sp mode. Although the explanation has been given by taking as an example the case where the value is 1.0H in the OH, LP mode and 0.5H in the BP mode, the present invention is not limited to this, and can be appropriately modified and is effective.

〔Effect of the invention〕

According to the present invention, it is possible to prevent image deterioration due to color fading when performing intermittent playback in a helical scan VTR compatible with the Denrotsuba television system.

[Brief explanation of the drawing]

FIG. 1 is a system block diagram showing an example of the overall configuration of a rotary helical force scan type VTR as an embodiment of the present invention, and FIG. 2 is an assembly explanatory diagram showing a specific example of the configuration of the rotating cinder 104 in FIG. 1. , FIG. 3 is an explanatory diagram showing an example of a video trunk on a magnetic tape and a head scanning locus during intermittent drive playback, and FIG. 4 is an illustration of the circuit of FIG. 1 when the magnetic tape is driven intermittently as shown in FIG. 5 to 7 are tape pattern diagrams, FIG. 8 is an explanatory diagram showing an example of the horizontal scanning area scanned by the video head, and FIG. 9 is a diagram showing the main parts of FIG. 1. A block diagram showing an example, Fig. 10 is a block diagram showing a specific example of other main parts, Fig. 11 is an explanatory diagram at SP momo time similar to Fig. 3, and Fig. 12 corresponds to the S I) mode. FIG. 13 is an explanatory diagram in LP mode similar to FIG. 3, FIG. 14 is a signal waveform diagram of each part in FIG. 10 corresponding to LP mode, and FIG. An explanatory diagram in the LP mode similar to FIG. 3, FIG. 16 is a signal waveform diagram of each part in FIG. 10 corresponding to the LP mode, and FIG. 17 is an explanation showing still another specific example of the main part in FIG. 1. FIG. 18 is a flowchart showing the flow of processing operations in the circuit of FIG. 17. Explanation of symbols 132...Intermittent drive control circuit, 109...Video signal processing circuit, 212...Video signal control circuit, 210...
- TJP signal processing circuit, 207... color signal processing circuit,
208...0,5H delay circuit, 126...Preamplifier representative Patent attorney Akio Namiki Fig. 13 Fig. 14 (g) DLC Fig. 15 1116 Fig.

Claims (1)

[Scope of Claims] 1. A detection means for detecting a discontinuity point in a reproduced color signal, and a correction means for correcting the discontinuity in the color signal using a discontinuity detection signal detected by the detection means; In a magnetic recording and reproducing apparatus compatible with the European television system, the discontinuity point detection signal detected by the detecting means is used to detect the discontinuous point during the still playback period when the drive of the magnetic recording medium is stopped. The discontinuity of the color signal is corrected by the correction means, but during intermittent driving in which the magnetic recording medium is alternately driven and stopped, means for disabling the function of the detection means for detecting discontinuity points in the reproduced color signal. Prepare
A magnetic recording and reproducing device characterized in that a discontinuous point detection signal is disabled.