JPS5954392A - Video signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent color deletion and color missing, by switching two delay circuits at the rewinding reproducing mode and other modes in a circuit switching a reproduced video signal and a delayed reproduced signal every time when there exists any shift in the interval of horizontal synchronizing signals. CONSTITUTION:A common contact 8c of a switching circuit 8 is selected to the position of contact 8b with a mode signal applied to an input terminal 2 at the high speed rewinding reproducing mode and a 1.5H delay circuit 7 is selected. A 0.5 H delay circuit 6 is selected in other modes. When there exists a skew of 0.5H in the reproducing video signal, an output of a detecting circuit 3 inverts the output of a T FF4 at each time, a switching circuit 9 is changed over and a reproducing video signal without delay and a reproducing video signal with delay are switched alternately for output. The skew is compensated at 0.5H and the disturbance of the order of phase of a chrominance signal is compensated for 1H in the delay time of 1.5H.

Description

[Detailed Description of the Invention] This invention provides video signal recording and reproduction'! Regarding & placement, especially l
For example, in a video tape recorder (referred to as a VTR) that reproduces a PAL video signal from a magnetic tape,
- Improved video signal recording to prevent disturbances in the reproduced image that occur when the video signal recorded with A-Matsu 1- (does not satisfy the average condition) is played back in special playback mode such as high-speed playback. Regarding a playback device.

As is well known, in a cassette VTR that performs inclined azimuth recording using a helical scanning device, the playback output from the video head in special playback modes such as stop, slow, and high-speed playback depends on the azimuth of the head gap matching. Depends on how much of the track you want to trace. That is, reproduction output is obtained from the portion where the video signal recorded on rack 1 and the azimuth of the head match, but there is no reproduction output from the portion where the azimuth does not match, resulting in only noise.

However, formats that do not satisfy the alignment conditions,
For example, if a video signal is recorded in the 4-hour mode of the Vl-IS method or the 2-hour mode of the β method, there will be no problem in the normal playback mode, but in the special playback mode,
A time lag of half the normal horizontal synchronization signal interval (referred to as 0.58 skew) occurs in the horizontal synchronization signal interval between the above-mentioned noise parts, and the H arrangement condition is that the adjacent video tracks This refers to a state in which the recording positions of horizontal synchronization signals are adjacent to each other. For this reason, conventionally, when the horizontal synchronization signal interval becomes discontinuous, the playback video signal through the 0.5H delay circuit and the normal playback video signal are alternately switched to maintain the continuity of the horizontal synchronization signal, and the image It prevented disturbances. However, with PAL video signals where the phase of the color signal is inverted every horizontal synchronization signal @period, it is not possible to correct the horizontal synchronization signal interval, especially when performing high-speed rewind playback. Conversely, the phase order of the color signals is also disturbed. As a result, the color burst signal is no longer detected, and the color killer circuit is activated, resulting in color fading and color omission Gj.

Therefore, the main object of the present invention is to prevent color fading or loss of color when playing back a PAL video signal recorded on a Format 1 format that does not satisfy the -1 average condition in the special playback mode. An object of the present invention is to provide a video signal recording and reproducing device capable of correcting image disturbances.

In summary, the present invention provides a first delay means that has a delay time twice as long as the recording position shift of a horizontal synchronizing signal between adjacent video tracks and delays a reproduced video signal by the delay time; In parallel, a second delay means has a delay time of one horizontal scanning period in addition to a delay time twice the recording position deviation of the horizontal synchronization signal between video tracks, and delays the reproduced video signal by the delay time. A switching means is provided which selects the second delay means in the rewind playback mode and selects the first delay means in other modes. , the undelayed reproduced video signal and the reproduced video signal derived from the first switching means are alternately switched and outputted.

The above objects and other objects and features of the present invention will become more apparent from the following detailed description with reference to the drawings.

The figure is a schematic block diagram showing one embodiment of the present invention. In the figure, an input terminal 1 receives a reproduced video signal reproduced from a magnetic tape (not shown). This reproduced video signal is a PAL format reproduced video signal. Further, input terminal 2 is supplied with a mode signal indicating that the VTR is in high speed rewind playback mode. This mode signal is a signal that is at a high level in the high-speed rewind playback mode and is at a low level in other modes. The reproduced video signal inputted from the input terminal 1 is fed to the 0.5 day skew detection circuit 3. The 0.5 day skew detection circuit 3 detects the occurrence of 0.58 skew in the reproduced video signal.
This is a circuit that detects when something happens. , 0.5 day skew detection circuit 3 is applied to a T-type flip-flop 4. The T-type flip-flop 4 inverts the polarity of its output every time the input signal rises. The output of the T-type flip-flop 4 is given as a switching command signal to a switching circuit 9, which will be described later.Furthermore, the reproduced video signal input from the input terminal 1 is given to a delay circuit 6 and a delay circuit 7. . ;The delay circuit 6 has a delay time (for example, 0.5l-1) that is twice the recording position shift of the horizontal synchronization signal between adjacent video racks 1. In addition to the delay time that the delay circuit 6 has, the delay circuit 7 has a delay time of one horizontal scanning period (eg, has a delay time of 1.5H). The output of the delay circuit 6 is applied to one contact 8a of the switching circuit 8. The output of the delay circuit 7 is given to the other contact 81) of the switching circuit 8. This switching circuit 8 further includes a common contact 8C, and switching is controlled according to the mode signal from the input terminal 2 described above. For example, when the mode signal is at a high level, that is, when the VTR is in the high-speed rewind playback mode, the common contact 8C is connected to the other contact 8b. Conversely, when the L-do signal is low level,
That is, when the VTR is in a mode other than the high-speed rewind playback mode, the common contact 80 is connected to the one contact 8a side. The output derived from the common contact 8C is given to one contact 9a of the switching circuit 9. The other contact 9b of the switching circuit 9 receives the reproduced video signal inputted from the input terminal 1 as is.

The switching circuit 9 further includes a common contact 9C. The switching is controlled according to the output from the T-type flip-flop 4 having a switching circuit. That is, each time the output of the T-type flip-flop 4 is inverted, the common contact 9C is alternately switched to one contact 9a side or the other contact 9b side. The output derived from the common contact 9C is given to the output terminal 10.

Then, from this output terminal 10, a reproduced video signal whose horizontal synchronization interval deviation has been corrected is taken out.

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

First, the case of normal playback mode will be explained. In this case, since the mote signal applied to the input terminal 2 is at a low level, the common contact 8C of the switching circuit 8 is connected to the one contact 8a side.

Here, in the normal playback mode, since 0.51-1 skew does not occur, switching in the switching circuit 9 is not performed. Therefore, if the common contact 9C of the switching circuit 9 is connected to the other contact 9b, the reproduced video signal output from the output terminal 10 is the undelayed video signal input from the human horn terminal 1. ! signal, and conversely, the switching circuit 9
If the common contact 9C is connected to the one contact 9a, then iI! This is a reproduced video signal delayed by 0.5t-1 by the delay circuit 6. Note that regardless of whether the video signal output from the output terminal is a signal delayed by 0.5N or a redundant signal that is not delayed, at this time the switching circuit 8
Since switching is not performed in any of C and 9, the continuity of the horizontal synchronizing signal is maintained.

Next, the case of the fj outside playback mode other than the high speed rewind playback mode will be explained. In this case, since the mode signal given to the pano pane 2 is at a low level, the common contact 8C is connected to the other contact 8a, as in the case of the normal reproduction mode.

Here, suppose that the common contact 9C of the switching circuit 9 is connected to the other contact 91), and if a 0.5H knee occurs, then the output of the flip-flop 4 is reversed and the common The contact 9C is switched to the contact 9a side.Therefore, the reproduced video signal output from the output terminal 10 is switched from the original undelayed reproduced video signal to the reproduced video signal delayed by 0.51-1. This maintains the continuity of the horizontal homogeneous signal and corrects the 0.51-1 square knee.

Next, when the 0.5H skid occurs again and the output of the D-type flip knob 4 is reversed, the common contact 9C is switched to the other contact 9b. Therefore, the reproduced video signal outputted from the output 10 is switched from the reproduced video signal delayed by 0°511 to the original reproduced video signal that is not delayed by 11%. 0.51-(skew is corrected. After 1 meter,
0.51(st-]- occurs 1J, - conversion circuit 9
Then, the reproduced video signal is changed by υ, and the 0.5H skew is corrected.

Next, the case of high-speed rewinding and one-stop playback, which is particularly interesting in this embodiment, will be explained. In this case, since the U-1' signal applied to the input terminal 2 becomes a high 1 novel, the common contact 8c of the switching circuit 8 is switched to the other contact 8b. Therefore, one contact 9a of the switching circuit 9 has 1.5
A reproduced video signal extended by 1 to 1f71 is given. On the other hand, the switching circuit 9'c is switched every time a 0.51'' skid occurs. However, the terminal 10
From then on, the original reproduced video signal without delay and the reproduced video signal delayed by 1.5 days are alternately switched and outputted every time 0.58 skew occurs. Therefore, 0.58 skew is corrected by the delay time of 0.51-1 of lJ: extension time of 1.5H, and the remaining 11
−1 corrects the disturbance in the phase order of the ζ color signal.

As described above, according to the present invention, when a PAL video signal recorded in a format that does not satisfy the requirements f1 to average is played back in the special playback mode, color fading or loss of color does not occur. It is possible to correct image disturbances.

[Brief explanation of the drawing]

The drawing is a schematic block diagram of tW4 showing one embodiment of the present invention. In the figure, 1 is an input terminal into which a reproduced video signal is input;
2 is an input terminal into which a mode signal indicating the high-speed rewind playback mode is input; 3 is a 0°5 day skew detection circuit; 6 and 7 are delay circuits; 8 and 9 are switching circuits (
.

Claims (1)

[Scope of Claims] Video signal recording and playback for reproducing video signals from a magnetic tape on which PAL video signals are recorded in a pine tree in which recording positions of horizontal synchronizing signals are not adjacent to each other between streaming video tracks] The apparatus includes: means for manually inputting a reproduced video signal; means for detecting that an interval of horizontal synchronizing signals included in the reproduced video signal from the input means deviates from a normal interval; a first delay means having a delay time twice the recording position shift of the horizontal synchronization signal between adjacent video tracks and delaying the reproduced video signal from the input means by the delay time; a second delay means having a delay time of one horizontal scanning period in addition to a delay time twice the recording position shift of the second delay means, which delays the reproduced video signal from the input means by the delay time; a rewind reproduction mode; means for inputting a mode signal indicating that the rewinding mode is selected and derived from the output of the second delay means in response to the mode signal; When in a mode other than the reproduction mode, the first delay means selects and derives the output of the first delay means.
in response to the detection signal from the switching means and the shift detection means, the reproduced video signal from the input means and the second
1. A video signal recording and reproducing apparatus comprising: a second switching means that alternately switches and outputs the output derived from the switching means.