JP2000165775A - Waveform shaping device and display device equipped with the same and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waveform shaping device and a display device equipped with this device for displaying a video signal having a synchronizing signal with a part beyond the black level of a video at a display device having a picture frame different from a picture frame in which a video signal is originally displayed, and for waveform- shaping the synchronizing signal for preventing the synchronizing signal from being displayed at the display device, and electronic equipment. SOLUTION: The black level of a video signal is detected by a black level period detecting means 2, and the timing of a period for replacing the black level is adjusted by a black level period extending and delaying means 4. One of a blanking signal, vertical blanking signal, and VD is inputted to a synchronizing signal exchanging period extracting means 5, and the period of the part of the synchronizing signal to be replaced with the black level is extracted. A switch controlling means 6 is controlled by a signal indicating the extracted period, and the output of an analog/ digital converter 3 is replaced with the black level so that the part beyond the black level of the synchronizing signal is replaced with the black level, and the synchronizing signal can be waveform-shaped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveform shaping device, a display device having the same, and an electronic apparatus. More specifically, the present invention relates to a video signal having a synchronization signal exceeding a black level of a video, and the video signal originally displays the video signal. And a waveform shaping device for shaping the synchronization signal so that a portion of the synchronization signal exceeding the black level of the video is not displayed on the display device when displayed on a display device having an image frame different from an image frame to be performed. The present invention relates to a display device and an electronic device.

[0002]

2. Description of the Related Art A case where a conventional HDTV video signal is displayed on a multi-scan monitor having different picture frames will be described with reference to FIGS. FIG. 4 shows an HDTV synchronization signal. As shown in FIG. 4, the HDTV synchronizing signal has three levels: a positive level C exceeding the black level A of the video, a pedestal level B, and a negative level D. The ternary level is adopted as described above because the synchronization separation performance with respect to noise can be improved.

An HDTV video signal has a horizontal synchronization frequency of 33.3.
Since the frequency is 75 KHz and the vertical synchronization frequency is 60 Hz, it can be displayed on a display device such as a multi-scan monitor that supports the horizontal synchronization frequency of 30 KHz and the vertical synchronization frequency of 60 Hz. In fact, most information processing display devices can display HDTV video signals.

[0004]

SUMMARY OF THE INVENTION However, HDT
Since the V video signal is originally configured to be displayed on a display device having an image frame having a horizontal / vertical ratio of 16: 9, the V video signal is displayed on a multi-scan monitor having a horizontal / vertical ratio of 4: 3. , The upper and lower portions of the screen are lost as shown in FIG. However, this display method is already established as a habit.

The problem is that, as shown in FIG. 5B, a portion exceeding the black level of the ternary level synchronizing signal of the HDTV video signal is displayed at the bottom of the screen. Since there is only a blanking function corresponding to the 4: 3 screen in the multi-scan type monitor,
It is necessary to provide a waveform shaping device for erasing a portion of the synchronization signal of the DTV video signal exceeding the black level, or to provide a waveform shaping device in a device on the sending side of the HDTV video signal.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and is intended to convert a video signal having a synchronization signal having a portion exceeding a black level of a video into an image different from an image frame in which the video signal is originally displayed. An object of the present invention is to provide a waveform shaping device capable of displaying on a display device having a frame, shaping a waveform of a synchronization signal, and preventing the synchronization signal from being displayed on the display device, a display device including the same, and an electronic device. .

[0007]

In order to achieve the above-mentioned object, a waveform shaping device according to the present invention, a display device having the same, and an electronic device have a synchronization signal having a portion exceeding a black level of an image. Displaying the video signal on a display device having an image frame different from the image frame where the image signal is originally displayed,
In a waveform shaping device that shapes a synchronization signal and prevents the synchronization signal from being displayed on a display device, a black level period detection unit that detects a black level period of a video from a video signal, and a black level period of the video. A synchronous signal exchange period extracting means for extracting a period of a portion of the synchronous signal video exceeding the black level from a logical product of a signal specifying a synchronous signal period for waveform shaping and an output of the synchronous signal exchange period extracting means. Switch control means for replacing a portion of the synchronization signal exceeding the video black level with the video black level, and switch control by extending and delaying the black level period of the video detected by the black level period detection means. The portion of the synchronization signal replaced by the means exceeding the black level of the video exceeds the black level of the video extracted by the synchronization signal exchange period extracting means. It has and a black level period extended delay means to be included within minute period characterized.

[0008] Further, preferred embodiments of the waveform shaping device of the present invention and a display device provided with the same are as follows (1) to (1).
(4). (1) The synchronous signal exchange period extracting means extracts a period of a portion of all the synchronous signals of the video signal which exceeds the black level of the video. (2) The synchronization signal exchange period extracting means extracts a period of a portion of the vertical blanking period of the video signal which exceeds the black level of the video of the synchronization signal. (3) The synchronous signal exchange period extracting means extracts a period of a portion of the vertical signal (VD) of the video signal which exceeds the black level of the video of the synchronous signal. (4) The synchronizing signal erasing period extracting means extracts a period of a portion of the vertical driving signal (VD) of the video signal which exceeds the black level of the video of every other synchronizing signal.

The operation of the above means will be described below. The black level period of the image is detected by the black level period detecting means from the video signal, and the detected black level period is extended and delayed by the black level period extending delaying means to match the timing, and the black level period with the adjusted timing is adjusted. And a signal specifying the period of the synchronizing signal whose waveform is to be shaped is extracted by a synchronizing signal exchange period extracting means, which extracts a period of a portion of the synchronizing signal exceeding the black level of the video, and during this period, the switch controlling means Accordingly, the portion of the synchronization signal exceeding the black level of the video can be replaced with the black level of the video, and the portion exceeding the black level of the video can be removed from the synchronization signal.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the following, as an embodiment example,
An HDTV video signal is given as a video signal having a synchronization signal having a portion exceeding the black level of a video, and a 4: 3 image such as a multi-scan monitor is used for a 16: 9 image frame where the video signal is originally displayed. A case where the video signal is displayed in a frame will be described. However, the waveform shaping device of the present invention, a display device including the same, and an electronic device are not limited thereto, and a general device having a portion exceeding the black level of a video is generally used. This can be applied to the case of the video signal.

FIG. 3 shows a waveform shaping device 7 according to the present invention. First, the general operation of the waveform shaping device 7 will be described, and then the operations of waveform shaping (1) to (4) to be described later will be described. The HDTV video signal is added with a ternary level synchronization signal by the video output processing circuit 10.
The data is input to the waveform shaping device 7 in the form of bit digital data.

The black level is detected by the black level period detecting means 2. The black level period detecting means 2 is, for example, a digital comparator, and outputs, for example, 1 when the digital data value is larger than the black level value 240 of the HDTV video signal, and outputs 0 when the digital data value is opposite.

[0013] When it is detected that the level is higher than the black level,
The black level period extension delay means 4 extends and delays the period in which the black level has been exceeded. The black level period extension delay unit 4 is configured using, for example, a digital delay circuit 8 and an OR gate 9. At the output of OR gate 9,
A signal is generated which becomes, for example, 1 during the period in which the black level is higher than the black level and becomes 0 with a delay of the digital delay circuit 8 after the time when the black level is lower than the black level.

Thus, the black level period extension delay means 4
The purpose of extending and delaying the black level period is to adjust the timing when the switch control means 6 described later replaces the portion of the synchronization signal to be waveform-shaped with the black level. That is, the portion of the synchronization signal to be shaped of the video signal input to the switch control means 6 is
The timing is adjusted so as to be within the period of the black level generated, extended and delayed by the black level period extension delay unit 4.

The synchronizing signal exchange period extracting means 5 takes the logical product of the output of the black level extension delay means 4 and any one of blanking, vertical blanking, and VD, and calculates the synchronizing signal portion to be replaced with the black level. A signal indicating a period is generated.

The switch control means 6 converts the part of the synchronization signal to be waveform-shaped by the signal indicating the period of the part of the synchronization signal to be replaced with the black level extracted by the synchronization signal exchange period extraction means 5 to the black level of the HDTV video signal. replace.

On the other hand, 10-bit digital data is
3 (digital-to-analog converter), which is converted to an analog signal and input to the switch control means 6, the signal from the synchronous signal exchange period extracting means 5 replaces the portion of the synchronous signal exceeding the black level with the black level. The analog HDTV video signal is obtained from the switch control means 6. The switch 10 is for stopping the operation of the synchronization signal exchange period extracting means 5, and stops when connected to the ground B side. At this time, the original HDTV video signal whose waveform is not shaped is obtained from the switch control means 6.

In this embodiment, the switch control means 6 is constituted by an analog device. However, it is needless to say that the switch control means 6 can be constituted by a digital device. In this case, the DAC 3 becomes unnecessary. In this embodiment, the waveform-shaped HDTV
Since it is assumed that the video signal is supplied to the multi-scan type monitor as it is, only an example of an analog device is shown.

Next, a method of waveform shaping will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 1A shows the HDT shown in FIG.
The ternary level synchronizing signal of the V video signal is shown again along with a vertical drive signal (hereinafter referred to as VD) for comparison below.

The method of shaping the waveform of the ternary level synchronizing signal of the HDTV video signal is classified into the following (1) to (4). The part whose waveform is to be shaped is extracted by the synchronization signal exchange period extracting means 5 described above.

(1) FIG. 1 (b) shows a case where every other portion of the synchronizing signal exceeding the video black level in the VD period is replaced with the video black level. It is.

(2) FIG. 1C shows a case in which all portions of the synchronizing signal exceeding the black level of the video within the VD period are replaced with the black level of the video.

(3) FIG. 2D shows a case in which all portions of the synchronization signal exceeding the black level of the video in the vertical blanking period are replaced with the black level of the video. .

(4) FIG. 2 (e) shows a case in which all portions of the synchronizing signal exceeding the black level of the video are replaced with the black level of the video.

Next, the waveform shaping of the above (1) to (4) will be described in correspondence with the operation of the waveform shaping device 7 with reference to FIGS. 1, 2 and 3. In the case of (1) VD is input to the synchronous signal exchange period extracting means 5, and the logical product is taken with the output of the black level period extending delay means 4, so that V
The portion of the synchronization signal in the period D exceeding the black level is shaped. At this time, the black level period detecting means 2 outputs VD
Are detected only every other synchronization signal within the period. For example, although illustration is omitted, this is performed by using another logic circuit.
The black level period detecting means 2 may be controlled by a pulse generated every other synchronization signal in the period D. As described above, the signal indicating the predetermined period within the VD period and including the portion exceeding the black level of the synchronization signal in every other synchronization signal is obtained from the synchronization signal exchange period extracting means 5. When input to the switch control means 6, the waveform shaping described in (1) is performed.

In the case of (2) VD is input to the synchronous signal exchange period extracting means 5 and the logical product of the VD and the output of the black level period extending delay means 4 is obtained.
For all the synchronization signals in the D period, the portion exceeding the black level is shaped. A signal indicating a period within the VD period and including a portion exceeding the black level of all the synchronization signals is obtained from the synchronization signal exchange period extraction means 5. The waveform shaping described above is performed.

In the case of (3) The vertical blanking signal is input to the synchronous signal exchange period extracting means 5, and the logical product of the vertical blanking signal and the output of the black level period extending delay means 4 is obtained. The portion exceeding the black level is shaped. From the synchronization signal exchange period extracting means 5, a signal indicating a predetermined period within the vertical blanking period and including a portion exceeding the black level of the synchronization signal is obtained.
, The waveform shaping described in (3) is performed.

In the case of (4) The blanking signal is input to the synchronous signal exchange period extracting means 5, and the output of the black level period extending delay means 4 is logically ANDed. Waveform shaping is performed on the portion exceeding. From the synchronous signal exchange period extracting means 5, a signal indicating a period within the horizontal and vertical blanking periods and including a portion exceeding the black level of the synchronous signal is obtained. If this signal is input to the switch control means 6, The waveform shaping described in 4) is performed.

The above-mentioned waveform shaping device 7 may be mounted on an electronic device for transmitting an HDTV video signal, or may be provided on a display device such as a multi-scan monitor.
In any case, when an HDTV video signal is displayed on a screen having a different image frame, a synchronization signal exceeding the black level of the video can be prevented from being displayed.

[0030]

As described above, according to the waveform shaping apparatus of the present invention, a video signal having a synchronizing signal having a portion exceeding the black level of a video is converted to an image different from the frame in which the video signal is originally displayed. It is possible to display on a display device having a frame, shape the synchronization signal so that the synchronization signal is not displayed on the display device, and further display the waveform shaping device of the present invention on the display device, and When the electronic device is provided, there is an effect that a high quality image can be obtained.

[Brief description of the drawings]

FIG. 1 is a timing chart illustrating a method of replacing a portion of a synchronization signal exceeding a black level of a video to be waveform-shaped by a waveform shaping device of the present invention with a black level.

FIG. 2 is another timing chart illustrating a method of replacing a portion of a synchronization signal exceeding a black level of a video to be waveform-shaped by the waveform shaping device of the present invention with a black level.

FIG. 3 is a configuration diagram illustrating a schematic configuration of a waveform shaping device according to the present invention.

FIG. 4 is a timing chart showing a waveform of a synchronization signal of an HDTV video signal.

FIG. 5 is an explanatory diagram illustrating a screen state when an HDTV video signal having a 16: 9 image frame is displayed on a multi-scan monitor having a 4: 3 image frame.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Video output processing circuit, 2 ... Black level period detection means, 3
... Digital-to-analog converter, 4 ... Black level period extension delay means, 5 ... Synchronous signal exchange period extraction means, 6 ... Switch control means, 7 ... Waveform shaping device, 8 ... Digital delay circuit, 9
… OR gate

Claims (7)

[Claims] An image signal having a synchronization signal having a portion exceeding a black level of an image is displayed on a display device having an image frame different from an image frame in which the image signal is originally displayed, and the synchronization signal is waveform-shaped. Then, in the waveform shaping device that prevents the synchronization signal from being displayed on the display device, a black level period detecting unit that detects a black level period of the video from the video signal; and a black level period of the video. Synchronizing signal exchange period extracting means for extracting a period of a portion of the synchronizing signal exceeding the black level of an image from a logical product of the synchronizing signal and a signal designating the period of the waveform, and an output of the synchronizing signal exchanging period extracting means Switch control means for replacing a portion of the synchronization signal exceeding the black level of the video with the black level of the video, and the video signal detected by the black level period detecting means. The portion exceeding the black level of the video of the synchronization signal replaced by the switch control means by extending and delaying the black level period of the video signal is black level of the video extracted by the synchronization signal exchange period extraction means. And a black level period extension delay means for causing the period to be included in the period of the portion exceeding. 2. The waveform shaping apparatus according to claim 1, wherein said synchronization signal exchange period extracting means extracts a period of a portion of all the synchronization signals of the video signal which exceeds a black level of the video. 3. The apparatus according to claim 1, wherein the synchronization signal exchange period extracting means extracts a period of a portion of the synchronization signal exceeding a black level of the video within a vertical blanking period of the video signal. Waveform shaping device. 4. The synchronization signal exchange period extracting means extracts a period of a portion of the synchronization signal exceeding a black level of the video within a period of a vertical drive signal (VD) of the video signal. 2. The waveform shaping device according to 1. 5. The synchronous signal exchange period extracting means extracts a period of a portion of the vertical signal (VD) of the video signal, which exceeds a black level of the video, of every other synchronous signal. The waveform shaping device according to claim 1, wherein 6. A display device comprising the waveform shaping device according to claim 1. 7. An electronic apparatus comprising the waveform shaping device according to claim 1.