JP2841369B2 - Television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to strobe display of a video signal (frame image display).
The present invention relates to a television receiver that has made it possible.

[Summary of the Invention]

The present invention relates to a television receiver, which converts one field of an interlaced scanning input video signal into 2 nV (where n
= 1, 2, 3,..., V is a vertical period), the data is written to the storage means for a first period equal to the one-field period, and then the writing is stopped, By controlling the storage means so as to repeatedly read out the video signal for one field stored in the storage means over a second period longer than the period, fluctuations in the image in the vertical direction during strobe display are avoided. That's what I did.

[Conventional technology]

2. Description of the Related Art Conventionally, there has been proposed a television receiver capable of strobe display (frame image display) of a video signal. In such a conventional television receiver, a memory (video RAM) capable of storing a field signal (a frame signal is also possible) of a video signal is provided. In the strobe display mode, one field of the input video signal is stored for one field period. Over
The data is written into the storage means, and then the writing is stopped, and the data is repeatedly read out over a predetermined field period, for example, 8 field periods.
The video signal for the field is supplied to the CRT for display, and then the writing is stopped, and one field of the input video signal is stored in the storage means for one field period, as described above. By repeating the writing and thereafter, strobe display in which the image changes every nine field periods of the input video signal is performed on the screen of the CRT.

This strobe display is based on the video signal of a certain channel, and the strobe display is performed on the entire screen of the CRT. On the other split screen, there is a screen in which a strobe display based on the video signal of another channel is performed, and the screen is switched between a normal display and a strobe display at predetermined time intervals.

[Problems to be solved by the invention]

By the way, in the television receiver capable of performing the strobe display, as described above, one field of the input video signal is stored in the storage means over one field period every 9 (= 1 + 8) fields, that is, every odd field period. And the writing is stopped thereafter, and the video signal for one field stored in the storage means is repeatedly read out for eight field periods longer than the writing period. In the case of a scanning video signal, 9 fields,
That is, the odd / even of the first video signal field of the video signal written to the storage means for each odd field alternates with odd, even, odd, and ‥‥. In this case, there is a disadvantage that the image appears to fluctuate in the vertical direction.

In view of such a point, the present invention intends to propose a television receiver in which vertical fluctuation of an image during strobe display is avoided.

[Means for solving the problem]

Television receiver according to the present invention, an input video signal selecting means for selecting an input video signal of the jump operation method,
Storage means for storing one field of the input video signal from the input video signal selection means; detection means for detecting a vertical synchronizing signal in the input video signal from the input video signal selection means; The number of vertical synchronizing signals counted is counted, and when the count value becomes 8, the counter means is reset, and when the operation unit for starting the strobe display is operated, based on the count value of the counter means, At every eight vertical periods, the input video signal from the input video signal selecting means is written to the storage means for one field period, and then the writing is stopped, and the video signal for one field stored in the storage means is written. First control means for controlling the storage means so as to repeatedly read out over seven field periods to perform strobe display, and strobe display is performed. During the operation, when an operation of the operation unit for starting the selection of the input video signal selection unit is performed, one field of the first input video signal stored in the storage unit is stored based on the count value of the counter unit. The input video signal selection means is selected such that the input video signal selection means selects the second video signal from the first input video signal within the seven-field period in which the video signal of the same length is repeatedly read out. And second control means for controlling.

[Action]

According to the present invention, when the operation unit for starting the strobe display is operated by the first control unit, the input video signal selection is performed every eight vertical cycles based on the count value of the counter unit. The input video signal from the means is written into the storage means for one field period, the writing is stopped thereafter, and the video signal for one field stored in the storage means is stored so as to be repeatedly read out for seven field periods. The means is controlled to provide a strobe display.

Also, when the operation of the operation unit for starting the selection of the input video signal selecting means is performed during the strobe display by the second control means, based on the count value of the counter means. During the seven-field period in which the video signal for one field of the first input video signal stored in the storage means is repeatedly read, the second input video signal from the first input video signal by the input video signal The input video signal selection means is controlled so that the selection to the video signal is performed.

Embodiment FIG. 1 shows an embodiment of a television receiver according to the present invention, which will be described below. In FIG.
A signal received from the antenna (1) is supplied to a tuner circuit (2), where a television signal of a desired channel is selected, and the selected television signal is converted into a video intermediate frequency signal by the frequency conversion circuit. Is converted to

This television receiver employs a PLL synthesizer type channel selection circuit, and performs AFT control when selecting a channel. Hereinafter, this will be described.

The PLL circuit (3) shown in FIG. 1 includes a pre-frequency divider, a frequency divider, a phase comparator, a reference signal oscillator, and a low-pass filter (all of which are not shown). Then, a local oscillation signal from a local oscillator (not shown) of the tuner circuit (2) is supplied to the phase comparator via a pre-frequency divider and a frequency divider of the PLL circuit (3). On the other hand, PLL
A reference signal from the reference signal oscillator of the circuit (3) is supplied to the phase comparator. In this phase comparator, the output of the frequency divider and the reference signal from the reference signal oscillator are compared in phase, and the comparison output is supplied to the tuner circuit (2) via a low-pass filter. The oscillation frequency of the local oscillator is controlled based on the comparison output.

At the time of the first channel selection, AFT control is performed. That is, the frequency division ratio of the frequency divider of the PLL circuit (3) is set so that the local oscillation frequency is close to the frequency corresponding to the normal carrier frequency. This frequency division ratio is set by the microcomputer (4) based on the channel data stored in advance. Then, the local oscillation frequency is moved stepwise upward and downward, that is, AFT control is performed. AFT
When a television signal is pulled in by control, offset channel data based on the frequency division ratio at that time is stored. At the next channel selection, a desired channel is selected using the offset channel data stored at the time of the first channel selection.

By the way, in the microcomputer (4),
Various commands such as a channel switching command and a source switching command are given from the key switch (5) and the remote control transmitter (6). When a channel switching command is given to the microcomputer (4), the frequency division ratio of the frequency divider of the PLL circuit (3) is reset for a desired channel.
When a source switching command is given to the microcomputer (4), the first switch circuit (7) is switched according to the commanded input source.

The video intermediate frequency signal output from the tuner circuit (2) is supplied to an intermediate frequency signal processing circuit (8). The intermediate frequency signal processing circuit (8) amplifies the video intermediate frequency signal, detects the video, and outputs a composite color video signal. This composite color video signal is supplied to the first switch circuit (7).

An input terminal (9) for an external video signal is supplied with an external composite color video signal from a video device such as a VTR or a video disc playback device. The external composite color video signal from the input terminal (9) is supplied to a first switch circuit (7).

In the first switch circuit (7), a color video signal is switched by a control signal output from the microcomputer (4) based on a source switching command of the remote control transmitter (6) or the key switch (5). Will be That is, one of the composite color video signal from the intermediate frequency signal processing circuit (8) and the external composite color video signal from the input terminal (9) is selected by the first switch circuit (7).

The composite color video signal output from the first switch circuit (7) is supplied to a Y / C separation circuit (10).

The Y / C separation circuit (10) converts the selected composite color video signal into a luminance signal Y and red and blue difference signals RY and BY.
And the luminance signal Y and the color difference signals RY, BY
A / D conversion circuit (11) and second switch circuit (12)
And a vertical synchronizing signal separated from the luminance signal to the microcomputer (4).

Y / C separation circuit (10) via second switch circuit (12)
The luminance signal Y and the color difference signals R-Y and B-Y are supplied to a color video signal processing circuit (13),
R, G, and B are demodulated, and the three primary color signals R, G, and B are converted to a color CRT (1
4) is supplied to display a color image.

On the other hand, the A / D conversion circuit (11) converts the luminance signal Y, the color difference signals RY and BY supplied from the Y / C separation circuit (10) into A / D signals, respectively.
Convert. One field (one frame is acceptable) of the digital luminance signal and both digital color difference signals from the A / D conversion circuit (11) is stored in a field memory (video RAM) (frame memory also specified by the controller (16)). Possible) It is sequentially written to the address of (15). The memory (15) is used when performing frame photographing display (strobe display) based on a command from the remote control transmitter (6) or the key switch (5).

When a channel switching command or a source switching command for switching the channel of the television signal is input to the microcomputer (4) from the remote control transmitter (6) or the key switch (5), the microcomputer (4) Control signal is supplied to the controller (16).

The controller (16) writes and reads a digital video signal (digital luminance signal and both digital color difference signals) in the memory (15) and a second switch circuit (12) based on a control signal from the microcomputer (4). ) Is controlled. Then, based on the control signal input thereto, the controller (16) writes the digital video signal to the memory (15) for one field period, and then stops (freezes) it. As a result, in the memory (15), the odd or even field is set to one of the last and even fields by the microcomputer (4). ] Is stored. Controller (1
6) reads out the digital video signal, performs D / A conversion by a D / A conversion circuit (17), and outputs a luminance signal Y, a color difference signal RY, B
-Y is obtained and supplied to the second switch circuit (12). Further, the controller (16) supplies a switch switching signal to the second switch circuit (12), and the luminance signal Y, the color difference signals RY, BY from the D / A conversion circuit (17) are converted to a color image. The signal is supplied to the signal processing circuit (13).

The luminance signal Y and the color difference signals RY and BY are demodulated as three primary color signals R, G and B by a video signal processing circuit (13) and supplied to a color CRT (14) to perform strobe display. Will be

Then, a digital video signal for one field of the odd or even field in the memory (15) is read out, and a color CRT (1) is displayed as a strobe display image composed of seven still images.
The switching operation of the input color video signal is performed during the seven field period displayed in 4). This switching operation is, for example, in the case of a television signal, to lock the frequency of a new channel by the PLL circuit (3) and pull in a new television signal. When the input source of the composite color video signal is changed, switching between the television signal and the external composite color video signal from the video device is performed. For this reason, a disturbed image due to the flow of synchronization or a blank image subjected to blanking is not displayed, and a comfortable use feeling can be provided to the user. This operation is performed by the software of the microcomputer (4) that controls the memory (15), and can be realized with a small burden on the software and no cost increase.

Then, after the digital video signal in the memory (15) is read for a period of 7 fields, the same one field of the digital video signal, which is odd and even, is again written in the memory (15) within one field period, and then the writing is performed. Is stopped, the digital video signal is read out for seven field periods, and strobe display is performed on the color CRT (14). In this case, the still image is
Switching at (1/60) × 8 = 1 / 7.5 second intervals makes it easy to see as strobe display, and the input video signal for one field written to the memory (15) is always a video signal for even or odd fields. Since it is fixed, vertical fluctuation of the image is avoided.

In the above-described embodiment, the luminance signal Y, the color difference signals RY, BY from the Y / C separation circuit (10) and the D / A conversion circuit (17) are provided by the second switch circuit (12). ), The luminance signal Y and the color difference signals RY and BY are switched. However, the present invention is not limited to this. For example, as shown in FIG.
The output terminal of the D / A conversion circuit (17) may be directly connected to the video signal processing circuit (13). That is, the control signal from the microcomputer (4) is transmitted to the controller (16).
When the digital video signal is input to the memory (15), the writing of the digital video signal to the memory (15) is stopped, the digital video signal in the memory (15) is read, and D / A conversion is performed by the D / A converter (17). At the same time, a control signal is supplied from the controller (16) to the color video signal processing circuit (13) to perform blanking. The video signal from the D / A converter (17) may be superimposed on the blanked video signal to display a still image on the color CRT (14).

The operation of this embodiment, particularly the operation during strobe display, will be described below with reference to the flowchart of FIG.

First, in step ST-1, the presence / absence of detection of the vertical synchronization signal separated from the luminance signal Y by the Y / C separation circuit (10) is determined by the vertical synchronization signal detection means of the microcomputer (4). When a signal is detected,
Move on to step ST-2.
Return to ST-1.

In step ST-2, the count value of the counter (counter means) for counting the vertical synchronization signal of the microcomputer (4) is incremented by one each time the vertical synchronization signal arrives from zero. In this case, it is determined whether to start counting the vertical synchronization signal from the vertical synchronization signal of the odd or even field.

In step ST-3, whether or not the count value of the counter has reached 8 is determined by the count value detection means for detecting the count value of the counter of the microcomputer (4). Moves to step ST-4, and if not 8, moves to step ST-6.

In step ST-4, the counter control means of the microcomputer (4) sets the count value of the counter to 0 (reset), and proceeds to step ST-5. Step ST
In -5, the instruction means of the microcomputer (4) determines whether the writing (freezing) (and thus the end of reading) of the digital video signal (digital luminance signal and both digital color difference signals) to the memory (15) is performed by the controller. After instructing (16), the process returns to step ST-1.

In step ST-6, the count value detecting means for detecting the count value of the counter of the microcomputer (4)
It is determined whether or not the count value of the counter has become 1; if the count value of the counter has become 1, the process proceeds to step ST-7; otherwise, the process returns to step ST-1.

In step ST-7, after the instruction means of the microcomputer (4) instructs the controller (16) to end (freeze) the writing of the digital video signal to the memory (15) (and thus start the reading), ST−
Return to 1.

According to the television receiver described above, the storage means (1
Since the odd and even fields of the video signal stored in 5) are fixed to either odd or even fields,
Vertical fluctuation of the image during strobe display is avoided.

〔The invention's effect〕

According to the present invention described above, the vertical fluctuation of the image during the strobe display is avoided, and the image of the strobe display is disturbed when the input video signal is switched, or a black image with blanking is displayed. And a television receiver that is not likely to be damaged.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing a part of another embodiment of the present invention, and FIG.
The figure is a flowchart for explaining one embodiment. (2) is a tuner circuit, (3) is a PLL circuit, (4) is a microcomputer, (13) is a color video signal processing circuit, (15) is a memory, and (16) is a controller.

Claims (1)

(57) [Claims] 1. An input video signal selecting means for selecting an input video signal of a jump operation method, a storage means for storing one field of an input video signal from the input video signal selecting means, and the input video signal selecting means Detecting means for detecting a vertical synchronizing signal in the input video signal from the CPU, counter means for counting the number of vertical synchronizing signals detected by the detecting means, and resetting when the counted value reaches 8, and strobe display. When the operation section is operated to start the operation, the input video signal from the input video signal selecting means is stored for one field period every eight vertical periods based on the count value of the counter means. Means, and then stop writing, so that the video signal for one field stored in the storage means is repeatedly read over a seven-field period. First control means for controlling the storage means to perform strobe display; and operation of an operation unit for starting selection of the input video signal selection means during the strobe display. If there is, the video signal for one field of the first input video signal stored in the storage means is repeatedly read out within the seven-field period based on the count value of the counter means. And a second control means for controlling the input video signal selecting means so that the input video signal selecting means selects the first input video signal to the second video signal. Television receiver.