JPH05143041A - Display device - Google Patents

Abstract

PURPOSE:To provide the display device which is applicable to more modes by detecting the frequencies of a horizontal and a vertical synchronizing signal and their polarities and performing multi-mode control. CONSTITUTION:The display device consists of a frequency detecting circuit 11 which detects the horizontal synchronizing frequency and vertical synchronizing frequency and their synchronism polarities and outputs the detection results as a code signal and an electronic variable resistor 1 which selects plural previously stored voltage values with the code signal outputted from the frequency detecting circuit 11 and outputs the DC voltages to a deflecting circuit block 5 and a power circuit block 6, thus providing the multi-mode type display device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device capable of inputting video signals having a plurality of different sync signal frequencies and changing the deflection frequency corresponding to each sync signal frequency for display.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for display devices to display finer characters, graphics, images, etc., and therefore, the sync signal frequency has increased and devices having sync signals of various frequencies have appeared. Therefore, multi-mode display devices have been developed in which the deflection frequency can be changed corresponding to a plurality of different sync signal frequencies.

In order to realize such a multi-mode display device, an electronic volume IC for selecting and outputting a plurality of preset voltage values by a mode signal from the outside has come to be used.

A conventional display device will be described below with reference to the drawings. As shown in FIG. 2, the display device includes an electronic volume 1, a video circuit block 2, a cathode ray tube (hereinafter abbreviated as CRT) 3, a deflection yoke 4, a deflection circuit block 5, a power supply circuit block 6, a sync separation circuit 7, and the like. It is configured.

With respect to the display device having the above components, the relationship and operation of the components will be described below.
First, the video signal input from the input terminal 8 is input to the CRT 3 via the video circuit block 2 and an image is displayed. The video signal is also input to the sync separation circuit 7,
The horizontal synchronizing signal and the vertical synchronizing signal are separated and input to the deflection circuit block 5. The sync separation circuit 7 detects the polarities of the horizontal sync signal and the vertical sync signal, and supplies the results to the electronic volume 1 via the sync polarity signal line 10.

In the deflection circuit block 5, power is supplied from the power supply circuit block 6 and a deflection current is supplied to the deflection yoke 4.

On the other hand, in the electronic volume 1, commands and data are input from the communication signal line 9 to deflect the DC voltage output and store the DC voltage value data. Then, a DC voltage corresponding to the sync polarities of the horizontal synchronizing signal and the vertical synchronizing signal is output from a plurality of DC voltage values stored in advance, and is supplied to the deflection circuit block 5 and the power supply circuit block 6.

Next, the operation of the multi-mode control will be described. The electronic volume 1 stores the DC voltage value supplied from the communication signal line 9 to each circuit block.

Now, a horizontal synchronizing signal is applied to the electronic volume 1,
Further, DC voltage values corresponding to four combinations of polarities of the vertical synchronizing signal are stored as shown in (Table 1).

[0010]

[Table 1]

When the polarities of the horizontal synchronizing signal and the vertical synchronizing signal included in the video signal inputted from the input terminal 8 are both positive, the sync separating circuit 7 and the sync polarity signal line 10 are connected.
The signal of the state (a) of (Table 1) is output to the electronic volume 1 via. In the electronic volume 1, the DC voltage value in the state (a) of (Table 1) is output to each circuit block. The deflection circuit block 5 operates at a deflection frequency corresponding to the DC voltage Va1, and the power supply circuit block 6 supplies an output voltage corresponding to the DC voltage Va2 to the deflection circuit block 5.

Next, when a video signal is input from the input terminal 8 and the polarities of the horizontal synchronizing signal and the vertical synchronizing signal both change to the negative polarity, the sync separation circuit 7 sends an electronic signal through the sync polarity signal line 10. For volume 1 (Table 1)
Signal of state (d). In the electronic volume 1, the DC voltage value in the state (d) of (Table 1) is output to each circuit block. In the deflection circuit block 5, the DC voltage Vd1
The power supply circuit block 6 supplies the deflection circuit block 5 with an output voltage corresponding to the DC voltage Vd2.

Similarly, when the input synchronizing signal changes to the other states (b) and (c) of (Table 1), the DC voltage value corresponding to each circuit block from the electronic volume 1 is changed. Is output.

As described above, the deflection frequency can be changed by storing four types of DC voltage values in the electronic volume 1 in which the polarities of the horizontal synchronizing signal and the vertical synchronizing signal are combined and switching the polarities of the synchronizing signals. it can. Therefore, if data is stored in the electronic volume 1 so that the deflection frequency differs depending on the polarity of the synchronization signal, the multi-mode control can be easily realized.

[0015]

However, in the above configuration, since multi-mode control is performed by the sync polarity, only four types of modes can be supported. Further, since it is necessary to freely change the polarity of the synchronization signal, the polarity of the synchronization signal is fixed for the input of the composite synchronization signal or the video signal in which the synchronization signal is superimposed on the video signal. It has a problem that it cannot perform multi-mode control.

The present invention solves the above-mentioned conventional problems, and a display device capable of supporting more modes by detecting the frequencies and polarities of the horizontal synchronizing signal and the vertical synchronizing signal and performing multimode control. The purpose is to provide.

[0017]

In order to achieve the above-mentioned object, a display device of the present invention inputs a horizontal sync signal, a vertical sync signal and a sync polarity signal output from a sync separation circuit to obtain a horizontal sync frequency. , A vertical sync frequency and a sync polarity are detected, and a frequency detection circuit having means for outputting the detection result as a code signal, and a plurality of voltage values stored in advance are selected by the code signal output from the frequency detection circuit. , And an electronic volume that outputs a DC voltage, and has a configuration in which each circuit block is multimode-controlled by the output of the electronic volume.

[0018]

According to the present invention, the multi-mode control is performed by using the frequency detecting circuit in the above-mentioned structure, so that the electronic volume can cope with a plurality of frequency states up to the maximum storage capacity.

Further, since the sync polarity is also detected, compatibility with the conventional system can be achieved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the display device of the present invention has the same components as those of the conventional example shown in FIG.

The present embodiment differs from the conventional one in that the frequency detection circuit 11 is newly provided. The operation of the display device configured as described above will be described with reference to FIG. First, the video signal input from the input terminal 8 is separated into a horizontal sync signal and a vertical sync signal in the sync separation circuit 7. Further, the polarities of the horizontal synchronizing signal and the vertical synchronizing signal are detected, and the result is output to the synchronizing polarity signal line 10.

In the frequency detection circuit 11, the sync separation circuit 7
The horizontal sync signal, the vertical sync signal, and the sync polarity signal separated by are input, the horizontal sync frequency and the vertical sync frequency are detected, and the code signal is output according to the result and the status of the sync polarity signal. The code signal output from the frequency detection circuit 11 is sent via the detection code signal line 12 to the electronic volume 1
To enter.

On the other hand, in the electronic volume 1, commands and data are input from the communication signal line 9 to change the DC voltage output and store the DC voltage value data. Then, a DC voltage corresponding to the code signal is output from a plurality of DC voltage values stored in advance and supplied to the deflection circuit block 5 and the power supply circuit block 6.

Next, the operation of the multimode control will be described. Now, the DC voltage value corresponding to the code signal is stored in the electronic volume 1 as shown in (Table 2).

[0026]

[Table 2]

When the sync signal contained in the video signal input from the input terminal 8 is in the state (a) of (Table 2), the frequency detection circuit 11 outputs the code signal as shown in the state (a) of (Table 2). Is output. With electronic volume 1 (Table 2)
The corresponding DC output voltage value of is output to each circuit block. The deflection circuit block 5 operates at a deflection frequency corresponding to the DC voltage Va1, and the power supply circuit block 6 supplies an output voltage corresponding to the DC voltage Va2 to the deflection circuit block 5.

Next, when the state of the synchronizing signal input from the input terminal 8 changes to the state (d) in (Table 2), the code signal from the frequency detection circuit 11 to the electronic volume 1 (see Table 2). 2) It changes like the state (d). The electronic volume 1 outputs the corresponding DC voltage value of (Table 2) to each circuit block. The deflection circuit block 5 operates at a deflection frequency corresponding to the DC voltage Vd1, and the power supply circuit block 6 supplies an output voltage corresponding to the DC voltage Vd2 to the deflection circuit block 5.

Similarly, when the input synchronizing signal changes to another state shown in (Table 2), the electronic volume 1 outputs the corresponding DC voltage value to each circuit block.

As described above, if the DC voltage value of the electronic volume 1 is set to a value that operates at the corresponding deflection frequency with respect to the code signal output from the frequency detection circuit 11, the horizontal synchronizing frequency and the vertical synchronizing frequency are set. It is possible to easily realize multimode control in which the deflection frequency can be switched depending on the frequency and the polarity of the synchronization signal.

[0031]

As is apparent from the above embodiments, according to the present invention, the frequency detection having means for detecting the horizontal synchronizing frequency, the vertical synchronizing frequency and the synchronizing polarity and outputting the detected result as a code signal. The multi-mode control is configured by a circuit and an electronic potentiometer that outputs a DC voltage by selecting a plurality of voltage values stored in advance by the code signal output from the frequency detection circuit, thereby enabling the horizontal synchronization frequency and the vertical synchronization frequency. , And the polarity of the sync signal, and an excellent display device capable of performing multi-mode control corresponding to video signals with more sync signal frequencies can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of a display device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional display device.

[Explanation of symbols]

 1 Electronic Volume 5 Deflection Circuit Block 6 Power Supply Circuit Block 7 Sync Separation Circuit 11 Frequency Detection Circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 3/27 7037-5C 5/66 D 7205-5C

Claims (1)

[Claims] 1. A video signal having a plurality of different sync signal frequencies is input, and a horizontal sync signal is input from the input video signal.
A sync separation circuit having means for separating a vertical sync signal and a sync polarity of the horizontal sync signal and the vertical sync signal; and a horizontal sync signal, a vertical sync signal, and a sync polarity output from the sync separator circuit. A signal is input to detect a horizontal synchronizing frequency, a vertical synchronizing frequency, and a synchronizing polarity, and a frequency detecting circuit having means for outputting the detection result as a code signal, and a code signal output from the frequency detecting circuit in advance. A deflection voltage corresponding to the DC voltage output from the electronic volume is selected by the deflection circuit and an electronic volume that outputs individual DC voltages to the power supply circuit. It operates at a frequency and is arranged so that the power supply circuit outputs an output voltage corresponding to the DC voltage output by the electronic volume. Display device.