JP3368796B2 - Display circuit controller - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a multi-scan display circuit capable of displaying video signals from both a television receiver and a personal computer.

[0002]

2. Description of the Related Art A conventional television signal display device, as described in the NHK television technical textbook issued by the Japan Broadcasting Corporation, is a point scan capable of displaying only a signal of a specific limited frequency. The display.

Further, a conventional personal computer signal display device detects a synchronizing signal frequency of an input video signal and other input conditions, as shown in Japanese Patent Publication No. 6-93174, for example, and converts the result into an input signal. It was a multi-scan display controlled by a control device that determines and outputs display circuit control data for proper image display.

[0004]

When displaying both a personal computer signal and a television signal in the multi-scan display as described above, compared to the personal computer signal,
Since the television signal frequently changes in the synchronizing frequency of the input signal due to changes in the electric field strength, switching of the CH, and the like, and the change width is large, the television signal in the multi-scan display for personal computer signals described as the prior art. The control method when is displayed is to detect the frequency of the input signal, detect the detection result, consider the detection error, the influence of noise, etc., and determine whether the input signal has changed from the signal currently used for control. If it is determined that the input signal has changed, the preset data is calculated when the detected input signal is registered as a preset signal, and the control data is calculated from the detected frequency value of the input signal when it is not registered, and that data is output. Performs the operation of displaying.

Since there is almost no frequency change when displaying a normal personal computer signal, the multi-scan display for a personal computer quickly responds to the change in frequency even when there is a change in frequency, and calculates control data from the input frequency. It is displayed based on that data. However, when the electric field strength of the terrestrial wave is weak, the frequency of the input signal of the television signal fluctuates frequently when switching channels, so when displaying the television signal on a normal PC multi-scan display, the In order to deal with the change in frequency, the change in output data and the data output frequently occur, which causes a problem that the stable display of the video screen cannot be performed.

Since various personal computer signals have the same synchronizing signal frequency as that of a specific television signal, in order to optimally display two different types of input signals, It was necessary to enable different motion control at the same frequency.

In view of the above problems, the present invention uses a switching means for switching between a display for a personal computer signal and a display for a television signal, and switches the control method in both modes, specifically, a signal for a personal computer and a television signal. Switch the frequency change detection confirmation time, change determination confirmation time, and change determination frequency permissible range.When selecting a personal computer signal, perform multi-scan control of the personal computer signal data and change the frequency of the television signal. The present invention provides a display circuit control device capable of performing stable and optimal display of an input signal for both of the above signals by performing point scan control using television signal data when selected.

[0008]

In order to solve the above-mentioned problems, the control device of the present invention uses a means for switching the display of a personal computer signal and a television signal to determine the fixed time and the change judgment of the frequency change detection of the input signal. The first means for solving the problem is to switch the frequency permissible range, and by the means for switching between the personal computer signal and the television signal, the personal computer is selected as a multi-scan display and the television is selected as a point scan display. Circuit control is the second means for solving the problem,
It holds one or more of the first and second means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention uses a signal from a switching means for switching the display of a personal computer signal and a television signal to determine the frequency change detection time of the input signal and the change judgment. A display circuit control device characterized by switching a frequency permissible range, wherein a fixed time and a change in frequency change detection for realizing stable operation are performed for each of a PC signal selection and a television signal selection. The values of the allowable frequency range of judgment are held separately for the television and the personal computer, and even when the frequency of the frequency fluctuation and the width of the frequency fluctuation are different between the personal computer signal and the television signal, by switching and using the values, This has the effect of enabling stable image display for each of the two signals.

According to a second aspect of the present invention, there is provided a switching means for controlling display switching between a personal computer signal and a television signal, a frequency measuring section for measuring a frequency of an input signal, and the frequency measuring section. A frequency change detection unit that determines a frequency change of the input signal based on the output, a control data determination unit that determines signal control data corresponding to the input signal based on a signal from the frequency change detection unit, and a signal control data A storage unit that holds the data necessary for the decision,
The frequency change detection unit is provided with a data output unit for outputting the signal control data, and the frequency change detection unit uses a signal from the switching unit to determine a frequency change detection time depending on whether the personal computer signal is selected or the television signal is selected. It is a display circuit control device characterized by switching the frequency allowable range for change judgment, and when selecting a signal for a personal computer,
For each selection of the television signal, the fixed time of frequency change detection for achieving stable operation and the value of the frequency allowable range of change determination are held separately for the television and the personal computer. Even when the frequency variation frequency and the variation width of the John signal are different, by switching and using the values, it is possible to achieve stable image display for each of the two signals.

[0011]

[0012]

(Embodiment 1) An embodiment of a display circuit control device according to the present invention will be described below with reference to FIG.
This will be described with reference to FIGS. 2 and 3.

FIG. 1 shows a configuration of a control device for implementing the present invention. In FIG. 1, reference numeral 1 is a microcomputer in a control circuit, which is for a horizontal synchronizing signal, a vertical synchronizing signal, a personal computer signal and a television signal. To output a television / PC switching signal for selecting which signal to display, an input port for inputting a display circuit control data adjustment signal, and a display circuit control signal for display control of the display Holds the output port of. Reference numeral 2 is a non-volatile memory connected to the microcomputer 1.

FIG. 2 shows a block diagram of a software configuration in the microcomputer 1. In FIG. 2, 3 is a frequency measuring unit for the horizontal synchronizing signal and the vertical synchronizing signal input to the microcomputer 1, and 4 is a frequency. It is a frequency change detection unit that detects a frequency change between the measurement result data of the measurement unit 3 and the frequency data currently used for display circuit control.

When the frequency change detection unit 4 determines that the frequency of the input signal has changed due to the signal from the frequency measurement unit 3, the frequency data determined by the frequency measurement unit 3 and the television / PC switching signal are used. The control data determination unit 5 is a control data determination unit for controlling the display circuit based on the switched mode (state) and the data stored in the nonvolatile memory 2.

A data output unit 6 outputs the control data determined by the control data determination unit 5 to the display circuit for control.

FIG. 3 shows a flow chart for the change detecting process of the frequency change detecting unit 4, which is executed after the frequency measuring unit 3 is executed. In FIG. 3, fnew is the horizontal frequency data measured in 3 above, fold is the horizontal frequency data confirmed in 4 above, and fnext is a temporary value until the fnew changes from the fold and is confirmed. Further, Ntv is a definite time for frequency change detection in the television mode, Wtv is a permissible variation range of frequency data in the television mode, which is variable according to the frequency data as an argument. Npc is a fixed time for frequency change detection in the personal computer mode, Wpc is a function that takes frequency data as an argument, and is a permissible variation range of frequency data in the personal computer mode, which varies depending on the frequency data of the argument. n is a time counter for confirming the frequency change detection.

The frequency measuring unit 3 and the frequency change detecting unit 4 are regularly and continuously executed. The operation of the frequency change detector 4 will be described with reference to FIG.

Fnew measured by the frequency measuring unit 3 is
First, a comparison is made with the current fixed frequency fold. In the comparison between fnew and fold, since there are variations in the measured values, it is determined whether the frequency is changing within the allowable range of the amount of change. The allowable range is different for television signals and PC signals, so it can be switched.
Allowable range Wtv (fold) when selecting television signal
Is, for example, fold / 100, and the permissible range Wpc (fold) at the time of selecting a signal for a personal computer is
By setting it to 0, it is possible to double the allowable change range for the television signal as compared with that for the personal computer and to widen the pull-in range.

Next, in the comparison between the frequency fnew and the frequency fold, the frequency difference is outside the allowable range, and n =
If it is 0, the value of fnew is set in fnext, and n = 1 is set, and the process is ended.

In the comparison between fnew and fold, if the frequency difference is outside the allowable range and n is not 0, then fn
ext and fnew are compared. Also in this comparison, the allowable range Wtv (fnext) and the allowable range Wpc (fnext) are the same as in the comparison of the frequencies of fnew and fold.
t). When fnew is within the change allowable range of fnext, if the counter n is equal to or less than the definite time of the input signal, n is incremented and the process ends. on the other hand,
When the fixed time is exceeded, it is determined that the change of the input frequency is fixed, and the value of fnext is substituted for the fixed frequency fold.

This fixed time is Ntv, for example, 8 when the television signal is selected, and the fixed time Np when the personal computer signal is selected.
By setting c to 4, for example, it eliminates the hypersensitivity to changes such as noise when selecting a television signal than when using a signal for a personal computer, and when inputting a signal for a personal computer, responds swiftly to switching input signals. Is possible.

If the frequency comparison is outside the allowable change range, then n = 0 is set and the process is terminated.

Next, the control data determination section 5 and the data output section 6 operate only when the fold changes, so that useless operations can be eliminated.

In this way, the processes of the frequency measuring unit 3 and the frequency change detecting unit 4 are continuously operated at regular intervals, and in the operation in the frequency change detecting unit 4, when a television signal is selected, | fold-fnew | > Wtv (fold) and | fnext-fnew | <Wtv (fnext) are satisfied consecutively Ntv times, or when selecting a personal computer signal, | fold-fnew |> Wpc (fol
d) and | fnext-fnew | <Wpc (fnext
If the condition of t) is satisfied Npc times in succession, it is determined that each frequency has changed and is confirmed, and the value of fnext is substituted for the confirmed frequency fold.

With this configuration, the frequency measuring unit 3 and the frequency change detecting unit 4 are periodically operated with respect to the horizontal synchronizing signal and the vertical synchronizing signal, and the change in the input synchronizing signal frequency by the frequency changing detecting unit 4 is waited and confirmed. By operating the control data determination unit 5 and the data output unit 6 by using the above-mentioned fold, it is possible to quickly respond to changes in the input signal when inputting a signal for a personal computer, and even when inputting a television signal, Even when the input signal is not stable, it is filtered in the above 4, so that unnecessary operation transition can be eliminated.

(Second Embodiment) Next, another embodiment of the present invention will be described with reference to FIGS. 1, 2 and 4.
1 and 2 are the same as those in the above-described embodiment,
Save the explanation.

FIG. 4 is a schematic diagram of the above-mentioned non-volatile memory 2. In FIG. 4, 7 is a data table for a television signal, which is horizontal synchronizing signal frequency data, vertical synchronizing signal frequency data, and display circuit control data. The block composed of is composed of several blocks. Reference numeral 8 is a data table for personal computer signals, which includes the frequency of the horizontal synchronizing signal, the polarity data, the frequency of the vertical synchronizing signal,
A block composed of the polarity data and the display circuit control data is composed of several blocks. Reference numeral 9 is composed of reference data for calculating the default control data of the display circuit based on the frequency data of the horizontal and vertical synchronizing signals of the input signal.

FIG. 5 is a flowchart showing the operation of the control data determining section when switching between the television signal and the personal computer signal and when the frequency changes. That is, FIG. 5 is a flowchart for explaining the operation of the control data determination unit 5 that determines the output data from the frequency value determined by the frequency change detection unit 4. This flowchart will be described.

The method of determining the control data corresponding to the frequency value fold determined by the frequency change detector 4 can be switched between the time of selecting the television signal and the time of selecting the personal computer signal. For a television signal, the frequency value is fold from the television signal data table 7 of the non-volatile memory 2.
And a block that is re-close to is searched, and the control data of that block is used as the output data. In the case of a personal computer signal, the non-volatile memory 2 personal computer signal data table 8 is searched to see if there is a block with the same frequency value as fold.
When the same data block exists, the control data of the corresponding block is used as output data, and when the same data block does not exist, it is calculated by using the display circuit control reference data 9 and the display circuit control reference data 9 of the display circuit control reference data 9. Determine the output data.

With such a configuration, when the frequency data determined by the frequency change detection unit 4 changes, the control data determination unit is operated according to the flowchart shown in FIG. Thus, for the television signal, the point scan operation is performed by using the data 7 for the television signal, and for the signal for the personal computer, the multi-scan operation is performed by using the data table 8 for the personal computer signal and the reference data 9 for controlling the display circuit. Is possible.

Further, when the personal computer signal is selected, the control data adjusting means shown in FIG. 2 adjusts the control data to an optimum value and saves it in the personal computer signal data table of the non-volatile memory. The optimum display is possible.

As described above, according to the control device of the present invention, the television signal / personal computer signal switching means is used for receiving the television signal for each of the television signal and the personal computer signal having different frequency fluctuations. By making the frequency change allowable range larger than when inputting a signal for a PC and lengthening the time for fixing the input frequency, it eliminates an irritable reaction to changes such as noise when a television signal is selected, while when selecting a personal computer. It is possible to quickly respond to the switching of the input signal.

Further, even for a television signal and a personal computer signal having the same frequency, the television / personal computer signal switching means switches the data table used for determining the control data so that both signals can be properly displayed. It becomes possible to provide a display.

[0036]

As described above, according to the display circuit control device of the present invention, when the television signal and the personal computer signal are switched between the television signal and the personal computer signal having different frequency fluctuations, the television circuit and the personal computer signal are switched. By making the allowable frequency change range of the PC larger than that of a personal computer and lengthening the time for fixing the input frequency, it eliminates the hypersensitive reaction to changes such as noise when a television signal is selected and when the personal computer is selected. It is possible to quickly respond to the switching.

Also, for a television signal and a personal computer signal signal having the same frequency, the data table used for determining the control data is switched by the television / personal computer signal switching means so that the two signals are appropriate. It becomes possible to provide a display capable of displaying.

Further, according to the display circuit control device of the present invention, it is possible to provide a display which can stably and optimally display both the personal computer signal and the television signal with a single circuit configuration.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a control device according to first and second embodiments of the present invention.

FIG. 2 is a block diagram of a software configuration in the microcomputer according to the first and second embodiments of the present invention.

FIG. 3 is a flowchart of a frequency change detection unit according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram of a nonvolatile memory according to a second embodiment of the present invention.

FIG. 5 is a flowchart of a control data determination unit according to the second embodiment of the present invention.

[Explanation of symbols]

1 microcomputer 2 Non-volatile memory 3 Frequency detector 4 Frequency change detector 5 Control data determination unit 6 Data output section 7 Television signal data table 8 PC signal data table 9 Display circuit control reference data

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Claims (2)

(57) [Claims] 1. A display circuit control device, characterized in that, by a signal from a switching means for switching display of a personal computer signal and a television signal, a fixed time for detection of frequency change of an input signal and a frequency allowable range for change judgment are switched. . 2. A switching means for controlling display switching between a personal computer signal and a television signal, a frequency measuring section for measuring a frequency of an input signal, and a judgment of a frequency change of the input signal by an output of the frequency measuring section. Required for determining the signal control data, and a control data determining unit for determining signal control data corresponding to the input signal based on a signal from the frequency change detecting unit. A storage unit for holding data and a data output unit for outputting the signal control data are provided, and the frequency change detection unit uses a signal from the switching means to select a signal for a personal computer. A display circuit control device characterized in that a decision time for frequency change detection or a frequency allowable range for change judgment is switched depending on when a television signal is selected.