KR20000043614A - External input video signal standard decision and signal process apparatus - Google Patents

Abstract

PURPOSE: A video signal standard decision and signal process apparatus is provided to prevent the deterioration of the image quality by controlling the switching to a PC screen after deciding whether a PC signal exists. CONSTITUTION: A synchronous signal converter(201) converts the polarity of a horizontal synchronous signal included in an external input video signal into a positive or a negative polarity regardless of the polarity of the horizontal synchronous signal. A synchronous signal detector(202) detects whether a synchronous signal is outputted from the synchronous signal converter(202). A standard signal deciding unit(203) decides whether the synchronous signal corresponds to a twofold frequency(2fH) in case that the synchronous signal is detected from the synchronous signal detector(202).

Description

External input video signal standard judgment and signal processing device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal determination and processing apparatus, and in particular, to determine an external input video signal specification for determining a standard of an external input video signal according to a resolution and determining a video signal of a personal computer or the like input from an external device. And a signal processing apparatus.

The video signals output from the personal computer, which is one of the external input video signals of the television, can be classified into VGA, SVGA, XGA, etc. according to the resolution, and the horizontal frequencies of these signals are different.

That is, the standard VGA signal having a resolution of 640 × 480 has a horizontal frequency of 31.5KHz, and the SVGA or XGA signal has a higher horizontal frequency than the standard VGA signal at 35.1KHz or 35.6KHz.

In general, in the signal processing method of a digital television, the image quality is improved by converting the image frequency into two-fold vertical signals by double scanning or by converting the image signal to two-fold horizontal frequency by progressive scan.

The progressive scan-converted high resolution signal, which is an external video input signal input from a personal computer or the like, is converted into an interlaced signal by the standard conversion unit 101 for compatibility of signal processing as shown in FIG. Thereafter, the 2H converter 102 doubles and outputs the horizontal frequency by the progressive scan conversion method.

However, according to the related art, the high resolution progressive signal output from the personal computer is passed through the standard conversion unit 101 regardless of the type. Therefore, the image quality deterioration and the screen in the signal processing process of the standard conversion are performed. A trembling phenomenon has occurred.

In particular, the horizontal frequency of the VGA signal output from the personal computer is equal to the frequency obtained by doubling the horizontal frequency of the television by the progressive method. That is, the VGA signal has the same standard as the signal output from the 2H converter 102.

Nevertheless, according to the related art, signals such as VGA, SVGA, XGA, etc. output from a personal computer cannot be discriminated. In television, the standard of the signal must be determined by the standard conversion unit 101 regardless of the signal input from the personal computer. By converting and processing, there is a problem in that signal degradation and screen shaking are unnecessarily generated in standard VGA signal processing. In addition, there is a problem that the external video signal input from the personal computer cannot be processed without using the standard conversion unit.

The technical problem to be solved by the present invention is to determine the presence of a PC synchronization signal input from the outside to determine the presence of an external input signal of the personal computer, and to determine whether the external input video signal has a VGA standard in order to solve the above problems The present invention provides an external input video signal specification determination and signal processing apparatus capable of processing an external PC input signal without using a standard conversion unit.

1 is a block diagram of an external input video signal processing apparatus according to the prior art.

2 is a configuration diagram of an external input video signal standard determining apparatus according to the present invention.

FIG. 3 is a detailed block diagram of the building block shown in FIG. 2.

4A to 4F are signal waveform diagrams of respective parts of FIG. 3.

5 is a configuration diagram of an external input video signal processing apparatus according to the present invention.

In order to achieve the above technical problem, the external input video signal specification determining apparatus according to the present invention is an external input video signal processing apparatus, which is positive (or negative) regardless of the polarity of the horizontal synchronization signal included in the external input video signal. Synchronous signal converting means for converting, synchronous signal detecting means for detecting whether synchronous signal is output from said synchronous signal converting means, and when said synchronous signal is detected in said synchronous signal detecting means, 2fH), characterized in that it comprises a standard signal discrimination means for discriminating.

According to another aspect of the present invention, in an external input video signal processing apparatus, a video signal processing apparatus may convert a positive (or negative) signal regardless of a polarity of a horizontal synchronization signal included in the external input video signal. A synchronous signal converting means for detecting the synchronous signal, and synchronous signal detecting means for generating a synchronous detection signal when the synchronous signal is detected, and the synchronous detection signal is applied. Standard signal discrimination means for generating a standard signal detection signal when the synchronization signal corresponds to a 2 times horizontal frequency (2fH), and when the user applies a PC screen output command, the standard signal detection signal is inputted. Control unit for generating a PC switching control signal only when the And a switching unit for inputting a progressive video signal signal-processed inside the television set to select and output the external PC input signal to the display means only when the PC switching control signal is input.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the apparatus for determining an external input video signal specification according to the present invention includes a synchronization signal conversion block 201, a synchronization signal presence / absence determination block 202, and a VGA standard signal determination block 203.

FIG. 3 shows a detailed circuit configuration of each block shown in FIG.

The synchronization signal conversion block 201 includes first integrators R1 and C1, first inverters Q1 and R3, and an exclusive OR gate XOR1.

The synchronization signal presence determining block 202 includes a first multivibrator MV1, second integrators R4 and C2, and second inverters Q2 and R5.

The VGA standard signal discrimination block 203 includes a third inverter IN1, a second multivibrator MV2, and fourth inverters Q3, R6, and R7.

Then, the operation of each block will be described with reference to the waveform diagrams of FIGS. 4 (a) to 4 (f).

In the synchronization signal conversion block 201, an operation for converting the horizontal synchronization signal PC-H of the personal computer input from the outside of the television into a synchronization signal of one polarity is performed regardless of whether it is a positive synchronization signal or a negative synchronization signal. In the exemplary embodiment of the present invention, a negative synchronous signal is converted and output regardless of the polarity of the input horizontal synchronous signal. This will be described in more detail as follows.

First, when the input horizontal synchronizing signal PC-H is a negative synchronizing signal, the input horizontal synchronizing signal PC-H is integrated by a first integrator composed of R1 and C1, and is output in a "high" state of 0.7 V or more in all sections. Accordingly, the transistor Q1 is turned on to apply the output of the "low" state to the first input terminal of the exclusive OR gate XOR1. The second input terminal of the exclusive OR gate XOR1 is applied with the input horizontal synchronizing signal PC-H after the level is adjusted by the resistor R2.

Then, the exclusive OR gate XOR1 generates a "high" output only when the signals input to the first and second input terminals have opposite logic states, and thus does not change the polarity of the negative sync signal applied to the second input terminal. Without the output.

Secondly, when the input horizontal synchronizing signal PC-H is a positive synchronizing signal, the input horizontal synchronizing signal PC-H is integrated by a first integrator composed of R1 and C1, and is output in a "low" state of 0.7 V or less in all sections. Accordingly, the transistor Q1 is cut off to apply the output of the "high" state to the first input terminal of the exclusive OR gate XOR1. The second input terminal of the exclusive OR gate XOR1 is applied with the input horizontal synchronizing signal PC-H after the level is adjusted by the resistor R2.

Then, the exclusive OR gate XOR1 generates a “high” output only when the signals input to the first and second input terminals have opposite logic states, thereby inverting the polarity of the positive sync signal applied to the second input terminal. Output a negative horizontal sync signal.

Third, when the horizontal synchronization signal is not input, since the input of the PC-H is in the "low" state, the transistor Q1 is cut off to apply the "high" state to the first input terminal of the exclusive OR gate XOR1. The "low" state is inputted to the two input terminals so that the output of the exclusive OR gate XOR1 always remains "high".

In the synchronization signal presence determining block 202, it is determined whether or not the synchronization signal is input from the personal computer regardless of the resolution standard.

That is, the first multivibrator MV1 properly sets an internal integral constant and pulses when the horizontal synchronization signal outputted from the exclusive OR gate XOR1 is a two-fold horizontal synchronization signal 2fH as shown in FIG. 4 (d) when a standard synchronous pulse as shown in FIG. 4 (c) corresponding to the input of the input signal is generated, and a synchronous signal having a frequency higher than the two-fold horizontal synchronous signal as shown in FIG. 4 (b) is input. Produces an "high" state output such as When the input terminal of the first multivibrator MV1 is input to the "high" state, the output of the "low" state is generated.

Then, when the output signal of the first multi-vibrator (MV1) is integrated by the second integrator consisting of R4, C2, when the signal shown in Figs. 4 (c) and 4 (d) is inputted, The transistor Q2 is turned on to generate a sustained output to generate a "low" state output to the synchronous detection confirmation signal IDENT terminal.

When the output signal of the first multivibrator MV1 is in the "low" state, the transistor Q2 is cut off to generate an output of the "high" state to the synchronous detection confirmation signal IDENT terminal.

Therefore, when the horizontal synchronization signal is input, regardless of the frequency of the horizontal synchronization signal, the synchronization detection confirmation signal (IDENT) terminal generates an output of "low" state, and when the horizontal synchronization signal is not input, the synchronization detection confirmation signal. The (IDENT) terminal generates an output of "high" status.

In the VGA standard signal discrimination block 203, it is discriminated whether or not the input horizontal synchronization signal has a two-fold horizontal frequency (2fH). This will be described in detail below.

A signal obtained by inverting the output signal of the first multivibrator MV1 by the third inverter IN1 is applied to the second multivibrator MV2 input terminal, or is output from the inverted output terminal of the first multivibrator MV1. Apply a signal.

Then, the second multivibrator MV2 appropriately sets the internal integral constant so that when the signal applied to the input terminal is the inverted signal of FIG. 4C, the output of the "low" state as shown in FIG. When the input signal of the "high" or "low" state is applied, the output of the "high" state as shown in FIG. 4 (f) at the output terminal of the 2nd multivibrator MV2 irrespective of the integral constant inside. Generates.

Then, if the output of the second multivibrator MV2 is inverted by the fourth inverters Q3, R6, and R7, the VGA standard signal detection signal PROTECT terminal has a horizontal frequency of 2 times the horizontal frequency corresponding to the VGA standard signal. When the synchronization signal is input, an output of "high" state is generated, otherwise an output of "low" state is produced.

Therefore, the PC screen output switching can be controlled using the synchronous detection confirmation signal IDENT and the VGA standard signal detection signal PROTECT in the television connected to the personal computer as follows.

As shown in FIG. 5, the interlaced video signal processed inside the television is progressively scanned by the 2H converter 501 to increase the horizontal frequency twice, and then to the first input terminal of the switching unit 502. Is authorized. An external PC video signal is applied to the second input terminal of the switching unit 502.

Next, the control operation of the switching unit 502 by the control unit 503 will be described.

First, when the synchronous detection confirmation signal IDENT is in the "low" state and the user applies the switching command to the PC screen output mode while the VGA standard signal detection signal is in the "high" state, the switching unit ( Since the video signal of the personal computer input to 502 has the resolution of the VGA standard, the controller 503 controls the switching unit 502 to select the PC video signal to switch the television to the PC screen output mode.

Second, when the user inputs a switching command to the PC screen output mode while the synchronous detection confirmation signal IDENT is in the "low" state and the VGA standard signal detection signal is in the "low" state, the control unit 503 ) Controls the switching unit 502 to select the signal of the first input terminal without selecting the PC video signal, and then generates a control signal for displaying the phrase "video input signal is not a standard VGA signal." Tells you to reset the resolution of your personal computer's output video.

Third, when the user applies a command for switching to the PC screen while the synchronous detection confirmation signal IDENT is "high", the control unit 503 controls the switching unit 502 to switch to the PC screen output mode. If the horizontal sync signal is not inputted, the message "Check the input of the PC signal" is displayed so that the user can check the input status.

As described above, according to the present invention, by determining the presence or absence of a PC signal and determining whether the PC signal is a standard VGA signal in a television connected to a personal computer, and controlling the switching to the PC screen, VGA without using a standard conversion unit as compared to the prior art Since the PC signal can be output to the TV, the material cost can be lowered, and the image quality deterioration and screen shake caused by the standard conversion unit can be improved.

Claims (6)

An external input video signal processing apparatus, Synchronizing signal converting means for converting to a positive (or negative) irrespective of the polarity of the horizontal synchronizing signal included in the external input video signal; Synchronizing signal detecting means for detecting whether a synchronizing signal is output from said synchronizing signal converting means; And And standard signal discriminating means for discriminating whether the synchronizing signal corresponds to a 2-fold horizontal frequency (2fH) when the synchronizing signal is detected by the synchronizing signal detecting means. 2. The synchronization signal converting means according to claim 1, A first integrator for inputting, integrating and outputting the horizontal synchronization signal; A first inverter for inputting and inverting the output of the first integrator; And And an exclusive logical sum gate using the horizontal synchronizing signal and the inverter output signal as input signals. The synchronization signal detecting means of claim 1, wherein When the output signal of the synchronization signal converting means is input, and when the 2 fold horizontal synchronous signal is input, a standard synchronous pulse corresponding to the input of the pulse is generated, and a synchronous signal having a frequency higher than the 2 fold horizontal synchronous signal is input. A first multivibrator having an integral constant for generating a first logic state and generating a second logic state inverted from the first logic state if a synchronous signal is not input; A second integrator for inputting, integrating and outputting an output signal of the first multivibrator; And And a second inverter for inputting and inverting the output of the second integrator. The method of claim 1 or 3, wherein the standard signal discrimination means When the output signal of the first multi-vibrator is input and the standard synchronous pulse is input, a third logic state is generated. When the first logic state or the second logic state is input, the third logic state and the third logic state are generated. And a second multivibrator having an integral constant for generating an inverted fourth logical state. The method of claim 1, wherein when setting the external input video signal to an external PC input signal, A control unit for generating a PC switching control signal when it is determined that the standard signal is determined as a standard signal when the user applies the PC screen output command; And And a switching unit for inputting the external PC input signal and the progressive video signal processed inside the television to select and output the external PC input signal only to a display means when the PC switching control signal is input. External input video signal processing device characterized in that. The apparatus of claim 5, wherein the controller is further configured to display a warning message for confirming input of an external PC signal when a sync signal is not detected by the sync signal detecting means when a user applies a PC screen output command. The control signal is generated, and if the synchronization signal is detected, but the standard signal discriminating means determines that the signal is not a standard signal, the control unit generates a phrase that is not a standard VGA signal and does not switch to the PC screen output. External input video signal processing device.