KR20090003899A - Apparatus for processing image signal - Google Patents

Abstract

The present invention relates to an image signal processing apparatus.

An image signal processing apparatus of the present invention includes a tuner; A demodulator including a demodulation IC to demodulate the broadcast signal received through the tuner and bypass the internal trap filter; And a filter unit for blocking noise of a signal output from the CVBS terminal of the demodulator.

According to the present invention, when the broadcast signal received through the tuner is demodulated and applied, the first filter unit and the second filter unit pass only the video signal and block the audio signal corresponding to the noise, but the COLOR TRANSIENT of the video signal is excessive. By controlling the occurrence of RINGING (vibration pattern) due to the phenomenon and the transient phenomenon, it is possible to improve the color mixing phenomenon in the image.

Description

Image Signal Processing Equipment {APPARATUS FOR PROCESSING IMAGE SIGNAL}

1 is a state diagram of color mixing due to transient phenomenon when using a trap filter in a conventional demodulation IC.

Figure 2 is a state of the ring occurs due to the transient phenomenon when using the trap filter inside the conventional demodulation IC.

3 is a block diagram schematically showing a configuration according to an embodiment of the present invention.

4 is a circuit diagram showing in detail the configuration according to an embodiment of the present invention.

Figure 5 is a state in which the degree of color mixing is reduced through the present invention.

6 is a state diagram in which the level and number of RINGING is reduced through the present invention.

<Description of Signs of Major Parts of Drawings>

10: image quality improvement circuit 1: demodulation unit

11 filter unit 11A first filter unit

L1: resonant reaction means 11B: second filter part

13 amplifier unit 14 buffer unit

C1: resonance control means

The present invention relates to an image signal processing apparatus.

In general, digital televisions reproduce various sources such as digital broadcast signals, composite video broadcast signals (CVBS), super video signals (S-VHS), and components (COMPONENT).

When the input sources are diversified as described above, a difference occurs in the output level for each input source, that is, the size from the black level to the white level. The conventional digital television will be described in detail as follows.

First, a tuner for selectively receiving a digital broadcast signal; A residual sideband converter for converting and transmitting the broadcast signal received through the tuner into a residual sideband method; A system and a video decoder for decoding the output of the residual sideband converter; An NTSC decoder which receives an input source such as a broadcast signal, a composite video broadcast signal (CVBS), a super video signal (S-VHS), a component (COMPNENT), etc., applied through the tuner, and decodes the signal to an NTSC standard; A display processing unit for performing a process such as converting a format by receiving outputs of the system, the video decoder, and the NTSC decoder; A D / A converter converting the image signal processed by the display processor into an analog signal; The display driver is configured to drive a display by receiving the output of the D / A converter.

As described above, the conventional digital television configured as described above can receive and reproduce various types of input sources.

Through the tuner, NTSC standard broadcasting signal, composite video broadcasting signal (CVBS), super video signal (S-VHS), and component (COMPONENT) can be applied and played. The broadcast signal selected and received through the tuner is left. It is transmitted through the waveband converter and decoded by the system and the video decoder. The format is converted by the display processor and necessary processing such as the determination of the scanning method is performed.

Then, the broadcast signal processed by the display processor is converted into an analog signal by the D / A converter, and the analog output signal of the D / A converter is displayed on the display through the display driver.

The above signal flow is an example of a broadcast signal, and another input source, that is, a composite video broadcast signal (CVBS), a super video signal (S-VHS), a component (COMPONENT) is applied to an NTSC decoder and decoded, and then its output is It is applied to the display processor to perform the necessary processing, and the result is converted into an analog signal by the D / A converter and displayed on the display through the display driver.

In the conventional digital television, various standard broadcasts can be applied in addition to the NTSC standard broadcast, and a system capable of processing broadcasts for each standard is required, and recently, a broadcast for each standard is provided through one broadcast signal demodulation IC chip. I can handle it.

However, in the case of the broadcast signal demodulation IC chip as described above, the trap filter mounted inside the IC is switched to 4.5, 5.5, 6.0, and 6.5 Mhz to receive broadcast signals for each standard.

In such a case, since the trap filter inside the IC is used in common, a DELAY performance is low in a broadcast of a specific standard, for example, an NTSC standard broadcast. As shown in FIGS. 1 and 2, a COLOR TRANSIENT (transient) is used. Phenomenon) and RINGING (vibration pattern) occurs.

The ringing phenomenon is a phenomenon in which the ripple of the video signal appears as white or black-bar on the screen when the brightness of the video signal changes suddenly and stabilizes to a steady state.

Such RINGING occurrence factors include SAW Filter's own Group Delay characteristics, Video Spectrum high frequency region (4 ~ 4.2MHz) characteristics, Sound trap filter circuit Y / C Delay characteristics, TV Set Delay characteristics, Matching characteristics of Chroma signal processing parts, TV Screen characteristics (large size LD, weak PDP TV).

Such ringing occurs at the interface between two different color signals. When the high frequency of the color signal becomes large, ripples of different color signals occur at the interface with the other color signals, resulting in noise on the screen.

The present invention can improve color mixing in an image.

The present invention is a tuner; A demodulator including a demodulation IC for demodulating the broadcast signal received through the tuner and bypassing an internal trap filter; And a filter unit for blocking noise of a signal output from the CVBS terminal of the demodulator.

Preferably, the demodulation IC is a programmable IC that turns off the trap trap when the internal trap filter is turned on (B0 = '1').

The filter unit preferably removes the audio signal from the input broadcast signal and passes only the video signal.

The filter unit may include: a first filter unit controlling a transient phenomenon by varying a time constant; It is preferable to include a second filter unit for removing residual noise from the image signal and finely controlling the transient phenomenon.

Preferably, the first filter unit is a sound trap filter in which resonance control means and resonance reaction means are connected in parallel to an image signal output terminal of the demodulator.

Preferably, the resonance control means is a capacitance variable capacitor.

The resonance reaction means is preferably an inductor.

Preferably, the second filter part is an LC filter in which an inductor and a capacitor are connected in series between an output terminal of the first filter part and a ground line.

 An amplifier unit for amplifying the level of the attenuated video signal; Preferably, the filter unit further includes a buffer unit that matches the mutual impedance of the amplifier unit.

Preferably, the amplifier unit is a PNP transistor connected to the output of the filter unit, an emitter connected to a + 5V side, and a collector connected to a ground line.

The buffer part is connected between both the filter part and the amplifier part, a base is connected to the output end of the first filter part and the second filter part, a collector is connected to the base of the transistor of the + 5V side and the amplifier part, and It is preferable that it is an NPN type transistor in which an emitter is connected to the collector of the transistor of an amplifier part.

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

3 is a block diagram schematically showing a configuration according to an embodiment of the present invention, Figure 4 is a circuit diagram showing a configuration according to an embodiment of the present invention in detail, Figure 5 is a degree of color mixing through the present invention 6 is a state diagram in which the level and number of ringings are reduced through the present invention, and reference numeral 10 denotes an image signal processing apparatus of the present invention.

3 and 4, in the video signal processing apparatus for demodulating a broadcast signal received through a tuner through a demodulator, and converting the format into a displayable state, a trap filter is provided inside. A demodulation unit (1) mounted thereon, including a demodulation IC for bypassing an internal trap filter through a program setting; And a filter section 11 for blocking noise of a signal output from the CVBS stage of the demodulation section 1.

In the present invention, the demodulation IC is a programmable IC chip that is programmed to be "internal trap filter ON (B0 = '1')" and is set to "internal trap filter ON (B0 = '1')". The internal trap filter is turned off. Accordingly, the CVBS output level is down to 1.0 Vp-p.

On the other hand, in the present invention, the filter unit 11 includes: a first filter unit (11A) for removing the audio signal from the input broadcast signal and passing only the video signal, and controlling the transient by varying the time constant; The second filter unit 11B may remove residual noise from the image signal and finely adjust the transient phenomenon.

Here, the first filter part 11A is a sound trap filter in which the resonance control means C1 and the resonance reaction means L1 are connected in parallel to the CVBS output terminal of the demodulator 1 on the image signal input side.

In this case, the resonance adjusting means C1 of the sound trap filter is a variable capacitance capacitor, and the resonance reaction means L1 is an inductor.

The sound trap filter performs a band pass filter (BPF) function that passes only a desired signal, that is, removes an audio signal and passes only an image signal, and adjusts the capacitance, spacing, and position of the resonance adjusting means C1. By adjusting the resonant frequency by adjusting the pass band of the video signal and the audio signal included in the video signal, it is possible to adjust the degree of transient and vibrating pattern of the image.

At this time, if necessary, the transient phenomenon and vibrating pattern of the image can be almost removed, but not completely removed to clarify the boundary between colors.

The second filter part 11B is an LC filter in which an inductor 2 (L2) and a capacitor 2 (C2) are connected in series between an output terminal of the first filter part 11A and a ground line.

While performing the filtering function, the LC filter adjusts the capacitance of the inductor 2 (L2) or the capacitor 2 (C2) to remove the fine noise, that is, the audio signal remaining in the video signal.

On the other hand, the present invention includes an amplifier section 13 for amplifying the level down to the setting of the demodulation section; The filter unit 11 may further include a buffer unit 14 for matching impedances between the amplifier unit 13 and the amplifier unit 13.

At this time, the amplifier 13 is a PNP type transistor 1 (Q1) having an emitter connected to a + 5V side and a collector connected to a ground line.

In this manner, the amplifier unit 13 is set to bypass the internal trap filter of the demodulation IC constituting the demodulator 1 (program setting to "internal trap filter ON (B0 = '1')") to 1.0 Vp. The output level down to -p is amplified to 2Vp-p, and in the present invention, an emitter floor amplification circuit will be applied.

In general, when amplifying a signal using a transistor, the emitter side (corresponding to the cathode of the vacuum tube) is usually grounded to obtain a high voltage amplification ratio, but in the case of an emitter follower, the collector side (corresponding to the anode of the vacuum tube). Since the input signal from the base is taken out as an output signal from the emitter side, the voltage amplification rate is rather low, but the current amplification rate is very high.

In this case, when the signal is applied to the base at the buffer unit 14, that is, when the signal is high, the transistor 1 (Q1) is turned off so that the load current does not flow. If is not applied, that is, when the output goes low, transistor 1 (Q1) is turned on so that a current flows to the load side.

In addition, the buffer unit 14 has a base connected to the output terminal of the first filter unit 11A and the second filter unit 11B, and to the base of the transistor 1 (Q1) of the + 5V side and the amplifier unit 13. The collector is connected and the emitter is connected to the ground line and the collector of transistor 1 (Q1).

The buffer unit 14 matches the impedance of the filter unit 11 and the amplifier unit 13 at a constant level. When a signal is input from the filter unit 11, the buffer unit 14 is turned on to signal the amplifier unit 13. To pass.

5 and 6, the number of rings and the level are reduced, and the color mixing phenomenon of the interface between colors is improved.

While the invention has been described and illustrated in connection with a preferred embodiment for illustrating the principles of the invention, the invention is not limited to the configuration and operation as such is shown and described.

Rather, those skilled in the art will appreciate that many modifications and variations of the present invention are possible without departing from the spirit and scope of the appended claims.

Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

According to the present invention, when the broadcast signal received through the tuner is demodulated and applied, the first filter unit and the second filter unit pass only the video signal and block the audio signal corresponding to the noise, but the transient phenomenon and the transient of the video signal By controlling the occurrence of the vibrating pattern due to the phenomenon, it is possible to improve the color mixing phenomenon in the image.

Claims (11)

Tuner; A demodulator including a demodulation IC to demodulate the broadcast signal received through the tuner and bypass the internal trap filter; And a filter unit to block noise of a signal output from the CVBS terminal of the demodulator. The method of claim 1, wherein the demodulation IC And "internal trap filter ON (B0 = '1')" is a programmable IC that turns off an internal trap Peter. The method of claim 1, wherein the filter unit The video signal processing apparatus, characterized in that the audio signal is removed from the broadcast signal to pass only the video signal. The method of claim 1, wherein the filter unit A first filter unit controlling a transient by varying a time constant; And a second filter unit which removes residual noise from the image signal and finely adjusts the transient phenomenon. The method of claim 4, wherein the first filter unit And a sound trap filter having a resonance control means and a resonance reaction means connected in parallel to an image signal output terminal of the demodulator. The method of claim 5, wherein the resonance control means An image signal processing apparatus, characterized in that the capacitive variable capacitor. The method of claim 5, wherein the resonance reaction means Image signal processing apparatus, characterized in that the inductor. The method of claim 4, wherein the second filter unit And an LC filter in which an inductor and a capacitor are connected in series between an output terminal of the first filter unit and a ground line. The apparatus of claim 1, further comprising: an amplifier unit for amplifying the level of the attenuated video signal; And a buffer unit which matches the mutual impedance of the filter unit and the amplifier unit. The method of claim 9, wherein the amplifier unit And a PNP type transistor connected to an output terminal of the filter unit, an emitter connected to a + 5V side, and a collector connected to a ground line. The method of claim 9, wherein the buffer unit It is connected between both ends of the filter unit and the amplifier unit, the base is connected to the output terminal of the first filter unit and the second filter unit, the collector is connected to the base of the transistor of the + 5V side and the amplifier unit, the ground line and the transistor of the amplifier unit An image signal processing apparatus, characterized in that the transistor is an NPN type transistor is connected to the collector.

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