JPH0686099A - Picture quality improving device - Google Patents

Abstract

PURPOSE:To improve the picture quality of broadcast waves of the inferior signal quality. CONSTITUTION:A picture quality improving device 20 including a high frequency signal processing part and a base band signal processing part is provided in an outdoor booster set near an antenna or a desk booster set near a TV receiver. The high frequency signal inputted through the antenna is transmitted through a band limiting circuit 22, a high frequency signal amplifier circuit 23, and a distortion component eliminating circuit 24 respectively. Thus a signal whose S/N value and amplitude are improved is supplied to a tuner part of a video reproducer 26. The base band signal selected by the reproducer 26 is once outputted to the outside and then applied to a base band signal processing circuit 29 to eliminate the ghost signal component, etc., for improvement of the picture quality. Then the base band signal is applied again to the reproducer 26. Thus it is possible to eliminate the proper reception fault that is caused by the installing environment of the reproducer 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image quality improving device for improving the image quality of a received television signal.

[0002]

2. Description of the Related Art Some television receivers are provided with an image quality improving device in front of a circuit for demodulating a video baseband signal in order to prevent deterioration of received image quality. FIG. 3 is a block diagram showing an example of a conventional image quality improving apparatus. In the figure, the high frequency signal input terminal 1 is, for example, VHF and U.
It is an input terminal for a high-frequency signal received by each antenna of HF radio waves and input from the antenna. Band separation circuit 2
Is a circuit for separating the high-frequency signal from the input terminal 1 into bands, for example, the VHF signal is output to the first high-frequency signal amplifier circuit 3, and the UHF signal is output to the second high-frequency signal amplifier circuit 4. It The high frequency signal amplifier circuits 3 and 4 are preamplifiers for amplifying VHF and UHF signals, respectively.

The first distortion component removing circuit 5 is a filter for removing harmonic components contained in the output signal of the high frequency signal amplifying circuit 3, and the second distortion component removing circuit 6 is also the output signal of the high frequency signal amplifying circuit 4. Is a filter that removes the harmonic components included in. The band mixing circuit 7 includes distortion component removing circuits 5 and 6.
Is a circuit that mixes the VHF and UHF signals output by the above and outputs the amplified high frequency signal of the broadcast wave to the high frequency signal output terminal 8. The power supply circuit 9 is a built-in power supply provided in the vicinity of the high-frequency signal amplification circuits 3 and 4, and converts the alternating current or direct current supplied from a cable (not shown) into direct current that does not contain noise to the high-frequency signal amplification circuits 3 and 4. It is a circuit to supply.

The image quality improving device 10 thus constructed is mounted in the vicinity of a receiving antenna (not shown) and constitutes an outdoor booster. There is also a case of a tabletop booster provided in the vicinity of the television receiver via a coaxial cable from the receiving antenna.

[0005]

However, in the image quality improving device having such a configuration, the weak broadcast radio wave inputted to the receiving antenna is amplified by the high frequency signal amplifying circuits 3 and 4,
The S / N is improved at the level of the high frequency signal.
For example, due to the installation location of the receiving antenna, the image quality cannot be improved even if a high-quality high-frequency signal (C / N is bad) on which a ghost signal is superimposed is amplified.

The present invention has been made in view of such conventional problems, and outputs a video signal with improved image quality by using signal processing for a high frequency signal and signal processing for a baseband signal together. It is an object of the present invention to provide an image quality improving device that realizes the above.

[0007]

The present invention provides a high frequency signal processing section for improving the S / N value of a high frequency signal input from an antenna, a high frequency output terminal for outputting the signal of the high frequency signal processing section to the outside, and a high frequency signal. The signal of the output terminal is given to the image reproducing device, the signal selected by the tuner section is converted into a baseband signal, and the signal of the baseband signal input terminal for inputting the baseband signal and the signal of the baseband signal input terminal are supplied. It is characterized by comprising a baseband signal processing unit for inputting and improving received image quality, and a baseband signal output terminal for outputting the signal of the baseband signal processing unit to the outside.

[0008]

According to the present invention having such characteristics, the S / N value of the high frequency signal input from the antenna is improved by the high frequency signal processing section. This signal is input to the image reproducing device via the high frequency output terminal. Next, the signal selected by the tuner unit of the video reproducing apparatus is converted into a baseband signal and is given to the image quality improving apparatus again via the baseband signal input terminal. Then, the baseband signal processing section improves received image quality by baseband signal processing. This signal is input to the video reproducing apparatus again via the baseband signal output terminal. This makes it possible to perform optimum signal processing with respect to an inherent reception failure caused by the installation environment of the antenna or the video reproduction device.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image quality improving apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the overall configuration of an image quality improving device according to an embodiment of the present invention. In this embodiment, the image quality improving device 20 shown by the alternate long and short dash line is installed in an outdoor booster installed in the vicinity of an antenna for receiving broadcast waves, or installed in the vicinity of a television receiver which is a video reproducing device. Built into the desktop booster. The high frequency signal input terminal 21 is an input terminal for a high frequency signal input from the antenna. The band limiting circuit 22 is a filter that filters signal components in the broadcast frequency band. The high frequency signal amplifier circuit 23 is the band limiting circuit 2
2 is a preamplifier that amplifies the output signal of 2. The distortion component removal circuit 24 is a filter that removes harmonic components from the signal output from the high frequency signal amplification circuit 23. The high frequency signal output terminal 25 is an output terminal for the high frequency signal output from the distortion component removal circuit 24, and is provided in the housing of the image quality improving device 20. Here, the band limiting circuit 22 and the high frequency signal amplifying circuit 2
3. The distortion component removal circuit 24 constitutes a high frequency signal processing unit that improves the S / N value of the high frequency signal input from the antenna.

On the other hand, the video reproduction device 26 is an AV type television receiver having a tuner section for selecting broadcast radio waves, a video signal demodulation section, and a video display section. The video reproducing device 26 is provided with an input terminal 26a of a tuner section, an output terminal 26b for outputting a baseband signal of an image selected by the tuner section, and an input terminal 26c for inputting an external baseband image signal. ing.

Further, the image quality improving device 20 is provided with a baseband signal input terminal 27 for inputting a video baseband signal and a baseband signal output terminal 28 for outputting a baseband video signal with improved image quality. . The baseband signal processing circuit 29 is a circuit that inputs a baseband signal input from the input terminal 27 and performs signal processing for image quality improvement. The output is given to the input terminal 26c of the video reproducing device 26 via the output terminal 28. The power is supplied through any cable that connects the video reproducing device 26 and the image quality improving device 20. The power supply circuit 30 is a power supply that converts an AC or DC power supply into a noise-free DC power supply and supplies it to the high-frequency signal amplification circuit 23 and the baseband signal processing circuit 29, respectively.

A configuration example of the baseband signal processing circuit 29 is shown in FIG. FIG. 2 is a block diagram of a signal processing circuit that removes a ghost signal component included in a video signal. In the figure, an A / D converter 31 is a circuit which inputs the baseband signal of the video output from the video playback device 26 of FIG. 1 and outputs a digitally converted composite signal.
The proximity ghost removal digital filter 32 is a digital filter that receives the signal from the A / D converter 31 and removes the proximity ghost signal delayed by, for example, about 1 μsec.
The adder circuit 33 is a circuit that adds the output of the digital filter 32 and the output signal of the normal ghost removing digital filter 34. The digital filter 34 is a digital filter that removes a normal ghost signal having a long delay component that cannot be removed by the digital filter 32.
Is connected between the output end of the adder 33 and one input end of the adder 33.
The D / A converter 35 is a circuit that converts the output of the adder 33 into an analog composite signal.

The sampling clock generating circuit 36 is
It is a circuit that extracts a horizontal synchronizing signal from a baseband video signal input to the baseband signal processing circuit 29 and generates a high-frequency sampling clock phase-locked by this synchronizing signal. Sampling clock generation circuit 36
The clock signal output by the A / D converter 31, D / A
It is applied to the converters 35, respectively. The CPU 37 is a circuit that gives control signals to the digital filters 32 and 34, respectively, and controls the digital filters 32 and 34 so that the ghost component included in the video signal is minimized.

In the image quality improving apparatus 20 thus constructed, when the television viewer sets the tuner section of the image reproducing apparatus 26 to a specific channel, the weak radio wave incident on the antenna passes through the high frequency signal input terminal 21. It is given to the band limiting circuit 22. Here, after the signal components in the unnecessary band are removed, the high frequency signal is pre-amplified by the amplifier circuit 23. Next, the harmonic components of the amplified signal are removed by the distortion component removal circuit 24, and the video reproduction device 2 is output through the output terminal 25.
6 is input.

When the baseband signal processing circuit 29 is used, the high-frequency video signal selected by the tuner section of the video reproduction device 26 is converted into a baseband signal via an intermediate amplification circuit and a detection circuit (not shown). This baseband signal is temporarily sent through the output terminal 26b to the image quality improving device 2
Is transferred to 0.

The transferred baseband signal is input to the baseband signal processing circuit 29 shown in FIG. 2, and the ghost signal component contained in the composite video signal is removed by the digital filters 32 and 34. This signal is converted into an analog composite signal by the D / A converter 35, and is given to the input terminal 26c of the video reproducing device 26 via the output terminal 28 shown in FIG. Then, it is separated into a luminance signal and a color signal by a video signal processing circuit (not shown) and output to the display section.

Although the baseband signal processing circuit 29 is designed to remove the ghost component from the digitally converted composite video signal by using the digital filters 32 and 33 and the CPU 37, another digital signal processing circuit is used. For example, a cross color obstacle or a dot obstacle may be eliminated, and a unique one is selected according to a use condition. Also, the receiving antenna is the image quality improving device 2.
It may be an indoor antenna built in 0.

The installation environment of the image reproducing device 26 and the receiving antenna shown in FIG. 1 differs depending on the viewer of the television. Also, few of the video reproducing devices 26 themselves have a built-in image quality improving device for preventing image quality deterioration. In this way, by incorporating the baseband signal processing circuit 29, which is unique in the installation location and which prevents the deterioration of the image quality, into the booster on the table or outdoors, it is possible to improve the image quality suitable for the receiving environment of the broadcast radio wave.

Alternatively, the baseband signal processing section and the high frequency signal processing section may be independent of each other, and a power supply circuit may be provided in either one and supplied to the other.

[0020]

As described in detail above, according to the present invention, the baseband signal processing section is provided inside the image quality improving apparatus including the high frequency signal processing section, so that the base is independent of the video reproducing apparatus. It is possible to improve the image quality by performing band signal processing. Therefore, it is possible to improve the image quality by performing the optimum signal processing with respect to the inherent reception failure caused by the installation environment of the antenna or the video reproduction device.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an image quality improving device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of the configuration of a baseband signal processing circuit used in the image quality improving apparatus of this embodiment.

FIG. 3 is a block diagram showing a configuration example of a conventional image quality improving device.

[Explanation of symbols]

 20 image quality improving device 21 high frequency signal input terminal 22 band limiting circuit 23 high frequency signal amplifying circuit 24 distortion component removing circuit 25 high frequency signal output terminal 26 video reproducing device 26a, 26c input terminal 26b output terminal 27 baseband signal input terminal 28 baseband signal Output terminal 29 Baseband signal processing circuit 31 A / D converter 32 Proximity ghost removal digital filter 33 Adder 34 Normal ghost removal digital filter 35 D / A converter 36 Sampling clock generation circuit 37 CPU

Claims (5)

[Claims] 1. The S of a high frequency signal input from an antenna
/ N value for improving a high-frequency signal processing unit, a high-frequency output terminal for outputting the signal of the high-frequency signal processing unit to the outside, the signal of the high-frequency output terminal is given to the image reproducing device, the tuner unit tuned A baseband signal input terminal for converting a signal to a baseband signal and inputting the baseband signal; a baseband signal processing section for inputting a signal from the baseband signal input terminal to improve received image quality; An image quality improving apparatus, comprising: a baseband signal output terminal that outputs a signal of a signal processing unit to the outside. 2. The image quality improving apparatus according to claim 1, wherein the high-frequency signal processing unit includes a high-frequency amplifier circuit. 3. The image quality improving apparatus according to claim 1, wherein the high frequency signal processing unit has a built-in indoor antenna. 4. The high frequency signal processing unit and the baseband signal processing unit are independent of each other, a power supply unit is provided in the baseband signal processing unit, and power is supplied from the power supply unit to the high frequency signal processing unit. Claim 1, 2, or 3
The image quality improving device described. 5. The high frequency signal processing unit and the baseband signal processing unit are independent of each other, a power supply unit is provided in the high frequency signal processing unit, and power is supplied from the power supply unit to the baseband signal processing unit. Claim 1, 2, or 3
The image quality improving device described.