KR20000034562A - Tv including gain control unit for improving receiving property - Google Patents

Abstract

PURPOSE: A TV including a gain control unit for improving a receiving property is provided. In a general TV system, an AGC unit is installed to automatically compensate for a gain in an electric field strength detected within 20dBuV to 90dBuV. Thus, in a region where a strength of an electric wave is small(0dBuV), although a maxima-amplified gain signal is outputted, a broadcasting signal cannot be detected and outputted to a predetermined level. In addition, in a region where the strength of the electric field is over a predetermined value(110dBuV), such as a transmitting tower, a beat property of a receiving signal becomes inferior. CONSTITUTION: A TV comprises a gain control unit(100) operated as an attenuator(30) in regard to a strong signal, and as a low noise amplifier(20) in regard to a weak signal according to a voltage inputted from the automatic gain control unit to a front end of a TV tuner unit. As a result, a receiving property in a region where users are not able to watch TV is improved, and a beat property of a receiving signal in a region where a signal level is high is also improved, thereby stably receiving a TV signal which is not compensated for by an AGC unit.

Description

TV with gain adjuster for improved reception

The present invention relates to a TV having a gain adjusting unit for improving reception characteristics, and more particularly, a gain adjusting unit operating as a low signal amplifier and a low signal amplifier as a strong signal attenuator according to a voltage input from an automatic gain adjusting unit in front of the TV tuner unit. The present invention relates to a TV having a gain adjusting unit for improving the reception characteristic to improve the reception characteristics of an astigmatism region by improving the bit characteristics of a received signal in an area having a high signal level.

In general, the front end of the TV system includes a tuner unit 200 for tuning and amplifying the broadcast signal received from the antenna shown in FIG. 1, and amplifying the broadcast signal tuned from the tuner unit 200 at an intermediate frequency. The intermediate frequency amplifier 300, a detector 400 for applying the intermediate frequency amplified broadcast signal from the intermediate frequency amplifier 300 to each signal processor for demodulating, and an input signal from the detector 400. The AGC unit 500 detects the electric field strength and automatically applies the gain correction signal to the tuner unit 200 and the intermediate frequency resonator unit 300.

The tuner unit 200 is connected with a microcomputer 600 for outputting a predetermined international language, and the microcomputer 600 has a key input unit 700 for selecting a plurality of functions.

On the other hand, the operation of the TV system composed of such a configuration is as follows.

First, when a user inputs a channel setting signal through the key input unit 700, a signal corresponding thereto is input to the microcomputer 600. The microcomputer 600 then applies a predetermined control signal to the tuner unit 200. At this time, the tuner 200 tunes and amplifies the corresponding broadcast frequency received through the antenna and applies the corresponding signal to the intermediate frequency amplifier 300. Then, the intermediate frequency amplifier 300 amplifies the input broadcast signal to the intermediate frequency and outputs to the detector 400. The detector 400 demodulates the input broadcast signal and applies the broadcast signal to the video and audio signal processor.

In addition, the strength of the signal according to the broadcast signal input to the detector 400 is applied to the AGC unit 500, where the AGC unit 500 of the detector 400 in accordance with the strength of the radio wave induced from the antenna The screen is designed to compensate for the change in contrast according to the change in the detection output, and it is installed so that a constant image detection output can be obtained at all times by controlling the gain of the TV.

Therefore, the AGC unit 500 converts the high frequency automatic gain control signal corresponding to the electric field strength of the corresponding electric wave from the gain signal of the applied broadcast signal to the tuner 200 and outputs the intermediate frequency automatic gain control signal to the intermediate frequency amplifier 300. ) Is applied.

That is, if the electric field strength of the broadcast signal detected by the detector 400 is weak, the amplified gain compensation signal is automatically output to compensate. If the electric field strength of the broadcast signal is strong, the attenuated gain compensation signal is automatically output. do. Therefore, a stable image screen can be obtained by preventing the variation due to the intensity of the radio wave from appearing in the associative detection output through the detector 400.

However, in the conventional TV system as described above, the AGC unit is usually installed within a certain field strength range, that is, the gain is automatically compensated only in the electric field strength detected within 20 dBuV to 90 dBuV. For example, the strength of the radio wave is weak. In the region (0dBuV), even if the highest amplified gain signal is output, the broadcast signal cannot be detected and output at a constant level.In the region (110dBuV) where the electric field strength is stronger than the specified value such as near the transmission tower, the beat characteristics of the received signal There was a problem of deterioration.

Therefore, the present invention has been invented to solve the above problems, by providing a gain control unit that operates as a strong signal and attenuator in the weak signal and low noise amplifier in accordance with the voltage input from the automatic gain adjustment unit in front of the TV tuner section An object of the present invention is to provide a TV with a gain adjusting unit for improving the reception characteristic of the receiver to improve the reception characteristic of the signal and improve the bit characteristic of the received signal in a region having a high signal level.

In order to achieve the above object, the present invention provides a tuner unit for tuning and amplifying a broadcast signal received from an antenna, an intermediate frequency amplifier for amplifying a broadcast signal tuned from the tuner to an intermediate frequency, and the intermediate frequency. A detector for applying the intermediate frequency amplified broadcast signal to the signal processor for demodulating, and detecting the electric field strength of the input signal from the detector and automatically applying the gain correction signal to the tuner and the intermediate frequency amplifier. In the TV provided with an AGC unit, a microcomputer that receives a high frequency gain signal and an intermediate frequency gain signal output from the AGC unit and performs a control operation according to gain adjustment, and is applied to a tuner unit according to the gain control signal of the microcomputer A gain adjusting unit for adjusting the reception strength is provided.

1 is a block diagram illustrating a general TV system,

2 is a block diagram of a TV system to which the present invention is applied;

3 is a block diagram showing a detailed configuration of the gain adjusting unit shown in FIG.

<Explanation of symbols for main parts of drawing>

10: first switch unit 20: low noise amplifier

30: attenuator 40: second switch unit

100: gain adjustment unit 200: tuner unit

300: intermediate frequency amplifier 400: detector

700: key input unit 800: AGC unit

900: microcomputer

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

The TV system to which the present invention is applied includes a tuner unit 200 for tuning and amplifying a broadcast signal received from an antenna as shown in FIG. 2 and amplifying the broadcast signal tuned from the tuner unit 200 at an intermediate frequency. The intermediate frequency amplifier 300, a detector 400 for applying the intermediate frequency amplified broadcast signal from the intermediate frequency amplifier 300 to each signal processor for demodulating, and an input signal from the detector 400. The AGC unit 800 detects the electric field strength of the signal and automatically applies the gain correction signal to the tuner unit and the intermediate frequency amplification unit, and receives the high frequency gain signal and the intermediate frequency gain signal output from the AGC unit 800. The microcomputer 900 performs a control operation according to the adjustment, and the gain adjusting unit 100 adjusts the reception strength applied to the tuner unit 200 according to the gain control signal of the microcomputer 900.

In addition, the microcomputer 900 has a key input unit 700 for setting an operation according to the TV function.

Here, the specific configuration of the gain adjusting unit 100 and the first switch unit 10 and the second switch unit 40 and the switching operation to the same contact according to the control signal of the microcomputer 900 as shown in FIG. A low noise amplifier 20 connected to the A contact point of the first switch unit 10 and the A ′ contact line of the second switch unit 40 to amplify the intensity of radio waves induced from the antenna, and the first switch unit And an attenuator 30 connected to the B contact point of (10) and the B 'contact line of the second switch portion 40 to reduce the intensity of radio waves emitted from the antenna.

Next, a gain adjusting operation according to the present invention having the above configuration will be described.

First, when a user inputs a channel setting signal through the key input unit 700, a signal corresponding thereto is input to the microcomputer 900. The microcomputer 900 then applies a predetermined control signal to the tuner unit 200. In addition, the control signal of the microcomputer 900 is applied to the gain adjusting unit 100. At this time, the first switch unit 10 and the second switch unit 40 perform a switching operation between the C contact and the C 'contact by the signal applied to the gain adjusting unit 100.

At this time, the tuner unit 200 receives the signal received from the antenna through the gain adjusting unit 100 and tunes and amplifies the corresponding broadcast frequency and applies the corresponding signal to the intermediate frequency amplifier 300. Then, the intermediate frequency amplifier 300 amplifies the input broadcast signal to the intermediate frequency and outputs to the detector 400. Accordingly, the detector 400 demodulates the input broadcast signal and applies the broadcast signal to the video and audio signal processor.

In addition, the strength of the signal according to the broadcast signal input to the detector 400 is applied to the AGC unit 800, where the AGC unit 800 of the detector 400 in accordance with the strength of the radio wave induced from the antenna The screen is designed to compensate for the change in contrast according to the change in the detection output, and it is installed so that a constant image detection output can be obtained at all times by controlling the gain of the TV.

Therefore, the AGC unit 800 converts the high frequency automatic gain control signal corresponding to the electric field strength of the corresponding electric wave from the gain signal of the applied broadcast signal into the tuner unit and converts the intermediate frequency automatic gain control signal into the intermediate frequency amplifying unit ( 300).

Meanwhile, the AGC unit 800 applies the high frequency automatic gain control signal and the intermediate frequency automatic gain control signal according to the signal according to the electric field strength measured by the detector 400 to the microcomputer 900. Then, the microcomputer 900 detects the input gain signal, determines whether the value is greater than or equal to the predetermined value, and applies the predetermined control signal to the gain adjusting unit 100.

For example, when the signal input from the detector 400 is strong and the voltage according to the high frequency amplification output from the AGC unit 800 is input to the microcomputer 900 with a predetermined value or less (1V), the normal reception signal is 90 dBuV or more. Therefore, the microcomputer 900 applies a control signal according to the attenuation to the first switch unit 10 and the second switch unit 40 of the gain adjusting unit 100. Then, the first switch section 10 and the second switch section 40 are connected to the contact B and the contact B 'by the switching operation at the contact C and the contact C'. Then, the broadcast signal induced from the antenna is attenuated by a predetermined level through the attenuator 30 of the auto gain unit 100 and then applied to the tuner unit 200.

Here, the attenuation degree of the attenuator 30 is preferably set to -20 dB.

In addition, when the signal input from the detector 400 is weak and the voltage according to the intermediate frequency amplification output from the AGC unit 800 is input to the microcomputer 900 at a predetermined value or more (for example, 5V), the normal reception signal Since it is 20 dBuV or less, the microcomputer 900 applies a control signal according to amplification to the first switch unit 10 and the second switch unit 40 of the gain adjusting unit 100. Then, the first switch section 10 and the second switch section 40 are connected to the contact A and the contact A 'by the switching operation at the contact B and the contact B'. Then, the broadcast signal induced from the antenna is amplified by a predetermined level through the low noise amplifier 20 of the automatic gain unit 100 and then applied to the tuner unit 200.

The amplification gain of the low noise amplifier 20 is preferably about 20 dB.

Therefore, even in a region where the reception state is not improved by the automatic gain operation of the AGC unit 800 according to the reception field, the amplification and attenuation operation of the reception field of the gain adjustment unit 100 installed at the front end of the tuner unit 200 may cause You can watch stable broadcasts with no change in the screen even in over-the-field intensity areas.

As described above, the present invention includes a gain adjusting unit in front of the tuner unit, and detects the high frequency automatic gain signal and the intermediate frequency automatic gain signal output from the AGC unit, and performs the amplification and attenuation operation of the corresponding reception field from the AGC unit. Even if the signal of the TV is not compensated for, the stable screen reception is possible.

Claims (2)

A tuner section 200 for tuning and amplifying a broadcast signal received from an antenna, an intermediate frequency amplifier 300 for amplifying a broadcast signal tuned from the tuner 200 at an intermediate frequency, and the intermediate frequency amplifier section A detector 400 for applying the intermediate frequency amplified broadcast signal to the signal processor for demodulating, and detecting the electric field strength of the input wave from the detector 400 and automatically converting the gain correction signal into a tuner unit; In the TV having an AGC unit 800 applied to the intermediate frequency amplification unit, The microcomputer 900 which receives the high frequency gain signal and the intermediate frequency gain signal output from the AGC unit 800 and performs a control operation according to the gain adjustment, and the tuner unit 200 according to the gain control signal of the microcomputer 900. TV having a gain adjustment unit for improving the reception characteristics, characterized in that it is provided with a gain adjustment unit 100 for adjusting the received strength applied to). According to claim 1, The gain adjusting unit 100 switches the first switch unit 10 and the second switch unit 40 to the same contact point according to the control signal of the microcomputer 900, and the A of the first switch unit 10. A low noise amplifier 20 connected to the contact point A 'contact line of the second switch unit 40 to amplify the intensity of radio waves induced from the antenna, and the B contact point and the second switch unit of the first switch unit 10. TV having a gain adjusting unit for improving reception characteristics, characterized in that it comprises an attenuator (30) connected to the B 'contact line (40) to reduce the intensity of radio waves induced from the antenna.