KR20070071547A - If gain control device of digital tuner - Google Patents

If gain control device of digital tuner Download PDF

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Publication number
KR20070071547A
KR20070071547A KR1020050135095A KR20050135095A KR20070071547A KR 20070071547 A KR20070071547 A KR 20070071547A KR 1020050135095 A KR1020050135095 A KR 1020050135095A KR 20050135095 A KR20050135095 A KR 20050135095A KR 20070071547 A KR20070071547 A KR 20070071547A
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South Korea
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signal
intermediate frequency
gain
tuner
gain control
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KR1020050135095A
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Korean (ko)
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정재길
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엘지이노텍 주식회사
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/4446—IF amplifier circuits specially adapted for B&W TV
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/455—Demodulation-circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/50—Tuning indicators; Automatic tuning control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/52—Automatic gain control

Abstract

An IF(Intermediate Frequency) gain control device of a digital tuner is provided to control the gain of an IF signal output from a tuner by using an RF(Radio Frequency) gain control signal of a digital demodulator to improve the IF gain control performance of the tuner. An IF gain control device of a digital tuner includes a tuner(20) for controlling the gain of an RF signal received through an antenna and converting the RF signal into an IF signal, a first surface acoustic wave filter(21) for removing an unnecessary component from the IF signal output from the tuner, an IF amplifier(22) for amplifying the IF signal gain of the first surface acoustic wave filter, and a second surface acoustic wave filter(23) for removing an unnecessary component from the IF signal. The IF gain control device further includes a variable IF amplifier(24) for controlling the IF signal gain of the second surface acoustic wave filter, and a digital demodulator(25) for demodulating the IF signal inputted to the variable IF amplifier or controlling the IF signal gain and outputting an RF gain control signal and an IF gain control signal. The IF gain of the IF amplifier is controlled using the RF gain control signal of the digital demodulator.

Description

디지털 튜너의 중간주파이득조절장치{IF GAIN CONTROL DEVICE OF DIGITAL TUNER} IF GAIN CONTROL DEVICE OF DIGITAL TUNER}

도 1은 종래 디지털 튜너의 중간주파이득조절장치의 블럭도1 is a block diagram of an intermediate main gain control device of a conventional digital tuner

도 2는 종래 디지털 튜너의 중간주파이득조절장치의 블럭도Figure 2 is a block diagram of the intermediate main gain control device of the conventional digital tuner

도 3은 본 발명 디지털 튜너의 중간주파이득조절장치의 블럭도 Figure 3 is a block diagram of the intermediate main gain control device of the present invention digital tuner

*도면의 주요부분에 대한 부호의 설명* * Description of the symbols for the main parts of the drawings *

20; 튜너 21; 제1 표면탄성파 필터20; Tuner 21; First surface acoustic wave filter

22; 중간주파증폭기 23; 제2 표면탄성파 필터22; Intermediate frequency amplifier 23; Second surface acoustic wave filter

24; 가변중간주파증폭기 25; 디지털 복조기24; Variable intermediate frequency amplifier 25; Digital demodulator

본 발명은 디지털 튜너의 중간주파 이득조절장치에 관한 것이다.The present invention relates to an intermediate frequency gain control apparatus of a digital tuner.

일반적으로 디지털 튜너는 안테나로부터 수신된 여러 전파중 특정 채널 주파수만을 선택해 내는 장치로서, 상기 디지털 텔레비젼은 아날로그 텔레비젼에 비해 보다 선명한 화면을 볼 수 있을 뿐만 아니라, 하나의 채널에서 여러 개의 프로그램을 시청할 수 있다.In general, a digital tuner is a device that selects only a specific channel frequency among a plurality of radio waves received from an antenna, and the digital television not only displays a clearer screen than analog television, but also can watch several programs on one channel. .

이렇게 여러 개의 프로그램을 시청하게 할 수 있는 디지털 튜너에는 입력되는 고주파신호에 대하여 양호한 수신상태를 유지할 수 있도록 신호이득을 조절하는 자동이득제어기(AGC)가 구비되게 된다.The digital tuner capable of watching a plurality of programs is provided with an automatic gain controller (AGC) that adjusts the signal gain so as to maintain a good reception state for the input high frequency signal.

그 이유는, 송신 측에서 송신되는 신호 이득은 항상 일정하지만, 송신된 신호를 수신하는 수신 측은 송신 측과의 거리 및 기타 지형지물 또는 전파장애 등에 의하여 방해를 받아 신호 이득이 변화되어 수신되기 때문이다.The reason is that the signal gain transmitted from the transmitting side is always constant, but the receiving side receiving the transmitted signal is disturbed by the distance from the transmitting side and other features or radio interference, and thus the signal gain is changed and received. .

그래서 상기 수신신호 이득의 변화에 대하여 양호한 수신 전계와 인접 특성을 좋게 하기 위하여, 종래의 디지털 튜너의 중간주파 출력단에는 도 1에 도시한 바와 같이, 안테나(ANT)를 통해서 수신된 고주파(RF)신호에서 원하는 채널 주파수만을 선택하여 튜닝한 후 이 튜닝된 채널 주파수에 고주파(RF)신호의 이득을 제어하여 중간주파(IF)신호로 변환하는 튜너(1)와; 상기 튜너(1)에서 출력되는 중간주파(IF)신호의 대역만을 남기고 불필요한 신호를 제거하는 제1 표면탄성파필터(2)와; 상기 제 1 표면탄성파필터(2)에서 불필요한 신호가 제거된 중간주파(IF)신호를 증폭하는 중간주파증폭기(3)와; 상기 중간주파증폭기(3)에서 증폭된 중간주파 신호(IF)에서 불필요한 신호를 제거하는 제 2 표면탄성파필터(4)와; 상기 제 2 표면탄성파필터(4)에서 필터링된 중간주파신호(IF)의 이득을 피드백되어 입력되는 중간주파이득제어신호(IF AGC)에 의하여 이득을 조절하는 가변중간주파증폭기(5)와; 상기 가변중간주파증폭기(5)에서 이득이 제어된 중간주파(IF)신호를 복조하거나, 입력되는 중간주파 신호이득을 판단하여 상기 판단된 이득에 따라 상기 튜너(1)의 고주파(RF)이득과 가변중간주파증폭기(5)의 중간주파(IF)이득을 원하는 신호이득으로 조 절하는 디지털 복조기(6)로 구성하거나, 도 2 에 도시한 바와 같이, 제 1, 제 2 표면탄성파 필터(2)(4)의 후단에 2개 가변 중간주파증폭기(7)(5)를 각각 구성하여 이득을 조절하도록 구성하였다.Therefore, in order to improve a good reception electric field and adjacent characteristics with respect to the change in the received signal gain, a high frequency (RF) signal received through an antenna ANT is shown at the intermediate frequency output of the conventional digital tuner as shown in FIG. A tuner (1) which selects and tunes only a desired channel frequency at and then controls gain of a high frequency (RF) signal at the tuned channel frequency and converts it into an intermediate frequency (IF) signal; A first surface acoustic wave filter (2) for removing unnecessary signals while leaving only a band of the intermediate frequency (IF) signal output from the tuner (1); An intermediate frequency amplifier (3) for amplifying the intermediate frequency (IF) signal from which the unnecessary signal is removed from the first surface acoustic wave filter (2); A second surface acoustic wave filter (4) for removing unnecessary signals from the intermediate frequency signal (IF) amplified by the intermediate frequency amplifier (3); A variable intermediate frequency amplifier (5) for adjusting gain by an intermediate frequency gain control signal (IF AGC) fed back with the gain of the intermediate frequency signal IF filtered by the second surface acoustic wave filter 4; The variable intermediate frequency amplifier 5 demodulates the gain-controlled intermediate frequency (IF) signal or determines the gain of the input intermediate frequency signal to determine the gain of the high frequency (RF) of the tuner 1 according to the determined gain. The first and second surface acoustic wave filters 2 are constituted by a digital demodulator 6 that adjusts the intermediate frequency IF gain of the variable intermediate frequency amplifier 5 to a desired signal gain, or as shown in FIG. In the rear stage of (4), two variable intermediate frequency amplifiers (7) and (5) were respectively configured to adjust gain.

그러나 상기 종래의 중간주파증폭기(3)를 사용하는 경우 중간주파(IF)이득을 조절하지 않고 증폭하게 되므로, 가령 수신 전계 강도변화 즉 약전계인 경우에는 별문제가 없으나, 수신 전계 강도변화가 강전계인 경우 상기 중간주파증폭기(3)의 이득조절을 할 수 없어 한 개의 가변중간주파증폭기(5)로 중간주파이득을 조절하게 되므로 튜너의 성능개선을 하는데 미흡한 점이 있으며, 반면에 상기 중간주파증폭기(3)를 가변중간주파증폭기(7)로 하여 중간주파이득을 2중으로 가변조절하는 경우에는 수신 전계 강도변화에 대하여 2중으로 중간주파이득을 가변할 수 있어 중간주파 이득성능을 향상할 수 있으나, 2개의 가변중간주파증폭기의 구성에 따른 비용이 상승 되는 문제점을 가지게 되었다. However, when the conventional intermediate frequency amplifier (3) is used, the intermediate frequency (IF) gain is amplified without adjusting the gain. For example, if there is no problem in the received electric field strength change, that is, a weak electric field, but the received electric field strength change is a strong electric field. Since the gain control of the intermediate frequency amplifier 3 is not possible, the intermediate frequency gain is controlled by one variable intermediate frequency amplifier 5, and thus the performance of the tuner is insufficient. On the other hand, the intermediate frequency amplifier 3 In the case where the intermediate frequency gain is variably adjusted by using the variable intermediate frequency amplifier 7, the intermediate frequency gain can be varied in double with respect to the change in the received field strength, thereby improving the intermediate frequency gain performance. The cost of the intermediate frequency amplifier has been increased.

본 발명의 목적은 튜너로부터 출력되는 중간주파신호의 이득을 디지털 복조기의 고주파이득제어신호(RF AGC)로 조절할 수 있도록 하여 상기 튜너의 중간주파(IF)이득조절 성능을 향상하고자 하는데 있다.An object of the present invention is to improve the intermediate frequency (IF) gain control performance of the tuner by adjusting the gain of the intermediate frequency signal output from the tuner to the RF AGC of the digital demodulator.

본 발명의 다른 목적은 튜너의 중간주파(IF)이득조절 성능을 저해하지 않으면서 생산 비용을 낮추는데 있다.Another object of the present invention is to reduce the production cost without impairing the tuner's intermediate frequency (IF) gain control performance.

상기의 목적을 실현하기 위하여 본 발명은 안테나를 통해서 수신된 고주파신호의 이득을 제어하여 중간주파신호로 변환하는 튜너와; 상기 튜너에서 출력되는 중간주파신호에 불필요한 신호를 제거하는 제1 표면탄성파필터와; 상기 제 1 표면탄성파필터의 중간주파신호이득을 증폭하는 중간주파증폭기와; 상기 중간주파증폭기의 이득을 중간주파신호에 불필요한 신호를 제거하는 제2 표면탄성파 필터와; 상기 제2 표면탄성파 필터의 중간주파신호 이득을 조절하는 가변중간주파 증폭기와; 상기 가변중간주파증폭기에서 입력된 중간주파신호를 복조하거나, 중간주파신호이득을 조절하여 고주파이득제어신호와 중간주파이득제어신호를 출력하는 디지털 복조기에 상기 중간주파 증폭기의 중간주파 이득을 상기 디지털 복조기의 고주파이득제어신호로 조절하는 것을 포함하여서 된 것이다. In order to achieve the above object, the present invention includes a tuner for controlling the gain of a high frequency signal received through an antenna and converting it into an intermediate frequency signal; A first surface acoustic wave filter for removing unnecessary signals from the intermediate frequency signal output from the tuner; An intermediate frequency amplifier for amplifying the intermediate frequency signal gain of the first surface acoustic wave filter; A second surface acoustic wave filter for removing a gain of the intermediate frequency amplifier from a signal unnecessary for the intermediate frequency signal; A variable intermediate frequency amplifier for adjusting an intermediate frequency signal gain of the second surface acoustic wave filter; Demodulating the intermediate frequency signal inputted from the variable intermediate frequency amplifier, or adjusting the gain of the intermediate frequency signal to output a high frequency gain control signal and an intermediate frequency gain control signal to the digital demodulator to obtain the intermediate frequency gain of the intermediate frequency amplifier. This includes adjusting to the high-frequency gain control signal of.

따라서 본 발명에 의하면, 튜너로부터 변환 출력되는 중간주파신호를 증폭하는 고정 중간주파증폭기를 디지털 복조기로부터 피드백되는 고주파신호 이득제어신호로 중간주파 신호이득을 조절하도록 함으로써, 수신 전계 강도변화에 대하여 튜너의 중간주파 이득 조절 성능을 향상할 수 있게 되는 것이다.Therefore, according to the present invention, the fixed intermediate frequency amplifier for amplifying the intermediate frequency signal outputted from the tuner is adjusted by the high frequency signal gain control signal fed back from the digital demodulator, thereby adjusting the gain of the tuner with respect to the change in the received electric field strength. This improves the mid-frequency gain control.

이하 첨부되는 도면에 의거 본 발명을 상세히 설명하면 다음과 같다.Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

도 3은 본 발명 디지털 튜너의 중간주파이득제어장치의 블럭도로서, 본 발명은 튜너(20), 제 1 표면탄성파필터(21), 중간주파증폭기(22), 제 2 표면탄성파 필터(23), 가변 중간주파증폭기(24), 디지털복조기(25)로 구비하되, 상기 디지털 복조기(25)의 고주파 이득제어신호로 중간주파증폭기(22)의 이득을 조절하도록 구성된다.3 is a block diagram of an intermediate frequency gain control device of the digital tuner of the present invention. The present invention is a tuner 20, a first surface acoustic wave filter 21, an intermediate frequency amplifier 22, and a second surface acoustic wave filter 23. As shown in FIG. A variable intermediate frequency amplifier (24) and a digital demodulator (25) are provided, and the high frequency gain control signal of the digital demodulator (25) is configured to adjust the gain of the intermediate frequency amplifier (22).

상기 튜너(20)는 안테나(ANT)를 통해서 수신된 고주파신호(RF)에서 원하는 채널 주파수만을 선택하여 튜닝하고, 피드백되어 입력되는 고주파자동이득제어신호(RF AGC)신호를 받아 튜닝된 고주파신호(RF)의 이득을 자동 조절하여 중간주파신호(IF)로 변환 출력하게 된다.The tuner 20 selects and tunes only a desired channel frequency from the high frequency signal RF received through the antenna ANT, receives a high frequency automatic gain control signal RF AGC signal fed back, and tunes the tuned high frequency signal ( The gain of RF is automatically adjusted and converted into an intermediate frequency signal IF.

상기 제 1 표면탄성파필터(21)는 튜너(20)에서 변환되어 입력되는 중간주파신호(IF)에서 필요한 대역만을 남기고 불필요한 잡음신호를 제거하여 출력하게 된다. The first surface acoustic wave filter 21 removes and outputs an unnecessary noise signal while leaving only a necessary band in the intermediate frequency signal IF converted and input from the tuner 20.

상기 중간주파증폭기(22)는 상기 표면탄성파필터(21)에서 불필요한 잡음신호가 제거된 중간주파신호(IF)를 피드백되는 고주파이득제어신호(RF AGC)를 받아 중간주파이득을 최대 또는 중간주파이득을 작게 증폭하여 출력하게 된다.The intermediate frequency amplifier 22 receives the high frequency gain control signal RF AGC fed back to the intermediate frequency signal IF from which the unnecessary noise signal is removed from the surface acoustic wave filter 21 to obtain the maximum or intermediate frequency gain. Will be amplified small.

상기 제 2 표면탄성파필터(23)는 상기 중간주파증폭기(22)에서 증폭되어 입력되는 중간주파신호(IF)에서 필요한 대역만을 남기고 불필요한 잡음신호를 제거하여 출력하게 된다. The second surface acoustic wave filter 23 removes and outputs an unnecessary noise signal while leaving only a necessary band in the intermediate frequency signal IF amplified by the intermediate frequency amplifier 22.

상기 가변중간주파증폭기(24)는 제 2 표면탄성파필터(23)에서 불필요한 잡음신호가 제거된 중간주파신호(IF)에 대하여 피드백되는 중간주파이득제어신호(IF AGC)를 받아 중간주파신호(IF)의 이득을 조절하여 출력하게 된다.The variable intermediate frequency amplifier 24 receives the intermediate frequency gain control signal IF AGC fed back to the intermediate frequency signal IF from which the unnecessary noise signal is removed from the second surface acoustic wave filter 23. The gain of) is adjusted.

상기 디지털 복조기(25)는 상기 가변중간주파증폭기(24)에서 이득이 조절되어 입력되는 중간주파신호(IF)를 복조하여 출력하거나, 입력되는 중간주파수의 이득을 자동이득제어기(AGC)를 통해서 수신강도에 따른 이득을 조절하고 상기 조절된 이득신호를 상기 튜너(20)의 고주파이득제어신호(RF AGC)와 중간주파증폭기(22)의 중간주파이득제어신호(IF AGC)에 출력하게 된다. The digital demodulator 25 demodulates and outputs the intermediate frequency signal IF input by adjusting the gain in the variable intermediate frequency amplifier 24 or receives the gain of the input intermediate frequency through the automatic gain controller AGC. The gain according to the intensity is adjusted and the adjusted gain signal is output to the high frequency gain control signal RF AGC of the tuner 20 and the intermediate frequency gain control signal IF AGC of the intermediate frequency amplifier 22.

여기서 R1-R4는 저항이고, C1-C4는 노이즈 제거 콘덴서이다.Where R1-R4 are resistors and C1-C4 are noise canceling capacitors.

상기와 같이 구성되는 본 발명은 안테나(ANT)를 통해서 수신되는 다수의 텔레비젼 방송 채널 중 원하는 하나의 채널 고주파(RF)신호만을 튜너(20)를 통해서 선택하고, 이 선택된 고주파신호(RF)는 잡음제거와 함께, 디지털 복조기(25)로부터 피드백되어 입력되는 고주파자동이득제어신호(RF AGC)에 의하여 고주파신호(RF)의 이득을 조절한 후 중간주파신호(IF)로 변환하여 제 1 표면탄성파필터(21)로 출력되게 된다.According to the present invention configured as described above, only one desired channel high frequency (RF) signal among a plurality of television broadcasting channels received through the antenna ANT is selected through the tuner 20, and the selected high frequency signal RF is noise. Along with the removal, the gain of the high frequency signal RF is adjusted by the high frequency automatic gain control signal RF AGC fed back from the digital demodulator 25 and then converted into an intermediate frequency signal IF to convert the first surface acoustic wave filter. It is outputted to (21).

상기 제 1 표면탄성파필터(21)에서는 입력되는 중간주파신호(IF)에 대하여 필요한 중간주파신호(IF)만을 남기고 불필요한 잡음을 제거한 중간주파신호를 중간주파증폭기(22)에 출력하게 된다.The first surface acoustic wave filter 21 outputs the intermediate frequency signal to the intermediate frequency amplifier 22 from which unnecessary noise is removed while leaving only the intermediate frequency signal IF necessary for the input intermediate frequency signal IF.

상기 중간주파증폭기(22)에서는 제 1 표면탄성파필터(21)로부터 입력된 중간주파신호(IF)를 증폭하여 제 2 표면탄성파필터(23)로 출력하게 되는데, 이때 상기 중간주파증폭기(22)에서는 후술할 상기 디지털 복조기(25)로부터 입력되는 중간주파이득제어신호(IF AGC)를 토대로 이득이 조절된 고주파이득제어신호(RF AGC)로 중간주파(IF)신호를 조절 증폭하여 출력하게 된다.In the intermediate frequency amplifier 22, the intermediate frequency signal IF input from the first surface acoustic wave filter 21 is amplified and output to the second surface acoustic wave filter 23. In this case, the intermediate frequency amplifier 22 Based on the intermediate frequency gain control signal IF AGC input from the digital demodulator 25 to be described later, the intermediate frequency IF signal is adjusted and amplified by a high frequency gain control signal RF AGC whose gain is adjusted.

한편 상기 제 2 표면탄성파필터(23)에서는 상기 중간주파증폭기(22)로부터 입력된 중간주파신호에서 불필요한 신호를 제거한 중간주파신호를 가변중간주파증폭기(24)로 출력하게 되고, 상기 가변중간주파증폭기(24)에서는 상기 중간주파신호(IF)를 증폭하여 상기 디지털 복조기(25)에 출력하되, 상기 가변중간주파증폭기(24)에서는 상기 디지털 복조기(25)로부터 피드백되어 입력되는 중간주파이득제어 신호(IF AGC)에 의하여 중간주파신호(IF)의 이득을 조절 증폭하여 디지털 복조기(25)에 출력하게 된다.Meanwhile, the second surface acoustic wave filter 23 outputs an intermediate frequency signal from which an unnecessary signal is removed from the intermediate frequency signal input from the intermediate frequency amplifier 22 to the variable intermediate frequency amplifier 24, and the variable intermediate frequency amplifier In 24, the intermediate frequency signal IF is amplified and output to the digital demodulator 25. In the variable intermediate frequency amplifier 24, an intermediate frequency gain control signal fed back from the digital demodulator 25 is input ( IF AGC) adjusts and amplifies the gain of the intermediate frequency signal IF and outputs it to the digital demodulator 25.

따라서 상기 디지털 복조기(25)에서는 증폭된 중간주파신호(IF)에 대하여 상기 잔류측파대로 복조하여 출력하게 되는데, 이때 상기 디지털 복조기(25)에서는 자체의 자동이득조절기(AGC)를 통해서 수신되는 신호 감도에 따라 이득을 조절하게 되는데, 가령 수신 신호가 큰 경우 고주파신호(RF)의 이득과 중간주파신호(IF)의 이득을 작게 조절하여 상기 튜너(20)의 고주파신호와 중간주파증폭기(22)의 중간주파신호의 이득을 조절하게 되고, 반대로 수신 신호가 작은 경우에는 고주파신호 (RF)와 중간주파신호(IF)의 이득을 최대로 조절하여 상기 튜너(20)의 고주파신호이득과 중간주파증폭기(22)의 중간주파신호의 이득을 조절하게 된다.Therefore, the digital demodulator 25 demodulates and outputs the amplified intermediate frequency signal IF as the residual side wave, and at this time, the digital demodulator 25 receives the signal received through its automatic gain controller AGC. The gain is adjusted according to the sensitivity. For example, when the received signal is large, the gain of the high frequency signal RF and the gain of the intermediate frequency signal IF are adjusted to be small so that the high frequency signal and the intermediate frequency amplifier 22 of the tuner 20 are adjusted. If the received signal is small, the gain of the high frequency signal (RF) and the intermediate frequency signal (IF) is adjusted to the maximum, thereby adjusting the gain of the high frequency signal of the tuner 20 and the intermediate frequency amplifier. The gain of the intermediate frequency signal of (22) is adjusted.

이와 같이 수신신호의 크기에 따라 신호 이득을 조절한 상기 디지털 복조기(25)에서는 상기 이득이 조절된 신호 이득 중 고주파신호(RF)의 이득을 상기 중간주파증폭기(22)로 피드백시켜 상기 중간주파증폭기(22)로 하여금 중간주파신호(IF)의 이득을 작게 혹은 최대로 조절하도록 함으로써, 튜너의 이득조절 성능을 향상하게 되는 것이다.The digital demodulator 25 in which the signal gain is adjusted according to the magnitude of the received signal is fed back to the intermediate frequency amplifier 22 of the gain of the adjusted signal gain to the intermediate frequency amplifier 22. By making (22) adjust the gain of the intermediate frequency signal IF small or maximum, the gain control performance of the tuner is improved.

이상에서 설명한 바와 같이 본 발명은 안테나를 통해서 입력되는 고주파신호 를 중간주파신호로 변환 출력하는 튜너에서 수신신호 이득의 변화에 대하여 양호한 수신 전계와 인접 특성을 좋게 하기 위하여 2중으로 증폭하고 필터링하는 중간주파증폭단을 디지털 복조기를 통해서 수신신호 감도에 따라 이득이 조절된 고주파이득 제어신호로 중간주파 증폭단의 중간주파이득을 조절함으로써, 디지털 튜너의 중간주파 이득 조절성능을 향상할 수 있는 효과를 제공하게 되는 것이다.As described above, in the present invention, a tuner converting and outputting a high frequency signal input through an antenna into an intermediate frequency signal outputs a double frequency amplification and filtering in order to improve a good reception electric field and adjacent characteristics with respect to a change in received signal gain. The amplification stage is a high frequency gain control signal whose gain is adjusted according to the received signal sensitivity through a digital demodulator to adjust the intermediate frequency gain of the intermediate frequency amplification stage, thereby improving the intermediate frequency gain control performance of the digital tuner. .

Claims (1)

안테나를 통해서 수신된 고주파신호의 이득을 제어하여 중간주파신호로 변환하는 튜너와; 상기 튜너에서 출력되는 중간주파신호에 불필요한 신호를 제거하는 제1 표면탄성파필터와; 상기 제 1 표면탄성파필터의 중간주파신호이득을 증폭하는 중간주파증폭기와; 상기 중간주파증폭기의 이득을 중간주파신호에 불필요한 신호를 제거하는 제2 표면탄성파 필터와; 상기 제2 표면탄성파 필터의 중간주파신호이득을 조절하는 가변중간주파증폭기와; 상기 가변중간주파증폭기에서 입력된 중간주파신호를 복조하거나, 중간주파신호이득을 조절하여 고주파이득제어신호와 중간주파이득제어신호를 출력하는 디지털 복조기를 포함하고, 상기 중간주파 증폭기의 중간주파 이득을 상기 디지털 복조기의 고주파이득제어신호로 조절하는 것을 특징으로 하는 디지털튜너의 중간주파이득조절장치.A tuner for controlling the gain of the high frequency signal received through the antenna and converting the gain into an intermediate frequency signal; A first surface acoustic wave filter for removing unnecessary signals from the intermediate frequency signal output from the tuner; An intermediate frequency amplifier for amplifying the intermediate frequency signal gain of the first surface acoustic wave filter; A second surface acoustic wave filter for removing a gain of the intermediate frequency amplifier from a signal unnecessary for the intermediate frequency signal; A variable intermediate frequency amplifier controlling an intermediate frequency signal gain of the second surface acoustic wave filter; And a digital demodulator for demodulating the intermediate frequency signal inputted from the variable intermediate frequency amplifier, or adjusting the gain of the intermediate frequency signal to output a high frequency gain control signal and an intermediate frequency gain control signal. Adjusting the intermediate main gain of the digital tuner, characterized in that the control by the high frequency gain control signal of the digital demodulator.
KR1020050135095A 2005-12-30 2005-12-30 If gain control device of digital tuner KR20070071547A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101469635B1 (en) * 2008-11-24 2014-12-05 엘지이노텍 주식회사 Circuit for controlling automatic gain of digital intermediate frequency

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101469635B1 (en) * 2008-11-24 2014-12-05 엘지이노텍 주식회사 Circuit for controlling automatic gain of digital intermediate frequency

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