KR20070103586A - Satellite digital tuner - Google Patents

Satellite digital tuner Download PDF

Info

Publication number
KR20070103586A
KR20070103586A KR1020060035338A KR20060035338A KR20070103586A KR 20070103586 A KR20070103586 A KR 20070103586A KR 1020060035338 A KR1020060035338 A KR 1020060035338A KR 20060035338 A KR20060035338 A KR 20060035338A KR 20070103586 A KR20070103586 A KR 20070103586A
Authority
KR
South Korea
Prior art keywords
high frequency
signal
frequency
automatic gain
low noise
Prior art date
Application number
KR1020060035338A
Other languages
Korean (ko)
Inventor
유병석
Original Assignee
엘지이노텍 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 엘지이노텍 주식회사 filed Critical 엘지이노텍 주식회사
Priority to KR1020060035338A priority Critical patent/KR20070103586A/en
Publication of KR20070103586A publication Critical patent/KR20070103586A/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3036—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers
    • H03G3/3042—Automatic control in amplifiers having semiconductor devices in high-frequency amplifiers or in frequency-changers in modulators, frequency-changers, transmitters or power amplifiers
    • 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

A satellite digital tuner is provided to maintain signal reception sensitivity stable by reducing an interference between an amplified high frequency signal and signals in other frequency bands. A satellite digital tuner includes a variable HPF(High Pass Filter)(21), an LNA(Low Noise Amplifier)(22), a high frequency automatic gain amplifier circuit(23), and a demodulator(25). The variable HPF performs filtering a high frequency signal using a desired pass band. The LNA removes a noise from the filtered frequency and amplifies the result. The high frequency automatic gain amplifier circuit adjusts a reception gain by using an automatic gain adjusting signal, which is fed back from the LNA. An I/Q converting circuit mixes the result from the high frequency automatic gain amplifier circuit with a local oscillator frequency and outputs an intermediate frequency signal. The demodulator demodulates the I/Q signal to obtain original video and audio digital data.

Description

위성파 튜너{SATELLITE DIGITAL TUNER}Satellite Tuner {SATELLITE DIGITAL TUNER}

도 1은 종래 위성파 디지털 튜너의 블럭도1 is a block diagram of a conventional satellite wave digital tuner

도 2는 도 1의 주파수 특성도2 is a frequency characteristic diagram of FIG.

도 3은 본 발명의 일실시예도에 따른 위성파 튜너의 블럭도3 is a block diagram of a satellite wave tuner according to an embodiment of the present invention.

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

21; 가변고역통과필터 22; 저잡음증폭기21; Variable high pass filter 22; Low noise amplifier

23; 고주파자동이득증폭회로 24; I/Q변환회로23; High frequency automatic gain amplifier circuit 24; I / Q conversion circuit

25; 복조기25; Demodulator

본 발명은 위성파 튜너에 관한 것이다.The present invention relates to a satellite wave tuner.

일반적으로 위성파 튜너는 공중파를 이용한 50MHZ ~ 860MHZ의 주파수를 수신하는 지상파 튜너와는 달리 위성으로부터 송신되는 높은 주파수인 900MHZ ~ 2200MHZ를 수신하게 된다.In general, unlike a terrestrial tuner that receives a frequency of 50MHZ ~ 860MHZ using airwaves, the satellite tuner receives a high frequency 900MHZ ~ 2200MHZ transmitted from the satellite.

상기 위성파 튜너는 도 1에 도시한 바와 같이, 고주파입력단(RF-IN)으로부터 입력되는 고주파신호에 대하여 고정된 대역주파수만을 필터링하는 대역통과필 터(11)와; 상기 대역통과필터(11)로 필터링 된 주파수를 저잡음 증폭하는 저잡음증폭기(LNB)(12)와; 상기 저잡음증폭기(12)에서 증폭된 고주파신호를 피드백되는 자동이득조절신호에 의하여 수신 이득을 조절 증폭하는 고주파자동이득증폭회로(13)와; 상기 고주파자동이득증폭회로(13)에서 이득이 조절되어 증폭된 고주파신호를 국부 발진주파수와 혼합하여 I/Q신호를 출력하는 I/Q변환회로(14)와; 상기 I/Q변환회로(14)에서 출력되는 I/Q신호를 원래의 디지털 데이타로 복조하는 복조부(15)로 구성된다.As shown in FIG. 1, the satellite tuner includes: a band pass filter (11) for filtering only a fixed band frequency for a high frequency signal input from a high frequency input terminal (RF-IN); A low noise amplifier (LNB) 12 for low noise amplifying the frequency filtered by the band pass filter 11; A high frequency automatic gain amplifier circuit (13) for controlling and amplifying a reception gain by an automatic gain control signal fed back from the high frequency signal amplified by the low noise amplifier (12); An I / Q conversion circuit 14 for outputting an I / Q signal by mixing a high frequency signal whose gain is controlled and amplified by the high frequency automatic gain amplifier circuit 13 with a local oscillation frequency; And a demodulation section 15 for demodulating the I / Q signal output from the I / Q conversion circuit 14 into original digital data.

이와 같이 구성되는 위성파 튜너는 위성으로부터 고주파입력단(RF-IN)을 통해서 수신된 900MHZ ~ 2200MHZ의 고주파신호를 대역통과필터(11)를 통해서 고정된 대역주파수만을 필터링하여 저잡음증폭기(12)에 출력하게 된다.The satellite tuner configured as described above filters the fixed high frequency signal of 900MHZ ~ 2200MHZ received through the RF-IN from the satellite through the bandpass filter 11 to output to the low noise amplifier 12. do.

상기 저잡음증폭기(12)에서는 필터링된 주파수 대역에 대하여 위성전파 잡음과 노이즈를 제거하고 일차 저잡음 증폭하여 상기 고주파자동이득증폭회로(13)에 출력하게 된다.The low noise amplifier 12 removes the satellite propagation noise and noise with respect to the filtered frequency band, and first outputs the low noise amplification to the high frequency automatic gain amplifier circuit 13.

상기 고주파자동이득증폭회로(13)에서는 일차 저잡음 증폭된 고주파신호에 대하여 증폭한 후 자동이득제어신호로 고주파신호의 수신강도를 조절하고, 조절되는 고주파신호를 I/Q변환회로(14)를 통해서 국부발진주파수와 혼합하여 I/Q신호를 출력하며, 상기 출력된 I/Q신호는 필터를 통해서 불필요한 주파수를 제거한 후 중간주파증폭기를 거쳐 복조기(15)에서 원래의 신호로 복조하여 출력하게 된다.The high frequency automatic gain amplifier circuit 13 amplifies the first low noise amplified high frequency signal, and then adjusts the reception intensity of the high frequency signal with the automatic gain control signal, and adjusts the controlled high frequency signal through the I / Q conversion circuit 14. The I / Q signal is output by mixing with the local oscillation frequency, and the output I / Q signal is demodulated to the original signal by the demodulator 15 through an intermediate frequency amplifier after removing unnecessary frequencies through a filter.

그러나 상기 저잡음증폭기(12)에서 일차 저잡음 증폭되어 출력되는 900MHZ ~ 2200MHZ의 고주파신호에 대한 주파수의 특성을 살펴보면, 도 2에 도시한 바와 같 이, 1600MHZ 이하의 신호 대역에서는 상당히 이득이 크고, 신호 상태가 안정적인 반면에, 상기 1600MHZ 이상의 신호 대역에서는 현격하게 신호 감쇄가 많아져 주파수간의 이득 편차가 10dB 이상으로 차이가 발생되어 안정적이지 못하다. However, when looking at the frequency characteristics of the high frequency signal of 900MHZ ~ 2200MHZ that is output by amplifying the first low noise in the low noise amplifier 12, as shown in Figure 2, in the signal band of 1600MHZ or less, the gain is large, the signal state On the other hand, in the signal band of 1600MHZ or more, the signal attenuation increases significantly, and the gain deviation between frequencies is more than 10dB, which makes it unstable.

이렇게 주파수간의 이득 편차가 심한 상태에서 상기 고주파자동이득증폭회로(13)에서 I/Q신호를 출력하기 위하여 증폭하는 경우, 상기 1600MHZ 이하의 신호 대역에서는 상대적으로 상당히 커져서 안정적이지만, 상기 1600MHZ 이상의 신호 대역은 상기 1600MHZ 이하의 신호 대역의 증폭에 의하여 인접 채널 방해 또는 고조파 영향에 의하여 상대적으로 성능 열화가 발생되어 수신 감도가 좋지 않은 문제점이 있다.When the amplification is performed to output the I / Q signal by the high frequency automatic gain amplifier circuit 13 in a state where the gain deviation between the frequencies is severe, the signal band of 1600MHZ or less is relatively large and stable, but the signal band of 1600MHZ or more is stable. Due to the amplification of the signal band of 1600MHZ or less, performance degradation occurs due to interference of adjacent channels or harmonics, resulting in poor reception sensitivity.

본 발명의 목적은 안정적인 수신감도를 유지하는 위성파 튜너를 제공하는데 있다.An object of the present invention is to provide a satellite wave tuner that maintains a stable reception sensitivity.

상기의 목적을 실현하기 위하여 본 발명은 고주파입력단을 통해서 입력되는 고주파신호에 대하여 원하는 통과 대역주파수로 가변하여 필터링하는 가변고역통과필터와; In order to achieve the above object, the present invention includes a variable high pass filter for varying and filtering the desired high pass signal for the high frequency signal input through the high frequency input stage;

상기 가변고역통과필터에서 가변하여 필터링된 주파수에 대하여 노이즈를 제거하고 증폭하는 저잡음증폭기와; A low noise amplifier which removes and amplifies noise with respect to the filtered frequency, which is variable in the variable high pass filter;

상기 저잡음증폭기에서 증폭된 고주파신호를 피드백되는 자동이득조절신호로 수신이득을 조절 증폭하는 고주파자동이득증폭회로와; A high frequency automatic gain amplifier circuit for controlling and amplifying the reception gain of the high frequency signal amplified by the low noise amplifier with an automatic gain control signal fed back;

상기 고주파자동이득증폭회로에서 증폭되는 고주파신호를 국부발진주파수로 혼합하여 중간주파신호를 출력하는 I/Q변환회로 및 상기 I/Q변환회로에서 출력되는 I/Q신호를 원래의 비디오 및 오디오 디지털데이터로 복조하는 복조기를 포함한다.An I / Q conversion circuit for outputting an intermediate frequency signal by mixing a high frequency signal amplified by the high frequency automatic gain amplifier at a local oscillation frequency and an I / Q signal output from the I / Q conversion circuit. And a demodulator to demodulate data.

상기 가변고역통과필터는 외부 제어부의 채널정보에서 임의로 기설정된 제어신호에 의하여 통과 대역주파수를 가변한다.The variable high pass filter varies the pass band frequency by a control signal arbitrarily preset in the channel information of the external controller.

따라서 본 발명에 의하면, 입력되는 고주파신호에 대하여 가변고역통과필터로 원하는 대역주파수만을 필터링한 후 저잡음증폭기로 증폭하여 I/Q신호를 출력하기 위해 고주파자동이득증폭회로로 다시 증폭하더라도 이 증폭된 고주파신호는 다른 대역주파수에 영향을 받지않게 되어 안정된 수신감도를 유지할 수 있게 되는 것이다.Therefore, according to the present invention, the high frequency signal is amplified by a high frequency automatic gain amplifier circuit to output the I / Q signal by filtering only the desired band frequency with a variable high pass filter and then amplifying it with a low noise amplifier. The signal is not affected by other band frequencies, so that stable reception sensitivity can be maintained.

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 발명의 일실시예도에 따른 위성파 튜너의 블럭도로서, 본 발명은 가변고역통과필터(21), 저잡음증폭기(22), 고주파자동이득증폭회로(23), I/Q변환회로(24), 복조기(25)를 포함한다.3 is a block diagram of a satellite wave tuner according to an embodiment of the present invention. The present invention provides a variable high pass filter 21, a low noise amplifier 22, a high frequency automatic gain amplifier circuit 23, and an I / Q conversion circuit. 24) and a demodulator 25.

상기 가변고역통과필터(21)는 고주파입력단(RF-IN)으로부터 입력되는 900MHZ ~ 2200MHZ의 고주파신호에 대하여 외부 제어부의 채널정보에 의하여 기설정된 제어신호를 받아 통과 대역주파수로 가변하게 된다.The variable high pass filter 21 receives a control signal preset by channel information of an external control unit for a high frequency signal of 900 MHZ to 2200 MHZ inputted from a high frequency input terminal RF-IN, and varies the passband frequency.

상기 가변고역통과필터(21)는 가변대역통과필터를 사용할 수도 있다.The variable high pass filter 21 may use a variable band pass filter.

상기 저잡음증폭기(22)는 통상적으로 입력필터, RF 증폭회로, 혼합회로, 국부발진회로, IF 증폭회로로 구성되어 수신되는 미약한 신호의 이득을 40dB에서 50dB 만큼 증폭시키고 난 후, 주파수를 낮추어 변환한다.The low noise amplifier 22 is typically composed of an input filter, an RF amplification circuit, a mixing circuit, a local oscillation circuit, and an IF amplification circuit to amplify the gain of a weak signal received by 40 dB to 50 dB, and then convert the frequency by lowering it. do.

상기 고주파자동이득증폭회로(23)는 증폭기로 구성되어 상기 저잡음증폭기(22)에서 증폭된 고주파신호를 증폭하고, 피드백되는 자동이득조절신호에 의하여 수신 이득을 조절 증폭하여 출력한다.The high frequency automatic gain amplifier circuit 23 is configured as an amplifier to amplify the high frequency signal amplified by the low noise amplifier 22, and adjusts and amplifies the received gain by the automatic gain control signal fed back.

상기 I/Q변환회로(24)는 상기 고주파자동이득증폭회로(23)에서 증폭되는 고주파신호를 위상고정루프, 국부발진기, 혼합기를 통해서 국부발진주파수와 혼합하여 I/Q신호를 출력한다.The I / Q conversion circuit 24 mixes the high frequency signal amplified by the high frequency automatic gain amplifier circuit 23 with the local oscillation frequency through a phase locked loop, a local oscillator, and a mixer to output an I / Q signal.

상기 복조기(25)는 상기 I/Q변환회로(24)로부터 출력되는 I/Q신호를 필터와 증폭기를 통해서 증폭된 I/Q신호를 디지털데이터로 복조한다.The demodulator 25 demodulates the I / Q signal output from the I / Q conversion circuit 24 into digital data by amplifying the I / Q signal amplified through a filter and an amplifier.

상기와 같이 구성되는 본 발명은 고주파입력단(RF-IN)으로 900MHZ ~ 2200MHZ의 고주파신호가 입력되면, 상기 입력된 고주파신호는 가변고역통과필터(21)에서 원하는 대역주파수로 필터링하게 되는데, 이때 상기 가변고역통과필터(21)는 저잡음증폭기(22)로 증폭시 신호 감쇄가 많은 대역 즉 입력되는 고주파신호(900MHZ ~ 2200MHZ)에서 대역주파수(1600MHZ) 이상에서 필터링 될 수 있도록 설정하고, 반면에 상기 대역주파수(1600MHZ) 이하에서는 그대로 통과될 수 있도록 가변 설정하게 된다. According to the present invention configured as described above, when a high frequency signal of 900MHZ ~ 2200MHZ is input to a high frequency input terminal (RF-IN), the input high frequency signal is filtered at a desired band frequency by the variable high pass filter 21, wherein The variable high pass filter 21 is set so that the signal attenuation during amplification by the low noise amplifier 22 can be filtered at a band frequency (1600MHZ) or more in a band having a large signal attenuation, that is, an input high frequency signal (900MHZ ~ 2200MHZ), whereas the band If the frequency (1600MHZ) or less is set to be variable so that it can pass through as it is.

그러므로 상기 가변고역통과필터(21)에 상기 대역주파수(1600MHZ)이하로 고주파신호가 입력되는 경우, 상기 입력되는 고주파신호는 가변고역통과필터(21)를 통과하여 저잡음증폭기(22)에서 노이즈를 제거하고 증폭하여 상기 고주파자동이득증폭회로(23)로 출력하게 된다.Therefore, when a high frequency signal is input to the variable high pass filter 21 or less than the band frequency 1600MHZ, the input high frequency signal passes through the variable high pass filter 21 to remove noise from the low noise amplifier 22. And amplified and outputted to the high frequency automatic gain amplifier circuit 23.

따라서 상기 고주파자동이득증폭회로(23)에서는 증폭된 고주파신호에 대하여 다시 증폭하더라도 대역주파수 이상에 대하여 아무런 영향을 주지 않고 I/Q변환회로(24)를 통해서 국부발진주파수와 혼합하여 I/Q신호를 출력하며 상기 I/Q신호는 복조기(25)를 통해서 원래의 디지털데이터로 복조하여 출력하게 된다.Therefore, in the high frequency automatic gain amplifier circuit 23, even if amplified again with respect to the amplified high frequency signal, the I / Q signal is mixed with the local oscillation frequency through the I / Q conversion circuit 24 without any influence on the band frequency or more. The I / Q signal is demodulated to original digital data through a demodulator 25 and output.

한편 상기 가변고역통과필터(21)에 상기 대역주파수(1600MHZ)이상으로 고주파신호가 입력되는 경우, 외부 제어부로부터 제어신호에 의하여 상기 대역주파수 이하는 차단하고, 대역주파수 이상만을 필터링하여 상기 저잡음증폭기(22)에 출력하게 된다. On the other hand, when a high frequency signal is input to the variable high pass filter 21 above the band frequency (1600MHZ), the low frequency amplifier cuts the band frequency below the band frequency by a control signal from the external controller, and filters only the band frequency or more. 22).

상기 저잡음증폭기(22)에서는 필터링 된 대역주파수에 대하여 노이즈를 제거하고 증폭한 후 상기 고주파자동이득증폭회로(23)에 출력하게 되는데, 이때 상기 고주파자동이득증폭회로(23)에서는 증폭된 고주파신호에 대하여 다시 증폭하더라도 상기 증폭되는 고주파신호가 상기 대역주파수 이하의 주파수에 대하여 전혀 영향을 받지 않게 된다.The low noise amplifier 22 removes and amplifies noise with respect to the filtered band frequency, and then outputs the amplified high frequency signal to the high frequency automatic gain amplifier circuit 23. Even if the signal is amplified again, the amplified high frequency signal is not affected at all by frequencies below the band frequency.

그러므로 상기 고주파자동이득증폭회로(23)에서는 증폭되어 입력되는 고주파신호에 대하여 I/Q변환회로(24)에서 국부발진주파수와 혼합하여 L/Q신호를 출력하고 이 출력되는 I/Q신호는 복조기(25)를 통해서 원래의 디지털데이터로 복조하여 출력하게 된다.Therefore, in the high frequency automatic gain amplifier circuit 23, the L / Q signal is output by mixing with the local oscillation frequency in the I / Q conversion circuit 24 with respect to the high frequency signal amplified and input, and the output I / Q signal is a demodulator. The demodulation is performed on the original digital data through (25).

이상에서 설명한 바와 같이 본 발명은 고주파입력단으로 입력되는 고주파신호를 가변고역통과필터를 통해서 원하는 대역주파수만을 필터링한 후 저잡음증폭기 로 증폭하고, 상기 증폭된 고주파신호에 대하여 I/Q신호를 출력하기 위하여 고주파자동이득증폭회로에서 다시 증폭하더라도 상기 증폭된 고주파신호는 입력되는 다른 대역주파수에 영향을 받지않게 되어 원하는 채널을 선국하는데 있어서 안정된 수신감도를 유지할 수 있게 되는 것이다.As described above, in the present invention, the high frequency signal inputted to the high frequency input terminal is filtered through a variable high pass filter to a desired band frequency and then amplified by a low noise amplifier to output an I / Q signal to the amplified high frequency signal. Even if the high frequency automatic gain amplification circuit is amplified again, the amplified high frequency signal is not affected by other input frequency bands, thereby maintaining stable reception sensitivity in tuning a desired channel.

Claims (1)

고주파입력단을 통해서 입력되는 고주파신호에 대하여 원하는 통과 대역주파수로 가변하여 필터링하는 가변고역통과필터와; A variable high pass filter configured to filter the high frequency signal input through the high frequency input terminal at a desired passband frequency; 상기 가변고역통과필터에서 가변하여 필터링된 주파수에 대하여 노이즈를 제거하고 증폭하는 저잡음증폭기와; A low noise amplifier which removes and amplifies noise with respect to the filtered frequency, which is variable in the variable high pass filter; 상기 저잡음증폭기에서 증폭된 고주파신호를 피드백되는 자동이득조절신호로 수신이득을 조절 증폭하는 고주파자동이득증폭회로와; A high frequency automatic gain amplifier circuit for controlling and amplifying the reception gain of the high frequency signal amplified by the low noise amplifier with an automatic gain control signal fed back; 상기 고주파자동이득증폭회로에서 증폭되는 고주파신호를 국부발진주파수로 혼합하여 중간주파신호를 출력하는 I/Q변환회로 및 상기 I/Q변환회로에서 출력되는 I/Q신호를 원래의 비디오 및 오디오 디지털데이터로 복조하는 복조기를 포함하는 위성파 튜너.An I / Q conversion circuit for outputting an intermediate frequency signal by mixing a high frequency signal amplified by the high frequency automatic gain amplifier at a local oscillation frequency and an I / Q signal output from the I / Q conversion circuit. Satellite tuner including a demodulator to demodulate data.
KR1020060035338A 2006-04-19 2006-04-19 Satellite digital tuner KR20070103586A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020060035338A KR20070103586A (en) 2006-04-19 2006-04-19 Satellite digital tuner

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020060035338A KR20070103586A (en) 2006-04-19 2006-04-19 Satellite digital tuner

Publications (1)

Publication Number Publication Date
KR20070103586A true KR20070103586A (en) 2007-10-24

Family

ID=38817891

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020060035338A KR20070103586A (en) 2006-04-19 2006-04-19 Satellite digital tuner

Country Status (1)

Country Link
KR (1) KR20070103586A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114844517A (en) * 2022-04-21 2022-08-02 上海钮沃科技有限公司 Multi-frequency multi-satellite GNSS radio frequency front end and processing method of high-frequency and low-frequency signals thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114844517A (en) * 2022-04-21 2022-08-02 上海钮沃科技有限公司 Multi-frequency multi-satellite GNSS radio frequency front end and processing method of high-frequency and low-frequency signals thereof

Similar Documents

Publication Publication Date Title
US8428536B2 (en) Low-cost receiver using automatic gain control
JP2006042350A (en) Radio receiver using agc and rf receiving method
KR100726782B1 (en) Terrestrial-Digital Multimedia Broadcasting and Digital Audio Broadcasting Low-IF Receiver.
JP2012138769A (en) Electronic tuner and electronic apparatus using the same
US20090086859A1 (en) Receiving unit receiving digital television broadcasting
JP2005513903A (en) Automatic gain control for tuners
KR20070045828A (en) Tuner having compensation circuit of input signal on strong electric field built-in
EP1845625A2 (en) Double conversion receiver
KR20070103586A (en) Satellite digital tuner
KR20080004877A (en) Tuner
US7310505B2 (en) Attenuation control for tuners
EP1868308A2 (en) Terrestrial-digital multimedia broadcasting receiver
JP5169677B2 (en) Receiver
KR100340434B1 (en) Tuner for receiving satellite broadcasting
KR100406349B1 (en) Digital groundwave receiving module with improved function of removal of adjacent channel beat
KR20070063210A (en) Analog video control circuit 0f tuner use as analog and digital
KR20020030379A (en) Double conversion type tuner for using trap circuit
KR100380723B1 (en) Digital satellite receiver with capability of improving receiving sensitivity in low field area
KR20070052422A (en) Radio frequency receiver
KR100558503B1 (en) Filter for removing high harmonic of double conversion type tuner
KR0116899Y1 (en) A circuit for improving s/n ratio of tuner
KR19980020721A (en) Primary Conversion Tuner for Satellite Broadcasting
KR100560000B1 (en) circuits of tuner for satellite broadcasting
KR200425362Y1 (en) UHF audio receiving apparatus
KR20070071547A (en) If gain control device of digital tuner

Legal Events

Date Code Title Description
WITN Withdrawal due to no request for examination