KR890004653Y1 - Midium frequency circuits for catv tuner - Google Patents
Midium frequency circuits for catv tuner Download PDFInfo
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- KR890004653Y1 KR890004653Y1 KR2019860002410U KR860002410U KR890004653Y1 KR 890004653 Y1 KR890004653 Y1 KR 890004653Y1 KR 2019860002410 U KR2019860002410 U KR 2019860002410U KR 860002410 U KR860002410 U KR 860002410U KR 890004653 Y1 KR890004653 Y1 KR 890004653Y1
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- circuit
- double
- output
- gain
- intermediate frequency
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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
- H04N5/50—Tuning indicators; Automatic tuning control
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J3/00—Continuous tuning
- H03J3/02—Details
- H03J3/06—Arrangements for obtaining constant bandwidth or gain throughout tuning range or ranges
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N7/00—Television systems
- H04N7/10—Adaptations for transmission by electrical cable
- H04N7/102—Circuits therefor, e.g. noise reducers, equalisers, amplifiers
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- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
Abstract
내용 없음.No content.
Description
제1도는 종래의 2차중간 주파수 회로도.1 is a conventional secondary intermediate frequency circuit diagram.
제2도는 본 고안에 따른 중간 주파수 회로도.2 is an intermediate frequency circuit diagram according to the present invention.
제3도는 혼변조 특성 그래프이다.3 is a graph of intermodulation characteristics.
* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings
1 : 단동조회로부 2 : 증폭회로부1: single tuning circuit part 2: amplification circuit part
3 : 복동조회로부 4 :이득조절부3: double-tuning circuit part 4: gain control part
C1C11C12: 콘덴서 L1L2L11L12L13: 코일C 1 C 11 C 12 : Condenser L 1 L 2 L 11 L 12 L 13 : Coil
MIX2: 제2혼합기 OUT : 출력단MIX 2 : 2nd mixer OUT: Output terminal
A, B : 그래프 VR : 가변저항A, B: Graph VR: Variable resistor
FET : 전계효과 트랜지스터FET: Field Effect Transistor
본 고안은 유선 텔레비젼의 튜브에 사용되는 중간 주파수 회로에 관한 것으로, 특히 유선텔레비젼 튜너의 중간주파수 회로에 복동조회로와 함께 단종조회로와 증폭기를 설치하여 선택도를 중가시킨 유선 텔레비젼 튜너의 중간주파수 회로에 관한 것이다.The present invention relates to an intermediate frequency circuit used for a tube of a cable television. In particular, an intermediate frequency circuit of a cable television tuner has a double frequency tuning circuit and a single frequency tuning circuit and an amplifier installed to increase the selectivity. It is about a circuit.
유선 텔레비젼(CATV:CablerTelevision)은 50MHZ로부터 500MHZ이상의 광범위한 대역폭을 이용하여 송신되는 그 주파신호를 케이블을 통해 수신하여 혼합, 증폭검파등을 행함으로써 영상신호와 음성신호를 추출하여 재생시키는 장치인데, 특히 광대역을 수신, 처리하기 위해서는 튜너회로부의 특성개선이 요구되어진다.Cable TV (CATV: CablerTelevision) is a device that extracts and reproduces video and audio signals by receiving, mixing, amplifying and detecting the frequency signals transmitted using a wide bandwidth from 50 MHz to 500 MHz. In order to receive and process wideband, improvement of characteristics of the tuner circuit portion is required.
종래의 경우 튜너의 제2중간 주파수 회로부는 제1도에 도시된 바와같이 복동조회로와 필터회로가 결합된 구조로 되어 제2혼합기로 부터의 신호를 동조시키고 필터링시켰는데 그 구조를 좀 더 상세히 살펴보면, 튜너의 제2혼합기(MIX2)로 부터 인가되는 중간주파수신호를 코일(L1)(L2)과 콘덴서(C1)로 구성된 복동조회로를 통해 동조시켜준 다음 콘덴서-코일 필터회로를 통해 필터링하여 출력단(OUT)으로 출력시켜 주는 구조로 되어 있다.In the conventional case, the second intermediate frequency circuit of the tuner has a structure in which a double tuning circuit and a filter circuit are combined as shown in FIG. 1 to tune and filter the signal from the second mixer. In this case, the intermediate frequency signal applied from the second mixer (MIX 2 ) of the tuner is tuned through a double-tuning circuit composed of coils (L 1 ) (L 2 ) and condenser (C 1 ), and then condenser-coil filter circuit. Filter through and output to the output terminal (OUT).
그러나 상기와 같은 종래의 중간 주파수 회로는 복동조회로를 사용하여 양호는 특성을 얻을수 있었으나 출력이득이 매우 적어 고이득용으로 사용할 경우에는 특성이 떨어질뿐만 아니라 실제로 고이득용으로 사용하는 것이 불가능하였다.However, the conventional intermediate frequency circuit as described above was able to obtain good characteristics by using a double-tuning circuit, but the output gain was very small, and when used for high gain, the characteristics were not only lowered, but it was impossible to actually use it for high gain.
또한 고이득을 실현하기 위해 단순히 증폭기만을 연결시켜 주게 되면 신호의 왜곡이 발생하여 출력특성이 저하되게 되며, 특히 유선 텔레비젼의 중요한 특성인 혼변조(Cross-Modulation)특성이 저하되는 문제점이 있었다.In addition, if only the amplifier is connected to realize high gain, signal distortion occurs and output characteristics are deteriorated. In particular, cross-modulation characteristics, which are important characteristics of cable television, are deteriorated.
따라서 상기와 같은 종래 중간주파수회로의 문제점을 해결하고 출력이득을 개선하여 고이득을 얻을수 있도록할 뿐만아니라 혼변조특성을 개선하여 그 선택도를 더욱 좋게 하기 위해서, 단동조 회로부와 증폭기를 복동조회로부와 함께 설치하고, 출력단에 가변저항을 설치하여 이득을 조절할 수 있도록된 유선 텔레비젼튜너의 중간주파수회로를 제공하는데 목적이 있다.Therefore, in order to solve the problems of the conventional intermediate frequency circuit as described above and to improve the output gain to obtain high gain, and to improve the intermodulation characteristics to improve the selectivity, the single-tuning circuit part and the amplifier are double-tuning circuits. It is an object of the present invention to provide an intermediate frequency circuit of a wired television tuner, which is installed together with the unit and a variable resistor is installed at the output terminal to adjust the gain.
이하 본 고안의 구성 및 작용효과를 첨부된 예시도면에 의거하여 상세히 설명하면 다음과 같다.When described in detail below on the basis of the accompanying drawings and the configuration and effect of the present invention.
본 고안은 단동조회로부(1)와 증폭회로부(2), 복동조회로부(3) 및 이득조절부(4)로 구성되되 상기 단동조회로부(1)는 코일(L11)과 콘덴서(C11)로 구성되고 상기 증폭회로부(2)에는 전계효과 트랜지스터(FET)로 구성되며, 복동조회로부(3)는 코일(L12)(L13)과 콘덴서(C12)로 구성되고, 이득조절부(4)는 가변저항(VR)을 사용한 구조로 되어 있다.The present invention consists of a single tuning circuit unit 1, an amplifying circuit unit 2, a double tuning circuit unit 3 and a gain control unit 4, the single tuning circuit unit 1 is a coil (L 11 ) and a condenser (C 11 ) and the amplifying circuit section (2) is composed of a field effect transistor (FET), the double-tuning circuit section (3) is composed of a coil (L 12 ) (L 13 ) and a capacitor (C 12 ) The gain control section 4 has a structure using a variable resistor VR.
미설명부호 A, B는 그래프 fo, fs는 주파수 Is, Is는 전류이다.Unexplained symbols A and B are graphs fo, fs is frequency Is, and Is is current.
상기와 같은 구조를 가는 본 고안은 튜너의 제2혼합기(MIX2)로 부터 IF신호를 전달받아 증폭, 동조시킨 다음 양호한 상태의 주파수 신호를 출력단(OUT)으로 출력시켜준다. 이와같은 작용을 제2도의 회로도를 통해 좀더 상세히 살펴보면 튜너의 제2혼합기(MIX2)를 통해 중간주파수신호가 인가되면 코일(L11)과 콘덴서(C11)로 구성된 단동조회로부(1)를 통해 동조시켜주고, 상기 동조신호는 증폭회로부(2)의 전계효과 트랜지스터(FET)를 통해 증폭되어지며, 증폭된 신호는 복동조회로부(3)의 코일(L12)(L13)과 콘덴서(C12)를 통해 복동조되어 출력단(OUT)으로 출력되어진다.The present invention having the above structure receives the IF signal from the second mixer MIX 2 of the tuner, amplifies and tunes it, and then outputs a good frequency signal to the output terminal OUT. Looking at such an operation in more detail through the circuit diagram of Figure 2 when the intermediate frequency signal is applied through the second mixer (MIX 2 ) of the tuner single-tuning circuit unit (1) consisting of a coil (L 11 ) and a condenser (C 11 ) And the amplified signal is amplified by the field effect transistor (FET) of the amplifying circuit unit 2, and the amplified signal is coupled to the coil L 12 (L 13 ) of the double tuning circuit unit 3; It is double-tuned through the capacitor C 12 and output to the output terminal OUT.
이때 출력단(OUT)의 앞에는 이득조절부(4)를 설치하여 이득조절부(4)의 가변 저항(VR)값을 조절함으로써 출력신호의 이득을 조절할 수 있도록 한다.In this case, the gain adjusting unit 4 is provided in front of the output terminal OUT so that the gain of the output signal can be adjusted by adjusting the variable resistance VR of the gain adjusting unit 4.
한편 본 고안은 단동조된 신호를 증폭시켜주기때문에 출력신호에 왜곡이 발생하지 않을뿐 아니라 오히려 혼변조특성이 개선되어 그 선택도가 더욱 향상된 양호한 출력을 얻을 수 있다.On the other hand, the present invention amplifies the mono-tuned signal, so that the distortion does not occur in the output signal. On the contrary, the intermodulation characteristic is improved, so that a good output with improved selectivity can be obtained.
이는 제3도를 통해 알수 가 있는데 제3도의 실선 그래프(A)는 종래의 중간 주파수 회로를 사용한 경우의 혼변조 특성그래프이고 점선그래프(B)는 본 고안에 따른 중간주파수 회로를 사용한 경우의 혼변조 특성그래프로서 주파수에 따른 선택도가 종래의 그래프(A)에 비해 본 고안에 따른 그래프(B)에서 더욱 향상된 것을 알수 있다.This can be seen from FIG. 3, where the solid line graph (A) of FIG. 3 is a cross-modulation characteristic graph when a conventional intermediate frequency circuit is used, and the dotted line graph (B) is a horn when an intermediate frequency circuit according to the present invention is used. As the modulation characteristic graph, it can be seen that the selectivity according to frequency is further improved in the graph B according to the present invention as compared with the conventional graph A.
즉 공진주파수(fo)로부터 상하로 선택하고자 하는 주파수범위(fs)에 있어서 그래프(A)는 전류(Is)이상의 출력을 나타내게 되나, 그래프(B)의 경우에는 전류(Is')의 출력을 나타내게 되어 그 선택도가 더욱 향상되어진 것을 알수있다.That is, in the frequency range fs to be selected up and down from the resonant frequency fo, the graph A shows an output of more than the current Is, but in the case of the graph B, it shows the output of the current Is'. It can be seen that the selectivity is further improved.
상기와 같은 구조 및 작용에 의해 본 고안은 신호의 왜곡이 없이 양호한 상태로 신호의 고이득을 얻을수 있으며, 단동조 회로와 복동조 회로를 조합하여 혼변조 특성을 개선함으로써 그 선택도를 더욱 향상시켜줄 뿐만아니라, 이득조절을 위한 가변저항(VR)을 사용하여 출력이득을 저역으로부터 고역에 이르기까지 광범위하게 조절할 수 있는 효과가 있다.By the above structure and operation, the present invention can obtain high gain of the signal in a good state without distortion of the signal, and improve the selectivity by improving the intermodulation characteristics by combining the single modulation circuit and the double modulation circuit. In addition, by using a variable resistor (VR) for gain control, the output gain can be adjusted in a wide range from low to high range.
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Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019860002410U KR890004653Y1 (en) | 1986-02-28 | 1986-02-28 | Midium frequency circuits for catv tuner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019860002410U KR890004653Y1 (en) | 1986-02-28 | 1986-02-28 | Midium frequency circuits for catv tuner |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| KR870014029U KR870014029U (en) | 1987-09-11 |
| KR890004653Y1 true KR890004653Y1 (en) | 1989-07-15 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR2019860002410U KR890004653Y1 (en) | 1986-02-28 | 1986-02-28 | Midium frequency circuits for catv tuner |
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| Country | Link |
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| KR (1) | KR890004653Y1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3648113B2 (en) * | 2000-01-12 | 2005-05-18 | アルプス電気株式会社 | Intermediate frequency input circuit |
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1986
- 1986-02-28 KR KR2019860002410U patent/KR890004653Y1/en not_active IP Right Cessation
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| Publication number | Publication date |
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| KR870014029U (en) | 1987-09-11 |
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