KR910007984Y1 - Double conversion tv tuner - Google Patents
Double conversion tv tuner Download PDFInfo
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- KR910007984Y1 KR910007984Y1 KR2019890016771U KR890016771U KR910007984Y1 KR 910007984 Y1 KR910007984 Y1 KR 910007984Y1 KR 2019890016771 U KR2019890016771 U KR 2019890016771U KR 890016771 U KR890016771 U KR 890016771U KR 910007984 Y1 KR910007984 Y1 KR 910007984Y1
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
- H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
- H03D7/16—Multiple-frequency-changing
- H03D7/161—Multiple-frequency-changing all the frequency changers being connected in cascade
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
- H03J3/00—Continuous tuning
- H03J3/02—Details
- H03J3/16—Tuning without displacement of reactive element, e.g. by varying permeability
- H03J3/18—Tuning without displacement of reactive element, e.g. by varying permeability by discharge tube or semiconductor device simulating variable reactance
- H03J3/185—Tuning without displacement of reactive element, e.g. by varying permeability by discharge tube or semiconductor device simulating variable reactance with varactors, i.e. voltage variable reactive diodes
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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
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- Channel Selection Circuits, Automatic Tuning Circuits (AREA)
- Superheterodyne Receivers (AREA)
Abstract
내용 없음.No content.
Description
제1도는 종래의 더블컨버젼 TV 튜너의 블록도.1 is a block diagram of a conventional double conversion TV tuner.
제2도는 제1도에 사용된 더블튠드 밴드패스필터의 회로구성도.FIG. 2 is a circuit diagram of a double tuned band pass filter used in FIG.
제3도는 본 고안 더블컨버젼 TV 튜너의 블록도.3 is a block diagram of the present invention double conversion TV tuner.
제4도는 본 고안에 사용도인 싱글튠드밴드패스필터의 회로구성도.4 is a circuit diagram of a single tuned band pass filter used in the present invention.
제5도는 본 고안에 사용된 RF 버퍼 엠프의 회로구성도.5 is a circuit diagram of the RF buffer amplifier used in the present invention.
* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings
10, 11 : 더블튠드(Double Tuned)밴드패스필터10, 11: Double Tuned Bandpass Filter
10', 11' : 싱글튠드(Single Tuned)밴드패스필터10 ', 11': Single Tuned Bandpass Filter
12, 13 : 다이플렉서(Diplexer) 14, 19 : 1, 2차믹서12, 13: Diplexer 14, 19: 1, 2nd mixer
15 : VCO 16, 18 : 1차 전,후단 IF 필터15: VCO 16, 18: 1st front and rear IF filter
17, 20 : 1,2차 IF 앰프 21 : RF버퍼앰프17, 20: 1st and 2nd IF amplifier 21: RF buffer amplifier
22, 23 : RF앰프 24 : LO22, 23: RF amplifier 24: LO
Q1: 트랜지스터 D1-D5: 다이오드Q 1 : transistor D 1 -D 5 : diode
VD1-VD6: 버랙터다이오드 L1-L8: 코일VD 1 -VD 6 : Varactor diode L 1 -L 8 : Coil
C1-C5: 콘덴서 R1-R7: 저항C 1 -C 5 : Capacitor R 1 -R 7 : Resistance
본 고안은 50-800MHz 대의 광대역 TV 신호를 수신하기 위한 더블컨버젼(Double Conversion)튜너에 관한 것이다.The present invention relates to a double conversion tuner for receiving broadband TV signals in the 50-800 MHz band.
일반적인 더블 컨버젼 TV튜너는, 제1도에 도시하고 있는 바와같은 회로계통을 가진다.A general double conversion TV tuner has a circuit system as shown in FIG.
이는, 스위칭다이오드(D1, D2)를 통한 RF 입력신호가 각각 더블튠드밴드패스필터(10,11)에서 각각 VHF 대역인 50-360MHz와 UHF 대역인 360-800MHz로 나뉘어져 필터링된 후 각각의 다이플렉서(12, 13)를 거쳐 1차믹서(14)로 입력되게 구성된다.This is because the RF input signals through the switching diodes D 1 and D 2 are divided into 50-360 MHz, which is the VHF band, and 360-800 MHz, which is the UHF band, respectively, in the double tuned band pass filters 10 and 11, respectively. It is configured to be input to the primary mixer 14 via the diplexers 12 and 13.
이때 50-360MHz의 VHF하이대역으로 나뉘어지게 된다.At this time, it is divided into the VHF high band of 50-360MHz.
상기 1차믹서(14)에서는 입력되는 신호가 955-1700MHz의 VCO(15)의 발진주파수로 믹싱되어 IF신호로서 1차전단필터(16)와 1차 IF앰프(17)와 1차후단 IF필터(18)를 차례로 통하여 2차믹서(19)로 입력되게 구성된다.In the primary mixer 14, the input signal is mixed at the oscillation frequency of the VCO 15 of 955-1700 MHz, and the primary front end filter 16, the primary IF amplifier 17, and the primary rear end IF filter as IF signals. It is configured to be input to the secondary mixer 19 through (18) in sequence.
상기 2차믹서(19)에서는 입력되는 신호와 LO(24)의 855MHz 발진주파수신호에 의해 믹싱된 2차 IF신호가 발생되며, 이 2차 IF신호는 2차 IF 앰프(20)를 거쳐 IF 출력으로 나타나게 구성된다.In the secondary mixer 19, a secondary IF signal mixed by an input signal and a 855 MHz oscillation frequency signal of the LO 24 is generated, and the secondary IF signal is output through the secondary IF amplifier 20. It is configured to appear.
이러한 기존의 회로구성에서, 더블 튠드밴드패스필터(10, 11)는 제2도에서 도시하고 있는 바와같은 일예시적인 회로구성을 가진다.In this conventional circuit configuration, the double tuned band pass filters 10, 11 have one exemplary circuit configuration as shown in FIG.
여기에서 VT는 튜닝전압, BH는 VHF 하이밴드선택시의 B+전압, BL은 VHF 로우밴드선택시의 B+전압을 나타낸다.Where V T is the tuning voltage, BH is the B + voltage at VHF highband selection, and BL is the B + voltage at VHF low band selection.
따라서, VHF 하이밴드 선택시는 BH에 의해 스위칭다이오드(D3, D4)가 온되므로, 이 더블튠드밴드패스필터회로는 버팩터다이오드(VD1-VD4)의 용량 및 코일(L1, L2)에 의한 필터특성을 가지고 다이플렉서(12,13)에 RF신호를 출력하게 되며, 튜닝전압(VT)의 변화에 다라 해당채널의 밴드가 선택되게된다.Therefore, when the VHF high band is selected, the switching diodes D 3 and D 4 are turned on by the BH. Thus, the double tuned band pass filter circuit has the capacitance of the factor factor VD 1 -VD 4 and the coil L 1 ,. L 2 ) has a filter characteristic and outputs an RF signal to the diplexers 12 and 13, and the band of the corresponding channel is selected according to the change of the tuning voltage V T.
한편 VHF 로우밴드선택시는 BH전압은 발생되지 않으므로, 이 회로는 비팩터다이오드(VD1-VD4)의 용량 및 코일(L1-L4)에 의한 필터링 특성을 가지고, 튜닝전압(VT)의 변화에 따른 해당 채널의 밴드가 선택되는 것이다.On the other hand, since the BH voltage is not generated when the VHF low band is selected, this circuit has the capacitance of the non-factor diodes (VD 1 -VD 4 ) and filtering characteristics by the coils (L 1 -L 4 ), and the tuning voltage (V T). The band of the corresponding channel is selected according to the change of).
여기에서 C1, C2는 바이패스콘덴서이고 R1, R2는 바이어스저항이다.Where C 1 and C 2 are bypass capacitors and R 1 and R 2 are bias resistors.
그러나 이상에서 설명한 바와같은 종래의 더블튠드밴드패스필터는 다수의 버팩터다이오드(4개)와 스위칭다이오드(2개)가 소요됨에 따라 회로구성상의 복잡화 및 원가상승을 초래하고 있었으며, 특히 튜닝전압(VT)이 낮을경우 상기 버팩터다이오드 들에서의 신호 전송손실이 많이 발생되므로 VHF 하이, VHF 로우 및 UHF 밴드에서의 가장 낮은 채널에서는 튜닝전압이 낮기 때문에 노이즈 특성이 매우 나빠지는 문제점이 있었다.However, as described above, the conventional double tuned band pass filter requires a large number of verifier diodes (4) and switching diodes (2), leading to complications and cost increases in circuit configuration. When V T ) is low, signal transmission losses are generated in the factor diodes, and thus the noise characteristics are very poor because the tuning voltage is low in the lowest channels in the VHF high, VHF low, and UHF bands.
본 고안은 상기한 바와같은 문제점을 해결하기 위한 것으로, 다이플렉서의 전단에 설치되는 밴드패스필터를 싱글튠드회로로 구성하고, 또한 상기 싱글튠드밴드패스필터와 다이플렉서 후단에 각각 RF 앰프를 부가하여 신호전송손실을 보상하여 줌으로써 노이즈 특성을 현저히 개선할수 있게되는 더블 컨버젼 TV튜너를 제공하는데 그 목적이 있다.The present invention solves the problems described above, and the bandpass filter installed at the front of the diplexer is composed of a single tuned circuit, and the single tuned bandpass filter and the RF amplifier are respectively provided at the rear end of the diplexer. In addition, it is an object of the present invention to provide a double conversion TV tuner that can significantly improve noise characteristics by compensating for signal transmission loss.
이하 첨부한 도면에 따라 본 고안을 설명한다.Hereinafter, the present invention will be described according to the accompanying drawings.
제3도에서 도시하고 있는 바와같이, 스위칭다이오드(D1, D2)를 RF 입력신호는 각각 싱글튠드밴드패스필터(10,11')를 거친후 각 RF앰프(22, 23)로 증폭되어 각 다이플렉서(12, 13)로 입력되게 연결하고, 상기 다이플렉서(12, 13)의 출력은 공통으로되어 RF 버퍼앰프(21)을 통하여 1차믹서(14)로 입력되게 연결한다.As shown in FIG. 3, the RF input signals of the switching diodes D 1 and D 2 are respectively amplified by the respective RF amplifiers 22 and 23 after passing through the single tuned band pass filters 10 and 11 '. The diplexers 12 and 13 are connected to be input, and the outputs of the diplexers 12 and 13 are common to be connected to the primary mixer 14 through the RF buffer amplifier 21.
상기 1차믹서(14)에서는 다이플렉서(12, 13)의 RF 출력신호를 VCO(15)의 995-1700MHz 발진주파수로 믹싱하여 1차 IF 신호를 발생하게 되며, 이 신호는 1차전단 IF필터(16)와 1차 IF앰프(17)와 1차후단 IF필터(18)를 차레로 통하여 2차믹서(19)로 입력되게 연결하고, 상기 2차믹서(19)에서 LO(24)의 855MHz 발진신호로 믹싱되어 2차 IF신호는 2차 IF 앰프(20)를 거쳐 IF 출력으로 나타나게 연결한다.In the first mixer 14, the RF output signals of the diplexers 12 and 13 are mixed at the 995-1700 MHz oscillation frequency of the VCO 15 to generate a first IF signal, which is the first shear IF. A filter 16, a primary IF amplifier 17, and a primary rear stage IF filter 18 are connected to the secondary mixer 19 through a sequence, and the LO 24 of the secondary mixer 19 is connected. The secondary IF signal is mixed with the 855 MHz oscillation signal and connected to the IF output via the secondary IF amplifier 20.
상기 싱글튠드밴드패스필터(10',11')의 구체적인 회로구성은 제4도에서 도시하고 있는 바와같이, RF 입력신호가 튜닝전압(VT)에 의해 그의 용량값이 변화되는 버팩터다이오드(VD5, VD6)와, 코일(L5, L6)및 콘덴서(C4)의 직력회로를 통하여 RF 출력신호로 출력되게 연결하고, 상기 코일(L5)과 코일(L6)사이의 접속점에는 스위칭 다이오드(D5)를 통한 BH(VHF 하이선택시의 B+전압)가 인가되게 연결하고, 상기 코일(L6)과 콘덴서(C4)사이의 접속점에는 BL(VHF로우선택시의 B+전압)이 인가되게 연결하여 구성한다.As shown in FIG. 4, the specific circuit configuration of the single tuned band pass filter 10 ', 11' is a variable factor diode whose capacitance value is changed by the tuning voltage V T ( VD 5 , VD 6 ) and the coil L 5 , L 6 and the capacitor C 4 are connected to be outputted as RF output signals, and between the coil L 5 and the coil L 6 . BH (B + voltage at high VHF selection) is applied to the connection point via switching diode D 5 , and BL (VHF low selection) at the connection point between coil L 6 and capacitor C 4 . B + voltage) is configured to be applied.
여기에서 R3은 바이어스저항이고 C3, C4는 바이패스콘덴서이다.Where R 3 is bias resistor and C 3 and C 4 are bypass capacitors.
또한, 상기 RF버퍼앰프(21)는 제5도에서 도시하고 있는 바와같이, 다이플렉서(12,13)의 RF출력신호가 RF트랜지스터(Q1)의 베이스로 입력되게 연결하고, 상기 RF 트랜지스터(Q1)의 콜렉터 출력은 1차믹서(14)로 인가되게 연결하고, 여기에 상기 RF 트랜지스터(Q1)의 베이스와 콜렉터 사이에는 저항(R3, R4), 콘덴서(C5) 및 코일(L7)의 직렬회로에 의한 병렬궤환회로가 연결되고 RF 트랜지스터(Q1)의 에미터에는 저항(R4)에 의한 직렬궤환회로가 연결되는 바이폴라 버퍼앰프로 구성한다.In addition, the RF buffer amplifier 21 is connected to the RF output signal of the diplexers 12 and 13 to be input to the base of the RF transistor Q 1 , as shown in FIG. The collector output of (Q 1 ) is connected to be applied to the primary mixer 14, and between the base and the collector of the RF transistor (Q 1 ), resistors (R 3 , R 4 ), capacitor (C 5 ) and The parallel feedback circuit by the series circuit of the coil L 7 is connected and the emitter of the RF transistor Q 1 is configured as a bipolar buffer amplifier to which the series feedback circuit by the resistor R 4 is connected.
여기에서 L8, l5및 C6은 B+전압의 입력노이즈방지용코일, 저항 및 콘덴서이다.Where L 8 , l 5 and C 6 are the input noise protection coils, resistors and capacitors of voltage B + .
이와같이 구성된 본 고안의 작용 및 효과를 설명하면 다음과 같다.Referring to the operation and effects of the present invention configured as described above are as follows.
제3도 및 제4도에서, 다이오드(D1, D2)를 통하여 입력되는 RF 입력신호는 일예로 VHF로우밴드가 선택된 경우라면, BL전압이 발생되고 있으므로, 코일(L5, L6)에 의한 직렬회로와 버랙퍼다이오드(VD5, VD6)에 의해 이루어지는 비교적 토우패스필터를 통하여 RF 앰프(22, 23)를 거친후 RF버퍼앰프(21)로 입력되게 된다.3 and 4, when the RF input signal input through the diodes D 1 and D 2 is selected as the VHF low band, for example, the BL voltage is generated, and thus the coils L 5 and L 6 . After passing through the RF amplifiers (22, 23) through a relatively toepass filter formed by the series circuit and the buffer diodes (VD 5 , VD 6 ) by the input to the RF buffer amplifier 21.
이때, 채널선택에 따라 달리 나타나게되는 튜닝전압(VT)에 의해 상기 버랙퍼다이오드(VD5, VD6)의 용량이 조금씩 변하게 되므로 해당채널선택이 가능해지는 것이다.At this time, the capacity of the buffer diodes VD 5 and VD 6 is changed little by little by the tuning voltage V T which appears differently depending on the channel selection.
한편, VHF 하이밴드가 선택되었다면 BH전압이 일어나 스위칭다이오드(D5)를 온시키게되므로, 이 회로는 버랙퍼다이오드(VD5, VD6) 및 코일(L5)에 의해 이루어지는 비교적 하이패스필터로 되는 것이며, 또한, 이때에도 상기와 마찬가지로 튜닝전압(VT)에 의해 채널선택이 이루어지게되는 것이다.On the other hand, if the VHF high band is selected, the BH voltage is generated to turn on the switching diode (D 5 ), so this circuit is a relatively high pass filter formed by the buffer diodes (VD 5 , VD 6 ) and the coil (L 5 ). In this case, the channel selection is performed by the tuning voltage V T as described above.
이렇게 선택되어 다이플랙서(12, 13)를 통한 RF입력신호는 제5도의 RF 버퍼앰프(21)를 거쳐 증폭되어 1차믹서(14)로 입력하게 된다.The RF input signal selected through the diplexers 12 and 13 is amplified through the RF buffer amplifier 21 of FIG. 5 and input to the primary mixer 14.
상기 RF 버퍼앰프(21)는 직, 병력 부궤환되는 바이폴라 버퍼앰프로 설계됨에 따라 다이플렉서(12, 13)와 1차믹서(14)사이에서 발생되는 신호전송손실을 충분히 보상할수 있게되며, 또한 VCO(15)의 입력손실을 최소화시킬수 있게 되는 것이다.Since the RF buffer amplifier 21 is designed as a direct and history negative feedback bipolar buffer amplifier, it is possible to sufficiently compensate for the signal transmission loss generated between the diplexers 12 and 13 and the primary mixer 14, In addition, it is possible to minimize the input loss of the VCO (15).
상기 1차믹서(14)단이후에서의 회로동작은 앞에서 기술한 종래의 회로에서의 동작과 동일하므로 이에 대한 중복설명은 생략한다.Since the operation of the circuit after the stage of the first mixer 14 is the same as the operation of the conventional circuit described above, redundant description thereof will be omitted.
이상에서 설명한 바와같은 본 고안은 RF신호입력단에 싱글튠드밴드패스필터를 채용함에 따라 원가절감효과를 얻을수 있게되며, 다이플렉서와 1차믹서단사이에 RF 버퍼단을 추가하는 것으로 신호손실에 의한 노이즈 특성저하를 극소화시킬수 있는 효과가 나타나게 된다.As described above, the present invention can reduce the cost by adopting a single tuned band pass filter in the RF signal input stage, and adds an RF buffer stage between the diplexer and the primary mixer stage to reduce noise due to signal loss. The effect of minimizing the deterioration of properties will be shown.
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Application Number | Priority Date | Filing Date | Title |
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KR2019890016771U KR910007984Y1 (en) | 1989-11-14 | 1989-11-14 | Double conversion tv tuner |
Publications (2)
Publication Number | Publication Date |
---|---|
KR910010109U KR910010109U (en) | 1991-06-29 |
KR910007984Y1 true KR910007984Y1 (en) | 1991-10-10 |
Family
ID=19291790
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
KR2019890016771U KR910007984Y1 (en) | 1989-11-14 | 1989-11-14 | Double conversion tv tuner |
Country Status (1)
Country | Link |
---|---|
KR (1) | KR910007984Y1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100764372B1 (en) * | 2005-10-11 | 2007-10-08 | 삼성전기주식회사 | One-cam type dual tuning system for digital television |
-
1989
- 1989-11-14 KR KR2019890016771U patent/KR910007984Y1/en not_active IP Right Cessation
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100764372B1 (en) * | 2005-10-11 | 2007-10-08 | 삼성전기주식회사 | One-cam type dual tuning system for digital television |
Also Published As
Publication number | Publication date |
---|---|
KR910010109U (en) | 1991-06-29 |
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