KR940004969Y1 - Data modem of catv - Google Patents

Data modem of catv Download PDF

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Publication number
KR940004969Y1
KR940004969Y1 KR2019880019147U KR880019147U KR940004969Y1 KR 940004969 Y1 KR940004969 Y1 KR 940004969Y1 KR 2019880019147 U KR2019880019147 U KR 2019880019147U KR 880019147 U KR880019147 U KR 880019147U KR 940004969 Y1 KR940004969 Y1 KR 940004969Y1
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KR
South Korea
Prior art keywords
data
pass filter
band pass
amplifier
modem
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KR2019880019147U
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Korean (ko)
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KR900011145U (en
Inventor
강우현
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삼성전기 주식회사
서주인
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Priority to KR2019880019147U priority Critical patent/KR940004969Y1/en
Publication of KR900011145U publication Critical patent/KR900011145U/en
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Publication of KR940004969Y1 publication Critical patent/KR940004969Y1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/16—Analogue secrecy systems; Analogue subscription systems
    • H04N7/173—Analogue secrecy systems; Analogue subscription systems with two-way working, e.g. subscriber sending a programme selection signal
    • 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
    • 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)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

내용 없음.No content.

Description

쌍방향 유선 TV용 데이터 모뎀Data Modem for Interactive Cable TV

제1도는 본 고안의 블록다이어그램.1 is a block diagram of the present invention.

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

1,,3,8,9 : 벤드패스필터 2 : RF 증폭기1,3,8,9 Bend Pass Filter 2: RF Amplifier

4 : 믹서 5 : 크리스탈4: mixer 5: crystal

5 : 발진기 7 : 버퍼증폭기5: oscillator 7: buffer amplifier

10 : 데이터검파 IC 11 : 데이터튜닝부10: data detection IC 11: data tuning unit

12 : 리미터 13 : 비교기12 Limiter 13 Comparator

14 : 데이터정형부 15 : 복조기14: data shaping unit 15: demodulator

본 고안은 상용유로 유선 TV시스팀에 적합한 쌍방향유선 TV용 데이터모뎀에 관한 것이다.The present invention relates to a data modem for interactive wired TV suitable for wired TV systems as a commercial oil.

일반적으로 모뎀은 센터(방송국)와 각컨버터와의 사이에서 데이터 통신을 하므로 디지탈데이터를 RF대로 변조하여 전송로로 송출하고 또 전송로의 RF신호를 복조하여 디지탈신호를 꺼내게 된다.In general, a modem performs data communication between a center (broadcasting station) and each converter, so that digital data is modulated according to the RF band and transmitted to the transmission path, and the digital signal is demodulated by demodulating the RF signal of the transmission path.

이때, 중앙컴퓨터는 고유한 어드레스를 가진 컨버터에 대해 폴링 셀렉링방식등에 의해 쌍방향 통신을 하게된다.At this time, the central computer performs two-way communication with the converter having a unique address by a polling selection method or the like.

통상 데이터채널의 설정에는 자유도가 있으며 내림데이터채널은 70-76 MHz로 오름데이터채널은 46-45MHz로 된다.There is usually freedom in setting the data channel, and the descending data channel is 70-76 MHz, and the data channel is 46-45 MHz.

또한 변조방식으로서는 내림은 FSK(Frequency Shift Keying) 오름은 PSK(Phase Shift Keying)방식이 사용된다.In addition, as a modulation method, the frequency shift keying (PSK) method is used for the upswing (FSK) for the downlink.

이때, FSK로 변조된 내림데이터를 원래의 데이터로 복조하는데 모뎀이 필요하게된다.At this time, a modem is required to demodulate the down data modulated by FSK into original data.

이러한 모뎀은 RF 입력단 무신호시 데이터출력에 랜덤한 신호가 나타나므로 입력단에 항상 케리어를 보내주어야하는 문제가 있게된다.In such a modem, when a signal is not input to the RF input, a random signal appears at the data output, and thus there is a problem of always sending a carrier to the input terminal.

본 고안은 이와같은 문제점을 해결하기위한 것으로 RF증폭기와 버퍼증폭기를 케스코드방식으로하여 증폭기의 안정도를 향상시키고, 또한 크리스탈을 사용하여 발진기의 출력을 안정화시켜 데이터의 복조가 정확하게 이루어지게되는 쌍방향 유선 TV용 데이터모뎀을 제공하는데 있다.In order to solve this problem, the present invention improves the stability of the amplifier by cascading the RF amplifier and the buffer amplifier, and also uses a crystal to stabilize the output of the oscillator. To provide a data modem for TV.

이하 첨부한 도면에 따라 본 고안을 설명하면 다음과같다.Hereinafter, the present invention will be described with reference to the accompanying drawings.

제1도에서 도시하고 있는 바와같이 FSK 데이터 변조된 RF 신호가 25.5MHz 밴드패스필터(1), RF 증폭기(2), 상기 밴드패스필터(1)와 동일대역의 밴드패스필터(1)를 차례로 통하여 믹서(4)로 입력되게 연결구성하고, 크리스탈(5)에 의한 발진기(6)의 발진주파수가 버퍼증폭기(7) 및 35.9MHz 밴드패스필터(8)를 차례로 통하여 상기 믹서(4)로 입력되게 연결하고, 상기 믹서(4)의 출력주파수가 10.7MHz 밴드패스필터(9)를 통하여 데이터검파 IC(10)를 거쳐 컴퓨터에 데이터로 입력되게 연결구성한다.As shown in FIG. 1, an FSK data-modulated RF signal sequentially rotates a 25.5 MHz band pass filter 1, an RF amplifier 2, and the band pass filter 1 of the same band as the band pass filter 1. The oscillation frequency of the oscillator 6 by the crystal 5 is input to the mixer 4 through the buffer amplifier 7 and the 35.9 MHz band pass filter 8 in order. The output frequency of the mixer 4 is connected to the computer through the data detection IC 10 through the 10.7MHz band pass filter 9 and inputted to the computer.

상기 데이터검파 IC(10)는 밴드패스필터(9)의 출력주파수가 리미터(12), 비교기(13), 데이터정형기(14)를 차례로 통하여 컴퓨터에 데이터로 입력되게 연결하고, 상기 리미터(12)의 출력은 데이터튜닝부(11)의 LC튜닝으로 복조기(15)에서 복조되게 연결구성한다.The data detection IC 10 connects the output frequency of the band pass filter 9 to be inputted to the computer as data through the limiter 12, the comparator 13, and the data shaper 14, and the limiter 12 The output of is configured to be demodulated in the demodulator 15 by LC tuning of the data tuning unit 11.

이와같이 구성된 본 고안의 작용 및 효과를 복조의 경우를 일예로하여 상세히 설명하면 다음과같다.The operation and effects of the present invention configured as described above will be described in detail with an example of demodulation as follows.

제1도에서, FSK 데이터변조된 RF신호가 2개의 동일밴드(25.2MHz)의 밴드패스필터(1, 3)와 RF 증폭기(2)를 통하여 믹서(4)에 입력되고, 크리스탈(5)에 의한 발진기(6)의 발진주파수가 버퍼증폭기(7)를 통하여 35.9MHz 밴드패스필터(8)를 거친후 상기 믹서(4)에 입력되면, 믹서(4)에서는 25.2MHz와 35.9MHz의 차 주파수인 10.7MHz를 출력하게 된다.In FIG. 1, the FSK data modulated RF signal is input to the mixer 4 through the bandpass filters 1 and 3 of the same band (25.2 MHz) and the RF amplifier 2, and to the crystal 5. When the oscillation frequency of the oscillator 6 is input to the mixer 4 after passing through the 35.9 MHz band pass filter 8 through the buffer amplifier 7, the mixer 4 has a difference frequency of 25.2 MHz and 35.9 MHz. It will output 10.7MHz.

상기 차주파수는 10.7MHz 밴드패스필터(9)에서 여과된 후 데이터검파 IC(10)내의 리미터(12)로 출력된다.The difference frequency is filtered by the 10.7 MHz band pass filter 9 and then output to the limiter 12 in the data detection IC 10.

상기 리미터(12)의 출력은 데이터튜닝부(11)의 LC튜닝에 의해 복조기(15)에서 복조되어 데이터정형부(14)를 거쳐 컴퓨터에 데이터로 입력된다.The output of the limiter 12 is demodulated in the demodulator 15 by LC tuning of the data tuning unit 11 and input to the computer via the data shaping unit 14.

이상에서 설명한 바와같은 본 고안은 데이터모뎀의 신뢰도 향상을 가져오게되므로 헤드엔드 또는 컨버터에 적용시킬 경우 업 또는 다운 스트림데이터교신시 정확한 교신이 가능하게되는 효과가 나타나게된다.As described above, the present invention brings an improved reliability of the data modem, and thus, when applied to the headend or the converter, accurate communication can be performed during upstream or downstream data communication.

Claims (1)

상용유선 TV 시스팀에 있어서, 밴드패스필터(1), RF증폭기(2), 밴드패스필터(3)를 차례로 통한 FSK RF신호와 버퍼증폭기(7), 밴드패스필터(8)를 차례로 통한 크리스탈발진기(6)의 발진주파수가 믹서(4)에서 믹싱된 후 밴드패스필터(9)를 통하여 데이터컴파 IC(10)로 입력되게 연결구성되는 것을 특징으로하는 쌍방향 유선 TV용 데이터모뎀.In a commercial cable TV system, an FSK RF signal through a band pass filter (1), an RF amplifier (2), and a band pass filter (3), and a crystal oscillator through a buffer amplifier (7) and a band pass filter (8) in this order. The oscillation frequency of (6) is mixed in the mixer (4) and then connected via the band pass filter (9) to be input to the data comparator IC (10) characterized in that the data modem for interactive wire TV.
KR2019880019147U 1988-11-26 1988-11-26 Data modem of catv KR940004969Y1 (en)

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Application Number Priority Date Filing Date Title
KR2019880019147U KR940004969Y1 (en) 1988-11-26 1988-11-26 Data modem of catv

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Application Number Priority Date Filing Date Title
KR2019880019147U KR940004969Y1 (en) 1988-11-26 1988-11-26 Data modem of catv

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KR900011145U KR900011145U (en) 1990-06-04
KR940004969Y1 true KR940004969Y1 (en) 1994-07-23

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