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WO2001099428A1 - System and method for transmitting digital video signal and digital control signal in cctv - Google Patents

System and method for transmitting digital video signal and digital control signal in cctv Download PDF

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Publication number
WO2001099428A1
WO2001099428A1 PCT/KR2001/001034 KR0101034W WO0199428A1 WO 2001099428 A1 WO2001099428 A1 WO 2001099428A1 KR 0101034 W KR0101034 W KR 0101034W WO 0199428 A1 WO0199428 A1 WO 0199428A1
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WO
WIPO (PCT)
Prior art keywords
signal
video signal
data signal
data
transmitting
Prior art date
Application number
PCT/KR2001/001034
Other languages
French (fr)
Inventor
Jung Joo Lee
Original Assignee
Jung Joo Lee
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 Jung Joo Lee filed Critical Jung Joo Lee
Priority to AU2001274638A priority Critical patent/AU2001274638A1/en
Publication of WO2001099428A1 publication Critical patent/WO2001099428A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/18—Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
    • H04N7/181—Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast for receiving images from a plurality of remote sources
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/18—Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00095—Systems or arrangements for the transmission of the picture signal
    • H04N1/001—Systems or arrangements for the transmission of the picture signal specially adapted for transmission via digital wireline networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00095—Systems or arrangements for the transmission of the picture signal
    • H04N1/00114—Systems or arrangements for the transmission of the picture signal with transmission of additional information signals

Definitions

  • the present invention relates to a CCTV(Closed Circuit Television) system and its embodying method using a single coaxial cable, and more particularly, to a system and a method for transmitting video signal and data signal in a CCTV, which can save installation costs by transmitting video signal and data signal through a single coaxial cable and minimize distortion of video.
  • Background Art
  • the method is that data signal is inserted and transmitted together with video signal within the vertical flyback period of time containing vertical synchronization.
  • video signal is transmitted without any process as it is, and at this time, data signal is overlapped and transmitted within the vertical flyback period of time of the video signal to prevent data signal from being shown on a screen.
  • a receiving part detects data signal through time gap and amplitude of data signal on the basis of vertical sync signal.
  • vertical sync signal of video signal is distorted or instabilized due to unexpected obstacles occurring by a line condition or external factors during the transmission, it causes instability in detection of data signal or impossibility of detection in the worst case.
  • video signal and data signal are converted into different frequencies respectively and mixed.
  • the mixed signal is separated into two signals using frequency difference between video signal and data signal in a receiving part and demodulated respectively to return to original signal.
  • data signal is not influenced by sync signal of video signal.
  • FIG. 2 illustrates a distribution view of frequency according to the second method.
  • the present invention provides a system transmitting video signal without any process as it is, converting data signal into different frequency band, which is not influenced by video signal, and having an ground potential corrector mounted on a video receiving terminal to prevent occurrence of power frequency noise due to ground potential.
  • the ground potential corrector is a two-way ground potential corrector for correcting ground potential of two-way data since transmission directions of video signal and data signal are different from each other.
  • the system includes a camera part 100, a control receiving part 200 having a mixer, a separator, a modulator/demodulator and a control receiver, a control transmitting part 300 having a two-way ground potential corrector, a separator, a mixer, a converter/modulator, and a control transmitter, and a monitor 400.
  • the control receiving part 200 mixes data signals such as video signal, microphone signal, alarm signal and so on and transmits mixed signal to the control transmitting part 300 through a single coaxial cable.
  • the control transmitting part 300 corrects ground potential in two directions using the two-way ground potential corrector. Output from the two-way ground potential corrector is divided into video signal and data signal.
  • Video signal is transmitted to the monitor and data signal is output to an alarm speaker through the modulator/demodulator. Additionally, data signals, such as control signal, alarm signal, microphone signal, etc., of the control transmitter are modulated and mixed in the mixer and transmitted to the control receiver through the two-way ground potential corrector.
  • the present invention can be changed, converted, replaced and substituted within a range of the business model, technical method and system and is not restricted in the above.
  • FIG. 1 illustrates a view showing a conventional method of transmitting data signal within vertical flyback period of time of video signal
  • FIG. 2 illustrates a view showing a conventional method of modulating and transmitting video signal
  • FIG. 3 illustrates a schematic view of the present invention
  • FIG. 4 illustrates a distribution view of frequency of video signal and data signal according to the present invention
  • FIG. 5 illustrates an enlarged schematic view of the present invention. Best Mode for Carrying Out the Invention
  • a system according to the present invention largely includes a camera part
  • the camera part 100 includes a camera 110 for obtaining video of a monitored area or specific video, a lens 120 for adjusting distance, an illuminator 130 for adjusting luminosity and a rotary stand 140 for adjusting a location of the camera.
  • the control receiving part 200 includes a separator 260 for separating data signal, which is transmitted through the single coaxial cable from the control transmitting part 300, from video signal, a modulator/demodulator 250 for demodulating separated data signal, a control receiver 240 for transmitting demodulated data to the rotary stand 140, the lens 120 and the illuminator 130, and a mixer 270 for mixing video signal of the camera 110 and data signal for an alarm 220 and a microphone 210 modulated through the modulator/demodulator 250.
  • a separator 260 for separating data signal, which is transmitted through the single coaxial cable from the control transmitting part 300, from video signal
  • a modulator/demodulator 250 for demodulating separated data signal
  • a control receiver 240 for transmitting demodulated data to the rotary stand 140, the lens 120 and the illuminator 130
  • a mixer 270 for mixing video signal of the camera 110 and data signal for an alarm 220 and a microphone 210 modulated through the modulator/demodulator 250.
  • Video signal of the camera 110 is input into the mixer 270, and data signal for the lens 120, the illuminator 130 and the rotary stand 140 of the camera is received from the control receiver 240 through a plurality of control lines.
  • the control receiver 240 receives data signal transmitted from a control transmitter 340 of the control transmitting 300 and controls peripheral devices of the camera, such as a zoom lens, the illuminator, the rotary stand and so on.
  • Data signal for the microphone 210 and the alarm 220 is converted through the modulator/demodulator 250, mixed with video signal through the mixer 270, and transmitted to a two-way ground potential corrector 380 of the control transmitting part 300 through the single coaxial cable.
  • FIG. 4 illustrates a distribution view of frequency of video signal and data signal according to the present invention.
  • video signal is not modulated at all. Instead of the modulation of video signal, frequency, which does not influence on video signal, is selected and modulates data signal. Video signal and the modulated data signal are mixed and transmitted through the single coaxial cable.
  • the control transmitting part 300 includes the control transmitter 340 for generating data controlling the lens 120, the illuminator 130 and the rotary stand 140, a modulator/demodulator 350 for modulating or demodulating data signal, a mixer 360 for transmitting data signal modulated in the modulator/demodulator to the control receiving part 200 through the single coaxial cable, a separator 370 for separating signal transmitted from the two-way ground potential corrector 380 into video signal and data signal, and the two-way ground potential corrector 380 for preventing distortion of video signal and data signal.
  • the two-way ground potential corrector 380 corrects ground potential of video Signal and data signal transmitted in two directions through the single coaxial cable.
  • the separator 370 separates video signal from data signal. Video signal is transmitted to the monitor 400, and data signal is output to an alarm 33 and a speaker 320 after demodulated through the modulator/demodulator 350.
  • the two-way ground potential corrector 380 prevents distortion of video signal and data signal due to the ground potential.
  • the control transmitter 340 is to control the lens 120, the illuminator 130 and the rotary stand 140 of the camera part.
  • the modulator/demodulator 350 modulates data signal and transmits to the mixer 360.
  • the mixed signal is transmitted to the separator 260 of the control receiving part 200 through the two-way ground potential corrector 380.
  • FIG. 5 illustrates an enlarged schematic view of the present invention using a plurality of cameras.
  • one control transmitter 340 is connected to plural modulators/demodulators and controls each of them.
  • the present invention can provide clear and stable quality of video and stably send and receive even in a long distance. Moreover, the present invention can considerably reduce installation expenses since multiplexing and transmitting video signal and data signal. Furthermore, the present invention can prevent deterioration of the system even though the system is used for a long time since a circuit is simple.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Closed-Circuit Television Systems (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
  • Studio Devices (AREA)

Abstract

Disclosed are a system and a method for transmitting video signal and data signal in a CCTV, which can save installation costs by transmitting video signal and data signal through a single coaxial cable and minimize distortion of video. Video signal is transmitted without any process as it is, and data signal is converted into different frequency band, which is not influenced by video signal, and mixed and transmitted with video signal. A ground potential corrector is mounted at a video receiving terminal to prevent occurrence of power frequency noise due to ground potential. The ground potential corrector is a two-way ground potential corrector for correcting the ground potential of the signals, which have different transmission directions from each other.

Description

System and method for transmitting video signal and data signal in CCTV BACKGROUND OF THE INVENTION Technical Field
The present invention relates to a CCTV(Closed Circuit Television) system and its embodying method using a single coaxial cable, and more particularly, to a system and a method for transmitting video signal and data signal in a CCTV, which can save installation costs by transmitting video signal and data signal through a single coaxial cable and minimize distortion of video. Background Art
Recently, in a CCTV(Closed Circuit Television), various methods for transmitting both video signal and data signal through a single coaxial cable, in which a cable for transmission of video signal and a cable for transmission of data signal of a rotary stand, a lens and an illuminator of a camera, an alarm, a microphone and so on are united, have been used.
If one of the methods for transmitting video signal and data signal through the single coaxial cable is used, because an additional cable for data signal is not required, there is an advantage that installation costs such as material cost and personnel expenses for constructing the cable for data signal can be reduced in a case that a distance between the camera and a monitor is long.
Presently, the following methods for multiplexing and transmitting video signal and data signal through the one transmission cable have been disclosed.
First, there is a method for overlapping and transmitting data signal within a vertical flyback period of time of video signal.
As shown in FIG. 1, the method is that data signal is inserted and transmitted together with video signal within the vertical flyback period of time containing vertical synchronization.
According to the method, video signal is transmitted without any process as it is, and at this time, data signal is overlapped and transmitted within the vertical flyback period of time of the video signal to prevent data signal from being shown on a screen. A receiving part detects data signal through time gap and amplitude of data signal on the basis of vertical sync signal. However, if vertical sync signal of video signal is distorted or instabilized due to unexpected obstacles occurring by a line condition or external factors during the transmission, it causes instability in detection of data signal or impossibility of detection in the worst case. Furthermore, in case of a long distance transmission, if video signal is transmitted as it is, a loop between input and output of video signal is formed due to grounding of shield lines located at both sending and receiving sides of video signal cable, and thereby so-called ground potential occurs by induced mixing of DC power source and noise of power frequency is generated on the screen. Second, there is a so-called RF method (also, called a "CATV method").
In the RF method, video signal and data signal are converted into different frequencies respectively and mixed. The mixed signal is separated into two signals using frequency difference between video signal and data signal in a receiving part and demodulated respectively to return to original signal. At this time, data signal is not influenced by sync signal of video signal.
FIG. 2 illustrates a distribution view of frequency according to the second method.
However, when video signal is modulated and demodulated, it is difficult to reproduce original signal because of occurrence of signal distortion and noise. Moreover, because a transmission distance is reduced due to a rise of occupied frequency band of video signal by the modulation, an amplifier is required for long distance transmission, and thereby a circuit is complicated and decreased in stability and manufacturing cost is increased.
Disclosure of Invention
Therefore, it is an object of the present invention to provide a CCTV system and its embodying method using a single coaxial cable, which can provide clear and stable quality of video and stably send and receive even in a long distance.
It is another object of the present invention to provide a CCTV system and its embodying method using a single coaxial cable, which can considerably reduce installation expenses since multiplexing and transmitting video signal and data signal.
It is a further object of the present invention to provide a CCTV system and its embodying method using a single coaxial cable, which can prevent deterioration of the system even though the system is used for a long time since a circuit is simple.
To achieve the above objects, the present invention provides a system transmitting video signal without any process as it is, converting data signal into different frequency band, which is not influenced by video signal, and having an ground potential corrector mounted on a video receiving terminal to prevent occurrence of power frequency noise due to ground potential. The ground potential corrector is a two-way ground potential corrector for correcting ground potential of two-way data since transmission directions of video signal and data signal are different from each other.
The system includes a camera part 100, a control receiving part 200 having a mixer, a separator, a modulator/demodulator and a control receiver, a control transmitting part 300 having a two-way ground potential corrector, a separator, a mixer, a converter/modulator, and a control transmitter, and a monitor 400. The control receiving part 200 mixes data signals such as video signal, microphone signal, alarm signal and so on and transmits mixed signal to the control transmitting part 300 through a single coaxial cable. The control transmitting part 300 corrects ground potential in two directions using the two-way ground potential corrector. Output from the two-way ground potential corrector is divided into video signal and data signal. Video signal is transmitted to the monitor and data signal is output to an alarm speaker through the modulator/demodulator. Additionally, data signals, such as control signal, alarm signal, microphone signal, etc., of the control transmitter are modulated and mixed in the mixer and transmitted to the control receiver through the two-way ground potential corrector.
The present invention can be changed, converted, replaced and substituted within a range of the business model, technical method and system and is not restricted in the above.
Brief Description of the Drawings
Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawing in which: FIG. 1 illustrates a view showing a conventional method of transmitting data signal within vertical flyback period of time of video signal;
FIG. 2 illustrates a view showing a conventional method of modulating and transmitting video signal;
FIG. 3 illustrates a schematic view of the present invention; FIG. 4 illustrates a distribution view of frequency of video signal and data signal according to the present invention; and
FIG. 5 illustrates an enlarged schematic view of the present invention. Best Mode for Carrying Out the Invention
The present invention will now be described in detail in connection with preferred embodiments with reference to the accompanying drawings. For reference, like reference characters designate corresponding parts throughout several views.
Referring to FIG. 3, a structure of the present invention will be described in detail as follows. A system according to the present invention largely includes a camera part
100, a control receiving part 200, a control transmitting part 300 and a monitor 400. The camera part 100 includes a camera 110 for obtaining video of a monitored area or specific video, a lens 120 for adjusting distance, an illuminator 130 for adjusting luminosity and a rotary stand 140 for adjusting a location of the camera.
The control receiving part 200 includes a separator 260 for separating data signal, which is transmitted through the single coaxial cable from the control transmitting part 300, from video signal, a modulator/demodulator 250 for demodulating separated data signal, a control receiver 240 for transmitting demodulated data to the rotary stand 140, the lens 120 and the illuminator 130, and a mixer 270 for mixing video signal of the camera 110 and data signal for an alarm 220 and a microphone 210 modulated through the modulator/demodulator 250.
Video signal of the camera 110 is input into the mixer 270, and data signal for the lens 120, the illuminator 130 and the rotary stand 140 of the camera is received from the control receiver 240 through a plurality of control lines.
The control receiver 240 receives data signal transmitted from a control transmitter 340 of the control transmitting 300 and controls peripheral devices of the camera, such as a zoom lens, the illuminator, the rotary stand and so on.
Data signal for the microphone 210 and the alarm 220 is converted through the modulator/demodulator 250, mixed with video signal through the mixer 270, and transmitted to a two-way ground potential corrector 380 of the control transmitting part 300 through the single coaxial cable.
FIG. 4 illustrates a distribution view of frequency of video signal and data signal according to the present invention.
According to the present invention, to minimize distortion of video signal, video signal is not modulated at all. Instead of the modulation of video signal, frequency, which does not influence on video signal, is selected and modulates data signal. Video signal and the modulated data signal are mixed and transmitted through the single coaxial cable.
The control transmitting part 300 includes the control transmitter 340 for generating data controlling the lens 120, the illuminator 130 and the rotary stand 140, a modulator/demodulator 350 for modulating or demodulating data signal, a mixer 360 for transmitting data signal modulated in the modulator/demodulator to the control receiving part 200 through the single coaxial cable, a separator 370 for separating signal transmitted from the two-way ground potential corrector 380 into video signal and data signal, and the two-way ground potential corrector 380 for preventing distortion of video signal and data signal.
The two-way ground potential corrector 380 corrects ground potential of video Signal and data signal transmitted in two directions through the single coaxial cable. The separator 370 separates video signal from data signal. Video signal is transmitted to the monitor 400, and data signal is output to an alarm 33 and a speaker 320 after demodulated through the modulator/demodulator 350.
The two-way ground potential corrector 380 prevents distortion of video signal and data signal due to the ground potential. The control transmitter 340 is to control the lens 120, the illuminator 130 and the rotary stand 140 of the camera part. For the control, the modulator/demodulator 350 modulates data signal and transmits to the mixer 360.
The mixed signal is transmitted to the separator 260 of the control receiving part 200 through the two-way ground potential corrector 380.
Data separated in the separator 260 is demodulated in the modulator/demodulator 250 and output to the speaker 230 and the alarm 220, and at the same time, controls the lens 120, the illuminator 130 and the rotary stand 140 through the control receiver 240. FIG. 5 illustrates an enlarged schematic view of the present invention using a plurality of cameras.
In FIG. 5, one control transmitter 340 is connected to plural modulators/demodulators and controls each of them.
Industrial Applicability
As described above, the present invention can provide clear and stable quality of video and stably send and receive even in a long distance. Moreover, the present invention can considerably reduce installation expenses since multiplexing and transmitting video signal and data signal. Furthermore, the present invention can prevent deterioration of the system even though the system is used for a long time since a circuit is simple.
While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.

Claims

What Is Claimed Is;
1. A system for transmitting video signal and data signal in CCTV(Closed Circuit Television) using a single coaxial cable, the system comprising: a camera part having a camera for obtaining video, a lens for adjusting distance, an illuminator for adjusting luminosity and a rotary stand for adjusting a location of the camera; a control receiving part having a separator for separating signal, which is transmitted through the single coaxial cable, into data signal and video signal, a modulator/demodulator for demodulating the separated data signal, a control receiver for transmitting the demodulated data to the rotary stand, the lens and the illuminator, and a mixer for mixing video signal of the camera and data signal for an alarm and a microphone modulated through the modulator/demodulator; a control transmitting part having a control transmitter for generating data controlling the lens, the illuminator and the rotary stand, a modulator/demodulator for modulating or demodulating data signal, a mixer for transmitting data signal modulated in the modulator/demodulator to the control receiving part through the single coaxial cable, a two-way ground potential corrector for preventing distortion of video signal and data signal transmitted through the single coaxial cable, and a separator for separating signal transmitted from the two-way ground potential corrector into video signal and data signal; and a monitor for reproducing video.
2. A method for transmitting video signal and data signal in CCTV(Closed Circuit Television) using a single coaxial cable, the method comprising the steps of: mixing video signal obtained from a camera and data signal for an alarm and a microphone modulated through a modulator/demodulator in a mixer; transmitting the mixed signal through the single coaxial cable; correcting ground potential of video signal and data signal transmitted through the single coaxial cable using a two-way ground potential corrector; separating video signal and data signal in a separator, and then transmitting video signal to a monitor and outputting data signal to an alarm and a speaker through a modulator/demodulator; modulating data of a control transmitter in the modulator/demodulator and transmitting data to a mixer; transmitting data, which is transmitted to the mixer, to a separator of a control receiving part through a two-way ground potential corrector; and modulating data, which is separated in the separate of the control receiving part, in a modulator/demodulator of the control receiving part, outputting the modulated data to a speaker and an alarm of the control receiving part and controlling a lens, an illuminator and a rotary stand through a control receiver.
3. The method according to claim 2, wherein video signal is transmitted without any modulation.
4. The method according to claim 2, wherein the two-way ground potential corrector prevents distortion of video signal and data signal due to ground potential.
PCT/KR2001/001034 2000-06-19 2001-06-16 System and method for transmitting digital video signal and digital control signal in cctv WO2001099428A1 (en)

Priority Applications (1)

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AU2001274638A AU2001274638A1 (en) 2000-06-19 2001-06-16 System and method for transmitting digital video signal and digital control signal in cctv

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR2000/33739 2000-06-19
KR1020000033739A KR100334256B1 (en) 2000-06-19 2000-06-19 Method and apparatus for transmitting and receiving image signal and data signal in closed circuit

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WO2001099428A1 true WO2001099428A1 (en) 2001-12-27

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Publication number Priority date Publication date Assignee Title
KR100419560B1 (en) * 2001-05-19 2004-02-19 가락전자 주식회사 One cable multi data transceiver system and a means.
KR100899120B1 (en) * 2002-10-15 2009-05-27 한국항공우주산업 주식회사 Unmanned video surveillance system

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JPH09205639A (en) * 1996-01-25 1997-08-05 Hitachi Denshi Ltd Image transmission system
KR19980022612U (en) * 1996-10-26 1998-07-25 황병문 Female sexual enhancement

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JPH06296248A (en) * 1993-04-07 1994-10-21 Toa Corp Monitor camera
JPH06303602A (en) * 1993-04-15 1994-10-28 Towa Electron Kk Two-way multiplex communication interface device
KR950016383A (en) * 1993-11-30 1995-06-17 이대원 Video camera system
JP3100023B2 (en) * 1994-01-20 2000-10-16 株式会社富士通ゼネラル External synchronous television camera
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JPH09205639A (en) * 1996-01-25 1997-08-05 Hitachi Denshi Ltd Image transmission system
KR19980022612U (en) * 1996-10-26 1998-07-25 황병문 Female sexual enhancement

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KR100334256B1 (en) 2002-04-25
AU2001274638A1 (en) 2002-01-02

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