Hi folks. Is there such a thing as a CCTV Signal Detector available somewhere? The thing I have in mind would be placed in various spots in a CCTV system in order to detect if a valid TV signal comes through to each of the sensors. Basically, this device would detect and help locate breaches in the transmission lines in the CCTV system. Are such gadgets available? Rune
CCTV signal detector
Started by ●June 29, 2006
Reply by ●June 29, 20062006-06-29
"Rune Allnor" <allnor@tele.ntnu.no> skrev i en meddelelse news:1151564690.656520.45090@b68g2000cwa.googlegroups.com...> Hi folks. > > Is there such a thing as a CCTV Signal Detector available somewhere? > The thing I have in mind would be placed in various spots in a CCTV > system in order to detect if a valid TV signal comes through to each > of the sensors. Basically, this device would detect and help locate > breaches in the transmission lines in the CCTV system. > > Are such gadgets available? > > Rune >A monitor could be used :-) Cut the cable and put a connector on the two new ends. Combine them again and then you can open the cable and check the signal with a monitor. Do you want some remote test devices through LAN or just something attached to the cable for local check? /Rune
Reply by ●June 29, 20062006-06-29
Rune Christensen wrote:> "Rune Allnor" <allnor@tele.ntnu.no> skrev i en meddelelse > news:1151564690.656520.45090@b68g2000cwa.googlegroups.com... > > Hi folks. > > > > Is there such a thing as a CCTV Signal Detector available somewhere? > > The thing I have in mind would be placed in various spots in a CCTV > > system in order to detect if a valid TV signal comes through to each > > of the sensors. Basically, this device would detect and help locate > > breaches in the transmission lines in the CCTV system. > > > > Are such gadgets available? > > > > Rune > > > > A monitor could be used :-) > > Cut the cable and put a connector on the two new ends. Combine them again > and then you can open the cable and check the signal with a monitor. > > Do you want some remote test devices through LAN or just something attached > to the cable for local check?I would like an automatic devide that is independent of human operators watching and evaluating the image. Imagine a control room containing tens of monitors, and one or two of them go dark. I want to be able to raise an audiovisual alert to the one or two people on watch, and also help them find out where in the CCTV loop the problem is located. Rune
Reply by ●June 29, 20062006-06-29
Rune Allnor wrote:> Hi folks. > > Is there such a thing as a CCTV Signal Detector available somewhere? > The thing I have in mind would be placed in various spots in a CCTV > system in order to detect if a valid TV signal comes through to each > of the sensors. Basically, this device would detect and help locate > breaches in the transmission lines in the CCTV system. > > Are such gadgets available?It must be clear to you that a monitor will do what you want, so I guess you want something automatic. The CCTV signal has strong horizontal- and vertical-frequency components. The vertical is close to the line frequency and weaker, so the horizontal component is easier to detect. Although signal quality is not addressed, a detector at the horizontal frequency should provide a reasonable indication of the presence of signal. What kind of indication do you want? The detector itself could be an op-amp package and a few R's and C's. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●June 29, 20062006-06-29
Jerry Avins wrote:> Rune Allnor wrote: > > Hi folks. > > > > Is there such a thing as a CCTV Signal Detector available somewhere? > > The thing I have in mind would be placed in various spots in a CCTV > > system in order to detect if a valid TV signal comes through to each > > of the sensors. Basically, this device would detect and help locate > > breaches in the transmission lines in the CCTV system. > > > > Are such gadgets available? > > It must be clear to you that a monitor will do what you want, so I guess > you want something automatic. The CCTV signal has strong horizontal- and > vertical-frequency components. The vertical is close to the line > frequency and weaker, so the horizontal component is easier to detect. > Although signal quality is not addressed, a detector at the horizontal > frequency should provide a reasonable indication of the presence of signal. > What kind of indication do you want? The detector itself could be an > op-amp package and a few R's and C's.I want anything automatic that goes loud the very second the image goes quiet. Or shortly thereafter. I commented on the application in a post earlier today. Rune
Reply by ●June 29, 20062006-06-29
"Rune Allnor" <allnor@tele.ntnu.no> wrote in message news:1151564690.656520.45090@b68g2000cwa.googlegroups.com...> Hi folks. > > Is there such a thing as a CCTV Signal Detector available somewhere? > The thing I have in mind would be placed in various spots in a CCTV > system in order to detect if a valid TV signal comes through to each > of the sensors. Basically, this device would detect and help locate > breaches in the transmission lines in the CCTV system. > > Are such gadgets available? > > RuneThe guts of modern monitors include synchronization mechanisms. Something like that might be used as a sensor. Something like this: http://www.keene.co.uk/pages/downloads/dnl_files/pdfs/KSCi.pdf or this even better?: http://www.smarthome.com/manuals/8016.pdf I Googled on ["video signal present" sensor] Fred
Reply by ●June 29, 20062006-06-29
Rune Allnor wrote: ...> I want anything automatic that goes loud the very second the image > goes quiet. Or shortly thereafter. I commented on the application > in a post earlier today.Can you build something, or must it be store-bought? Is the system NTSC, PAL, SECAM, or what? Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●June 29, 20062006-06-29
Jerry Avins wrote:> Rune Allnor wrote: > > ... > > > I want anything automatic that goes loud the very second the image > > goes quiet. Or shortly thereafter. I commented on the application > > in a post earlier today. > > Can you build something, or must it be store-bought?Home-built will probably cause some stir....> Is the system NTSC, > PAL, SECAM, or what?I don't know. This is a Closed Cirquit TV system, could be anything. Rune
Reply by ●June 29, 20062006-06-29
Fred Marshall wrote:> "Rune Allnor" <allnor@tele.ntnu.no> wrote in message > news:1151564690.656520.45090@b68g2000cwa.googlegroups.com... > > Hi folks. > > > > Is there such a thing as a CCTV Signal Detector available somewhere? > > The thing I have in mind would be placed in various spots in a CCTV > > system in order to detect if a valid TV signal comes through to each > > of the sensors. Basically, this device would detect and help locate > > breaches in the transmission lines in the CCTV system. > > > > Are such gadgets available? > > > > Rune > > The guts of modern monitors include synchronization mechanisms. Something > like that might be used as a sensor. > Something like this: > http://www.keene.co.uk/pages/downloads/dnl_files/pdfs/KSCi.pdf > or this even better?: > http://www.smarthome.com/manuals/8016.pdf > > I Googled on ["video signal present" sensor] > > FredThanks! The smarthome link seems to be spot on. Rune
Reply by ●June 29, 20062006-06-29
"Rune Allnor" <allnor@tele.ntnu.no> skrev i en meddelelse news:1151574758.854096.209770@d56g2000cwd.googlegroups.com...> > Rune Christensen wrote: >> "Rune Allnor" <allnor@tele.ntnu.no> skrev i en meddelelse >> news:1151564690.656520.45090@b68g2000cwa.googlegroups.com... >> > Hi folks. >> > >> > Is there such a thing as a CCTV Signal Detector available somewhere? >> > The thing I have in mind would be placed in various spots in a CCTV >> > system in order to detect if a valid TV signal comes through to each >> > of the sensors. Basically, this device would detect and help locate >> > breaches in the transmission lines in the CCTV system. >> > >> > Are such gadgets available? >> > >> > Rune >> > >> >> A monitor could be used :-) >> >> Cut the cable and put a connector on the two new ends. Combine them again >> and then you can open the cable and check the signal with a monitor. >> >> Do you want some remote test devices through LAN or just something >> attached >> to the cable for local check? > > I would like an automatic devide that is independent of human operators > watching and evaluating the image. Imagine a control room containing > tens of monitors, and one or two of them go dark. I want to be able to > raise an audiovisual alert to the one or two people on watch, and also > help them find out where in the CCTV loop the problem is located. > > Rune >You can measure the length to the wire break by sending a pulse into the wire and measure how long it will take before the pulse returns. If you put some sensors along the wire then you need to make sure that a cable break will not also affect the cables to the sensors. If someone or somebody has cut the wires and the wires was placed next to each other then both wires can be broken. /Rune
