HUMBUG

HUM REJECTION AND ISOLATION Reduces hum in most systems Reduces hum in most systems THE BENEFITS The Humbug eliminates humbars, picture tearing, cross talk and rolling The Humbug improves existing and new installations Distortion free images enhance your companys reputation TECHNICAL BENEFITS AND Can avoid the use of expensive fibre optic cable SPECIFICATION Safety - isolation to 500V DC Power supply is not required Very low insertion loss of 0.5dB Passes video and camera control signals in both Very high frequency response, 0-3 dB at directions 10 MHz Colour compatible Zero colour distortion Prevents power cables laid by others interfering Suitable for 75 and 50 Ohms systems with the CCTV system. Will operate with non video signals Isolation voltage, min 500V DC INSTALLATION PROCEDURE Insulation resistance 100M Ohms The Humbug must be installed in the video Constant group delay cable that has come directly from the Connectors BNC camera, but before the cable has been Dimensions: width 50mm (70mm including connected to anything else. fixing tabs), height 48mm, length 90mm including connectors (approx 2 (3) x 2 x 4 inches) The shield of the coaxial cable between the Weight approximately 176 grams (6 oz) Humbug and the camera must not touch any metal surface between the camera housing and the Humbug. (This is unlikely with a standard insulated cable) Monitor Camera Humbug If several video cameras come from the same Building area, fix a Humbug in every cable, or a grground loound loop will still rop will still remain.emain. Tecton Limited, Fishers Pond, Eastleigh SO50 7HG, Great Britain Tel: +44 (0)2380 695858. Fax: +44 (0)2380 695702. Web site: HOW IT WORKS IN PRACTICE Picture distortion occurs in many installations. This can be caused by the following: Ground loops Mains pick up Cross talk Ground loops occur when the earth potential at the camera is different from the potential of the monitor. This difference may only be a small voltage but it can cause large current to flow through the shield of the coaxial cable. The Humbug breaks this circuit allowing only video and camera control signals through. These large currents will cause picture distortion and safety problems if they remain. Mains pick up occurs when coaxial cable runs in parallel to a power cable. A sinusoidal voltage develops on both the shields and the video core. This is often seen as a Hum Bar passing down the screen. As the Humbug only sees the difference between the signals connected to it the video is passed without hum. Cross talk occurs when a cable carrying high frequency signals lies next to the video cable. This is often seen as diagonal lines passing across the screen. Sometimes they come and go, the Humbug eliminates most of these as it only sees the difference between signals connected to it. RACK MOUNT HUMBUG 5KHz 8MHz Spectrum analyser trace showing frequency response (top) and group delay (bottom). The rack mount Humbug provides a tidy solution of having multiple humbugs which are isolated from each other. The rack mount humbug has 17 inputs/outputs and has the following dimensions: width 442mm, height 45mm, length 370mm (17.4 x 1.8 x 14.6 inches). The unit weighs approximately 5Kg. Rack mounting ears supplied. TECHNICAL BACKGROUND OTHER PRODUCTS The Humbug was developed because existing ground loop transformers performed badly 17 Way Rack Mounted during tests. Most transformers tested had low Video Distribution bandwidth, caused distortion of the video image Amplifier (VDA) and loss of colour. The Humbug is not a transformer in a box, it is an example of high quality magnetic engineering Internal circuit board using the latest ferrite materials which allow high Part Number: VDA01 bandwidth and compact size to be achieved. We suggest our customers issue them to their Video Over IP Network Toolkit installation and services teams to deal with TTrransmittansmitterer problems as they occur. It is preferable to design the Humbug into each system, one per camera. Product Part Numbers: PParart Nt Numbumberer:: NW NWTKITTKIT PParart Nt Numbumberer:: JVIP1 JVIP1 Humbug = HUMBUG Rack mount Humbug = HUO17R Tecton Limited, Fishers Pond, Eastleigh SO50 7HG, Great Britain Tel: +44 (0)2380 695858. Fax: +44 (0)2380 695702. Web site: