Help: Dm Dvr Picture Adjustment?

[jig]

Press and hold menu, then search for the termination bit.

Thanks, will give this a go on Monday when I get to the unit, I hope the 'termination' bit is easy to find.

If anyone can let me know where the manual is, it would be greatly appreciated.

thanks

[arfur mo]

Thanks for all the help everyone,but still not sure what is meant by a 'termination issue'

Also cant find the manual for this model on DM's website, can anyone point me in the right direction?

Jig

h i jig,

termination is simply a term for 'loading' a camera input at the receiver/mux/dvr/monitor end. it needs to be terminated at 75 ohms, on the back of cctv monitors the is often a switch shown as lo/hi z. impedence.

the reason it offered, or if you like done this way is if you have a camera say at a gate and you wish to see it in two or more places, assuming series run wiring, you can 'pass through' the first or subsequent monitor or even the dvr/mux without picture loss on the second monitor (hi z is chosen on intermediates), then the last monitor or dvr/mux is set to 75 ohms (or low z).

look in the camera setup menu and turn on the termination, a clue is if he picture is bleached (highly contrasted) then likely it is not terminated correctly.

if you get stuck grab a bnc 't' piece and a bnc plug, feed camera in one side of 't' piece and the plug with a 75 ohm ressistor fitted to the other side and then plug the 't' piece into you mux/dvr (you can buy ready made bnc 75 ohm terminators from maplins).

regs

alan

[Matt the Teckie]

The best analogy for Termination (data certainly, video in a very simplified capacity) I heard goes as follows....

Imagine a long steel rule running between two points. Each end rests on a metal strut. There may be other metal struts between these points. If you gat a lump hammer and smacked one end, the vibration would travel down the rule and would rattle the strut at the other end.

Now, imagine the steel rule at hovering over the end of a desk. Hit the end and it bounces up and down making a wobble-board sound.

Finally, think of each strut as a monitor. Normally when the vibration gets to end of the rule (wire), it bounces at end and is reflected back down the rule (wire). The result is double imaging or ghosting.

Terminating the cable can be thought of as encapsulating the end of the steel runle in a vat of oil. Any excess energy is absorbed and therefore not reflected.

Another reason for termination is inductance. Your cable is not just resistive. It also has either capacative or inductive reactance too. This means it more or less resistance to different frequencies within your video signal.

Let me know if you need more info and I'll sit down and come up with a proper expaination.

[arfur mo]

Let me know if you need more info and I'll sit down and come up with a proper expaination.

hi matt, i read that and had a pint, read it again and had two (or more) pints - now i'm too p'd to remember what it was i did not understand

i just knew it was 'technical' so had two more pints to celebrate arriving at that conclusion, and also had another one for the road.

slooowww shhappinesses is a sssspint jarss crsashaped sevrbeverage - hic!

regs

alan

s

[jig]

Hi all,

Thanks for all the creative explanations and the encouragement of intoxication during the world cup!I managed to find the termination bit and get the picture looking perfect, thanks guys!!

Jig:)

[Guest]

Hi all,

... creative ... intoxication ... termination ... picture looking perfect, thanks guys!!

Jig:)