Frage von Markus_Krippner:
What Experts:
How much cable loss (; in dB/100m) use a HD-SDI cables have a maximum?
Or the other way: s.wieviel dB/100m it will not work?
I do not need any tips for cable types, but figures "what the standard allows"
Also on Surftips on the subject I would be grateful.
Thanks ....
markus ... :-)
Antwort von WoWu:
Hello Mark.
For HDSDI regulates the cable loss situation, the SMPTE294M.
The standard defines the maximum cable length with
20db loss of half the clock frequency. Dar would be in HD 743 MHz.
The clock frequency is determined by the data coding scheme is identical with the data rate, ie 1.485 Gb / s (HD-SDI single channel) => 1 / 2 = 743 Gbit / s =>
743 MHz The result is, as a function of cable qualities, different values.
MHR26AWG = 29m
M59 24, AWG = 46m
RG 59, 20 AWG = 57m
RG6, 18 AWG = 87m
(I know, you wanted no recommendations have cable, but as you see, this is a very important factor. You must now you pick your cable.)
These lengths (of the different cable types) correspond to a safe operation, including the 10% margin to authorize "Cliff region," then in the sudden drop-outs secure transmission no longer absolute.
Of course, such values are synonymous heavily dependent on what equipment you use and how well your re-clocking is because it is linked from your course, with bit error rate.
And of course, synonymous, like tollerabel the signal in terms of error protection is behaving, how much bitrate So you've invested in the error correction (the signal) ".
It is therefore not really say that s.wann it does
not work anymore, but only to say, how far it still operates safely.
That is, as with the winter tires ... up to 100 kph, they work well and then you do not really know when it decomposed.
As literature, I always recommend the standards. In it you'll get the technical information first hand and guaranteed correct.
Then synonymous not only build these fantasies, how great may be the cable lengths. Synonymous, and then there are no nasty surprises.
Antwort von Markus_Krippner:
Hello Wolfgang
Thank you for your detailed answer :-)
Another demand: with how much dB loss, I must größenordungsmäßig
still count on high quality BNC connectors? (eg Neutrik PushPull)
Someone told me something of 2dB per connector comes out ... it?
markus ... :-)
PS is "ISBN 978-3-00-023484-2" a standard work, which would help me? ;-)
Antwort von WoWu:
The values are calculated incl connector on both sides. (Amphenol BNC, GK) has at 850 MHz 1.5 dB, for 743 I would have to calculate the value now synonymous. So is somewhat lower.
PS This is my book about HD.
Antwort von Markus_Krippner:
Oki, Wolfgang .... thanks for your advice at a late hour.
Let's see if I bring "ISBN 978-3-00-023484-2" maybe Santa Claus ;-)
markus ... :-)
Antwort von WoWu:
A little tip:
It is a Book on Demand Project. Such projects are not supported of the ancient book industry.
Therefore, the e-book version is always on the cutting edge of technology, whereas (the paper book systemic) on the stand Feb.08.
So it pays to always have the e-book version as a download and costs only half.
Thanks for your interest.
