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Rainer
May 26, 2007, 19:50:51
... calculate the bandwidth for a TIS camera

Hi,

How do you calculate the needed bandwidth for a TIS camera ?

Thank you

Stefan Geissler
May 29, 2007, 11:54:38
Hi Rainer,

The bandwidth calculation is a little bit complicated, because you have not only the image data, but also an header overhead. Thus we created a table with the bandwidth allocations of the different video formats. It can be downloaded at:

http://www.theimagingsource.com/en/resources/whitepapers/download/fwcamsbandwwp.en.pdf

Rainer
May 30, 2007, 16:56:37
Hallo Stefan,

Danke. I made some tests running several TIS cameras at the same time in IC Capture.

Here is the posting I made in the Yahoo group:
************************************************** ********
Hi,

Here is the test. 2 TIS cameras running in IC Capture. A DBK
21AF04.AS and a DBK 41AF02.AS

http://www.rainerehlert.com/DMK/IC-2-cameras-01.jpg

The 41 was running at 15 frames per second in BY8 and the 21 running
at 30 fps also in BY8.

Here another test.

http://www.rainerehlert.com/DMK/TIS-2-cameras-01.jpg

The 41 running in IC Capture and the 21 running in K3CCD Tools.

Here you can see 3 TIS cameras running in IC Capture e.g. DFK
21AF04.AS, DBK 21AF04.AS and a DBK 41AF02.AS

http://www.rainerehlert.com/DMK/IC-3-cameras-01.jpg

and here 2 cameras in IC Capture and 1 camera in K3CCD Tools

http://www.rainerehlert.com/DMK/TIS-3-cameras-01.jpg

as I have no more Firewire ports I can not connect more cameras to my
PC :-))

I hope you can see now the power of Firewire as well as IC Capture.

saludos Rainer
************************************************** ******

If I use your white paper data and the fps I achieved with 2 cameras then I get together 96% which covers then my Firewire speed.

Interesting again is, in order to confuse the enemy :p , that you do not list the BY8 color format as that is what I was using when making the test.

Why do you make to us amateur astronomers the life so hard by not having a common standard or compare things with what your cameras work with ?

Is BY8 in color the same as Y800 in B&W ?

How much can the header in total influence the speed ? Is the header that big that is has to be taken into account ?

Stefan Geissler
May 30, 2007, 17:19:45
Hi Rainer,

At least, I guess, the BY8 is newer than the document. But I tell the marketing to add this. BY8 is the same as Y800, just to be complete.

The header is specified in DCAM 1.3 and FireWire specification. I do not know how big it is. But the header guarantees that all connected devices receive the blocks, that are for them. I know protocols with bigger headers, e.g. CORBA, which is used in simulators.