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Author Topic: Cable spectrum  (Read 311 times)

CarlT

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Cable spectrum
« on: September 22, 2018, 02:17:37 PM »

Lots of pictures of xDSL spectra of all flavours here. Here's what the downstream section of VM plant looks like.

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CarlT

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Re: Cable spectrum
« Reply #1 on: September 22, 2018, 02:18:57 PM »

Here's the end of the spectrum - you can see the individual 8 MHz SC-QAM carriers then the roll-off where the signal ends.
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CarlT

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Re: Cable spectrum
« Reply #2 on: September 22, 2018, 02:23:19 PM »

For the eagle-eyed who spotted it there are a couple of spikes at exactly 1 MHz intervals a fair bit above the rest. These look like narrow-band ingress.
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Weaver

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Re: Cable spectrum
« Reply #3 on: September 23, 2018, 04:29:03 AM »

Very nice pictures, thank you for posting these. iPad Safari made it nice and awkward displaying these as about 10 foot wide and five foot high. So I have tried saving the images instead of struggling look at them with Safari.
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CarlT

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Re: Cable spectrum
« Reply #4 on: September 23, 2018, 01:14:30 PM »

You can see that the network is amplified - despite the downstream range being nearly 650 MHz power level is virtually constant throughout.

Delighted to answer any questions on cable in general. It's my specialist subject as far as broadband goes. I wrote an introduction to various broadband technologies for colleagues and probably went more into depth with cable than other things.
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