Bit rate on sat transponders

[Satphoenix]

How can I calculate the bit-rate of a sat-transponder?

27500 or 22000 or 29900 can't be the correct bitrates, so how can I calculate it?

[marian321]

Re: Bit rate on sat transponders

There are a few possibilities to do this. If you want the theoretically data rate of a sat-transponder you need to know the bandwidth. Many transponders have a bandwith of 36 MHz. Then you can calculate for normal DVB-S signals:

Bit rate [Mbit/s] = Bandwidth [MHz] * FEC * RS * modulation ratio / (1 + cosinus roll-off factor)

where:

FEC (forward error correction)
RS (Reed Solomon) = 188/204 (for DVB-S signals)
cosinus roll-off factor – usually 0.35 for DVB-S signals [0,2 or 0,25 for DVB-S2]
modulation ratio = 2 for QPSK modulation and 3 for 8PSK


The used bitrate is:

Bit rate [Mbit/s] = Symbol rate * FEC * RS * modulation ratio

Now it’s up to you to calculate…

[nush]

Re: Bit rate on sat transponders

hxxp://gstoyanov.com/satellite-bitrate-calculations/

does this help

[herrr]

Re: Bit rate on sat transponders

You can also simply test bitrate (both audio and video) with some receivers: I'm more expert in DVB-cards and for example with DvbDream you can do it in real time
You'll see that way all bitrates of channels in transponder, in a way that you will never calculate, since at present often they are variable bitrates:

In DvbDream go to: modules/bitrate view

[stu667]

Re: Bit rate on sat transponders

And often you have bad surprises with "so called" HD channels :/

[marian321]

Re: Bit rate on sat transponders

And often you have bad surprises with "so called" HD channels :/

What do you mean? Too low bit-rates for HD?



Then sometimes the discussion starts what is a good bitrate for HD or SD.

Here are the used bitrates of the most sat-transponders:

M-Symbols FEC Bit-rate (kbits/sec)

27500 1/2 25343
27500 2/3 33790
27500 3/4 38014
27500 5/6 42238
27500 7/8 44350

22000 1/2 20274
22000 2/3 27032
22000 3/4 30411
22000 5/6 33790
22000 7/8 35480

29900 1/2 27554
29900 2/3 36739
29900 3/4 41332
29900 5/6 45924
29900 7/8 48221