English Translation Italian Translation Spanish Translation French Translation German Translation Portugese Translation   
Russian Translation Arabic Translation Japanese Translation Hindi Translation Chinese Translation Hebrew Translation   
            Website Translations
IMPORTANT ANNOUNCEMENT: Satcoms UK is changing. The forums are closing and will be removed.
The tutorials will stay as well as the tools, news and jobs but the user accounts and forums have been removed. Satcoms UK TV will stay as will the satellite simulator and link budget calculators.

Forum Home Forum Home --- Satellite Communication Tutorials --- Tutorials - Course 5 - Digital Measurements & Tests
  New Posts New Posts RSS Feed - Data Communications - Test Sets & Eb/No
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Topic ClosedData Communications - Test Sets & Eb/No

 Post Reply Post Reply
Author
Message
Satcoms UK View Drop Down
Administration
Administration
Avatar
Satcoms UK

Joined: 29/March/2001
Location: United Kingdom
Status: Offline
Points: 9980
Direct Link To This Post Topic: Data Communications - Test Sets & Eb/No
    Posted: 14/August/2008 at 16:39

Data Communications - Test Sets

In any satcom system, there is a need to test the path of the data from end to end to ensure that the bit error rate (the amount of errors) is minimal or error free.

Test Sets

We use test sets to send test data across the system where it can either be received and analysed by a compatible test set for one way testing or looped round and sent back to be received and analysed by the same test set.

What the test sets are looking for is errors in the received data. Since they know what was originally transmitted they can accurately monitor errors in transmission.

Bit Error Rate

If you have sent 1,000,000 bits of data and receive 1 error then that is an error rate of 1 in 1 million bits or 1 x E-6. Acceptable error rates start from 1 error in 10 million bits or 1 x E-7. To measure this kind of error rate accurately the tests have to run over time to build up a statistical picture of the errors. 1 error in 24 hours and then 2 million in the next 10 minutes is not a good link but for the first 24 hours is was a superb link.

Eb/No & Bit Error Rates

Eb/N0 is a specification of the satellite modem which states the size of the signal for a given data rate to give a specified bit error rate. It comprises of the energy per bit in a 1 Hz bandwidth.

In order to calculate this we need the data rate.

Data Rate = 64 kBps

We simply subtract 10 Log this data rate from the measured C/N0 to give the Eb/N0.

Eb/N0 = 54 dBc/Hz - 48 = 6

Thus, to find the required C/N0 we simply rearrange:

C/N0 = 10 Log Data Rate + Eb/No required

C/N0 = 48 + 6 = 54 dBc/Hz

The modem manufacturer states the Eb/N0 for a given data rate so you can easily know the required C/N0 to acheive this.

Click Here for Next Tutorial


Edited by Satcoms UK - 16/April/2015 at 22:39
Satcoms UK

The Satellite Communications Engineering Resources Website.
Back to Top
Sponsored Links


Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.045 seconds.

 SUPPORTED PARTNERS & CHARITIES
 
Computer Aid International is a UK-registered ICT for development charity which aims to reduce poverty through practical ICT solutions. We collect IT equipment for distribution in hospitals, universities, schools and not-for-profit organisations in over 100 countries. Médecins Sans Frontières (MSF) is an international, independent, medical humanitarian organisation that delivers emergency aid to people affected by armed conflict, epidemics, natural disasters and exclusion from healthcare. MSF offers assistance to people based on need, irrespective of race, religion, gender or political affiliation. The Red Cross EU Office monitors and engages in relevant EU humanitarian aid and civil protection issues linked to the priorities of the Red Cross and Red Crescent Mouvement. Myeloma UK provides information and support to all those affected by myeloma and aims to improve treatment and care through research, education and raising awareness. Macmillan Cancer Support improves the lives of people affected by cancer. We provice practical, medical and financial support and push for better cancer care. Cancer affects us all. We can all help. We are Macmillan.
 
Satcoms UK - Satellite Communications Information Website
© Satcoms UK 2002 - 2018 , All rights reserved.
Privacy Policy | Terms of Use