Newbie ques: What is code rate? how do i calculate them?
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Newbie ques: What is code rate? how do i calculate them?

 
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Ant_Magma
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Posted: Tue Nov 29, 2005 9:16 am    Post subject: Newbie ques: What is code rate? how do i calculate them? Reply with quote
What is code rate? how do i calculate them?

How does a 1/2 convolutional encoder and a puncture produce a code rate
of 3/4?
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Mike Yarwood
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Posted: Tue Nov 29, 2005 11:46 pm    Post subject: Re: Newbie ques: What is code rate? how do i calculate them? Reply with quote
"Ant_Magma" <vcteo1@gmail.com> wrote in message
news:1133252860.825016.36030@f14g2000cwb.googlegroups.com...
Quote:
What is code rate? how do i calculate them?

How does a 1/2 convolutional encoder and a puncture produce a code rate
of 3/4?

Hi ant_magma,

You calculate them by dividing the number of bits you put in to the encoder
by the number of bits you get out of it.
If you throw away some of the bits just before the output then you have less
bits coming out so a higher code rate.

Best of Luck - Mike
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Ant_Magma
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Posted: Wed Nov 30, 2005 1:16 am    Post subject: Re: Newbie ques: What is code rate? how do i calculate them? Reply with quote
Thx for replying Mike. How about the calculations? Lets say i have a
convolutional encoder and puncture, i just multiply both their code
rates to get the final code rate?
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Mike Yarwood
Guest
Posted: Fri Dec 02, 2005 12:40 am    Post subject: Re: Newbie ques: What is code rate? how do i calculate them? Reply with quote
"Ant_Magma" <vcteo1@gmail.com> wrote in message
news:1133310829.754645.52410@g43g2000cwa.googlegroups.com...
Quote:
Thx for replying Mike. How about the calculations? Lets say i have a
convolutional encoder and puncture, i just multiply both their code
rates to get the final code rate?

Basically yes - say you've got a 1/2 rate code, so you get 6 bits out for

every three in , throw every third bit away (would you call that a 3/2 rate
puncturing? if so then 3/2 * 1/2 gives you 3/4 ) and you get 4 bits out for
every three bits in instead.

Best of Luck - Mike
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