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==Punctured convolutional codes==
{{See also|
[[File:Soft34.png|thumb|right|300px|Convolutional codes with 1/2 and 3/4 code rates (and constraint length 7, Soft decision, 4-QAM / QPSK / OQPSK).<ref>[https://ch.mathworks.com/help/comm/ug/punctured-convolutional-coding-1.html Punctured Convolutional Coding (MathWorks)]</ref>]]
Convolutional code with any code rate can be designed based on polynomial selection;<ref>{{Cite web|url=https://www.mathworks.com/help/comm/ref/poly2trellis.html|title=Convert convolutional code polynomials to trellis description - MATLAB poly2trellis}}</ref> however, in practice, a puncturing procedure is often used to achieve the required code rate. [[Punctured code|Puncturing]] is a technique used to make a ''m''/''n'' rate code from a "basic" low-rate (e.g., 1/''n'') code. It is achieved by deleting of some bits in the encoder output. Bits are deleted according to a ''puncturing matrix''. The following puncturing matrices are the most frequently used:
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