AR# 11146: DSP Reed Solomon - Can a Xilnix RS encoder/decoder hand a range of codeword lengths?
AR# 11146
DSP Reed Solomon - Can a Xilnix RS encoder/decoder hand a range of codeword lengths?
描述
Keywords: codeword, symbol
Urgency: Standard
General Description:
Can a Xilnix RS encoder/decoder hand a range of codeword lengths?
解决方案
Generally the codeword length is fixed at 'n'. Shortened codes just means the value of 'n' does not need to be 2**(symbol_width)-1. i.e. if the symbol width is 8 then n can be less than 255 but it is still fixed.
In some cases a trick can be used to make the encoder or decoder work for multiple codeword lengths. If n-k doesn't change and all parameters remain the same then n can be set to the longest codeword required. When smaller codewords are required the code word should be pre-pended with zeroes to make it up to n. So the actual codeword length is still n but it has been padded with zeroes.