i'm reading the article of Massey and Sain (here) and i cannot unserstand - what is "foreforward inversion"?
There is a description of circles in convolutional codes and a little bit description about catastrophic codes (i mean, codes that makes an infinite amount of errors on decoding if there was a couple of errors in channel).
Who can explain, what is "foreforward inversion", and which delay is meant?
Thanks in advance.
P.S. i interested in this theme because i want to understand the proof of Theorem 1 in that article, no more.