2. The procedure.

To load file Eff_Code. The appendix interface is shown in Figure 1.

Figure 1. The interface of appendix Eff_Code.

To construct an optimum non - uniform code of the message for which probabilities of occurrence of symbols of the primary alphabet further are calculated. To define average length of a code, factors of relative efficiency and statistical compression. To compare and prove distinctions in qualitative characteristics of the received codes. Code construction to execute by a technique of Shannon - Fano and Haffman.

3. Approbation of the received results

Students have to demonstrate ability of optimal unequal code construction and valuation of their ffective characteristics in the result of laboratory work carrying out.The two optimum non - uniform code, constructed for one input data by different methods (Huffmann and Shannon – Fano ) must be presented and determined their features. To establish the differences of coefficient.

4. Test questions

1. The notion of effective coding.

2. Entropy of information source.

3. A notion about statistical coding.

4. Coefficient of statistical pressure.

5. Coefficient of relative effectiveness.

List of References

1. Блейхут Р. Теория и практика кодов, контролирующих ошибки: Пер. с англ. М.: Мир, 1986. 576 с.

2. Питерсон У., Уэлдон Э. Коды, исправляющие ошибки: Пер. с англ. М.: Мир, 1976. 600 с.

3. Сергиенко А.Б. Цифровая обработка сигналов. / Учебник для вузов. – СПб.: Питер, 2003. – 608 с.

4. Айфичер Э., Джервис Б. Цифровая обработка сигналов. Практический подход. / М., "Вильямс", 2004, 992с.

5. S.M.Moser, Po – Ning Chen. A Student’s Guide to Coding and Information. Theory. Cambridge University Press, 2012.

Laboratory work 7 Noiseproof coding. HAmming Code

The Purpose: Research of system of transfer of the discrete information with use of Hamming Code.

1. Short theoretical data

In distinction from canonic systematic code in the Hamming code informational and checked bites aren’t spread into separate sub matrix but are interchanged. If to enumerate bites of code combinations starting from 1, from the left to the right then control bites are bites with numbers 1,2,4,8 номерами 1, 2, 4, 8 est. – the others are informational. Purpose of these exchange to make so as that syndrome of error indicates error localization. The purpose of these swaps – to make so that the error syndrome directly specified localization of errors, I pass the intermediate table of correspondences of syndromes and errors. Hamming code is started to build with checking matrix H, as its is credible: the columns of checked matrix are presented syndrome collection, corresponded dual presentation of column number. Then G generating matrix is built строят порождающую матрицу G, proceeding from that H and G are orthogonal, ie scalar producing of every line of matrix G to every line of H matrix is equal to zero, i.e.

H G^T = 0 и G H^T = 0 .