Laboratory task. 5.1 Acquaintance with a virtual model

5.1 Acquaintance with a virtual model. Start the program 4.2, using the icon TT (English) on a desktop. It is necessary to study the structure of a virtual model using its description in part 6 of this LW. Coordinate the plan of performance of the laboratory task the teacher.

5.2 Encoding process research. The cyclic code (10, 5) from home task is researched. For this purpose:

- choose in a menu "That do we research?" point "Encoding";

- choose a code (10, 5) and set a proper generate polynomial;

- enter information code word determined in home task.

Run the program and compare the code word on the encoder output with calculated in the home task.

5.3 Transmission by a communication channel process research. For this purpose:

- choose in a menu "That do we research?" point "Transmission by a channel";

- enter zero error word, length п.

Run the program at the same settings (from item 5.2). Make sure, that in the case of zero error code word on the output "Telecommunication channel" coincides with code word on the input.

Set error word, which corresponds to the single error е ₁(х) from Table 2 for your variant. Run the program, compare code words on the telecommunication channel input and output and make sure in the telecommunication channel with errors correct work.

5.4 Research of process of decoding. For this purpose:

- choose in a menu "That do we research?" point "Decoding";

- enter zero error word.

Run the program at the same settings. Make sure, that a syndrome is zeroes, and code word on the decoder output coincides with code word on the encoder input.

Set errors word which corresponds to the single error е ₁(х) from the home task. Run the program at the same settings in encoder. Make a table with the decoding results according to the sample Tabl. 4.

Table 4 – Cyclic code (10, 5) for the code word N + 8 = 22 (encoder input – 10110, encoder output - 1011001101) researches results

Errors word е (х)	Encoder input	Encoder output	Syndrome s (x)	Error symbol number, which decoder define
x 9	0 011001101		х 4 + х 3 + 1	x 9
…	…	…	…	…

Repeat research of decoding at double е ₂(х) and triple е ₃(х) errors from the home task. Compare got results with calculations in the home task results.

Repeat research of decoding at the arbitrary fourfold error е ₄(х). For certain error words, for example, е ₄(х) = х ⁶ + х ⁵ + х ³ + х syndrome is zeroes, that confirms that a code (10, 5) has code distance d _min = 4.

5.5 Other cyclic code (n, k) research.

Teacher gives a cyclic code (n, k). Repeat research item 5.4.