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HTET PGT Official Computer Science Paper - 2017

Option 4 : None of these

HTET PRT 2020: Full Mock Test

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- Error-correcting codes (ECC) are a sequence of numbers generated by specific algorithms for detecting and removing errors in data that has been transmitted over noisy channels.
- Error-correcting codes ascertain the exact number of bits that have been corrupted and the location of the corrupted bits, within the limitations in the algorithm.

The Error Correcting Codes are of the following types:

__Binary Convolutional Codes__:

The message comprises data streams of arbitrary length and a sequence of output bits are generated by the sliding application of Boolean functions to the data stream.

__Low-density parity check code (LDPC)__:

It is a linear error-correcting block code. They are suitable for large block sizes in very noisy channels. LDPC codes were developed by Robert G. Gallager, in his doctoral dissertation at the Massachusetts Institute of Technology in 1960. So, they are also known as Gallager codes.

**Reed - Solomon encoder**

It accepts a block of data and adds redundant bits (parity bits) before transmitting it over noisy channels. On receiving the data, a decoder corrects the error depending upon the code characteristics.

**Since all the given codes are error-correcting codes, Option (4) is the correct answer.**