1. Title
Knowing that the data information is 16 bits, at least ____ bit check bits should be added to achieve Hamming code error correction.
A 3
B 4
C 5
D 6
2. Theory
This question examines the check code. Actually, when you encounter it in your work, you can search for the algorithm implementation on the Internet. Just know that there is a check code technology.
But after all, it’s an exam. It requires not only knowing the check codes, but also knowing which check codes are available and the corresponding overview.
There are three types of check codes involved in the exam: parity, Hamming codes, and cyclic redundancy check codes (CRC). In fact, these types are often encountered in work, but I can't remember the specific implementation details. Just come to understand:
2.1 Parity check
One check bit is added to the code, so that the number of 1s in the code is an odd number is an odd check, and the number of 1s in the code is an even number is an even check, so the check bit is one bit.
2.2 Hamming code
Insert k check codes between the data bits. If the data bits are n, it must satisfy2^k>=n+k
2.3 Cyclic Redundancy Check Code CRC
CRC check code is composed of information code and check code 校验码位数=CRC的字长n-信息码位数k.
3. Analysis
Apply the formula directly 2^k>=n+k, where n=16, then k=3/4 does not meet, and k=5 meets, so the answer is C.