ISRO CSE 2008 | Question: 48

Question

Which of the following is termed as minimum error code ?

• A. Binary code
• B. Gray code
• C. Excess-$3$ code
• D. Octal code

Comments

reason why gray code is know as minimum error code?

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• Gray Code ka use errors minimize karne ke liye hota hai, kyunki isme ek time pe sirf ek bit hi change hoti hai.Matlab jab ek value se doosri value pe switch hota hai, to sirf ek bit change hoti hai, jisse errors hone ka chance kam hota hai.

Answer 1

b) Gray Code

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aka :
reflected binary code
cyclic permutation code

Answer 2

Error Code kya hote hain?

Error codes aise codes hote hain jo data transmission mein hone wale errors ko detect aur correct karte hain. Jaise jab hum data ko ek jagah se doosri jagah bhejte hain, to kabhi-kabhi data galat ho sakta hai. Error codes un galtiyon ko thik karne mein madad karte hain.

Ab jo options diye hain, unke baare mein samjhte hain:

1. Binary Code

• Binary code simplest form hai, jisme numbers ko 0s aur 1s mein represent kiya jaata hai.
• Ye code errors ko specifically detect ya correct nahi karta, bas simple representation hoti hai.

2. Gray Code

• Gray code ek aisa binary system hai jisme do successive values ke beech mein sirf ek hi bit change hoti hai. Isse yeh fayda hota hai ki jab data change ho raha hota hai, to ek waqt mein sirf ek bit hi flip hoti hai.
• Gray code ko minimum error code bhi kaha jaata hai, kyunki yeh errors ko minimize karta hai. Matlab jab ek value se doosri value pe switch hota hai, to sirf ek bit change hoti hai, jisse errors hone ka chance kam hota hai.
• Gray code ka use un situations mein hota hai jahan frequent value changes hoti hain, jaise rotary encoders ya digital-to-analog conversion mein.

3. Excess-3 Code

• Excess-3 code ek type ka binary-coded decimal (BCD) code hai, jisme har decimal digit ko uski corresponding 4-bit binary value mein 3 add karke represent kiya jaata hai.
• Yeh code bhi errors minimize nahi karta. Yeh mainly BCD arithmetic mein use hota hai.

4. Octal Code

• Octal code base-8 mein numbers ko represent karta hai (0 se 7 tak ke digits).
• Yeh large binary numbers ko compactly represent karne ke liye use hota hai, lekin errors ko minimize karne ka kaam nahi karta.

Answer:

• B: Gray Code bilkul sahi jawab hai, kyunki ismein sirf ek bit change hoti hai jab value change hoti hai. Isse errors hone ka chance kam ho jaata hai, isliye isse minimum error code kaha jaata hai.

Aur Kuch Error Codes ke Types:

1. Parity Bit: Ek bit jo add ki jaati hai data ke saath taaki total number of 1s odd ya even ho. Agar parity match nahi hoti, to error detect ho jaata hai.

2. Hamming Code: Ye ek error-correcting code hai jo single-bit errors ko detect aur correct karta hai. Isme redundant bits add ki jaati hain data mein.

3. Cyclic Redundancy Check (CRC): Ek hash function hai jo data mein accidental changes ko detect karta hai.

4. Reed-Solomon Code: Ye ek aur error-correcting code hai jo multiple errors ko correct karne mein kaam aata hai.

Summary:

• Gray Code ka use errors minimize karne ke liye hota hai, kyunki isme ek time pe sirf ek bit hi change hoti hai.
• Baaki jo codes hain, jaise Hamming, CRC, etc., wo errors ko detect aur correct karte hain, minimize nahi.

Answer 3

$\underline{\textbf{Answer:}\Rightarrow}\;\textbf{(B)}$

$\underline{\textbf{Explanation:}\Rightarrow}$

The gray code which is also known as the reflected binary code is a binary numeral system where two successive values differ in only one bit.

Gray codes are mostly used to facilitate error correction in digital communication.