Eg. Find out the parity bit (odd) for message 1101 and show us how it helps in detecting errors As 1101 has 3 i.e. odd number of 1’s so P=0 so that we still have the odd number of 1’s in the combination of 5 bits(message(4 bits) and parity bit(1 bit)) So message we send […]
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Parity bit
A parity bit is an extra bit that is attached to the information that is being sent from one position to the other. This bit is attached just to detect the error if any in the information during the transmission. This bit is used to make number of 1’s in the message or information either […]
M out of N coding scheme And its efficiency
In this coding scheme we have N total number of bits and fixed M of those bits are 1s and N – M bits are 0s. Hence this scheme is called M out of N coding scheme. It is a type of Error-Detecting coding scheme as if during transmission we have any error in the message we […]
Gray Code
This is also called unit distance code or reflected code. This coding system has a property that there is only one bit change between consecutive gray codes. The following table would show gray codes of decimal values. Binary to gray conversion: Starting from right to left If it is MSB then place it as it is […]
Excess-3 Code
It is also known as XS-3. We add 310 or 1102 to the each 4-bit combination of BCD codes to get excess-3 codes. We can see the corresponding Excess-3 codes of each BCD number: Decimal Binary BCD Excess-3 0 0000 0000 0011 0001 0001 0100 0010 0010 0101 0011 0011 0110 0100 0100 0111 0101 […]
Efficiency of BCD codes
Q- Calculate the efficiency of BCD codes wrt Binary number representation for (a) 4-bit (b) 8-bit. Ans: (a) With 4-bits we have 10 numbers represented in BCD while 16 in Binary hence Efficiency = (10/16)* 100 = 62.5% (b) With 8-bits we have 100(102) numbers represented in BCD while 256(28) in Binary hence Efficiency = (100/256)* 100 […]
BCD Codes
It is an abbreviation of Binary coded decimal. In this coding each decimal digit is represented by the equivalent 4 bits. So if we are to represent 1110 in binary it is 1011 while in BCD it is 0001 0001. So we can see corresponding binary & BCD equivalent of decimal numbers in the following table: […]
Type of BINARY CODES
We can categorize binary codes in following types: Weighted codes: These codes have fixed weights for different binary positions e.g. BCD codes, 8 4 -2 -1, 2 4 2 1 etc Non-weighted codes: These codes don’t have fixed weights for different binary positions e.g. excess-3 codes, gray code Sequential codes: In this coding system, we have consecutive codeswhosedecimal equivalents […]
Subtraction using (r-1)’s compliment
(r – 1) ’s compliment: (M – N) r This is similar to r’s compliment. There is a difference while dealing with the final carry we get If we have both M & N positives, then The Procedure for doing subtraction using (r – 1) ’s compliment is as follow: Take (r – 1) ’s compliment […]
Subtraction using compliments
Subtraction method mentioned earlier looks good when we do it on paper and pencil but to implement a subtraction method on a digital platform then subtraction using compliments is better and efficient. r’s compliment: If we are given numbers M & N with base r, then we can to have to find M – N […]