# Recent questions tagged carry-generator 1 vote
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(a) Redefine the carry propagate and carry generate as follows: $P _i = A _i + B _ i$ $G _i = A _iB _i$ Show that the output carry and output sum of a full adder becomes $C _i{+1} = (C _i'G _i + P _i')' = G _i + P _iC _i$ ... draw the two level look ahead circuit for this IC. [Hint: use the equation substitution method and AND-OR-INVERT funtion given in part (a) for $C _{i+1}$
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Using the AND-OR-Invert implementation procedure, show that the output carry in full adder can be expressed as $C _{i+1} = G _i + P _iC _i = (G _i'P _i + G _i'C _i')'$ IC type 74182 is a look-ahead carry generator MSI circuits that generate the carries with AND-OR ... -ahead carries $C _2 C _3 and C _4$ in this IC (HINT: Use the equation substitution method to derive carries in terms of $C _1'$).
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Refer : https://gateoverflow.in/8250/gate2015-2-48 Here i dont understood how they calculated 12ns . I got that the first full adder will take 4.8ns time at that 4.8 ns we'll get the carry as well as the sum, in that duration the first XOR Ai xor Bi will be done for subsequent operands but for final sum the carry first need to be propagated through all full adder first Why 4.8 + 3*2.4 ??
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The Cout function of a 3-bit adder is as follows: AB + Cin (A ⊕ B) ----- i It, being a majority function, can also be written as: AB+BCin+CinA which is equivalent to AB + Cin (A+B) ------- ii So, if we consider eqn i and ii, doesn't it show that (A ⊕ B) = (A+B). What am I missing here?
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can anyone tell me wat is the right equation for carry generator in carry lookahead adder ?? Confused .. $C_{i} = G_{i}+P_{i}C_{i-1}$ $C_{i+1}=G_{}i+P_{}iC_{}i$
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Q.A one bit full adder takes 75 nsec to produce sum and 50 nsec to produce carry.A 4 bit parallel adder is designed using this type of full adder. The maximum rate of additions per second can be provided by 4 bit parallel adder......?
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The condition for overflow in the addition of two 2's complement numbers in terms of the carry propagated by the two most significant bits is ___________.
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Count the 2 Input And, OR and EX-OR gates required in Carry Generator and Look ahead adder. Note :- In the question it is asking about 2 input, not multiple input, for Multiple input AND gates in n bit carry generator we require (n(n+1))/2 and OR Gates n.
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(i) Ci +1= Gi+ PiCi (ii) Ci +1= G(i+1) + P(i+1)Ci https://www.youtube.com/watch?v=9lyqSVKbyz8&index=116&list=PLBlnK6fEyqRjMH3mWf6kwqiTbT798eAOm i or ii ?
Given two three bit numbers $a_{2}a_{1}a_{0}$ and $b_{2}b_{1}b_{0}$ and $c$ ...
In a look-ahead carry generator, the carry generate function $G_i$ and the carry propagate function $P_i$ for inputs $A_i$ and $B_i$ are given by: $P_i = A_i \oplus B_i \text{ and }G_i = A_iB_i$ The expressions for the sum bit $S_i$ and the carry bit $C_{i+1}$ of the look ahead carry ... 4-bit adder with $S_3, S_2, S_1, S_0$ and $C_4$ as its outputs are respectively: $6, 3$ $10, 4$ $6, 4$ $10, 5$