Questions tagged [adder]
Digital circuits that adds values
284 questions
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does this design look suitable for a 4-bit adder
I am working on a project that will include a basic 4-bit adder, I have designed a layout is Adobe Illustrator and would like people to check over it to see if it looks like it should work. I am very ...
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Building a small 4-bit adder on a breadboard
I am very new to using IC and basically a breadboard in general, but I am doing a project on how computers add and thought it would be nice to have a practical demonstration.
My main question is, for ...
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Working of Prefix Adder
I am trying to understand the working of Brent Kung adder, but I have not been able to.
All that I see in tutorials is just the figure above for carry generation. Can anybody explain it to me with an ...
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Add fixed voltage to variable voltage
I want to add two voltages.
I have tried using the Op-Amp adder here. The resistor schematic before the summing amplifier contains resistors in parallel which would average the voltage.
My problem ...
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How to compare carry-lookahead and ripple-carry adders?
I am a bit stuck with the concept of carry-lookahead adder so I'd like to compare it with another concept I'm more familiar with: the ripple-carry adder. I'm trying to make some basic math comparison ...
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Is there a better way to plan a circuit to square a 3 bits binary number?
I need to plan a circuit that will square a 3 bit binary number:
$$\{Y_2, Y_1, Y_0\} \rightarrow \{S_5,S_4,S_3,S_2,S_1,S_0\} $$
I thought of the common way we multiply numbers and used it to plan the ...
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Complexity comparison of an adder and a multiplier
I have two algorithms with different requirements of addition and multiplication operations as follows:
Algorithm 1: 100 additions 200 multiplications, total = 300 operations.
Algorithm 2: 300 ...
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Design of an adder circuit
I have a adder circuit consisting of carry look ahead adders. However, I am not allowed to use the generate function to determine the sum of the two numbers. I am allowed to use basic logic operations(...
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How to calculate Gate Delays in normal Adders and Carry Look Ahead Adders
In my textbook the gate delays for the n-bit ripple adder is given as \$ 2n \$ for \$c_n\$ bits and \$ 2n-1 \$ for \$ s_n-1 \$ for the circuit as shown below:
But, for a 4-bit Carry Look Ahead Adder ...
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Ultra low power adders and multiplier
I am working on a low frequency 30 khz module that needs to have an ultra low power consumption. The problem is the research focuses on improving the performance of the adders and multiplier and doesn'...
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What happens to a 32-bit input when a gate will only output 1 bit?
For example, suppose I have a combinational circuit that takes 32 bits as input and outputs 1 bit that is equal to 1 if the 32-bits are equal to 0, and outputs 0 if the 32 bits are anything else. How ...
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What are carry-lookahead adders and ripple-carry adders?
I see carry-lookahead adders and ripple-carry adders terms being used often. I have no idea what either means (nor the type of architecture they describe).
Can someone please explain what each one is,...
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What is the minimum amount of 1bit Full Adders required to implement the equation 4X + 3Y + 13?
Using 1bit FAs and 0/1 constants only, while X(x1,x2,x3) and ...
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Why is carry on for an adder that is simply on? [closed]
I've understood that the behaviour is correct when I make a simple adder:
But why does carry on light up just because I switch on the + operation for my 4-bit system?
http://www.ict.kth.se/courses/...
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How to multiply using gates?
I need to multiply 2 3bit numbers. I tried that:
but it does not seem to work.
In this example, the output should be 49. so that is that 77?
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Designing a simple ALU
I need to design an ALU with two 8-bit inputs A and B and control inputs x, y, and z that supports the following operations:
...
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What is wrong with my 2-bit adder?
I attempted to build an 8-bit adder in Logisim by carefully chaining together a half-adder and 7 full adders, all made from basic logic gates. Unfortunately, it produced erroneous results; for example,...
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Test Cases for 16-bit Ripple Carry Adder
I'm working on a lab for a course I have on VHDL, and part of it is to implement an n-bit ripple carry adder and then test it as a 16 bit adder. My problem is that I don't really know HOW to test it, ...
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Carry Look ahead adder Propagate & Generate Outputs
I am taking comp architecture course, and we are given a task to write 32 bit look-ahead adder in VHDL. Instructor provided the instruction and diagram.
While reading, Wikipedia article, I stumbled on ...
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Determining the truth table and simplifying logic expressions (full adder)
I've been taking an intro computer architecture class and doing some research of my own, I've found the following exercise:
Determine the truth table and simplify the logic expression derived from the ...
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Carry-lookahead adder - what happens to carry bit?
I recreated and trying to understand for the sake of fun and learning the circuit that can be seen here on second page: Link . This is basically a 4-bit carry-lookahead adder, but there is one thing ...
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How to design system for n bits?
Say I want to design an n-bit system e.g. 256 bits. Can I generalize a 4-bit ALU which I think I know to 256 bits? These are my diagrams.
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8 bit octal full adder help
I have this project listen below and im not sure where to start maybe someone can give me a few pointers or perhaps point me in the right direction of starting this?
Thanks!!
Input: A, B = octal ...
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Verilog code task inputs do not match the passed values
I am using a task in my module in Verilog, and I have a problem in passing the argument values. The variables defined in the ...
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How does one use both half and full adders together?
I am trying to teach myself the concept of (half and full) adders from Wikipedia and am a bit confused.
Do I need to use both half adders and full adders together for performing multi-bit addition? ...
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How do I fit a 2 bit subtractor into its expression?
Regular Full subtractor has the following:
x,y as the inputs
Bin - as the borrow in
Bout - as the borrow out. Bout expression: x'y + x'Bin + yBin
D - difference ...
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Is this possible? produce 7 bit sum with one full adder?
i have no idea how to do this all I know is adding 2 bits with one half adder and use bunch of full adder to get a n bit sum...
the original question is below
Design a circuit that adds together 4X ...
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Why does design_vision compile my carry-lookahead adder into a ripple-carry adder?
At my school we have Synopsis "design_vision" in the computer labs. I don't know how to use any of the features so to me it's just a schematic-drawing tool.
Out of curiosity, I hand-coded in Verilog ...
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Truth Table Accuracy
I made a truth table for this sequential circuit, and I wanted to make sure that it is correct. Is this right? The top left is a full adder, and the top right is a D flip-flop.
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Critical path for Carry-Skip adder
Can anybody explain why Carry-Skip adder has the same critical path as regular Carry-Ripple adder. My textbook says that critical path occurs when carry is generated in LSB and then propagating it ...
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How to determine if a Carry Look Ahead Adder Overflows
I am implementing a 32 bit CLA Adder like how a 16 bit adder is implemented in Wikipedia
Problem is how do I determine if the block overflows? I will need the carry into bit 32 (which is now in the ...
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Carry look ahead adder/subtractor & Overflow, Negative Bits
I am suppose to design a carry look ahead adder with ...
Input flag bits
E (Enable)
S (Subtraction)
Output
The usual sum & carry out
O (Overflow)
N (Negative)
Z (Zero)
But the question is ...
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How to determine overflow from an adder/subtractor?
I suppose in binary addition (no negative numbers), overflow happens when theres a carry out?
Then for subtractor (2s complement), how do I determine it? From my understanding of my lecture notes, ...
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How does this carry look ahead block work?
This is a carry look ahead adder :
This adder is known to calculate one or more carry bits before the sum. From the figure we see that carry look ahead block calculates the carry C1,C2,C3,C4 . But i ...
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