3. 3
Subtractor Circuit
In digital electronics, a subtractor is a combinational circuit
that performs subtraction of binary numbers.
What does a Subtractor do?
It takes two binary inputs and subtracts one from the other,
producing:
A difference (the result)
A borrow (if needed, like a carry in addition)
Types of Subtractors:
1. Half Subtractor &
2. Full Subtractor.
4. 4
Half Subtractor
A half subtractor is a digital logic circuit that performs the
binary subtraction of two single-bit binary numbers. It has two
inputs, A and B, and two outputs, Difference and Borrow.
The Difference output represents the result of
subtracting B from A, while the Borrow output indicates whether
a borrow is needed when A is smaller than B.
The output equation:
Difference = A'B+AB'
Borrow = A'B
6. 6
Full Subtractor
A Full Sub-tractor is a combinational circuit used to perform
binary subtraction. It has three inputs:
A (Minuend)
B (Subtrahend)
B-IN (Borrow-in from the previous stage)
It produces two outputs
Difference (D): The result of the subtraction.
D = (A B) Bin
⊕ ⊕
Borrow-out (B-OUT): Indicates if a borrow is needed for the
next stage.
Bout = Bin (A ⊕ B)' + A'B
8. 8
Binary Multiplier
A binary multiplier is a combinational logic circuit that performs
the multiplication of two binary numbers (0 and 1).
The two binary numbers or the two binary inputs used in the
binary multiplication are multiplicand and multiplier to get the
binary product as a result.
9. 9
Key Components
AND gates
Used to generate the partial products by performing bitwise AND
operations between the multiplicand and the multiplier bits.
Binary adders (full and half adders)
Used to sum up the partial products to obtain the final product.
Registers
Often used to store the input numbers and the intermediate results
during the multiplication process.
10. 10
Binary Multiplier Types
The following are the binary multiplier types:
1. 2-bit multiplier or 2×2 Binary multiplier
– 2-bit multiplier using 2-bit full adder.
– 2-bit multiplier using individual single-bit adders.
2. 3-bit multiplier or 3×3 binary multiplier
– 3-bit multiplier using 3-bit full adders.
– 3-bit multiplier using single-bit adders.
3. 4-bit multiplier or 4×4 binary multiplier
– 4-bit multiplier using 4-bit full adders.
11. 11
2-bit multiplier (2×2 Binary multiplier)
A 2-bit multiplier is a digital circuit that multiplies two 2-bit
binary numbers and produces a binary product.
It takes two inputs:
A = A1 A0(2 bits)
B = B1 B0 (2 bits)
The product will be 4 bits long:
P = P3 P2 P1 P0 (4 bits)
12. 12
3-bit Multiplier
A 3-bit multiplier is a digital circuit that multiplies two 3-bit
binary numbers and produces a 6-bit binary product.
It takes two inputs:
A = A2 A1 A0(3 bits)
B = B2 B1 B0 (3 bits)
The product will be 6 bits long:
P = P5 P4 P3 P2 P1 P0 (6 bits)
13. 13
4-bit Multiplier
A 4-bit multiplier is a digital circuit that multiplies two 4-bit
binary numbers and produces a 8-bit binary product.
It takes two inputs:
A = A3 A2 A1 A0(4 bits)
B = B3 B2 B1 B0 (4 bits)
The product will be 8 bits long:
P = P7 P6 P5 P4 P3 P2 P1 P0 (8 bits)
14. 14
Binary Multiplier Applications
Digital Signal Processing:
Used in audio and video processing, filtering, and
modulation/demodulation.
Computer Arithmetic:
A fundamental component in CPUs and other processors for
performing arithmetic operations.
Communication Systems:
Used in modulation, demodulation, mixing, and phase
discrimination.