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Speech Processing. Complex Algebra Review. Complex Algebra Elements. Definitions: Note: Real numbers can be thought of as complex numbers with imaginary part equal to zero. Complex Algebra Elements. Euler’s Identity. Polar Form of Complex Numbers.
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Speech Processing Complex Algebra Review
Complex Algebra Elements • Definitions: • Note: Real numbers can be thought of as complex numbers with imaginary part equal to zero. Veton Këpuska
Complex Algebra Elements Veton Këpuska
Euler’s Identity Veton Këpuska
Polar Form of Complex Numbers • Magnitude of a complex number z is a generalization of the absolute value function/operator for real numbers. It is buy definition always non-negative. Veton Këpuska
Polar Form of Complex Numbers • Conversion between polar and rectangular (Cartesian) forms. • For z=0+j0; called “complex zero” one can not define arg(0+j0). Why? Veton Këpuska
Geometric Representation of Complex Numbers. Axis of Imaginaries Im Q2 Q1 z Axis of Reals |z| Im{z} Re{z} Re Q3 Q4 Complex or Gaussian plane Veton Këpuska
Geometric Representation of Complex Numbers. Axis of Imaginaries Im Q2 Q1 z Axis of Reals |z| Im{z} Re{z} Re Q3 Q4 Complex or Gaussian plane Veton Këpuska
Im z1 1 z2 -2 -1 Re z3 -1 Example Veton Këpuska
Conjugation of Complex Numbers • Definition: If z = x+jy∈ C then z* = x-jy is called the “Complex Conjugate” number of z. • Example: If z=ej (polar form) then what is z* also in polar form? If z=rej then z*=re-j Veton Këpuska
Geometric Representation of Conjugate Numbers • If z=rej then z*=re-j Im z y r x Re - r -y z* Complex or Gaussian plane Veton Këpuska
Complex Number Operations • Extension of Operations for Real Numbers • When adding/subtracting complex numbers it is most convenient to use Cartesian form. • When multiplying/dividing complex numbers it is most convenient to use Polar form. Veton Këpuska
Addition/Subtraction of Complex Numbers Veton Këpuska
Multiplication/Division of Complex Numbers Veton Këpuska
Useful Identities • z ∈ C, ∈ R & n ∈ Z (integer set) Veton Këpuska
Useful Identities • Example: z = +j0 • =2 then arg(2)=0 • =-2 then arg(-2)= Im j z -2 -1 0 1 2 Re Veton Këpuska
Silly Examples and Tricks Im j /2 -1 0 3/2 1 Re -j Veton Këpuska
Division Example • Division of two complex numbers in rectangular form. Veton Këpuska