Network Functions Definition, examples , and general property Poles, zeros, and frequency response Poles, zeros, and impulse response Physical interpretation of poles and zeros Application to oscillator design Symmetry properties
Definition, Examples , and General Property or where and
Resistor Inductor Capacitor Sinusoidal steady state driving point impedance = special case of a network function
Example 1 Parallel RC circuit
Example 2 Low pass filter
Mesh analysis gives Solve for I2
General Property For any lumped linear time-invariant circuit
Poles, Zeros, and Frequency Response phase magnitude Gain (nepers) Gain (dB)
Example 3 RC Circuit Frequency Response No finite zero Pole at s = -1/RC
At At
Example 4 RLC Circuit Frequency Response Zero at s = 0 Complex conjugate poles at
At For and
At For General Case
Example 3 zeros 4 poles
Poles, Zeros, and Impulse Response Example 5 RC Circuit See section 6 Chapter 4 for derivation of h(t)
Example 6 RLC Circuit Fig 3.2 For Fig 3.3 For See section 2 Chapter 5 for derivation of h(t)
Physical Interpretation of Poles and Zeros
Poles Any pole of a network function is a natural frequency of the corresponding (output) network variable. Using partial-fraction expansion Residue at pi
If a particular input waveform is chosen over the interval [0,T] For input current = For i = 1 Natural frequency p1 If a particular input waveform is chosen over the interval [0,T] then for t > T
Summary Any pole of a network function is a natural frequency of the corresponding (output) network variable, but any natural frequency of a network variable need not be a pole of a given network function which has this network variable as output.