Analog Electronics

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Analog Electronics

• http//www.miun.se/personal/kent.bertilsson/Course
  s/AnalogElectronics.htm
• Thomas L. Floyd,  "Electronic Devices -
  Conventional Current Version" ISBN
  0-13-615581-2
• Don Manchini, "Op Amps for Everyone" -Free
  downloadable pdf

• Lecturer
• Kent Bertilsson
• Kent.Bertilsson_at_miun.se
• S-Building Office S206
• Phone [phone]

Lab teacher Krister Hammarling Krister.Hammarling_at_
miun.se S-Building Office S207
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Examination

• This analog electronics is given as a stand alone
  course but also as one part of the Measurement
  System course.
• 12 x 2h scheduled lectures
• 10 Lectures
• 2 times for solving problems
• As appeared in the plan (Not as shown in
  schedule)
• 4 x 4h scheduled laboratory classes completing 3
  tasks that should completed and handed in to the
  laboratory teacher.
• A written exam will be held 27th October

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• Introduction

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Block Diagram

• Electronic systems is often described by block
  diagram
• Antenna Amplifier Filter
  Analog to
• 
  digital conversion

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Time domain vs Frequency domain

• Every signal can be described both in the time
  domain and the frequency domain.
• A periodic signal (in the time domain) can in the
  frequency domain be represented by
• A peak at the fundamental frequency for the
  signal, fs1/T
• and multiples of the fundamental f1,f2,f3,1xfs
  ,2xfs ,2xfs

V
T1/fs t
V fs 2 fs 3
fs 4 fs 5 fs f
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Time domain vs Frequency domain

• Every signal can be described both in the time
  domain and the frequency domain.
• A non periodic (varying) signal time domain is
  spread in the frequency domain.
• A completely random signal (white noise) have a
  uniform frequency spectra

V fs 2 fs 3
fs 4 fs 5 fs f
V
Noise

f
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Transfer function

• The transfer function is the relation between the
  amplitude for the output and input in the
  frequency domain.
• H(20kHz)10 mean that for a 20kHz signal the
  output is ten times larger than the input.
• H(f) is of course continuous function

H 10 5 0

f
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Filter

• A filter is a circuit that let some frequencies
  pass and block others.
• Low pass
• High pass
• Band pass
• Band stop

H
f
H
f
H
f
H
f
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j?-method

• The j?-method is a very powerful tool making it
  possible performing advanced frequency dependent
  (alternating current, AC) functions using the
  same rules that applies for direct current (DC)
• Resistor
  Capacitor Inductor
• Symbol
• Reactance

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j?-method

• Impedance calculations can be performed in the
  same way as for normal resistances.

R L R L
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RC - filter
Calculate the transfer function H(?) What is the
output voltage and power level at the cut-off
frequency?
R VIn C
VOut
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Amplifier

• Voltage amplification
• Current amplification
• Power amplification

IIN IOut PIN VIn
VOut POut
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Decibel, dB

• decibel, dB is very useful expressing
  amplification (and attenuation)

(Under assumption that RInAmpRLoad)
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dB AV AP
20 10 100
10 3.16 10
6 2 4
3 2
0 1 1
-3 0.5
-20 0.1 0.01
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Bode Diagram

• Absolute decibel value and phase of the transfer
  function is plotted against a logarithmic
  frequency axis

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RC-filter example

• Draw an asymptotic bode diagram for the RC filter.

R VIn C
VOut
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Bode diagram

• Complicated expressions can be factorized into
  sub-expressions as
• Const
• Differentiator Integrator
• Zero Pole

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Bode diagram

• According to logarithmic laws

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Example
R R2
C VIn R3 VOut

• Draw an asymptotic bode diagram for the shown
  filter.

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Amplifier model

• The amplifier model is often sufficient
  describing how an amplifier interacts with the
  environment

ROut
VIn RIn AVVIn
VOut

• RIn Input impedance
• AV Voltage gain
• ROut Output impedance

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Bandwidth

• The bandwidth is the frequency range where the
  transferred power are more than 50.

H(f) AVmax 0.707AVmax
f1
f2 f
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Distortion

• A nonlinear function between UIn and UOut
  distorts the signal
• An amplifier that saturates at high voltages
• A diode that conducts only in the forward
  direction

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Noise

• Random fluctuation in the signal
• Theoretically random noise contains all possible
  frequencies from DC to infinity
• Practical noise is often frequency limited to an
  upper bandwidth by some filter
• A limited bandwidth from the noisy reduce the
  noise power