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EEE211-Analog Electronics
Özgür Aktaşemail: [email protected], office/phone: EA-425/ 290-3394office hours: Thursday 10 to 12
Teaching assistantsNiyazi ŞenlikAhmet ErmeydanSinan TaşdelenYakup Kadri YazarelEnder ÖztürkZekeriya Şahin
EEE211-Analog Electronics
Tentative Grading
HW 5%Lab 40%Midterm 1 10%Midterm 2 11%Midterm 3 11%Final 20%Attendance 3%
PoliciesHomework should be submitted on timeCan work together/write individuallyAttendance > %75 !!
SuggestionsStudy on time, read the course-bookRead the references at the end of chaptersTry finish lab report in the labTry finish hw during the tutorial
Refer to the web page frequently for announcements
Midterm/Date1. : Wednesday, 5 October2. : Wednesday, 9 November 3. : Wednesday, 30 November
Schedule for section 1
Classes:Monday 13:40 to 15:30 at BZ05Thursday 15:40 to 17:30 at BZ05
Laboratory hours:Friday 13:40 to 17:30 at EA-121 and EA-111
Please buy your hand-tools before the first-lab hour
Course Objectives
See the online statement of course objectives
● Introduce circuit theory● Form analog electronics background● Advance laboratory skills● Present ideas/methods/tools that will be advanced in future classes
Construction of a transceiver will guide course development
We will closely follow the course book:EEE2111 Analog Electronics Lecture NotesProf. Dr. Hayrettin Köymen
➔ I will use figures from Prof. Köymen's book
Laboratory work has significant weightCourses paced to introduce ideas needed in laboratoryWorking transceiver is the goal
Chapter 1
Introduction to the operation of TRC-10● concepts for analysis of the system● main building blocks used in transceiver TRC-10
P W RP R E
B P F I L T E R
L P F I L T E R
L P F I L T E R B P F I L T E RM i c r o p h o n e
M i c r o p h o n ea m p l i f i e r
A m p l i t u d em o d u l a t o r
T X M i x e r T X P r e a m p l i f i e r
P R E
B P F I L T E R
T X p o w e ra m p l i f i e r
1 6 M H z o s c i l l a t o r V F O
B P F I L T E R
P R E
B P F I L T E R
P R E
L P F I L T E R
P W R
S p e a k e r
A u d i oa m p l i f i e r
E n v e l o p ed e t e c t o r I F F i l t e r R X M i x e r
A n t e n n a
H a r m o n i cf i l t e r
T X / R Xs w i t c h
P W RP R E
B P F I L T E R
L P F I L T E R
L P F I L T E R B P F I L T E RM i c r o p h o n e
M i c r o p h o n ea m p l i f i e r
A m p l i t u d em o d u l a t o r
T X M i x e r T X P r e a m p l i f i e r
P R E
B P F I L T E R
T X p o w e ra m p l i f i e r
1 6 M H z o s c i l l a t o r V F O
B P F I L T E R
P R E
B P F I L T E R
P R E
L P F I L T E R
P W R
S p e a k e r
A u d i oa m p l i f i e r
E n v e l o p ed e t e c t o r I F F i l t e r R X M i x e r
A n t e n n a
H a r m o n i cf i l t e r
T X / R Xs w i t c h
TRC-10
Transceiver : transmitter and receiver combinedUses the 10 meter band for amateur radioFrequency between 28 and 29.7 MHzamplitude modulation super heterodyne transceiveruses the same channel to transmit and receive (simplex)
only integrated circuits and passive discrete elementsover 200 components
c=fλc : speed of lightλ=wavelength (meter)f=frequency (second)c=speed of light (m/s)c=3E8 m/s
Frequency WavelengthName3-30 kHz 100-10km VLF (Very Low Frequencies)30-300 Hz 10-1km LF (Low Frequencies-Long Wave)300-3000 Hz 1-0.1km MF (Medium Frequencies-Medium wave)3-30MHz 100-10m HF (High Frequencies-Short waves)30-300 MHz 10-1m VHF (Very High Frequencies)300-3000 MHz 1-0.3m UHF (Ultra High Frequencies)3-30 GHz 30cm-1cm SHF (Super High Frequencies-Microwaves)30-300 GHz 10-1mm EHF (Extreme High Frequencies-Millimeter waves)
Naming of frequency bands
Decided by International Telecommunication Union (ITU)Each band has different propagation characteristics
Common usagemicrowaves : 1 to 26 GHz milimetre wave: 26 to 300 GHz (~10 to 1 mm)
Frequency allocation around the 10m band
Sinusoidal signals
v t=V1cos tvi t= I1 cos ti
amplitude V1, I1 (Volt, Ampere)
radial frequency ω (radian/second)
ω=2πf, where f is the frequency (1/second = Hertz)
θ is the phase angle
period T=1/f (second)
peak amplitude V1,
peak-to-peak amplitude 2V1
a.c. -> alternating current
Power
+
-v(t)
i(t)p(t)=v(t)∗i(t) (Watt=Joules/sec)
p t = I1 cos ti∗V1cos tv
p t =I1V1
2cosv−i
I1V1
2cos 2 tvi
Pa=lim T∞ 1T∫0
T
p t =I1 V1
2cosv−i
p(t) -> instantenous power, Pa -> average power
Sample speech signal and spectrum
Time (s) Frequency (Hz)
s(t)
(a.
u.)
S(f
)(a.
u.)
Most of the power concentrated to below 3kHz
Oscillators
Sinusoidal waveform : sinusoidal oscillatorSquare waveform : square wave oscillator
2 oscillators in TRC-1016 MHz fixed frequency crystal oscillator (square wave)Variable frequency oscillator (sinusoidal, f between 12 and 13.7 MHz)
Amplifiers
A
Voltage gain A:Power gain G:
A = Vo/ Vi G = Po/ Pi
Gain in decibelsA = 20 log (Vo/ Vi) dBG = 10 log(Po/ Pi) dB
Decibel used to define absolute levels G = 10 log (Vo/ 1W) -> dBWG = 10 log(Po/ 1mW) dBm
dB A G0 1 13 1.41 26 2 47 2.24 59 2.82 810 3.16 1020 10 100
Linearity and Superposition
+
-v(t)
i(t) Same criteria for linearity applies to circuit elements
A system is called linear if the principles of superposition applies:
Resistors, capacitors, inductors, transformers, voltage and current sources are linear elements
Circuits consisting of linear elements are linear
x(t) y(t)
a x1(t)+b x2(t)→ a y1(t)+b y2(t)x1(t)→y1(t)x2(t)→y2(y) ⇒
Representation of periodic signals in term of sinusoids
All signals of practical interest in electronics circuits can be representedas a linear combination of sinusoids.
If the signal is periodic with frequency ω, then only sinusoids at integer multiples of ω are needed.
If the signal is not periodic, then the spectrum is continuous
y t=∑n=0
∞
ansinn t
y t= ∫=0
∞
asin t
We refer to the sinusoids with frequencies 2ω, 3ω, 4ω,… , nω as harmonics of the fundamental component, sinωt.
The coefficients an form the spectrum of the signal y(t).
ampl
itude
(V)
0
0.5
1
1.5
2
T/2 T 3T/2 2T
time
s(t) =1+(4/π)sin(ωt)+(4/3π)sin(3ωt)+(4/5π)sin(5ωt)+(4/7π)sin(7ωt)+…..
1 9 ω1 7 ω
0 . 20
0 . 40 . 60 . 8
11 . 21 . 4
ω 2 ω 3 ω 4 ω 5 ω 6 ω 7 ω 8 ω 9 ω 1 1 ω 1 3 ω 1 5 ω
f r e q u e n c y
b n
a o
The square wave
50% duty cycle implies onlyodd harmonics
ampl
itude
(V)
0
0.5
1
1.5
2
T/2 T 3T/2 2T
time
a
b
c
d
The square wave
a) only ao+ fundamental, (b) waveform in (a) + 3rd harmonic,
(c) waveform in (b) + 5th harmonic, (d) all terms up to 13th harmonic.
Filters
Transfer function H(ω):
For Linear and Time-Invariant filters:
a1coss1 ta1 Hs1coss1 t
H(ω)x(ω) y(ω)
Filters
|H(ω)|
ω3dB= 2πf3dB
ω =2πf
(a) (b)
0.25
0
0.5
0.75
1
100
60
200
20log|H(ω)| ω= 2πf
Transfer function of a low-pass filter. Linear and in decibels
Cut-off frequency : H(ω-3dB)=1/Sqrt(2)
Filters
|X(ω )|
|Y(ω )|
|H(ω )|
Filter
Input Signal
Filtered signal
ω-3dB
(a)
|H(ω)|
ω3dB= 2πf3dB
ω =2πf0.25
0
0.5
0.75
1
(b)
|H(ω)|
ω =2πf0.25
0
0.5
0.75
1
Filters
High-pass filter Band-pass filter
Bandwidth=ω2-ω1
ω2ω1
Modulation
microphone
Baseband Signal
Baseband signal must be shifted to the transmission band
Modulation
ω
|X(ω )|
ω
|X(ω )|
Baseband signal
Signal to be transmitted
Modulation
Modulation
Amplitude modulation (DSB/WC)
Amplitude
(a)
(b)
(c)
time(d)
time
time
time
v t =Vccosc t vm t cos c t
Suppressed carrier amplitude modulation(DSB/SC)
v t =vm t cosc t
Frequency modulation
v t =Vccosc tk f∫vm t dt (a) modulating signal, (b) AM signal, (c) DSB/SC AM signal and (d) FM signal
t=d t
dt=ck f vm t
so that:
vm t
Vccosc t
message
carrier
Amplitude Modulationv t =Vccosc t vm t cosc t
Consider vm t =Vmcosm t
v t =Vccosc tVmcosm t cosc t
v t =Vc1Vm
Vc
cos m t cosc t
∣vm t
Vc∣max
is called “ Depth of Modulation”
Depth of modulation needs to be smaller than 1 for decoding by envelope detectors
Vc1vm t
Vc is called the envelope of the modulated signal
AM signal
Amplitude Modulation
Depth of modulation 0.5 Depth of modulation 1
Thin curve is the AM signalThick curve shows the envelope
modulating signal
v t =Vccosc t Vm
2cos cm t
Vm
2cos c−m t
v t =Vccosc t vm t cosc t
Consider vm t =Vmcosm t
v t =Vccosc t Vmcosm t cosc t
AM signal
Amplitude Modulation
vm t
Vccosc t
message
carrier
The spectrum is transferred to cm
∣c−m ∣
!! 2 new frequencies
ω
|X(ω )| ω
|X(ω )|
ω
|X(ω )|
Modulating signal(message)
Carrier
Modulated signal
ωc
ωc
AM DSB/WC
ωm
ω
|X(ω )| ω
|X(ω )|
ω
|X(ω )|
Modulating signal(message)
Carrier
Modulated signal
ωc
ωc
AM DSB/WC
Mixers
1+m*(t)
square waveform at ωif=16 MHz
[1+m*(t)]cos(ωct) = m2(t)
multiplies 2 input signalsused for modulation
m*2(t)
cos(ωvfot)
[m*2(t)]cos(ωvfot) 2nd mixer
1nd mixer
ω
|X(ω )| ω
|X(ω )|
ω
|X(ω )|
Modulating signal(message)
Carrier
Modulated signalfiltered to remove copies at harmonics
3ωifωif 5ωif
ωif
1st mixer
ω
|X(ω )|
|X(ω )|
ω
|X(ω )|
Modulating signal
Carrier
Modulated signalfiltered to remove copies at harmonics
ωvfo
ωif
2nd mixer
ωif+ωvfoωif−ωvfo
Receivers
The signal that the antenna receives must be demolulated
ω
|X(ω )| ω
|X(ω )|
ω
|X(ω )|
Received signal
Carrier
Audible signal
ωc
ωc
Direct Reception
ω
|X(ω )| ω
|X(ω )|
ω
|X(ω )|
Carrier
ωc
ωc
Direct Reception
Audible signal
Received signal
ω
|X(ω )| ω
|X(ω )|
ω
|X(ω )|
Carrier
ωc2
ωc2
Direct Reception
Audible signal
Received signal
●Received signal is mixed down to audio frequency directly●RF filter needs to be tunable●Other practical difficulties like reproducing the carrier signal with no●frequency shift.●Heterodyne reception is easier to implement.
Principle of direct-conversion reception
Principle of Superheterodyne receivers
For TRC-10: fif=16 MHzexampleChannel at 28.5 MHz: fvfo+fif=28.5 -> fvfo=28.5-16=12.5 MHzChannel at 28.7 MHz: fvfo+fif=28.7 -> fvfo=28.5-16=12.7 MHz Channel at 29.5 MHz: fvfo+fif=29.5 -> fvfo=28.5-16=13.5 MHz
fvfo
fif
P W RP R E
B P F I L T E R
L P F I L T E R
L P F I L T E R B P F I L T E RM i c r o p h o n e
M i c r o p h o n ea m p l i f i e r
A m p l i t u d em o d u l a t o r
T X M i x e r T X P r e a m p l i f i e r
P R E
B P F I L T E R
T X p o w e ra m p l i f i e r
1 6 M H z o s c i l l a t o r V F O
B P F I L T E R
P R E
B P F I L T E R
P R E
L P F I L T E R
P W R
S p e a k e r
A u d i oa m p l i f i e r
E n v e l o p ed e t e c t o r I F F i l t e r R X M i x e r
A n t e n n a
H a r m o n i cf i l t e r
T X / R Xs w i t c h
TRC-10
END CHAPTER 1
