EEE211-Analog Electronics - Bilkent Universitykilyos.ee.bilkent.edu.tr/~eee211/notes/c1v3.pdf ·...

EEE211-Analog Electronics

Özgür Aktaşemail: aktas@ee.bilkent.edu.tr, 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