Transcript Digital Signal Processing in Communication Systems

A Short History of Radio
and Signal Processing in
Modern Radios
fred harris
29-May 2007
Pulse Train
What The Customer Wants
What the Customer Will Pay
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When the Customer wants it.
O RE MO RE
MO RE MO RE MO RE M
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NE
XT
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TO
EK
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The Size Customer Wants.
Early Communication at a Distance†
(†Communicating Faster Than A Person Can Run)
776 BC
200100 BC
37 AD
Homing pigeons used to send message –
the winner of the Olympic Games to the Athenians.
Relay stations use fire messages to relay messagesstation to station.
Heliographs - mirrors send messages to
Roman Emperor Tiberius.
1793 AD Claude Chappe invents the first long-distance optical
semaphore telegraph line.
Very Early Communications at a Distance:
Free Space Acoustic and Optical Channels
Drums, Whistles,
Cannon Fire
Claude Chappe 1793
Optical Telegraph
Smoke Signals,
Beacon Fires
Semaphore, Ship Flags, Heliograph, Signal (Aldis) Lamp
Signal Fires: Early Warning
of Approaching Enemy
Carrier Pigeons in WW-1
CDMA-2000, WLAN, CR
GSM,CDMA, SDR
digital signal processing, DR
Shannon, television
transistor
audio broadcast
Marconi's experiments
Hertz's experiments
Maxwell equations
Mrs. Harris’s First Born
1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030
A Time Line
Telecommunications!
Applying Maxwell Equations
to communication Systems
Maxwell's equations (1873)
.
rot H  J  D
.
rot E  B
div D  
div B  0
H
E
D
B
J

magnetic field
electric field
electric displacement
magnetic flux density
current density
volume charge density
James Clerk Maxwell,
1831 – 1879
Milestones in
Electromagnetic Communications
H.C. Orsted, 1777-1841 “Electrici and Magneticam” 1820
Fraday, 1791-1867, Induction 1831
J.C. Maxwell, 1831-1879, “Treatise on Electricity and Magnetism”, 1873
H.L. Helmholtz, 1821-1894 Predicted E-M Waves
Heinrich Hertz, 1857-1894 Radio Propagation 1887
G. Marconi, Radio 1895
Valdemar Poulsen, Continuous Radio Waves 1905
Lee de Forest, Audion 1907
Edward Armstrong, Super-regenerative, Superheterodyne 1917
Frequency Modulation, 1934
Disruptive Technology
The electric telegraph arrived in the early 19th
century and redefined communications at a
distance.
It required the confluence of three ingredients:
the science of electromagnetism,
the ability to generate or store electricity
the Industrial Revolution to build the
required infrastructure
Communication at a Distance with
Electricity and Magnetism
1831 Joseph Henry invents the first electric telegraph.
1843 Samuel Morse invents the first
long distance electric
telegraph line.
1858 Cyrus Field’s Company Lays the
Transatlantic Cable.
1876 Alexander Graham Bell patents
the electric telephone.
Brunel’s Great Eastern
1889 Almon Strowger patents the direct dial telephone automatic
telephone exchange.
We Need Some Source Coding Here
Samuel Thomas von Sömmering’s (1808-10)
"Space Multiplexed" Electrochemical Telegraph
A B C D
7 8 9
A B C D
36 Lines
7 8 9
Cooke and Wheatstone Telegraph
B
A
B
F
E
1
D
G
H
I
K
L
M
N
O
P
R
2
S
V
3
4
8
7
Y
5
9
T
W
0
6
2 out of 5 Coding
(5*4 = 20 )
The Cooke and Wheatstone first commercial electrical telegraph
entered use on the Great Western Railway on April 9, 1839.
It ran for 13 miles from Paddington Station to West Drayton
On January 1, 1845 John Tawell was apprehended following the
use of a needle telegraph message from Slough to Paddington.
This is thought to be the first use of the telegraph to apprehend a
murderer.
The message was:
A murder has just been committed at Salt Hill and the suspected
Murderer was seen to take a first class ticket to London by the
train that left Slough at 7:42 pm. He is in the garb of a Kwaker
with a brown great coat on which reaches his feet. He is in the
last compartment of the second first-class carriage
Single Needle and
Variable Length Code
Cooke-Wheatstone
Single Needle Telegraph (c 1850)
THE TELEPHONE
1876 - Alexander Graham Bell invents
the Telephone. He offers the patent to
Western Union for $100,000.
The President of the Telegraph Company, appointed a committee to
investigate the offer. The often quoted report reads in part:
The Telephone purports to transmit the speaking voice over telegraph
wires. We found that the voice is very weak and indistinct, and grows even
weaker when long wires are used between the transmitter and receiver.
Technically, we do not see that this device will be ever capable of sending
recognizable speech over a distance of several miles.
Bell wants to install a “telephone device" in every city.
The idea is idiotic on the face of it.
“We do not recommend its purchase."
Early Telephone Instruments
Ericsson "Eiffel Tower"
Telephone, 1885
11 digit Potbelly
Dial Candlestick
Strowger 1905
Dial Candlestick
Automatic Electric
1921
Footnote: Western Electric
1877,
5 Phones
Engineers were
1894, 250,000 Phones
wrong! Very Wrong! 1906, 7,500,000 Phones
Communication at a Distance by
Electromagnetic Radiation (Radio or Wireless)
1894 Guglielmo Marconi
improves wireless telegraphy.
1902 Guglielmo Marconi
transmits radio signals across
the Atlantic Ocean.
1914 First cross continental
telephone call made.
1916 First radios with tuners
different stations.
1930 First television broadcasts
in the United States.
The Players
•
•
•
•
•
•
•
Wireless
Radio
Analog Radio
Digital Radio
DSP Radio
Software Defined Radio
Cognitive Radio
It all Started with…..
Heinrich Rudolph Hertz,1847-1894
Shocking!
3. Electromagnetic 2. Spark Produces Electromagnetic Waves
waves induce voltage in
resonator, producing
small spark in spark gap.
1. Induction Coil Produces High Voltage
Guglielmo Marconi, 1874-1937
December 12 1901
Spark Gap Transmitter
Early Radios Were Mechanical
(Many Moving Parts)
SPARK TRANSMITTERS
Spark Gap Wireless Transmitter
(Damped Oscillations)
Sparks came in all sizes
Marine Spark Transmitter
Radio Operators
aboard Ship Were Called
Sparky
Because they
Operated the
Spark Transmitter
Marconi Tower Radio
Mobile Communications: Communicate to a moving Train
150 ft Antenna stretched across 3-railway cars
(187.4 kilocycles, 1600 Meters)
2 KW 500 cycle quenching transmitter
The Eiffel Tower
The Eiffel Tower was built for an industrial exposition (1889) and the
centenary of the French Revolution.
It created amazement and outrage. The previous world champion, America's
Washington Monument was half the tower's height. The tower held the world’s
title for the world’s tallest structure till 1930, when it was surpassed by the
Chrysler Building.
Eiffel tried to find practical applications for his tower. He wanted the tower to
work, to pay its way. He could find no practical application for the tower!
Parisians spoke seriously of tearing the tower down.
Then Eiffel discovered the 20th century's killer app for towers, Marconi's radio!
The tower started broadcasting signals in 1904 and by 1908, the French military
had installed a radio espionage nest, where they could eavesdrop on German and
Austro-Hungarian stations.
Due to Marconi’s invention, the tower's future was secure.
Valdemar Poulsen, 1869-1942
Continuous (Undamped) Carrier
Arc Generator
Poulsen Arc Transmitter
Lee De Forest, 1877-1961
Put those sparks to rest!
Patent No. 879532
The path to the Triode Thermonic Valve,
Thomas Edison, John Fleming, Lee de Forest
Edwin Armstrong, 1890-1954
1912 regenerative receiver
Regenerative Receiver
A little Feedback Goes a Long Way
Tuned RF Radio
Early Mobile Communications
It may not be safe to
drive while using your
mobile phone!
Edwin Armstrong’s Super
Heterodyne Receiver
ANT
RF
AMP
IF
AMP
IF
AMP DET
AMP
From Disclosure: June 3, 1918
Replacing the Vacuum Tube
1947
Solid State Amplifier
Shockley, Brattain and Bardeen
Integrated Circuits
1958
Jack Kilby,
TI
Kilby Awarded
Nobel Prize in 2000
Robert Noyce,
Intel
Noyce Founded Intel
Ted Hoff worked for Noyce
s
or
ist ip
s
n h
Tra r c
pe
More, More, Moore
Critic s have predicted the imm inent
10,000,000,000
demise of Moore’s law ever since
Gordon Moore stated it in 1965.
s
1,000,000,000
th
Electric al Engineers continue to
on
m
4
defy physical c hallenges,
2
Ita nium2
y
er
592 Million
v
squeezing ever more
100,000,000
se
Ita nium 2
le
b
220 Million
u
circuitry into less spac e
d o Pentium 4
p
i
42 Million
Xeon 42 Million
and making inform ation
ch
a
10,000,000
Ita
nium 25 Million
n Pentium II
fly ever more
so
r
7.5
Million
Celeron 7.5 Million
o
ist
swiftly.
Pentium Pro 5.5 Millio n
ns
1,000,000
100,000
1958
Jac k Kilby (TI) &
Robert Noyc e
(intel) Invent
Integrated
Circuit
1965
Gordon Moore
States his fam ous
axiom , later c alled
Moore’s law
1,000
o
M
8080 4,500
8008 3,500
4004
First
 proc essor
2,000
1960
de
n
tra
Pentium 3.1 Million
486 1.2 Million
386 275,000
286 134,000
8088 29,000
10,000
1947
Transistor
Invented
1947 1950
e
Th
:
aw
sL
’
e
or
sit
f
yo
1970
1977
Apple II
1980
1999
1996 Blac kberry
DVD
Players
1991
Kodak
First
Digital Cam era
1983
Motorola
First
Mobile Phone
1990
2000
2010
We all own a Billion Transistors
NEXT-GENERATION VIRTEX FAMILY FROM XILINX
TO TOP ONE BILLION TRANSISTOR MARK
The 1 billion transistor processor: who will be first?
Semiconductor International, March 2003
Future Microprocessors - How to use a Billion Transistors
September 1997 issue of IEEE Computer
Eiffel Tower Contains 18,084 Parts
It is Fastened together by 2.5 Million Rivets
The World grows more transistors
than it grows grains of rice!
Harry Nyquist,(1889-1960)
The Sampling Theorem
fS>BW
Analog-to-Digital Converter
Digital-to-Analog Converter
Start of the Modern era
ADC and DSP Insertion
Sample The
Intermediate Frequency Stage
Perform Timing and Carrier
Synchronization in DSP Land
The Modern Era
Digital Radio (DR): The baseband signal processing is invariably implemented on a DSP.
radio analog-to-digital
baseband
data
frequency conversion
processing processing
A/D
RF
c
o
n
t
r
o
l
(
p
a
r
a
m
e
t
r
i
z
a
t
i
o
n
)
to user
radio frontend
from user
transmit
receive
Software Radio (SR): An ideal SR directly samples the antenna output.
Software Defined Radio (SDR): An SDR is a realizable version of an SR:
Signals are sampled after a suitable band selection filter.
Joe Mitola, 2000
Everything is in Place
A Simple
Communication System
INFORMATION
SOURCE
MODULATOR
CHANNEL
DEMODULATOR
BANDLIMITED
AWGN
Spec tral
Distribution
Amplitude
Distribution
x
f
INFORMATION
DESTINATION
All Channels are Waveform Channels
Repeaters are not!
N1(t)
AMP
ATTN
s(t)
NK(t)
N2(t)
ATTN
AMP
ATTN
s(t)+ N1
AMP
s(t)+ N1+ N2
s(t)+ N1+ N2+ ...+ NK
ANALOG REPEATER CHANNEL
N1(t)
ATTN
s(t)
NK(t)
N2(t)
ATTN
ATTN
^s1(t)
^s2(t)
DIGITAL REPEATER CHANNEL
^sK(t)
Why Digital Communications?
But Let Your Communications Be
Yea, Yea: Nay, Nay:
For What So Ever is
More Than These Cometh of Evil.
Sermon on the Mount,
Matthew, Ch. 5, verse. 37
Probability of Error
Conditional
Density Functions
d

Probability of Error, AWGN
10
-1
10
P(e)
-2
10
-3
10
-5
Slope at 10
1 Dec ade/dB
1 ERFC( Eb )
2
N0
-4
10
10
-0
SNR= 9.6 dB
-5
10
10
-5
P(e)= 10
-6
9.6
-7
SNR(dB)
-6 -5 -4 -3 -2 -1 0 1
10 log10(
0.8
1.0
2
3 4 5
6 7 8 9 10 11 12 13 14
Eb
2
)= 10 log 10( 1 [ d/2 ] )
N0
2 
1.5
2.0
d/2 =

3 .0
Eb
N0 /2
4.0
4.27
5.0
d/2

6.0
Bottom Line
100 Repeaters, P100 ( )  10
Given :
P100 ( )  10 5 :
5
Analog
SNR
Then : 10Log10 (
)  10dB
100
10Log10 (SNR )  10dB  10Log10 (100)  30dB
Given :
P100 ( )  10 5 : Digital
Then : 100P1 ( )  10 5
P1 ( )  10 7  SNR  12dB
Modulator and Demodulator
MODULATOR
BASEBAND
WAVEFORM
M-ARY
ALPHABET
BITS
DATA
TRANSFORMS
DIGITAL
BITS
MODULATOR
RF
ANALOG
SPECTRAL
TRANSFORMS
RF
CHANNEL
ANALOG
RADIO
FREQUENCY
WAVEFORM
SPECTRAL
TRANSFORMS
WAVEFORM
TRANSFORMS
RADIO
FREQUENCY
WAVEFORM
DIGITAL
WAVEFORM
TRANSFORMS
BASEBAND
WAVEFORM
DEMODULATOR
DATA
TRANSFORMS
M-ARY
ALPHABET
DEMODULATOR
BITS
BITS
Claude Shannon
Information is measurable.
Distortion is Controllable.
Noise Does not Limit Fidelity.
'The world has only 10
kinds of people.
Those who get binary,
and those who don't.'
Shannon’s Digital Model
DIGITAL
MODULATOR
BITS
DATA
TRANSFORMS
M-ARY
ALPHABET
DISCRETE CHANNEL
WAVEFORM
TRANSFORMS
SPECTRAL
TRANSFORMS
BASEBAND
WAVEFORM
RF
CHANNEL
M-ARY
ALPHABET
BITS
DATA
TRANSFORMS
DIGITAL
DEMODULATOR
BASEBAND
WAVEFORM
WAVEFORM
TRANSFORMS
SPECTRAL
TRANSFORMS
RF
Shannon’s Model
BITS
BANDWIDTH
REDUCING
BANDWIDTH
PRESERVING
BANDWIDTH
EXPANDING
SOURCE
ENCODING
ENCRYPTION
CHANNEL
ENCODING
BITS
SOURCE
DECODING
DECRYPTION
CHANNEL
DECODING
CHANNEL
It’s all Bits! Bits in, Bits out!
Shannon’s Legacy
• Communication System Resources
Bandwidth
Signal to Noise Ratio
Computational Complexity
• A Communication System needs a
Computer in Modulator and Demodulator!
• We have a Computer on Board!
• We
can use it to do some Heavy Lifting
The Four Pillars of
Modern Communications
SIGNAL to NOISE
SIGNAL TRANSFORMS
DATA TRANSFORMS
BANDWIDTH
MODERN
COMMUNICATIONS
The Modulator Digital to Analog Interface
Moves Towards the RF
BASEBAND
M-ARY
SIGNAL
CONDITIONER
DIGITAL
RF
TUNER
ANALOG
BASEBAND
M-ARY
SIGNAL
CONDITIONER
DIGITAL
TUNER
RF
ANALOG
BASEBAND
M-ARY
SIGNAL
CONDITIONER
TUNER
DIGITAL
ANALOG
RF
The Demodulator Analog to Digital Interface
Moves Towards the RF
BASEBAND
RF
M-ARY
SIGNAL
CONDITIONER
TUNER
ANALOG
DIGITAL
BASEBAND
RF
M-ARY
SIGNAL
CONDITIONER
TUNER
ANALOG
DIGITAL
BASEBAND
RF
M-ARY
SIGNAL
CONDITIONER
TUNER
ANALOG
DIGITAL
First Generation DSP Receiver
IMAGE
REJECT
FILTER
SAMPLER
I-F
FILTER
LNA
GAIN
LOW-PASS
FILTER
FIRST
LO
CARRIER
VCO
TUNING
LOOP
FILTER
DATA
DETECTOR
MATCHED
FILTER
TIMING
VCO
LOOP
FILTER
PHASE
DETECTOR
Second Generation DSP Receiver
IMAGE
REJECT
FILTER
SAMPLER
I-F
FILTER
LNA
GAIN
LOW-PASS
FILTER
FIRST
LO
CARRIER
VCO
TUNING
LOOP
FILTER
DATA
DETECTOR
MATCHED
FILTER
TIMING
VCO
PHASE
DETECTOR
LOOP
FILTER
SAMPLER
IMAGE
REJECT
FILTER
I-F
FILTER
LNA
GAIN
MATCHED
FILTER
LOW-PASS
FILTER
FIRST
LO
CARRIER
VCO
TIMING
VCO
TUNING
LOOP
FILTER
LOOP
FILTER
DATA
DETECTOR
PHASE
DETECTOR
Third Generation DSP Receiver
SAMPLER
IMAGE
REJECT
FILTER
I-F
FILTER
LNA
GAIN
MATCHED
FILTER
LOW-PASS
FILTER
FIRST
LO
CARRIER
VCO
TIMING
VCO
TUNING
LOOP
FILTER
LOOP
FILTER
I-F
FILTER
LNA
GAIN
FIRST
LO
TUNING
MATCHED
FILTER
DATA
DETECTOR
CARRIER
DDS
TIMING
DDS
PHASE
DETECTOR
LOOP
FILTER
LOOP
FILTER
LOW-PASS
FILTER
SECOND
LO
SAMPLING
CLOCK
PHASE
DETECTOR
INTERPOLATOR
SAMPLER
IMAGE
REJECT
FILTER
DATA
DETECTOR
SECOND GENERATION
DSP CENTRIC MODEL
DIGITAL
MODULATOR
BITS
DATA
TRANSFORMS
SAMPLED DATA CHANNEL
DSP
MODULATOR
WAVEFORM
TRANSFORMS
M-ARY
ALPHABET
M-ARY
ALPHABET
BITS
DATA
TRANSFORMS
BASEBAND
WAVEFORM
DIGITAL
SIGNALS
RF
CHANNEL
DATA
SIGNALS
SPECTRAL
TRANSFORMS
ANALOG
SIGNALS
BASEBAND
WAVEFORM
WAVEFORM
TRANSFORMS
DIGITAL
DSP
DEMODULATOR DEMODULATOR
SPECTRAL
TRANSFORMS
RF
THIRD GENERATION
DSP CENTRIC MODEL
DIGITAL
MODULATOR
BITS
DATA
TRANSFORMS
M-ARY
ALPHABET
M-ARY
ALPHABET
BITS
DATA
TRANSFORMS
DIGITAL
DEMODULATOR
WAVEFORM
TRANSFORMS
ANALOG CHANNEL
SPECTRAL
TRANSFORMS
RF
BASEBAND
WAVEFORM
ANALOG
SIGNALS
DIGITAL
SIGNALS
BASEBAND
WAVEFORM
WAVEFORM
TRANSFORMS
CHANNEL
DATA
SIGNALS
DSP
MODULATOR
SPECTRAL
TRANSFORMS
DSP
DEMODULATOR
RF
Mapping an Analog prototype
to its Digital Counterpart
PROTOTYPE ANALOG PROCESS
ANALOG
SIGNAL
PROCESSING
x(t)
y(t)
EQUIVALENT DIGITAL PROCESS
x(t)
x(t)
ANALOG
x(n)
TO
DIGITAL
CONVERTER
ANALOG
BLOCKS
y(t)
DIGITAL
SIGNAL
PROCESSING
y(n)
x(n)
DIGITAL
TO
ANALOG
CONVERTER
DIGITAL
BLOCKS
y(t)
y(n)
Good Advice!
• Don’t Copy Analog Legacy Prototype to
DSP Domain.
• Legacy Designs include Compromises
Appropriate for their Time.
• Return to First Principles!
• Start with a fresh slate using current
resources and perspectives.
Signal Processing in Transmitter-I
 Base Band Sigma-Delta ADC
 VCELPC Speech Source Coding
 Spectral Shaping
 Fixed Interpolation
 Arbitrary Interpolation
 I-Q Balance
 DC Canceling
 Digital Up-Conversion
 Sin(x)/(x) Predistortion
 IF Sigma-Delta DAC
 Direct Sequence Spreading
 Automatic Gain Control