Introduction ................................................................................................ 1
A science that people can understand...... .................................... 1
Target groups ................... . .. ...............................2
G raphic program m ing ....................... .............................................................. 3
The electronic document ..................4.... . .. ........................4
The Cam tasia video player ................................................................................ 10
Chapter 1
The concept: methods - content - objectives........................................ 11
Everything under one roof ................................................................................. 12
Hardware: Systems on a chip ............................................... 12
The software is the instrument .......................................................................... 13
A case for up-to-date education ......................................................................... 14
On the unity of theory and practice ................................................................... 14
M ultim edia and interactive learning.................................................................. 14
Science and M athem atics .................................................................................. 15
In search of other "tools". .................................................................................. 17
Physics as the point of departure ....................................................................... 22
Clarification of Objectives ................................................................................ 24
Preliminary conclusions: the concept takes on clearer contours.......................... 28
Exercises on Chapter 1 : .................................................................................... 30
Chapter 2
Signals in the time and frequency domain ............................................ 33
The FOURIER Principle ................................................................................... 33
Periodic oscillations ........................................................................................... 34
Our ear as a FOURIER-analyzer ....................................................................... 35
FOURIER -Transformation: from the time domain
to the frequency domain and back ..................................................................... 42
Important periodic oscillations/signals.................................................................. 47
Comparison of signals in the time and frequency domain................................... 48
The confusing phase spectrum .......................................................................... 50
Interference: nothing to be seen although everything is there.............................. 50
Opposites which have a great deal in common: sine and 8-pulse ........................ 52
Non-periodic and one-off signals ...................................................................... 56
Pure randomness: stochastic noise .................................................................... 57
N oise and inform ation ....................................................................................... 58
Exercises for Chapter 2: ...................... ........................... 61
Chapter 3
The Uncertainty Principle....................................................................... 65
A strange relationship between frequency and time
and its practical consequences.............................................................................. 65
Sinusoidal signal and 6-pulse as a limiting case of the Uncertainty Principle..... 69
W hy ideal filters cannot exist ............................................................................ 70
Frequency measurements in the case of non-periodic signals.............................. 74
N ear-periodic signals......................................................................................... 80
Tones, sounds and music ........................................................ 81
Limiting uncertainty: Short Time FFT and Wavelets ..................................... 85
Exercises on Chapter 3 ............................... 96
Chapter 4
Language as a carrier of information ........................................... 99
How speech, tones and sounds are generated and perceived .......................... 107
Case study: a simple system for voice recognition........................... 115
Refinement and optimisation phase................................... 120
Pattern recognition............................ ... 123
Exercises on Chapter 4 .............................................................. 125
Chapter 5
The Symmetry Principle ...................................... 127
For reasons of symmetry: negative frequencies ..................................... 127
Proof of the physical existence of negative frequencies.......................... 127
Periodic spectra............................................. .......... ......... ........................ 135
Inverse FOURIER transformation and GAUSSian plane .................................. 138
Exercises on Chapter 5 ....................................... 150
Chapter 6
System analysis ........................................ 151
Sw eep .................................................................................. ....................... 153
M odern test signals................................ ........... .. 158
The 8-pulse ....................................... 160
The transfer function as a locus curve .......................................... 164
The step function ........................................ 167
The GAUSSian pulse..... ................................... 173
The GAUSSian oscillation pulse .................................. 174
The Burst signal................................. 175
The Si-function and the Si-oscillation pulse................................ 176
N oise ......................... .... ................. ................................................. 178
Transients in systems.................................. 182
Exercises on Chapter 6 ....................................... 187
Chapter 7
Linear and non-linear processes ...................................... 189
System analysis and system synthesis .................................... 189
Measuring a process to reveal whether it is linear or non-linear..................... 189
Line and space ............................................ 190
Inter-disciplinary significance ........................................ 190
Mirroring and projection ........................................ 191
A complex component: the transistor ............................. .......... 193
There are only few linear processes ............................................. 193
Multiplication of a signal by a constant.............................. 194
Addition of two or more signals ........................................ 195
Delay..................................................... ...... ..... 195
D ifferentiation ...................................................... ........................................ 197
Integration.................... ..... ........................ .............................. 204
Malicious functions or signal curves ..................................... 211
Filters ................................................. 213
N on-linear processes ........................................................... ......................... 218
Multiplication of two signals .................................... 219
Formation of the absolute value .......................... .................. 223
Quantization ..... ........................................ 225
Windowing ...... ........................................ 228
Exercises on Chapter 7 ........................................ 229
Chapter 8
Classical modulation procedures ..................................... 231
Transmission media ................................... 231
M odulation with sinusoidal carriers ............................................................... 231
Modulation and demodulation in the traditional sense................................... 232
Amplitude modulation and demodulation AM............................ .......... 233
Wasting energy: double sideband AM with carrier.............................. 240
Single sideband modulation without a carrier ..................................... 241
Frequency m ultiplex.......................................................................................... 249
M ixing ................................ .......................................................................... 252
Frequency modulation FM ....................... ......... ......................254
Demodulation of FM-signals............................... 264
The phase locked loop PLL .................... ..................... 264
Phase modulation.............................. 270
Immunity to interference of modulation processes ........................................ 272
Practical information theory ..................................... 275
Exercises on Chapter 8 ....................................... 276
Chapter 9
Digitalisation .................................................................... 279
Digital technology does not always mean the same thing............................... 279
Digital processing of analog signals ..................................... 279
The gateway to the digital world: the A/D converter .................................... 281
Principle of a D/A converter................................ 283
Analog pulse modulation processes ........................................ 286
DASYLab and digital signal processing ..................................... 288
Digital signals in the time and frequency domain .................... .................... 290
The period length of digital signals ........................................ 291
The periodic spectrum of digital signals ............................. ........... 300
The Sampling Principle ..... ................................. 302
Retrieval of the analog signal ...... .................................. 307
Non-synchronicity ........................................ 309
Signal distortion as a result of signal windowing....................................... 312
Check list........................................... ........................................ 313
Exercises on Chapter 9 ........................................ 315
Chapter 10
Digital filters ................................. 317
Hardware versus software ........................................ 317
How analog filters work ........................................ 317
FFT filters ............................................... 320
Digital filtering in the time domain .......................... .......................... 325
Convolution ...................................... ... 329
Case study: Design and application of digital filters ..................................... 331
Avoiding ripple content in the conducting state region.................................. 336
Exercises on Chapter 10 .......................................... 341
Chapter 11
Digital transmission technology 1: source encoding ......................... 343
Encoding and decoding of digital signals and data ........................................ 345
Compression ......................... ........ ...................... 345
Low-loss and lossy compression ........................................................... ..... 347
RLE encoding ............................................ 348
Huffman encoding ......................................... 348
LZW encoding................................. ................... ....... ...................... 349
Source encoding of audio signals ........................................ 352
Delta encoding or delta modulation............ ...................... 352
Sigma-delta modulation or encoding (S-D-M) ..................................... 357
Noise shaping and decimation filter ........................................ 359
Frequency band coding and multiple resolution........................... 359
Quadrature Mirror Filter (QMF) ................................ 363
Discrete Wavelet Transformation and Multi-Scale Analysis MSA ............... 369
Exploiting psycho-acoustic effects (MPEG) ..................................... 376
Encoding and physics ........................................ 382
Exercises on Chapter 11 ................................................ 383
Chapter 12
Digital transmission technology 11: channel encoding ...................... 385
Error protection encoding for the reduction of bit error probability .................. 385
Distance ................................................... 386
Hamming codes and Hamming distance ..................................... 388
Convolutional encoding......................... ...... .. ...... ........... 390
Viterbi decoding ........................................... 394
Hard and soft decision ........................................ 396
Channel capacity................................. 398
Exercises on Chapter 12 ..................................... 400
Chapter 13
Digital Transmission Techniques III: Modulation ........................... 401
K eying of discrete states ........................................................... ....................... 404
Amplitude Shift Keying (2-ASK) .............................. ............. 404
Phase Shift Keying (2-PSK) ........................................ 404
Frequency Shift Keying 2-FSK ........................................ 406
Signal space ........................................ 407
Quadrature Phase Shift Keying - QPSK ........................................ 410
Digital Quadrature Amplitude Modulation (QAM) ........................................ 413
M ultiple Access ............ ... .. ..................................................... 417
Discrete Multitone ........................................ 420
Orthogonal Frequency division Multiplex (OFDM) ..................................... 425
Coded OFDM (COFDM) and Digital Audio Broadcasting (DAB) ................... 430
Global System for Mobile Communications (GSM).......................................... 432
Asymmetric Digital Subscriber Line (ADSL).................................................... 432
Spread Spectrum .............................................................................................. 435
Exercises on Chapter 13 .................................................................................. 439
Bibliography ........................................................................................... 441
Index ....................................................................................................... 443