ASK, OOK, FSK, BPSK, QPSK, 8PSK modulations in Matlab
Digital modulation
This article is intended to simulate some models in Matlab 7.1 digital modulation such as ASK, OOK, FSK, QPSK, 8PSK. The functions have as input parameter a vector of bits and the frequency of the carrier. Also, a graphical user interface (GUIDE) to generate random bits (10) for subsequent modulation is provided.
INTRODUCTION
The electronic communications industry has been gradually replacing the conventional analog modulation techniques, such as AM (amplitude modulation) and FM (Frequency Modulation) and PM (phase modulation) for digital communications systems. This is due to the advantages of digital modulation: better noise immunity, ease of processing, high data security and multiplexing.
Some are digital modulation: ASK (amplitude shift keying), OOK (On-Off Keying), FSK (frequency shift keying), BPSK (binary phase shift keying), QPSK (quadrature phase shift keying), 8PSK (8 phase shift keying).
This file contain several functions for digital modulation simulation.
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Copyright Protection of Digital Audio Data
The outstanding progress of digital technology has increased the ease with which digital data is reproduced and retransmitted. However, since the advantages of such a progress are broadly available, they offer equally increasing potential to both legal and unauthorized data manipulation. Consequently, the necessity arises for copyright protection of digital products against unauthorized recording attempts, knows as data piracy. Current research in image, audio and video copyright protection exploits the fact that the human visual and audio perception cannot detect slight changes in certain temporal or frequency domains of the image and the audio signal, respectively. This property is called masking, according to which a faint but perceptible signal becomes non-perceptible in the presence of another one under certain conditions. Most research methods consider a watermark signal produced in a unique way by a function of one or more input keys. These keys can be both owner and signal dependent and generate a signal which is embedded on the original one. The embedding signal is known as a watermark or copyright label. Temporal and frequency characteristics of the original signal should be taken into account in the watermark casting process to reduce perceptible distortions in the watermarked signal. Each individual that produces or possesses digital data owns a unique key that identifies its legal possession and is required for the watermark detection. Besides copyright purposes, a watermark serves authentication purposes, as well.
A watermark has to be statistically undetectable by others to prevent the efforts of its unauthorized removal. This condition is fulfilled if the potential number of keys that produce distinct watermarks is large enough to ensure statistical safety. The detection scheme should be as statistically reliable as possible. False rejection or acceptance of the existence of the watermark should be minimal. Finally, a watermark has to be robust to signal manipulation and impossible to be removed without significant alteration of the signal. In other words, a pirate should have to destroy the audio signal before he accomplishes to destroy the watermark. The robustness should extend to common signal processing operations, such as filtering, compression, resampling, requantization, cropping, noise, D/A conversion.
Index Terms: Matlab, source, code, watermarking, watermark, detection, embedding, audio, copyright, protection.
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Figure 1. Copyright protection |
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A simple and effective source code for Digital Audio Watermarking. |
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Demo code (protected P-files) available for performance evaluation. Matlab Signal Processing Toolbox is required.
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Release
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Date
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Major features
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1.0
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2008.04.19
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We recommend to check the secure connection to PayPal, in order to avoid any fraud. |
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Digital Audio Watermarking – Click here for your donation. In order to obtain the source code you have to pay a little sum of money: 90 EUROS (less than 126 U.S. Dollars).
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Once you have done this, please email us luigi.rosa@tiscali.it
As soon as possible (in a few days) you will receive our new release of Digital Audio Watermarking. Alternatively, you can bestow using our banking coordinates:
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The authors have no relationship or partnership with The Mathworks. All the code provided is written in Matlab language (M-files and/or M-functions), with no dll or other protected parts of code (P-files or executables). The code was developed with Matlab 2006a. Matlab Signal Processing Toolbox is required. The code provided has to be considered “as is” and it is without any kind of warranty. The authors deny any kind of warranty concerning the code as well as any kind of responsibility for problems and damages which may be caused by the use of the code itself including all parts of the source code.
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MATLAB for Digital Communication
This week we focus on this book for digital comunication from Won Yang.
The book is full of Matlab coded examples that can be downloaded here.
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- CHAPTER 1: FOURIER ANALYSIS
- 1.1 CONTINUOUS-TIME FOURIER SERIES (CTFS)
- 1.2 PROPERTIES OF CTFS
- 1.2.1 Time-Shifting Property
- 1.2.2 Frequency-Shifting Property
- 1.2.3 Modulation Property
- 1.3 CONTINUOUS-TIME FOURIER TRANSFORM (CTFT)
- 1.4 PROPERTIES OF CTFT
- 1.4.1 Linearity
- 1.4.2 Conjugate Symmetry
- 1.4.3 Real Translation and Complex Translation
- 1.4.4 Real Convolution and Correlation
- 1.4.5 Complex Convolution – Modulation/Windowing
- 1.4.6 Duality
- 1.4.7 Parseval Relation – Power Theorem
- 1.5 DISCRETE-TIME FOURIER TRANSFORM (DTFT)
- 1.6 DISCRETE-TIME FOURIER SERIES – DFS/DFT
- 1.7 SAMPLING THEOREM
- 1.7.1 Relationship between CTFS and DFS
- 1.7.2 Relationship between CTFT and DTFT
- 1.7.3 Sampling Theorem
- 1.8 POWER, ENERGY, AND CORRELATION
- 1.9 LOWPASS EQUIVALENT OF BANDPASS SIGNALS
- CHAPTER 2: PROBABILITY AND RANDOM PROCESSES
- 2.1 PROBABILITY
- 2.2 LINEAR FILTERING AND PSD OF A RANDOM PROCESS
- 2.3 FADING EFFECT OF A MULTI-PATH CHANNEL
- CHAPTER 3: ANALOG MODULATION
- 3.1 AMPLITUDE MODULATION (AM)
- 3.1.1 DSB (Double Sideband)-AM (Amplitude Modulation)
- 3.1.2 Conventional AM (Amplitude Modulation)
- 3.1.3 SSB (Single Sideband)-AM(Amplitude Modulation)
- 3.2 ANGLE MODULATION – FREQUENCY/PHASE MODULATIONS
- 3.1 AMPLITUDE MODULATION (AM)
- CHAPTER 4: ANALOG-TO-DIGITAL CONVERSION
- 4.1 QUANTIZATION
- 4.1.1 Uniform Quantization
- 4.1.2 Non-uniform Quantization
- 4.1.3 Non-uniform Quantization Considering Relative Errors
- 4.2 Pulse Code Modulation (PCM)
- 4.3 Differential Pulse Code Modulation (DPCM)
- 4.4 Delta Modulation (DM)
- 4.1 QUANTIZATION
- CHAPTER 5: BASEBAND DIGITAL TRANSMISSION
- 5.1 RECEIVER (RCVR) and SNR
- 5.1.1 Receiver of Filter Type
- 5.1.2 Receiver of Matched Filter Type
- 5.1.3 Signal Correlator
- 5.2 SIGNALING AND ERROR PROBABILITY
- 5.2.1 Antipodal (Bipolar) Signaling
- 5.2.2 OOK(On-Off Keying)/Unipolar Signaling
- 5.2.3 Orthogonal Signaling
- 5.2.4 Signal Constellation Diagram
- 5.2.5 Simulation of Binary Communication
- 5.2.6 Multi-level(amplitude) PAM Signaling
- 5.2.7 Multi-dimensional Signaling
- 5.2.8 Bi-orthogonal Signaling
- 5.1 RECEIVER (RCVR) and SNR
- CHAPTER 6: BANDLIMITED CHANNEL AND EQUALIZER
- 6.1 BANDLIMITED CHANNEL
- 6.1.1 Nyquist Bandwidth
- 6.1.2 Raised-Cosine Frequency Response
- 6.1.3 Partial Respone Signaling – Duobinary Signaling
- 6.2 EQUALIZER
- 6.2.1 Zero-Forcing Equalizer (ZFE)
- 6.2.2 MMSE Equalizer (MMSEE)
- 6.2.3 Adaptive Equalizer (ADE)
- 6.2.4 Decision Feedback Equalizer (DFE)
- 6.1 BANDLIMITED CHANNEL
- CHAPTER 7: PASSBAND DIGITAL TRANSMISSION
- 7.1 AMPLITUDE MODULATION – AMPLITUDE SHIFT KEYING (ASK)
- 7.2 FREQUENCY MODULATION – FREQUENCY SHIFT KEYING (FSK)
- 7.3 PHASE MODULATION – PHASE SHIFT KEYING (PSK)
- 7.4 DIFFERENTIAL PHASE SHFT KEYING (DPSK)
- 7.5 QUADRATURE AMPLITUDE MODULATION (QAM) – PAM/PSK
- 7.6 COMPARISON OF VARIOUS SIGNALINGS
- CHAPTER 8: CARRIER RECOVERY AND SYMBOL SYNCHRONIZATION
- 8.1 INTRODUCTION
- 8.2 PLL (PHASE-LOCKED LOOP)
- 8.3 ESTIMATION OF CARRIER PHASE USING PLL
- 8.4 CARRIER PHASE RECOVERY
- 8.4.1 Carrier Phase Recovery Using Squaring Loop for BPSK
- 8.4.2 Carrier Phase Recovery Using Costas Loop for PSK
- 8.4.3 Carrier Phase Recovery for QAM Signals
- 8.5 SYMBOL SYNCHRONIZATION (TIMING RECOVERY)
- 8.5.1 Early-Late Gate Timing Recovery for BPSK Signals
- 8.5.2 NDA-ELD Synchronizer for PSK Signals
- CHAPTER 9: INFORMATION AND CODIN
- 9.1 MEASURE OF INFORMATION – ENTROPY
- 9.2 SOURCE CODING
- 9.2.1 Huffman Coding
- 9.2.2 Lempel-Zip-Welch Coding
- 9.2.3 Source Coding vs. Channel Coding
- 9.3 CHANNEL MODEL AND CHANNEL CAPACITY
- 9.4 CHANNEL CODING
- 9.4.1 Waveform Coding
- 9.4.2 Linear Block Coding
- 9.4.3 Cyclic Coding
- 9.4.4 Convolutional Coding and Viterbi Decoding
- 9.4.5 Trellis-Coded Modulation (TCM)
- 9.4.6 Turbo Coding
- 9.4.7 Low-Density Parity-Check (LDPC) Coding
- 9.4.8 Differential Space-Time Block Coding (DSTBC)
- 9.5 CODING GAIN
- CHAPTER 10: SPREAD-SPECTRUM SYSTEM
- 10.1 PN (Pseudo Noise) Sequence
- 10.2 DS-SS (Direct Sequence Spread Spectrum)
- 10.3 FH-SS (Frequency Hopping Spread Spectrum)
- CHAPTER 11: OFDM SYSTEM
- 11.1 OVERVIEW OF OFDM
- 11.2 FREQUENCY BAND AND BANDWIDTH EFFICIENCY OF OFDM
- 11.3 CARRIER RECOVERY AND SYMBOL SYNCHRONIZATION
- 11.4 CHANNEL ESTIMATION AND EQUALIZATION
- 11.5 INTERLEAVING AND DEINTERLEAVING
- 11.6 PUNCTURING AND DEPUNCTURING
- 11.7 IEEE STANDARD 802.11A – 1999
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