SECURITY SINUSOIDAL TRANSFORM OF SPEECH CODING FOR MOBILE COMMUNICATION
TABLE OF CONTENT
Title page
Certification = = = = = = = = i
Dedication = = = = = = = = ii
Acknowledgment = = = = = = = iii
Abstract = = = = = = = = = iv
Table of content = = = = = = = v
Chapter one
- Back ground of the study == = = = = 1
- Characteristics of mobile communication with respect to speech coders = = = = = = = 5
- Statement of problem = = = = = 9
- Purpose of the study = = = = = 11
- Significance of the study = = = = 12
- Limitation of the study = = = = 13
- Definition of terms = = = = = 14
Chapter two
Literature review
2.0 Introduction = = = = = = = 16
2.1 source coding and rate distortion theory = = 16
2.2 analysis-by-synthesis speech coding = = = 20
2.3 transform coding = = = = = = 24
2.4 security sinusoidal coding = = = = = = 27
2.5 relative merits and demerits of different coding strategies = = = = = = = = = 29
Chapter three
3.0 research methodology = = = = = 34
3.1 system investigation = = = = = = 34
3.2 method of data collection = = = = = 35
3.3 interview method = = = = = = 35
3.4choosing an appropriate spectral representation
= = = = = = = = = = 37
3.5 preprocessing = = = = = = = 42
35.1 Pre-emphasis = = = = = = = 42
3.5.2 Band width expansion = = = = = 43
3.5.3 High frequency compensation = = = = 44
3.6 vector quantification of LPC parameters = = 45
3.5.1 stochastic vector quantification
3.5.2 techniques exploiting interface correlations selective encoding of sub-vectors
3.6 constrained (suboptimal) vq
3.6.1 the structured vq
3.6.2 classified vq
3.6.3 product code vq
3.6.4 basis vector vq
3.6.5 multi-stage vq
3.6.6 partitioned vq (split vq)
Chapter four
4.0 result presentation and discussion
4.1 multi-stage vq of LPC parameters
4.2 suboptimality of sequential search
4.2.1 optimality conditions for sequential search
4.3 search strategy
4.3.1 search complexity
4.3.2 detailed analysis of the search complexity
4.4 codebook design
4.4.1 controid computation
4.4.2 Outlier weighting
4.5 choices of parameter representation and distance measure
4.6 performance and complexity trade-offs
4.7 robustness issues
4.7.1 Effect of language and input spectral shape
4.7.2 Performance in the presence of channel errors
4.8 Improved codebook designs for multi stage vq
4.8.1 Iterative sequential design
4.8.2 Simultaneous Joint Design
4.9 A Low Rate Spectral Excitation Coder
4.9.1 Recent Development in MSVQ
Chapter five
5.0 Summary, Conclusion and Recommendation
5.1 Summary
5.2 Conclusion
5.3 Recommendation
References
CHAPTER ONE
- BACKGROUND OF THE STUDY
INTRODUCTION
The introduction of speech coding for mobile communication through security sinusoidal transformation. Speech coding is the application of data compression of digital audio signal containing speech. Speech coding uses speech-specific parameter estimation using audio signal processing techniques to model the speech signal, combined with generic data compression algorithms to represent the resulting modeled parameters in a compact bitstream. The two most important applications of speech coding are mobile telephony and voice over IP.
The techniques employed in speech coding are similar to those used in audio data compression and audio coding where knowledge in psychoacoustics is used to transmit only data that is relevant to the human auditory system. For example, in voice band speech coding, only information in the frequency band 400HZ to 3500Hz is transmitted but the reconstructed signal is still adequate for intelligibility.
Speech coding differs from other forms of audio coding in that speech is a much simpler signal then most other audio signals, and a lot more statistical information is available about the properties of speech. As a result, some auditory information which is relevant in audio coding can be unnecessary in the speech coding context. In speech coding, the most important criterion is preservation of intelligibility and pleasantness of speech, with a constrained amount of transmitted data. The intelligibility of speech includes, the actual literal content, speaker identity, emotions, intonation, timbre etc. In addition, most speech applications require low coding delay, as long as coding delays interfere with speech interaction
Communication is the exchange of thoughts, messages or information, as by speech, signals, writing or behaviour. It is derived from the latin word.
“Communis”, which means to share. Communication requires a sender, a message and a recipient, although the receiver need not be present or aware of the sender’s intent to communicate at the time of communication, thus communication can occur across vast distances in time and space. Communication requires that the communicating parties share an area of communicative commonality. The communication process is complete once the receiver has understood the message of the once the receiver has understood the message of the sender. Feedback is critical to effective communication between participants. Bandwidth is a key concept in many telephony applications. In radio communications, for example, band width is the frequency range occupied by a modulated carrier wave, whereas in optics, it is the width of an individual spectral line or the entire spectral range.
In many signal processing contexts, bandwidth is a valuable and limited range of frequencies. A government agency may apportion the regionally available bandwidth to broadcast license holders so that their signals do not mutually interfere.
For different applications there are different precise definitions for bandwidth. It could be defined as the range of frequencies beyond which the frequency function is zero. This would correspond to the mathematical notion of the support of a function. Bandwidth can also be referred to as the frequencies where the frequency function is small.
Bandwidth typically refers to base band or as a pass band for communication systems.
- CHARACTERISTICS OF MOBILE COMMUNICATION WITH RESPECT TO SPEECH CODERS
There are a number of additional characteristics of mobile communication, some of which are closely linked with handover.
The most important characteristics includes:
- a) Adaptive frame Alignment: Mobile staggers is transmitted by three timeslots after a burst from the base station. This means that there is a nominal delay of three TDM slots between transmit and receive frames at the base station. However, the propagation time between base and mobile depends on distance and it is possible for a burst from a mobile near the perimeter of a cell to overlap with a burst from a mobile close to the base station. GSM calculates the timing advance required to ensure that bursts arrive at the base station at the beginning of their timeslots. This information is transmitted to the mobile on the SACCH.
