Speech Recognition Analysis

1.7 Speech analysis One of the important characteristics of a speech waveform is the time-varying nature of the content of the speech pressure. Determination of the time-varying parameters of speech is a key area of analysis required in speech research. Another key area is classification of speech waveform segments into voiced or voiceless (mixed excitation is usually considered voiced). As mentioned previously, in the case where speech is voiced, the most important parameter is the fundamental frequency value f0. This section introduces these two areas of analysis and discusses the principles and limitation involved.

Timbre is the sound quality which differentiates musical notes of identical pitch, loudness and duration played by different instruments. Instruments have their own acoustic properties which generate the differences in listeners’ perceived timbres, and the key to it is the spectral and temporal features of the sound. In the aspect of spectra, most instruments generate harmonic resonances in which they produce energy at multiple numbers of fundamental frequency. These harmonic resonances are very similar to the speech produced by the vibration of vocal chords. Just like the varied vowels, the differed energy patterns across different harmonics determine distinct instrument properties.

This phenomenon is called frequency following response (FFR). The concept is that if one receives a stimulus with a frequency in the range of brain waves, the predominant brain wave frequency is said to be likely to move towards the frequency of the stimulus (a process called entrainment). Human hearing is limited to the range of frequencies from 20 Hz to 20,000 Hz, while the frequencies of human brain waves are below about 40 Hz. To account for this, binaural beat frequencies must be used. According to this view, when the perceived beat frequency corresponds to any of the brainwave frequencies, the brain entrains to or moves towards the beat frequency.

The CWT can be interpreted as a linear filtering operation (convolution between the signal x(t) and a filter with impulse response ψ(-t/s)).The CWT can be viewed as a type of bandpass analysis which modifies the center frequency and bandwidth of a bandpass filter by varying the scaling parameter (s). The CWT can be expressed as Inverse Continuous Wavelet Transform: CWT is highly redundant since 1-dimensional function x(t) is transformed into 2-dimensional function. Therefore, it is discretize to some suitably chosen sample grid. The is called as dyadic sampling: s=2-j, τ = k2-j. By using the dyadic sampling we can reconstruct exactly the signal

Introduction: A wave is a disturbance in the medium that transfers energy from one place to another, there are two types of waves; longitudinal waves and transverse waves. Longitudinal waves ' are waves that vibrate or travel in the direction of propagation; back and forth. Transverse waves ' are waves where the medium oscillates at right angles to the direction of the propagation; up and down. Sound waves are categorised as longitudinal waves as they produce oscillations, along with having compressions and rarefactions. The oscillations of the wave cause the medium surrounding it to oscillate along with it, allowing the sound to travel around the area.

- Vocal expression, the way the performer uses their voice to convey a character. Jo-Anne Bachorowski in Vocal Expression and Perception of Emotion states that “The expression of emotions in speech sounds and corresponding abilities to perceive such emotions are both fundamental aspects of human communication.” (1999) therefore, this element is an important aspect of the creation of the connection between the performer and the audience. - Inflection, Change in pitch or loudness of the voice. As the voice is a more permeable channel than the face, it is more challenging to control and therefore, is more likely to expose true feelings. The sound of one’s voice changes as the rate of vibrations changes.

Abstract Electrocardiogram (ECG) signal has been widely used for heart diagnosis. This paper presents a VLSI based design of high speed and area efficient distributive arithmetic discrete wavelet transform (DA-DWT) for Arrhythmia Detection and its FPGA implementation. The main focus of the work is to filter and detect the QRS complex in the ECG signal and to identify the time and frequency variations. By comparing these variations with that of the variations in the normal ECG waveform one may reach to a conclusion if the patient is suffering from Arrhythmia or not. The DA-DWT is also used to filter the ECG signal so as to detect the ECG signal for Arrhythmia Detection.

2.1 SPEECH ACTS There are many theories that facilitate the analysis of spoken language. Definitely, speech act is one of those theories which notice communicative purposes between speakers and listeners. This effective tool aids learners to identify and label the differences of communicative functions through utterances of interlocutors. According to the theory as pointed out by Adolphs (2008) that particular speech act can be illocutionary, the gist of an utterance that a speaker produces, and perlocutionary, the actual purpose of the saying which can be direct and indirect. For example, the question Are you with me?

In this work, a new stressed speech database is recorded. This recorded database is named as out-of-breath speech (OBS) database. The database contains three classes of speech corresponding to three different levels of breath emission. These three classes are out-of-breath speech, low out-of-breath speech and normal speech. The out- of-breath speech is defined as the speech produced with excessive emission of breath, where as low out-of-breath speech contains lower level of breath emission compared to the out-of-breath speech but higher than the normal speech.

The thoracic cavity is constrained by the mid-section divider and diaphragm. The potential space between the instinctive and parietal pleurae is known as the intrapleural space. The intrapleural and intrapulmonary pressures fluctuate amid ventilation. The intrapulmonary pressure is subatmospheric amid inspiration and more prominent than the atmospheric pressure amid expiration. Pressure changes in the lungs are delivered by varieties in lung volume, as per the opposite relationship between the volume and pressure of a gas portrayed by Boyle's law.