Speech Processing by Computer

 

LECTURE 1

SAMPLING AND EDITING

 

 

Objectives

 

By the end of the session you should:

q       be able to describe what ADC and DAC devices do

q       be able to describe the filtering, sampling and quantisation stages of analogue to digital conversion

q       have a qualitative understanding of how sampling rate and quantisation accuracy affects signal quality

q       know what is meant by aliasing and quantisation noise

q       appreciate the need for good signal management

 

Outline


 

1.      Sampling and Editing

1.1.   Analogue vs. Digital

1.1.1.      Storage as analogy

1.1.2.      Storage as encoding

1.2.   Analogue to Digital Conversion

1.2.1.      Pre-filtering

1.2.2.      Sample and Hold

1.2.3.      Voltage comparison

1.3.   Digital to Analogue Conversion

1.3.1.      Adding voltages

1.3.2.      Post-filtering

1.4.   Sampling Theorem

1.4.1.      Selection of sampling rate

1.5.   Quantisation

1.5.1.      Selection of sampling accuracy

1.6.   Editing

1.6.1.      Management of recordings

1.6.2.      Annotation

1.6.3.      Cutting and Pasting

 

Reading

 

            Rosen & Howell, Signals and Systems for Speech and Hearing, Chapter 14, Academic Press, 1990.