Speech Processing by Computer








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




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




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