Introduction To Speech Processing

Được đăng lên bởi Linh Sieu Li
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Introduction To Speech Processing

June 2010

  What is the Speech Processing
  Applications of Speech Processing
  Review of Signal Processing
  Fourier series
  Convolution
  Fourier Transform

What is the Speech Processing
 Speech processing is the application of digital

signal processing ( DSP) technique to the
processing and analysis of speech signals

Applications of Speech Processing
  Speech Coding
  Speech recognition
  Speaker Verification\Identification
  Speech Enhancement
  Speech Synthesis ( Text to Speech)
  Disease Diagnosis

Speech Signal


/s/ /ou/ /th/ /aa/ /m/ /p/ /t/ /a/ /n/

Speech Signal
/seven o eight/

Review of Signal Processing
  Analog Signal

Signals that are continuous in Time. Most environmental
signals are continuous-time signals.
  Digital Signal

These are created by quantizing and sampling continuoustime signals or as data signals (e.g., stock market price

Processing Real Signals
  Most of the signals in our environment are analog such as

sound, temperature and light

  To processes these signals with a computer, we must:

1. convert the analog signals into electrical signals, e.g., using a
transducer such as a microphone to convert sound into electrical
2. digitize these signals, or convert them from analog to digital,
using an ADC (Analog to Digital Converter)

Processing Real Signals
  Analog Signal

  Digital Signal
speech: 8 kbps (8bit * 1k sample)/s
…256 kbps

Discrete-Time Signals
  A sequence of numbers
  Mathematical representation:

x = {x[n]}, − ∞ < n < ∞
  Sampled from an analog signal, xa (t), at time t = nT,
x[n] = xa (nT ), − ∞ < n < ∞
  T is called the sampling period, and its reciprocal,
  F =1/T, is called the sampling frequency

SF =8000Hz ↔ T =1/8000=125μsec
SF =10000Hz ↔ T =1/10000=100μsec
SF =16000Hz ↔ T =1/16000=62.5μsec
SF =40000Hz ↔ T=1/40000=25μsec

Processing Real Signals
  Processed signal may need to be converted back to an

analog signal before being passed to an actuator (e.g., a
  Digital‐to‐analog conversion can be done by a DAC

(Digital‐to‐Analog Converter).

  Speech Enhancement, Speech Synthesis …

Signal Processing
  Time-Domain Signal Processing

Analyzing of the signal with respect to time. A time-domain graph
shows how a signal changes over time.
  Frequency-Domain Signal Processing

Signals are converted from time domain to the frequency domain
usually through the Fo...
Introduction To Speech Processing
June 2010
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