linear predictive coding-lpc

Upload: han-nguyen

Post on 04-Apr-2018

243 views

Category:

Documents


1 download

TRANSCRIPT

  • 7/30/2019 Linear Predictive Coding-LPC

    1/38

    Linear Predictive

    CodingTecniche avanzate per il Trattamento dei

    Segnali Audio

    Augusto Sarti

  • 7/30/2019 Linear Predictive Coding-LPC

    2/38

    Idea and motivations

  • 7/30/2019 Linear Predictive Coding-LPC

    3/38

    Idea and motivations

  • 7/30/2019 Linear Predictive Coding-LPC

    4/38

    Data model

    z If we assume that the signal is modeled by alinear combination of past samples and asource signal we may write that

  • 7/30/2019 Linear Predictive Coding-LPC

    5/38

    Data model

    z By Z-transforming the previous equation weobtain

  • 7/30/2019 Linear Predictive Coding-LPC

    6/38

    Data model

  • 7/30/2019 Linear Predictive Coding-LPC

    7/38

    Fundamentals of LPC

  • 7/30/2019 Linear Predictive Coding-LPC

    8/38

    Fundamentals of LPC

  • 7/30/2019 Linear Predictive Coding-LPC

    9/38

    Goal of prediction

  • 7/30/2019 Linear Predictive Coding-LPC

    10/38

    Goal of prediction

  • 7/30/2019 Linear Predictive Coding-LPC

    11/38

    Goal of prediction

  • 7/30/2019 Linear Predictive Coding-LPC

    12/38

    Goal of linear prediction

  • 7/30/2019 Linear Predictive Coding-LPC

    13/38

    Orthogonality principle

  • 7/30/2019 Linear Predictive Coding-LPC

    14/38

    Wiener-Hopf equations

  • 7/30/2019 Linear Predictive Coding-LPC

    15/38

    Wiener-Hopf equations

    z The above equations are known as Wiener-Hopf equations

  • 7/30/2019 Linear Predictive Coding-LPC

    16/38

    Wiener-Hopf equations

  • 7/30/2019 Linear Predictive Coding-LPC

    17/38

    Infinite memory Linear Prediction

  • 7/30/2019 Linear Predictive Coding-LPC

    18/38

    Infinite memory Linear Prediction

  • 7/30/2019 Linear Predictive Coding-LPC

    19/38

    Infinite Memory Linear Prediction

  • 7/30/2019 Linear Predictive Coding-LPC

    20/38

    Infinite Memory Linear Prediction

    z Whitening process

  • 7/30/2019 Linear Predictive Coding-LPC

    21/38

    Infinite Memory Linear Prediction

  • 7/30/2019 Linear Predictive Coding-LPC

    22/38

    Computation of LPC parameters

  • 7/30/2019 Linear Predictive Coding-LPC

    23/38

    Autocorrelation method

  • 7/30/2019 Linear Predictive Coding-LPC

    24/38

    Covariance method

  • 7/30/2019 Linear Predictive Coding-LPC

    25/38

    Frequency domain interpretation of LPC

    z Applying the DTFT to the error signal equationwe obtain that

  • 7/30/2019 Linear Predictive Coding-LPC

    26/38

    Power Spectrum Envelope Matching

    z After some passages (and the use ofParsevals theorem) we obtain that the errorEn is

  • 7/30/2019 Linear Predictive Coding-LPC

    27/38

    Power Spectrum Envelope Matching

  • 7/30/2019 Linear Predictive Coding-LPC

    28/38

    Power Spectrum Envelope Matching

  • 7/30/2019 Linear Predictive Coding-LPC

    29/38

    Power Spectrum Envelope Matching

  • 7/30/2019 Linear Predictive Coding-LPC

    30/38

    Power Spectrum Envelope Matching

  • 7/30/2019 Linear Predictive Coding-LPC

    31/38

    Power Spectral Envelope Matching

  • 7/30/2019 Linear Predictive Coding-LPC

    32/38

    Power Spectral Envelope Matching

  • 7/30/2019 Linear Predictive Coding-LPC

    33/38

    Power Spectral Envelope Matching

  • 7/30/2019 Linear Predictive Coding-LPC

    34/38

    Frequency Selective LPC

  • 7/30/2019 Linear Predictive Coding-LPC

    35/38

    Frequency Selective LPC

  • 7/30/2019 Linear Predictive Coding-LPC

    36/38

    Frequency selective LPC

  • 7/30/2019 Linear Predictive Coding-LPC

    37/38

    Applications of LPC

    z Speech coding/synthesisz Pitch Prediction (used in Codebook Excited

    Linear Prediction)z Computer Music: cross-synthesis

    z Spectral Envelope Estimation

    z ...

  • 7/30/2019 Linear Predictive Coding-LPC

    38/38

    References

    z J.O.Smith, Lecture notes of MUS 240/ EE625, available athttp://ccrma.stanford.edu/~jos/pubs.html

    http://ccrma.stanford.edu/~jos/pubs.htmlhttp://ccrma.stanford.edu/~jos/pubs.html