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Envelope and Waveform Preservation

Envelope Preservation

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Two methods based on spectral envelope analsys are used for the envelope preservation : True Envelope, and Linear Predictive Coding. To choose a method, select an item in the Method menu.

About LPC and True Envelope Analysis
LPC Estimation and Number of Orders

Linear predictive coding (LPC) is a method for signal source modelling in speech signal processing, based on the source-filter model of speech signal[1].

  • Specify a number of poles for the LPC.

  • Note that if a F0 analysis was executed, the temporary name of the analysis will be displayed although the method doesn't resort to the F0 analysis.

True Envelope and F0 Analysis

True envelope (TE) is one of the most efficient spectral envelope estimation techniques, designed to improve the results of the LPC. It is based on an F0 estimation and also uses a number of orders, which is deduced from the F0

  • Specifiy a frequency in the Maximum Fundamental Frequency prompt (1).

  • You can also se a previous F0 analysis file for a better rendering, whic allows SuperVP to choose the relevant order number dynamically.

  1. Check the Use Fundamental Frequency option

    • Click on Select to open a dialogue window and select any F0 analysis in the Analysis directory. Its name will then be displayed in the window (2).

    • If an F0 analysis has been calculated and is shown in the AS window, a temporary analysis name will be displayed, and it will be used by default (3).

Waveform Preservation

Specific Use

This option is efficient with monophonic sources. Check the Waveform Preservation (Single Voice) option.

Waveform Preservation and VUV Analysis

This mode is based on a Voiced/Unvoiced analysis, which allows to process the separate voiced and unvoiced parts of the signal separately.

You can use a previous voiced/unvoiced analysis file :

  1. Check the Use VUV File option

    • Click on Select to open a dialogue window and select any F0 analysis in the Analysis directory. Its name will then be displayed in the window (2).

    • If a VUV analysis has been calculated and is shown in the AS window, a temporary analysis name will be displayed, and it will be used by default (3).

  1. Source Filter Model of Speech

    Vocal sounds are produced by an excitator, the glottis. The resulting signal has a pitch and an intensity. The resonators are  the cavities of the phonation apparatus, which give rise to formants. Hisses and pops are produced by the tongue, lips and throat.

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