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README.md

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-SynthesisFilters.jl provides waveform generation filters for speech synthesis, especially from mel-generalized cepstrum. The core is re-coded from [Speech Signal Processing Toolkit (SPTK)](http://sp-tk.sourceforge.net/).
+SynthesisFilters.jl provides waveform generation filters for speech synthesis, especially from mel-generalized cepstrum.
+
+Note that this package is built on top of [SPTK.jl](https://github.com/r9y9/SPTK.jl). A part of the core is re-writen in Julia language from [Speech Signal Processing Toolkit (SPTK)](http://sp-tk.sourceforge.net/).
 
 ## Features
 
-- All Pole Digital Filter (AllPoleDF)
-- Log Magnitude Approximation Digital Filter (LMADF)
-- Mel-Log Spectrum Approximation Digital Filter (MLSADF)
-- Mel Generalized-Log Spectrum Approximation Digital Filter (MGLSADF)
+- **AllPoleDF**: All-pole digital filter for synthesis from LPC
+- **LSPDF**: LSP digital filter for synthesis from LSP
+- **LTCDF**: All-pole lattice digital filter for synthesis from PARCOR
+- **LMADF**: Log magnitude approximation digital filter for synthesis from cepstrum
+- **MLSADF**: Mel-log spectrum approximation digital filter for synthesis from mel-cepstrum
+- **MGLSADF**: Mel generalized-log spectrum approximation digital filter for synthesis from mel-generalized cepstrum
 
 ## Compare vocoders