ęcopyright Raimo Olavi Toivonen 1985-2021. All rights reserved. Last updated on Jan 30, 2021.

Home  Signal displays 1985-  Multi-envelope displays 1998-  FFT displays 1985-  Cepstrum displays 1983-  LPC displays 1992-  Auditory displays 1983-  Loudness displays 1995-  Loudness curves 1998-  Timbre spectrum 1983-  LTAS displays 1982-  Harmonic FFT displays 1989-  Waterfall displays 1983-  F0 displays 1983-  F0 histograms in semitone scale 1989-  Jitter/shimmer 1990-  Computer Voice Fields 1983-  FFT spectrogram displays 1985-  Auditory spectrogram displays 1985-  Formant charts in Bark, ERB, mel, semitone and Hz scales 1988-   Synte 2 demo video speech on 8.8.1977 analyzed 2018-  Formant charts of world languages in Bark scale 2018-    Other links

Works   Works before ISA

ISA software

LPC spectrograms in Hz/time scale

The calculation uses the PARCOR method. Over the years, I have coded as a DSP man PARCOR-laskennan of the Intelligent Speech Analyser™ (ISA) program
(1) for the Texas 16-bit TMS320 signal processor family in machine language,
(2) for Motorola's 16 and 32-bit M68000 microprocessor families in machine language and C language,
(3) for IBM 600 Series 32-bit PowerPC Microprocessor Family in machine language and C language,
(4) for Intel 32-bit and 64-bit microprocessor families in C++ language.

Signal windowing is done with a Hamming window, a rectangular window or a Blackman-Harris window with more than 90 dB.

Formants are tracked in a unique way by first filtering the LPC spectral curve by bandpass filtering and then searching for peaks in the sharpened spectrum by a unique method.

Analysis pictures I have coded from the very beginning in Neon object-oriented programming language.

LPC spectrogram display in Hz-scale

LPC spectrogram display on the Hz scale, formants expressed on the Hz scale.