©copyright Raimo Olavi Toivonen 19852019. All rights reserved. Last updated on August 8, 2019.

Home  Signal displays 1985–  Multi-envelope displays 1998–  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–  LPC spectrogram displays 1998–  Auditory spectrogram displays 1985–  Formant charts in Bark, ERB, mel, semitone and Hz scales 1988−  Bark scale 1983−  ERB scale 1996−  Semitone scale 1989−  Other links  Formant charts of world languages in Bark scale 2018–

Works 1972−

ISA software

FFT spectra in dB/Hz/Bark scale on Intelligent Speech Analyzer ™ (ISA)

|X(k)|dB (k=0...N/2-1) = 20log10(w(n)x(n)e-jk(2π/N)n)|, n=0... Signaali x(n) = xa(nT), n=0...N-1, T on näytejakso, xa= analogiasignaali. Jos xa on mikrofonin jännitesignaali, niin xa(nT) = kPa(nT), jossa Pa on paine ja k on vakiokerroin.

The computation uses the decimation-in-time (DIT) computation method. Over the years, I have coded as a DSP man FFT spectrum 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.

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

Signaalin ikkunointi tapahtuu Hamming-ikkunalla, suorakaide-ikkunalla tai yli 90 dB:n Blackman-Harris-ikkunalla.

Hamming-ikkuna w(n) = 0.54-0.46cos(2πn/(N-1)).

Blackman-Harris-ikkuna w(n) = 0.35875-0.48829cos(2πn/(N-1))+0.14128cos(4πn/(N-1))-0.01168cos(6πn/(N-1))

Hz:t muunnetaan Bark:eiksi kaavalla x/Bark=7ln(f/650+√(1+(f/650)2)) ja
Bark:it muunnetaan Hz:eiksi kaavalla f/Hz=650sinh(x/7).

Hz:t muunnetaan ERB:eiksi kaavalla x/ERB=21,3log
10(1+f/228,7) ja
ERB:it muunnetaan Hz:eiksi kaavalla f/Hz=228,7(10
x/21,3-1).

Hz:t muunnetaan mel:eiksi kaavalla x/mel=2595log
10(1+f/700) ja
mel:it muunnetaan Hz:eiksi kaavalla f/Hz=700(10
x/2595-1).

Psychoacoustic links to "en.wikipedia.org/wiki":  Psychoacoustics   Auditory   Auditive   Auditory phonetics   Auditory system anatomy   Sone scale   Phon scale   Loudness   Equal-loudness contours   Fletcher–Munson curves   Bark scale   Critical bands   Auditory Filters   ERB scale (Equivalent rectangular bandwidth)   Mel scale   Semitone scale   Hertz scale   Sound pressure   SPL (Sound pressure level)   Stevens's power law   Stanley Smith Stevens   Harvey Fletcher   Karl Eberhard Zwicker

FTT display in Hz-scale

FTT display in Hz-scale

FTT and LPC in the same display

FTT and LPC on the same screen, formant recognition. The picture shows both Hz and Bark scales.