Re: Is there a strong relationship between cepstrum of signal and2ndderivative of signal?

Rafael Deliano wrote:
I get the impression that though "articulation index" has been replaced as method for speech recognition there is current
research on using it as an aid in noisy environment.

It wasn´t a method of speech recognition, but used to a measure
speech intelligibility in noise. Old ANSI-standard, about 1969, not
so common anymore. But it shows which parts of the spectrum are important. It should be compared to the long term spectrum of speech:
http://www.embeddedforth.de/temp/hoth.pdf
( > Wish I could read German.
Looking at the pictures is usually sufficient ... )
Normally there is not much energy in the unvoiced parts of speech. The hoth noise mentioned there is a simulation of the noise in domestic/office environment. Its low frequency.
Both reasons for the (double-)differentiator.

Thats the original circuit for the VCP200 ( plus much German text ): http://www.embeddedforth.de/temp/vcp1.pdf

The very first speech recognition unit 1952 Davis, Biddulp, Balashek
did use a different circuit with two channels: http://www.embeddedforth.de/temp/vcp2.pdf
Resurfaced in the 70ies again.

What do you want to build ?

MfG JRD

Not planning on building anything. For want of a better term it's just my "learning style". I follow rabbit trails when doing general reading. Sometimes I think see a relation between things in an unfamiliar area. I'll then ask questions to see if the insight is a sign of progress in understanding or is proof that I do not understand.

.

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