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Figures 2 and 3 show a couple of examples of the data for each speech frame for two spoken words. The word in Figure 2 is “help” and the word in Figure 3 is “free”.

If you look closely at the speech data for the word “help” you will notice that, for a particular voiced sound, the value for each reflection coefficient (K’s) of each frame varies somewhat from those of the neighboring frames. With hand editing by an expert ear, many of these frames could be replaced by one of its neighboring frame’s data (see frames 8, 9 and 10 in Figure 2). If frames could have their K values replaced with those of an appropriately chosen frame, a repeat frame could be used – therefore, 10 bits could represent the frame rather than 48 bits for a voiced frame or 28 bits for an unvoiced frame. Figure 3b shows repeat frames for the synthesized word “free”.

The idea of repeat frames giving better quality became obvious to me as I was editing the spoken phrase “Texas Instruments”. I had trouble making the word “Texas” sound correct. I finally slowed the word down and realized that the “eh” vowel sound (in the word Texas) had been turned into a diphthong (two different sounds) giving a vowel sound of “aa – eh”. This should have been expected as the professional speaker was a Texan with a good Texas accent (I’ll tell other stories about the issues we had with a Texas accent later). What was amazing was that I could take any one of the 8 or so frames and repeat it through and make the sound of the word “Texas” better. What I was doing was reducing the string of vowel sounds to just one. This edit gave a better quality at a lower bit rate.

Coefficients for the word "help" before compression.

The spectral graph of the word Free before and after data compression.
The speech data for the word “Free” after compression. Note that the data rate after compression is 775b/s.

I've attached an appendix (Appendix 3) for those who would like to know how the speech data was formatted in the ROM. It is not a topic I thought would fit well into this chapter, but one which would be interesting to some readers. With all of this as background, let’s now discuss some of the compromises we made in a bit more detail.

Sample rate

The sample rate determined the frequency response of the sound output. The higher the sample rate the better the sound would be, particularly for the unvoiced sounds. But the higher the sample rate, the higher the data rate. Although it can be argued that this is not necessarily the case, we understood that there needed to be more reflection coefficients to capture the data properly at a higher sample rate. It seemed to follow a rule of sample rate plus two to determine the number of reflection coefficients. We didn’t have time to evaluate this rule so we chose to use the simpler solution of ten coefficients, sampling at 8kHz.

At the time we began to find the professional speaker for the product, we noticed that not everyone had an “LPC friendly” voice. One of the early speakers we looked at was marvelous at doing character voices. We used him to give a voice to several of the options we had for the final name of the product. Here are a few of those choices:

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, The speak n spell. OpenStax CNX. Jan 31, 2014 Download for free at http://cnx.org/content/col11501/1.5
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