# 0.13 Lab 9a - speech processing (part 1)  (Page 2/5)

 Page 2 / 5

In contrast, unvoiced speech has more of a noise-like quality. Unvoiced sounds are usually much smaller in amplitude,and oscillate much faster than voiced speech. These sounds are generally produced by turbulence,as air is forced through a constriction at some point in the vocal tract. For example, an h sound comes from a constriction at the vocal cords, and an f is generated by a constriction at the lips.

An illustrative example of voiced and unvoiced sounds contained in the word “erase” are shown in [link] . The original utterance is shown in (2.1).The voiced segment in (2.2) is a time magnification of the “a” portion of the word.Notice the highly periodic nature of this segment. The fundamental period of this waveform, which is about 8.5 ms here,is called the pitch period . The unvoiced segment in (2.3) comes from the “s” soundat the end of the word. This waveform is much more noise-like than the voicedsegment, and is much smaller in magnitude.

## Classification of voiced/unvoiced speech

For many speech processing algorithms, a very important step is to determine the type of sound that is being uttered in a given timeframe. In this section, we will introduce two simple methods for discriminatingbetween voiced and unvoiced speech.

Download the file start.au , and use the auread() function to load it into the Matlab workspace.

Do the following:

• Plot (not stem) the speech signal. Identify two segments of the signal: one segment that is voicedand a second segment that is unvoiced (the zoom xon command is useful for this).Circle the regions of the plot corresponding to these two segments and label them as voiced or unvoiced.
• Save 300 samples from the voiced segment of the speech into a Matlab vector called VoicedSig .
• Save 300 samples from the unvoiced segment of the speech into a Matlab vector called UnvoicedSig .
• Use the subplot() command to plot the two signals, VoicedSig and UnvoicedSig on a single figure.
Hand in your labeled plots. Explain how you selected your voiced and unvoiced regions.

Estimate the pitch period for the voiced segment. Keep in mind that these speech signals are sampled at 8 KHz, which means that the time betweensamples is 0.125 milliseconds (ms). Typical values for the pitch period are 8 ms for male speakers,and 4 ms for female speakers. Based on this, would you predict that the speaker is male, or female?

One way to categorize speech segments is to compute the average energy, or power.Recall this is defined by the following:

$P=\frac{1}{L}\sum _{n=1}^{L}{x}^{2}\left(n\right)$

where $L$ is the length of the frame $x\left(n\right)$ . Use [link] to compute the average energy of the voiced and unvoiced segments that you plotted above.For which segment is the average energy greater?

Another method for discriminating between voiced and unvoiced segments is to determine the rate at which the waveformoscillates by counting number of zero-crossings that occur within a frame (the number of times the signal changes sign).Write a function zero_cross that will compute the number of zero-crossings that occur within a vector, and apply this to the two vectors VoicedSig and UnvoicedSig . Which segment has more zero-crossings?

how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Do somebody tell me a best nano engineering book for beginners?
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
what is nano technology
what is system testing?
preparation of nanomaterial
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
what is system testing
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
how did you get the value of 2000N.What calculations are needed to arrive at it
Privacy Information Security Software Version 1.1a
Good
Berger describes sociologists as concerned with
Got questions? Join the online conversation and get instant answers!