<< Chapter < Page Chapter >> Page >
Gives details about the A/D and D/A converters used in our DMT project.

Why, you might ask, did we implement our system by using a sampled analog waveform as the input rather than an arbitrary bit stream? First, it allowed us to actaully see and hear the errors introduced by a noisy channel, rather than just having a tally of the bit errors. Second, we found it motivational to have a visible goal (i.e. the input waveform) to shoot for as we watched our results improved with every version of our code. Finally, it gave us more experience coding and lets us put these nifty plots in this module, which helps constrast the encoded time-domain plots seen in other subsystems with a real speech signal.

Analog-to-digital (a/d)

The A/D converter in our system takes in a MATLAB vector corresponding to a sampled analog signal and converts it to a bit stream. This is a two step process: quantization and bit assignment. In quantization , the amplitude axis of the input signal is broken up into 2^B levels and each sample is rounded to the nearest level. Each level is assigned a B -bit binary number, so the length Q input vector of samples is mapped to a length BQ bitstream. Below are figures of the input and quantized input waveforms.

Input sampled waveform

The input waveform used was the'Handel'sound file built into MATLAB

Quantized input waveform

Quantized version of'Handel'

Digital-to-analog (d/a)

The D/A converter in our system performs the inverse operation of the A/D converter: it takes in a MATLAB bitsream and converts it to sampled analog signal. Here, it is only a one step process: since we performed B -bit A/D conversion, we assign each block of B bits the original associated quantization level. There is an implicit error induced in D/A conversion due to quantization: since we originally rounded the sampled points to the nearest level, the information regarding their exact values is lost. This is called quantization error . However, with a speech waveform, a 4-bit (16 quantization level) approximation of the signal sounds reasonably close to the real thing. To actually see how well our output signal matched up with our input, we compared it with a quantized version of the input waveform.

Other sources for information about A/D conversion: Amplitude Quantization

Our related MATLAB functions: a2d.m , d2a.m

Home | Previous: Implementation | Next: Serial/Parallel, Parallel/Serial

Questions & Answers

how can chip be made from sand
Eke Reply
are nano particles real
Missy Reply
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
Lohitha
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
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
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
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
Berger describes sociologists as concerned with
Mueller Reply
what is hormones?
Wellington
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Ece 301 projects fall 2003. OpenStax CNX. Jan 22, 2004 Download for free at http://cnx.org/content/col10223/1.5
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Ece 301 projects fall 2003' conversation and receive update notifications?

Ask