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An overview of DSP optimization techniques, from the design stage, through high-level implementations, to assembly implementations.

Introduction to code optimization

Most practical DSP applications have a clock-cycle and/or memory budget. Initial implementations typically don't meet these budgets;therefore, the code must be optimized. Code development usually follows six steps:

  • Develop algorithm on paper
  • Simulate in MATLAB
  • Develop and simulate more efficient implementations
  • Implement algorithm in C
  • Use library routines when available
  • Use optimizing compiler
  • Manually write assembly routines for key routines

Develop algorithm on paper

The algorithm to be implemented should first be designed on paper. In addition to equations describing the algorithm, its design shouldinclude inputs and outputs of each routine and a flow chart of the operation of the complete program. Never design an algorithm or a program at a computer. While it may be possible to implement some basic algorithms and programs this way, compilers cannot overcome any designflaws that are likely to be introduced.

Simulate in matlab

Before any C code is written, the algorithm should be developed and simulated in MATLAB since problems with the algorithm design can befound more easily. This is done by applying the algorithm to test vectors and inspecting and/or plotting the results. Once thealgorithm is completely defined, C implementation can begin. Recall that in each of the previous labs a MATLAB simulation step was givenbefore assembly implementation.

Develop and simulate more efficient implementations

An efficient algorithm used as few multiplications and additions as possible. Applying DSP theory to "simplify" the algorithm is a commonway of doing this. The autocorrelation function is a simple example: a simple-minded way of implementing this is tocompute sums for each lag, but careful inspection of the autocorrelation function reveals that it is actually a function of the absolute value of the lag. Therefore each value at a negative lag is identical to the value at the correspondingpositive lag. Approximately half the apparent multiplications and additions aretherefore required. If the entire autocorrelation sequence is needed, the autocorrelation can be optimized even furtherif it is treated as a convolution of two sequences. An FFT and an inverse FFT can then be used to compute the autocorrelation.

C implementation

After the algorithm has been designed and optimized, an initial implentation in C is done. Tips on writing code with efficiency inmind can be found here . It is important, however, to get a working implementation ofthe algorithm in a reasonable amount of time as some optimizations cannot be anticipated by the programmer.Some of these coding techniques in the URL reference can be applied later on when it is clear which routines need the most optimization.This implementation can serve as a reference implementation to compare the correctness and speed of optimized versions.

Questions & Answers

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
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
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 ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
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
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Digital signal processing laboratory (ece 420 55x). OpenStax CNX. Jan 18, 2010 Download for free at http://cnx.org/content/col10397/1.10
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