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Use the Project Explorer (left pane in Eclipse) to open the different files and familiarize yourself with each component.

Building the project

Building the project actually consists of first building your Native C code as a library using ndk-build , and then building the Java code, which is responsible for loading the C library and executing your functions.

For this lab project, the build process in Eclipse has already been configured to build everything automatically, and so building your project is as simple as clicking Project>Build Project .

You may want to uncheck Build Automatically , and then build by first Clean ing the project and checking the "Immediately start build" option.

C syntax support

Open .\jni\process.c in the Eclipse editor. This file contains the processing function, which is where you will implement your signal processing. If you see notifications for syntax errors, then in the Project Explorer , right-click on the project name and go to Project Properties>C/C++ General>Paths and Symbols and add the following three files into the Include directories for GNU C : C:\NvPack\android-ndk-r8\platforms\android-9\arch-arm\usr\include C:\NvPack\android-ndk-r8\sources\cxx-stl\gnu-libstdc++\includeC:\NvPack\android-ndk-r8\sources\cxx-stl\gnu-libstdc++\libs\armeabi-v7a\include

Part 2: a development environment for signal-processing applications

Function declarations in java and c

In the Lab4Activity Java class, the following function declaration is made:

public static native void process(ShortBuffer inbuf, DoubleBuffer outbuf, int N);

Where is the Lab4Activity class defined?

According to the "Understanding the Android Project Structure" section in Part 1, you can find it in Lab4Activity.java in a sub-directory of .\src\

Here, the native keyword states that process() is a Native C function. The first argument points to the Java-equivalent of a short[N] array, which holds a block of the 16-bit audio data. The second argument points to the Java-equivalent of a double[N] array, which you have to fill with data to visualize on-screen.

In process.c , the C-equivalent function declaration for process() , along with pointers to the input and output buffers have already been written for you. Appropriate header files have also been included, including the FFTW library, a popular C library for implementing the FFT.

Debugging in java

To introduce the Java debugging environment, you will verify that the mechanism for using test vectors is working correctly. First, in the Lab4Activity class definition, set the variable FILE_INPUT to true . Set a breakpoint on the line where process() is called.

Click Run>Debug , and debug as an Android Application . The project will automatically rebuild if out-of-date, and should switch to the Debug Perspective . The application will automatically run and be halted at the set breakpoint.

Click Window>Show View>Expressions and add the following expression: sb.get(0) , which returns the first value in the buffer. Verify that the value is correct by comparing to the values in the lookup table defined in LOOKUP.java . Repeat this for other values in the table to convince yourself that the test vector values were copied correctly.

The Android Reference guide contains detailed information about the classes you will encounter in Java (e.g., the ShortBuffer class).

Questions & Answers

what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
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.
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
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
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
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
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
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.
what is the actual application of fullerenes nowadays?
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.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Ece 420 fall 2013. OpenStax CNX. Sep 26, 2013 Download for free at http://cnx.org/content/col11560/1.3
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