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In this project you will create an oscillator whose output tracks a specified amplitude and frequency trajectory. With this general-purpose oscillator you can define multiple frequency/amplitude trajectories that can be combined to create complex sounds. In particular, you will design the sound so that its spectrogram makes a recognizable picture!
This module refers to LabVIEW, a software development environment that features a graphical programming language. Please see the LabVIEW QuickStart Guide module for tutorials and documentation that will help you:
•Apply LabVIEW to Audio Signal Processing
•Get started with LabVIEW
•Obtain a fully-functional evaluation edition of LabVIEW


Additive synthesis builds up complex sounds from simple sounds (sinusoids). Additive synthesis implies more than just doing Fourier series, though: each sinusoidal component is assigned its own frequency and amplitude trajectory (resulting in a partial), so complex, time-varying sounds can be generated by summing these partials together.

In this project you will create an oscillator whose output tracks a specified amplitude and frequency trajectory. With this general-purpose oscillator you can define multiple frequency/amplitude trajectories that can be combined to create complex sounds. In particular, you will design the sound so that its spectrogram makes a recognizable picture!

Prerequisite modules

If you have not done so already, please study the prerequisite modules Additive Synthesis Concepts and Additive Synthesis Techniques . If you are relatively new to LabVIEW, consider taking the course LabVIEW Techniques for Audio Signal Processing which provides the foundation you need to complete this mini-project activity, including working with arrays, creating subVIs, playing an array to the soundcard, and saving an array as a .wav sound file.


  • All LabVIEW code that you develop (block diagrams and front panels)
  • All generated sounds in .wav format
  • Any plots or diagrams requested
  • Summary write-up of your results

Part 1: general-purpose sinusoidal oscillator

Develop a subVI called gposc.vi that accepts a frequency trajectory (in Hz), an amplitude trajectory, and a sampling frequency (in Hz) to produce a sinusoidal output whose amplitude and frequency tracks the two input trajectories, respectively. The two trajectories are arrays that should be of the same length.

Demonstrate that your oscillator works properly by showing the output of your VI (spectrogram and .wav file) for the amplitude and frequency trajectories produced by a LabVIEW MathScript node that contains the following code:

ff=[linspace(200,1600,2.5*fs) ... linspace(1600,800,1.5*fs)]; aa=[linspace(1,0,3*fs) ...linspace(0,0.75,fs)];

where fs is the sampling frequency in Hz, ff is the output frequency trajectory (also in Hz), and aa is the amplitude trajectory (between 0 and 1). Use a sampling frequency of 5 kHz when you make the spectrogram and soundfile.

Plot the trajectories ff and aa and compare to your spectrogram.

Remember, the instantaneous frequency of your general-purpose sinusoidal oscillator is related to the time-varying phase of the sine function. That is, if the sinusoidal signal is defined as y ( t ) = sin ( θ ( t ) ) , then the instantaneous frequency of the sinusoid is ω ( t ) = d θ ( t ) / d t radians per second. Because you are given a frequency trajectory that relates to ω ( t ) , which mathematical operation yields the phase function θ ( t ) ?

Here's a LabVIEW coding tip: You will find the built-in VI "Mathematics | Integ and Diff | Integral x(t)" to be essential for this part of the project.

Part 2: frequency trajectory design

You can make your spectrogram art project sound more musically appealing when you design the frequency trajectories to account for frequency perception ; refer to Perception of Sound for a detailed treatment of this subject. Design your trajectories in "log space" (using logarithmic graph paper) and then convert to actual frequency just before invoking your general-purpose sinusoidal oscillator.

Review Additive Synthesis Techniques to learn how to create your frequency trajectories for this part of the project.

Part 3: amplitude trajectory design

The discussion of Part 2 pertains to the design of your amplitude trajectories, as well. Perception of intensity (loudness) is also logarithmic (refer to Perception of Sound and review the section on intensity perception). In this part you will design your amplitude trajectory in "log space," but now using traditional decibels (dB). An intensity trajectory can be converted to amplitude by "undoing" the equation that relates a value to the same value expressed in decibels: X dB = 20 log 10 ( X ) .

Experiment with your spectrogram display device to learn the intensity-to-color mapping. Specifically, you could produce a sinusoidal signal with increasing intensity values over time, then match up the plotted colors to the known intensity values.

Part 4: spectrogram art

Design a spectrogram picture using multiple frequency/amplitude trajectories. Include your paper-and-pencil drawing of the spectrogram as part of your deliverables. Use your creativity to make an interesting and recognizable picture.

Better designs will go beyond straight lines to include curved lines such as arcs, exponentials, parabolas, sinusoids, polynomials, spline interpolations, and so on.

Include a .wav file of the sound associated with your spectrogram picture.

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
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Source:  OpenStax, Musical signal processing with labview -- additive synthesis. OpenStax CNX. Nov 07, 2007 Download for free at http://cnx.org/content/col10479/1.1
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