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Learn about the LabVIEW programming environment, create your first virtual instrument (VI), learn about LabVIEW's dataflow programming paradigm,become acquainted with some of LabVIEW's data types, and review some useful debugging techniques.

Overview

Welcome to the exciting world of LabVIEW for audio and signal processing applications! This module contains five screencast videos, meaning that the videos were captured directly from my computer screen. As I operate the LabVIEW software, I explain each step and discuss what is going on. After you watch each of the videos, you will possess a good idea of some fundamental LabVIEW concepts, including:

  • Front panel and block diagram programming paradigm
  • Dataflow paradigm
  • Data types
  • Broken wires
  • Debugging techniques

A bit of history

In 1986 National Instruments Corporation released the first version of LabVIEW ( Lab oratory V irtual I nstrument E ngineering W orkbench), which was designed to help engineers use a computer (the Apple Macintosh) to control and gather data from electronic instrumentation (voltmeters, oscilloscopes, and the like) all interconnected by the standard General Purpose Instrumentation Bus, or GP-IB. From its inception, LabVIEW programming was graphical in nature. Instead of writing a text file and compiling it to an executable, you connect various elements such as controls , indicators , nodes and subVIs together with wires , and in this way create a block diagram . The controls and indicators reside on the front panel , which looks just a traditional electronic instrument, i.e., it can have knobs, sliders, buttons, and display panels. The complete application is called a virtual instrument , or VI for short.

LabVIEW has since evolved into a complete programming environment; anything that you can imagine can probably be implemented in LabVIEW. Recent versions of LabVIEW have added a full suite of tools for doing signal processing, and since soundcard operations are provided, it becomes natural to develop audio signal processing applications in LabVIEW.

LabVIEW’s interactive front panel offers a unique opportunity to explore signal processing concepts in real time. As you work your way through other modules in this series, you will learn how to implement your own applications whose user interface consists of knobs, sliders and switches that can adjust processing parameters while you listen to the results.

Your first virtual instrument (vi)

Watch the following screencast video to learn how to connect front panel controls and indicators together. You will also learn how to use the While Loop structure to make your VI operate continuously until you press a “STOP” button on the front panel.

[video] Creating your first "VI" (Virtual Instrument)

The dataflow concept

The notion of LabVIEW’s dataflow programming paradigm must be grasped immediately in order for you to make forward progress learning about LabVIEW to create your own applications. Dataflow programming means that valid data must be present at all of the input terminals on a node (or subVI) before that node (or subVI) will produce valid data on its output terminals. Moreover, the node (or subVI) does not continually process its inputs data unless it is embedded in some sort of looping structure.

Click on the following animation of the dataflow concept to watch a screencast video that explains and further explores the dataflow programming concept.

[video] Understanding the LabVIEW "dataflow" paradigm

Data types

LabVIEW supports a broad range of data types , including numeric , Boolean , and string . The following screencast video will acquaint you with the floating point and integer styles of numeric data type, as well as the Boolean data type. The screencast explains the significance of the coercion indicator -- the red dot that flags a mismatch on data types applied to the input of a node or subVI -- as well as data type conversion nodes that you can use to intentionally convert a value from one data type to another.

[video] Datatypes: Numeric and Boolean

Broken wires

Broken wires indicate an error that must be corrected before your VI will run. Broken wires result from a number of causes, and it is important to understand why the wire is broken and how to correct the situation. The following screencast describes broken wires in detail.

[video] Understanding and correcting broken wires

Debugging techniques

As you begin learning LabVIEW so that you can develop your own VIs, you will find the debugging techniques described by the next screencast video helpful. Topics include adding additional indicators, using the Highlight Execution feature, using the Retain Wire Values feature, single-stepping , viewing wire values using probes , and creating breakpoints to pause execution when new data is available on a wire.

[video] Basic debugging techniques

For further study

If you are new to LabVIEW, I recommend the excellent text by Robert H. Bishop, Learning with LabVIEW 8 (Pearson Prentice Hall, 2007, ISBN 0-13-239025-6) . With this text you can learn basic LabVIEW programming techniques and get a better idea of everything that LabVIEW has to offer.

Once you have developed some skill with LabVIEW, consider Peter A. Blume’s text, The LabVIEW Style Book (Prentice Hall 2007, ISBN 0-13-145835-3) . This text covers a wide variety of techniques that will help you to develop robust and well-designed LabVIEW applications.

Don’t forget to check out the on-line documentation that is part of your LabVIEW product installation.

Visit the National Instruments website, including their Academic page and the NI Developer Zone .

Questions & Answers

List and explain four factors of production
Vuyo Reply
capital labour entrepreneur natural resources
Thembi
What is supply
Ogodo Reply
when the supply decreases demand also decreases
Thembi
types of demand and the explanation
akin Reply
what is demand
akin Reply
other things remaining same if demend is increases supply is also decrease and if demend is decrease supply is also increases is called the demand
Mian
if the demand increase supply also increases
Thembi
you are wrong this is the law of demand and not the definition
Tarasum
Demand is the willingness of buy and ability to buy in a specific time period in specific place. Mian you are saying law of demand but not in proper way. you have to keep studying more. because its very basic things in Economics.
Hamza
Demand is the price of Quantity goods and services in which consumer's are willing and able to offer at a price in the market over a period of time
Umar
Demand is the quantity of goods and services that the consumer are willing and able to buy at a alternative prices over a given period of time. But mind you demand is quite different from need and want.
Tarasum
Demand can be defined as the graphical representation between price&demand
alkasim
sorry demand is nt a graphical representation between price and quantity demand but instead that is demand curve.
Ebrima
Demand is the willingness and ability of a consumer to buy a quantity of a good over a given period of time assuming all other things remain constant.
Vedaant
what is commercialization?
Doris Reply
How to talk loan for bank?
Alfred Reply
what is the meaning of gpa?
Ritisha Reply
Answer: GPA stands for Grade Point Average. It is a standard way of measuring academic achievement in the U.S. Basically, it goes as follows: Each course is given a certain number of "units" or "credits", depending on the content of the course.
Yusuf
what is small and Microbuisenes
tadesse Reply
What is fiscal policy
Dansofo
Who is the funder of Economic
Dansofo
founder , that is Adam Smith
Daniel
what is model
Daniel Reply
The wealth of Nations
Yusuf Reply
the wealth of nations, is it the first?
Umar
Yes very sure it was released in 1759
Yusuf
thank you Yusuf.
Umar
then when did he died?
Umar
17 July 1790 Born: 16 June 1723, Kirkcaldy, United Kingdom Place of death: Panmure House, Edinburgh, United Kingdom
Yusuf
1790
Yusuf
that's my today questions, thank you Yusuf it's bed time see u after.
Umar
what is fiscal policy
kemigisha Reply
what's mode?
Umar Reply
mode is the highest occurring frequency in a distribution
Bola
mode is the most commonly occurring item in a set of data.
Umar
Please, what is the difference between monopoly and monopsony?
Olaleye Reply
is there monopsony word?
Umar
I have no idea though
Umar
please, in which year Adam smith was born?
Umar
monopsony is when there's only one buyer while monopoly is when there's only one producer.
Bola
who have idea on Banter
Ibrahim
like trade by barter?
Bola
Monopoly is when there's excessively one seller and there is no entry in the market while monopsony is when there is one buyer
kemigisha
Adam smith was born in 1723
Bola
 (uncountable) Good humoured, playful, typically spontaneous conversation. verb (intransitive) To engage in banter or playful conversation. (intransitive) To play or do something amusing. (transitive) To tease mildly.
Umar
which book Adam smith published first? the first book of Adam smith pls.
Umar
wealth on nation, 1776
Daniel
what is market power and how can it affect an economy?
Gab Reply
market power:- where a firm is said to be a price setter.market power benefits the powerful at the expense of others.
Umar
Market power refers to the ability of a firm (or group of firms) to raise and maintain price above the level that would prevail under competition is referred to as market or monopoly power. The exercise of market power leads to reduced output and loss of economic welfare
Kartheek
find information about the national budget
Molahlegi
three branches of economics in which tourism is likely to figure
Makgotso Reply
What are those three branches?
IlRegno
Difference between extinct and extici spicies
Amanpreet Reply
in a comparison of the stages of meiosis to the stage of mitosis, which stages are unique to meiosis and which stages have the same event in botg meiosis and mitosis
Leah Reply
Researchers demonstrated that the hippocampus functions in memory processing by creating lesions in the hippocampi of rats, which resulted in ________.
Mapo Reply
The formulation of new memories is sometimes called ________, and the process of bringing up old memories is called ________.
Mapo Reply
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Source:  OpenStax, Musical signal processing with labview -- programming techniques for audio signal processing. OpenStax CNX. Jul 18, 2007 Download for free at http://cnx.org/content/col10440/1.1
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