8/10/2019 hw1_labview

1/5

HW 1 LabVIEW Simulation(Generating Sine and White Gaussian

Waveforms)

Introduction

LabVIEW (short for Laboratory Virtual Instrumentation Engineering Workbench)

is a platform and development environment for a visual programming language from

National Instruments. he graphical language is named !"!. #riginally released for

the $pple %acintosh in &'* LabVIEW is commonly used for data ac+uisition*

instrument control* and industrial automation on a variety of platforms including

%icrosoft Windo,s* various flavors of -NI* Linu/* and %ac #0 . he latest

version of LabVIEW is version LabVIEW 12&&. he code files have the e/tension

3.vi4* ,hich is an abbreviation for 3Virtual Instrument4. LabVIEW offers lots ofadditional $dd5#ns and oolkits.

I. Dataflow Programming

he programming language used in LabVIEW* also referred to as "* is a dataflo,

programming language. E/ecution is determined by the structure of a graphical block

diagram (the LV5source code) on ,hich the programmer connects different function5

nodes by dra,ing ,ires. hese ,ires propagate variables and any node can e/ecute as

soon as all its input data become available. 0ince this might be the case for multiple

nodes simultaneously* " is inherently capable of parallel e/ecution. %ulti5processing

and multi5threading hard,are is automatically e/ploited by the built5in scheduler*

,hich multiple/es multiple #0 threads over the nodes ready for e/ecution.

II. Graphical Programming

LabVIEW ties the creation of user interfaces (called front panel) into the

development cycle. LabVIEW programs6subroutines are called virtual instruments

(VIs). Each VI has three components7 a block diagram* a front panel* and a connector

panel. he last is used to represent the VI in the black diagrams of other* calling Vis.

8ontrols and indicators on the front panel allo, an operator to input data into or

e/tract data from a running virtual instrument. 9o,ever* the front panel can also serve

as a programmatic interface. hus a virtual instrument can either be run as a program*

,ith the front panel serving as a user interface* or* ,hen dropped as a node through

the connector pane. his implies each VI can be easily tested before being embeddedas a subroutine into a larger program. he graphical approach also allo,s non5

programmers to build programs simply by dragging and dropping virtual

representations of lab e+uipment ,ith ,hich they are already familiar. he LabVIEW

programming environment* ,ith the included e/amples and the documentation*

makes it simple to create small applications. his is benefit on one side* but there is

also a certain danger of underestimating the e/pertise needed for good +uality 3"4

programming. :or comple/ algorithm or large5scale code* it is important that the

programmer possess an e/tensive kno,ledge of the special LabVIEW synta/ and the

topology of its memory management. he most advanced LabVIEW development

systems offer the possibility of building stand5alone applications. :urthermore* it is

possible to create distributed applications* ,hich communicate by a client6serverscheme* and are therefore easier to implement due to the inherently parallel nature of

"inan;ar 0u,asono $di

&2

8/10/2019 hw1_labview

2/5

"5code.

Experimental Method

In this section ,e create and design t,o different ,aveforms ,hich are 0ine and

White "aussian ,aveforms in LabVIEW. :irtly* ,e need to create pro;ect and start

,ith LabVIEW Virtual Instrument. here are several steps to make this comes true,hich are e/plained in the procedure bello,.

&. 8reate a pro;ect

1. #pen a ne, VI

a. File >> New

b. Create New list* select VI >> lan! VI >> "#

lock =iagram are created

8/10/2019 hw1_labview

3/5

(a) :ront ?anel (b) >lock =iagram panel

@. No, ,e make schematic for sine ,aveform in >lock =iagram panel

I. 8reate a ,hile loop in >lock =iagram panel and create control in the

loop condition.

II. We make a right click on >lock =iagram panel then* choose $ignal

Proce%%ing >> &fm Generation >> $ine &fm placed sine generatorblock in the inside of ,hile loop.

III. %ake a graph ,ith make a right click on front panel then* choose Graph

AA &a'eform Graph (block diagram for this graph ,ill be created

automatically in >lock =iagram panel)

IV. "o on to >lock =iagram panel* place all blocks inside ,hile loop. We

need to make connection bet,een $ine &fm and &a'eform Graph by

,iring %ignal outpin at $ine &fmblock to &a'eform Graphblock.

V. 0et fre+uency of sine ,aveform by right clicking fre(uenc)pin at $ine

&fmblock then choose Create AA Con%tant (default fre+uency is &2

but* ,e can change it as ,hat is re+uired).

VI. %ake a sampling info by right clicking %ampling infopin at $ine &fm

block then choose Create AA Control (default sampling info is &222

but* ,e can change it as ,hat is re+uired).

VII. We also can add an amplitude constant on the graph by right clicking

amplitude pin at $ine &fm block then choose Create AA Con%tant

(default amplitude is & but* ,e can change it as ,hat is re+uired).

B. ?icture bello, is the result of schematic block that ,e set for generating sine

,aveform in the >lock =iagram panel.

. :or White "aussian ,aveform ,e do the same step like point @ by changing

$ine &fm ,ith Gau%%ian &fm. ?icture bello, is the result of schematic

block that ,e set for generating White "aussian ,aveform in the >lock

=iagram panel.

8/10/2019 hw1_labview

4/5

*e%ult and Di%cu%%ion

In this part* ,e ,ill compare and analyCe about the result of generating sine and

White "aussian ,aveforms. #n the first picture ,e see the output of generating sine

,aveform ,hich appears on :ront ?anel graph.

his sine ,aveform has setting :s (fre+uency sampling) D &222 $mplitude D @

:re+uency D &2. 9o,ever* ,hat ,e see on the graph is a ,aveform in the time

domain (/ a/is). $s ,e kno, fre+uency has a strong relationship ,ith time. When ,e

look on the basic formula thatf =1/T (,heref is fre+uency in 9C and Tis time in

second* respectively) so* if ,e set &2 9C on the fre+uency side there ,ill be one sine

,aveform on 2.& second. #n the result of the graph ,e can see that there are &2 sine

,aveforms ,hich are periodically going through the range 2 to & second.

#n the second picture bello,* ,e get the outcomes of generating White "aussian

,aveform.

his White "aussian Noise has setting :s (fre+uency sampling) D &222 :re+uency D

&. It is +uite interesting that the amplitude of this ,aveform has various peaks. When,e see on the sine graph* the amplitude and the ,avelength of the ,aveform is static*

8/10/2019 hw1_labview

5/5

but here both parameters are dramatically changing all of the time and canFt be

predictable ,hile ,e started simulation.

Conclu%ion

here are some points that ,e can sum up the simulation result ,hich ,e have

done. :irstly* LabVIEW is the soft,are that allo,s non5programmers to build

programs simply by dragging and dropping virtual representations of lab e+uipment.0econdly on simulation result* there is a big different bet,een sine and White

"aussian ,aveforms. We get static ,aveform of sine graph that the result is based on

setting ,e set. #n the other hand* ,e cannot predict ,hat the outcomes of the

,aveform ,hen ,e create White "aussian Noise.