1 With the Parallax USB Oscilloscope Understanding Signals With the Parallax USB Oscilloscope Presented by: Andy Lindsay Parallax, Inc. [email protected]

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Understanding Signals With the Parallax USB OscilloscopeWith the Parallax USB Oscilloscope

Presented by: Presented by: Andy LindsayAndy LindsayParallax, Inc.Parallax, [email protected]@parallax.comom

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Copyrights and Trademarks

This documentation is copyright 2006 by Parallax Inc. By downloading or obtaining a printed copy of this documentation or software you agree that it is to be used exclusively with Parallax products. Any other uses are not permitted and may represent a violation of Parallax copyrights, legally punishable according to Federal copyright or intellectual property laws. Any duplication of this documentation for commercial uses is expressly prohibited by Parallax Inc. Duplication for educational use is permitted, subject to the following conditions: the text, or any portion thereof, may not be duplicated for commercial use; it may be duplicated only for educational purposes when used solely in conjunction with Parallax products, and the user may recover from the student only the cost of duplication.

BASIC Stamp, Stamps in Class, Board of Education, Boe-Bot SumoBot, SX-Key and Toddler are registered trademarks of Parallax, Inc. HomeWork Board, Propeller, Ping))) Parallax, and the Parallax logo are trademarks of Parallax Inc. If you decide to use trademarks of Parallax Inc. on our web page or in printed material, you must state that "(trademark) is a (registered) trademark of Parallax Inc.” upon the first appearance of the trademark name in each printed document or web page. Other brand and product names are trademarks or registered trademarks of their respective holders.

3 Chapter 1, Page 1

Software Versions and Stamps in ClassSoftware Versions and Stamps in Class

Version 4.0 Facts Version 4.0 Facts

For Windows 2K/XP For Windows 2K/XP

Compatible with Understanding Signals Compatible with Understanding Signals v1.0v1.0

Includes FFT and Zoom functionsIncludes FFT and Zoom functions

Includes Help fileIncludes Help file

Version 5.0 (Beta) FactsVersion 5.0 (Beta) Facts

For Windows XP/Vista. For Windows XP/Vista.

150 % Faster Refresh Rate150 % Faster Refresh Rate

Variable Persistence Display Variable Persistence Display featurefeature

Does not have FFT, Zoom, or Does not have FFT, Zoom, or HelpHelp

4 Chapter 1, Page 1

Software and Hardware Installation Software and Hardware Installation

Say somethingSay something

Say something elseSay something else

5 Chapter 1, Page 1

Calibrating your Probes Calibrating your Probes

6 Chapter 1, Page 1

What is an Oscilloscope?What is an Oscilloscope?

Analog vs. DigitalAnalog vs. Digital

Digital Storage ScopesDigital Storage Scopes

TriggeringTriggering

Oscilloscope Safety:Oscilloscope Safety:•Remove metallic Remove metallic jewelryjewelry

•Hands clean/dryHands clean/dry

•No food or drinksNo food or drinks

•Anti-stat mat if Anti-stat mat if availableavailable

•20 V maximum20 V maximum

•If anything gets hot, If anything gets hot, disconnect it.disconnect it.

•ALWAYS disconnect ALWAYS disconnect power to your circuit power to your circuit before leaving before leaving workstation.workstation.

7 Chapter 1, Pages 7 – 10

The Oscilloscope Display The Oscilloscope Display AreasAreas

Plot Area IndicatorPlot Area Indicator

Plot AreaPlot Area

Files/Settings, Files/Settings, Trigger, Trigger,

Cursors and Cursors and MeasurementMeasurement

s Tabss Tabs

Horizontal, Vertical, FFT and Run/Stop Horizontal, Vertical, FFT and Run/Stop ControlsControls

Cursors and Auto Measurements Display Cursors and Auto Measurements Display ScreenScreen

8 Chapter 1, Page 11

Files/Settings TabFiles/Settings Tab

Trigger TabTrigger Tab

9 Chapter 1, Pages 12 - 13

Cursors TabCursors Tab

Measurements TabMeasurements Tab

10 Chapter 1, Activity #1, Pages 14 - 17

Circuit: Figures 1-14 Circuit: Figures 1-14 and 1-15 on page 15.and 1-15 on page 15.

Program: PinHigh.bs2 Program: PinHigh.bs2 on page 16.on page 16.

√ √ Follow the Follow the checkmarks on pages checkmarks on pages 14-17.14-17.


Program: ToggleIO.bs2Program: ToggleIO.bs2

√ √ Follow the checkmarks on pages 18 - Follow the checkmarks on pages 18 - 20.20.


DODO

PULSOUT 5, 500 PULSOUT 5, 500

PAUSE 20 PAUSE 20

LOOPLOOP


Circuit: Figure 2-2, p. 25 and Figure 2-3, p. 26Circuit: Figure 2-2, p. 25 and Figure 2-3, p. 26


Program: ServoCentering.bs2 on page 29Program: ServoCentering.bs2 on page 29

√ √ Follow the checkmark instructions Follow the checkmark instructions on pages 28 - 30.on pages 28 - 30.


Program: ServoSweep.bs2, p.31Program: ServoSweep.bs2, p.31

√ √ Follow the checkmarks on page 31.Follow the checkmarks on page 31.


Circuit: Figures 3-3 and 3-4, p. 37 Circuit: Figures 3-3 and 3-4, p. 37

Program: TestPiezoWithFreqout.bs2, p. 38Program: TestPiezoWithFreqout.bs2, p. 38

√ √ Follow the checkmarks on pages 39 Follow the checkmarks on pages 39 - 40.- 40.


Digitally Synthesized Sine Digitally Synthesized Sine WaveWave


Program: Start with TestPiezoWithFreqout.bs2Program: Start with TestPiezoWithFreqout.bs2

√ √ Follow the checkmark instructions on pages 41 - 42.Follow the checkmark instructions on pages 41 - 42.


Program: DualSineWaves.bs2 on Program: DualSineWaves.bs2 on page 44.page 44.

√ √ Follow the checkmark Follow the checkmark instructions on pages 44 and 46.instructions on pages 44 and 46.


Resistor/Capacitor NetworksResistor/Capacitor Networks

Time Constant = R x CTime Constant = R x C

Where R is in ohms, C is in farads, T is in Where R is in ohms, C is in farads, T is in secondsseconds


Circuit: figures 4-4 & 4-5, pp. 52-Circuit: figures 4-4 & 4-5, pp. 52-5353Program:RCTimeConstant.bs2, p. Program:RCTimeConstant.bs2, p. 5454√ √ Follow checkmarks on pages 52 Follow checkmarks on pages 52 -56.-56.


Circuit: Figures 4-9 and 4-10 on page 58Circuit: Figures 4-9 and 4-10 on page 58

Program: RCTimeConstantWithPhotoresistor.bs2Program: RCTimeConstantWithPhotoresistor.bs2


√ √ Follow the checkmark Follow the checkmark instructions on pages 59 - 60.instructions on pages 59 - 60.



Program: ShiftinA2DExample1.bs2Program: ShiftinA2DExample1.bs2

√ √ Follow the checkmark instructions on pages 6 Follow the checkmark instructions on pages 6 and 7.and 7.


√ √ Follow the Follow the checkmarks on pages checkmarks on pages 67 - 71.67 - 71.

26 Chapter 6, Page 73

Asynchronous Serial Asynchronous Serial CommunicationCommunication


Circuit: Figures 6-2 & 6-3, p. 74 Circuit: Figures 6-2 & 6-3, p. 74 – 75– 75

Program: AsynchSerial.bs2, p. Program: AsynchSerial.bs2, p. 7676

Follow checkmark instructions Follow checkmark instructions on pages 75 – 76 and page 78.on pages 75 – 76 and page 78.

28 Chapter 6, Activity #2, Page 79

Program: Start with AsynchSerial.bs2Program: Start with AsynchSerial.bs2

√ √ Follow the checkmarks on page 79.Follow the checkmarks on page 79.


Pulse Width Modulation with InfraredPulse Width Modulation with Infrared

√ √ Assemble your Infrared Assemble your Infrared LED assembly as shown LED assembly as shown below.below.


Circuit: Figures 7-3 & 7-4, pp. 83-84.Circuit: Figures 7-3 & 7-4, pp. 83-84.

Program:38kHzInfrared.bs2 on page 85Program:38kHzInfrared.bs2 on page 85

√ √ Follow the Follow the checkmarks on checkmarks on pages 84 - 85.pages 84 - 85.


Object Detection with the Debug TerminalObject Detection with the Debug Terminal

Program: 38kHzInfraredWithDetect.bs2, p. 86Program: 38kHzInfraredWithDetect.bs2, p. 86

√ √ Follow instructions on pages 86 – 87.Follow instructions on pages 86 – 87.


Using the External TriggerUsing the External Trigger

Program: Program: 38kHzInfraredWithVaryingFrequency.bs2, p. 8938kHzInfraredWithVaryingFrequency.bs2, p. 89

√ √ Follow the checkmarks on pages 89 - 91.Follow the checkmarks on pages 89 - 91.


Program: DecodeSonyIrRemote.bs2, p. Program: DecodeSonyIrRemote.bs2, p. 9292

√ √ Follow the checkmark instructions on Follow the checkmark instructions on pages 91 – 92 and page 95.pages 91 – 92 and page 95.


Operational AmplifiersOperational Amplifiers

Schematic SymbolSchematic Symbol

Op-Amp Output Op-Amp Output with slow Slew with slow Slew RateRate

Op-Amp as a BufferOp-Amp as a Buffer

The LM358 outputs 20 mV - 3.5 V The LM358 outputs 20 mV - 3.5 V

Op-Amp Output with a Slow Slew Rate Op-Amp Output with a Slow Slew Rate

Supply Voltage Fact Supply Voltage Fact

An Op-Amp cannot An Op-Amp cannot create output signals create output signals any larger than the any larger than the voltage applied at the voltage applied at the Vcc and Vee pins, minus Vcc and Vee pins, minus “headroom.”“headroom.”


An Op-Amp used as a Voltage AmplifierAn Op-Amp used as a Voltage Amplifier

Inverting Voltage Inverting Voltage Amplifier CircuitAmplifier Circuit

Non - Inverting Non - Inverting Voltage Amplifier CircuitVoltage Amplifier Circuit

Gain = -Rf/RiGain = -Rf/Ri Gain = Rf/Ri + 1Gain = Rf/Ri + 1


Circuit: Figure 8-8, p. 106 and 8-9, p. Circuit: Figure 8-8, p. 106 and 8-9, p. 107107

√ √ Use 2 kΩ for Ri and 1 kΩ for RfUse 2 kΩ for Ri and 1 kΩ for Rf


Program: OpAmpExampleWithFreqout.bs2, page 109Program: OpAmpExampleWithFreqout.bs2, page 109

√ √ Follow the checkmark instructions on pages 108 and 109.Follow the checkmark instructions on pages 108 and 109.

Ri = 2 kΩRi = 2 kΩ

Rf = 1 kΩRf = 1 kΩ

Gain = Rf/Ri +1Gain = Rf/Ri +1

Gain = ½ + 1 = 1.5Gain = ½ + 1 = 1.5


√ √ Follow the checkmark instructions on page 110.Follow the checkmark instructions on page 110.




Gain = 1 + 1 = 2Gain = 1 + 1 = 2

Here, the top of the output Here, the top of the output signal is clipping because signal is clipping because the 9 V battery is nearing the 9 V battery is nearing the end of its useful lifethe end of its useful life






Gain = 2 + 1 = 3Gain = 2 + 1 = 3

The output signal is now The output signal is now clipping severely as the clipping severely as the 9 V battery fails9 V battery fails




Program: OpAmpExampleWithFreqout.bs2, page 109Program: OpAmpExampleWithFreqout.bs2, page 109




Gain = -Rf/Ri = 2Gain = -Rf/Ri = 2

DC Offset Applied with DC Offset Applied with PotentiometerPotentiometer

Documents

1 With the Parallax USB Oscilloscope Understanding Signals With the Parallax USB Oscilloscope Presented by: Andy Lindsay Parallax, Inc. [email protected]