Fluke Oscilloscope 4 Isolated Channels 200 Mhz Bandwidth CAT III 1000 CAT IV 600 Rated 2.5 GS/s sample rate Connect-and-View™ IP-51 Rated

Oscilloscopes Electrical Signals are measured in three domains X axis, time (Seconds) Y axis, Amplitude (Volts, dB) Z axis, Frequency (Hertz) Vac Volts time A multimeter precisely measures a signals amplitude An osciloscope displays a signal amplitude change over time A spectrum analyzer displays a signal power level (amplitude) with respect to frequency dB Frequency

What is a multimeter? A Multimeter accurately displays discreet Volts, Ohms and Amp measurements. A typical multimeter uses an integrating ADC to convert an unknown voltage –An integrating capacitor is charged for a precise time span, then discharged. –The discharge time is proportionate to the unknown signal charging the integrator. –The longer the integration time, the higher the resolution, therefore more accurate the measurement becomes. Accuracies as low as 10’s of parts per million (0.001 %) can be achieved Time in Seconds Amplitude in Volts

What is an Oscilloscope? An Oscilloscope graphically plots signals over time –The oscilloscope using high speed A to D conversion, samples the unknown input as fast as possible then graphically plots the unknown samples over time “A picture is worth a thousand words!” Amplitude in Volts Time in Seconds

DMM or Oscilloscope? A multimeter, presents a single precise measured value An oscilloscope presents a graphical representation of a signal change over time. –To obtain precise measurements, the typical DMM converts the unknown input at a rate of 5 or 10 times per second –To accurately represent a signal change over time, an oscilloscope can sample the unknown input up to 2.5 billion times per second (or faster)

Digital Storage Oscilloscope Input Coupling AC or DC Amplitude Control Attenuation Amplification Channel Isolation Up to 1000 Volt isolation Available on some scopes A to D Conversion Real time Up to 2.5 GSa/s System Control Sample Storage Measure functions Graphics processing User interface Ch A 2.5 GSa/s A/D Lf Hf Optional Ch Isolation Micro Processor Memory Triggering Edge Edge Delay Pulse Width N-Cycle

Input Coupling Input coupling determines what is passed on to the signal conditioning circuit –AC, Passes AC component only –DC, Passes both AC and DC components of the signal Gnd Ref Applied Input Resultant Output DC Coupling AC Coupling AC & DC Signal Components AC Signal Component, DC is blocked by capacitor Gnd Ref

Display Amplitude Control Controls the vertical span of the displayed signal, adjusted in volts per vertical display division –mV increases sensitivity –V decreases sensitivity mV V Gnd Ref Vertical Sensitivity (V/Div) Amplitude display range Pressing mV increases vertical sensitivity Pressing V deceases vertical sensitivity

Analog to Digital Conversion Horizontal Time base (s/Div) Sampling clock interval time Horizontal resolution mS/Div The unknown signal is applied to the analog to digital converter (A/D). –The A/D process divides the signal into segments at specified time intervals. –At each time interval the voltage of the signal is determined and stored into memory S/Div A to D Conversion Storage Memory Gnd Ref

Sample Rate & Memory A digital storage oscilloscope contains a fixed amount of memory points –The more memory, the higher the cost and the longer it takes to fill up over a complete acquisition cycle –The fewer memory points the lower the resolution, the displayed signal time span and frequency bandwidth The sample rate will increase or decrease relative to the amount of memory and maximum sample rate It will automatically adjust the sample rate from its maximum at the fastest time base setting (nano seconds/div) to a slower sample rate at the slower time base settings (example, milli seconds/div) Memory Depth time Cost Sample Rate Time base ns Min S gS

Digital Oscilloscope Aliasing If the acquisition rate is much slower than the frequency of the measured signal Aliasing can occur Aliasing displays incorrect signals Actual Signal Signal observed when Aliasing occurs

A/D – Glitch Detection Glitch Detect –At slow time base settings/ sampling intervals the A/D can miss glitches –Over sampling captures min and max sample points, preventing aliasing and displaying glitches Digitized Signal Actual Signal Over Sampling Glitch Detect The Min & Max samples displayed in each column Displayed Max Sample Displayed Min Sample Display Pixels

Oscilloscope Bandwidth Frequency 1 Frequency 2 Frequency 3 Bandwidth, determines the highest signal frequency the oscilloscope can accurately reproduce –The maximum frequency is usually determined by measuring the point at which the amplitude decreases as frequency increases by no more than -3 db’s (30% change) –Bandwidth is also dependent on sampling rate Test Signal Volume Perceived Volume

Triggering Triggering, synchronizes the waveform display process every time the waveform is refreshed or displayed Composite image of “Un- Triggered” scope T Triggered, resulting in stable display Acquisition cycles

Triggering Techniques Oscilloscopes use several techniques to trigger on unknown signals –Edge, a specific voltage level set relative to either a rising or falling edge. –Pulse Width, specifies both a specific voltage level relative to an edge, plus a time interval between the rise and falling edges (or visa versa). –Automatic Connect&View: As implied, connect then view, as simple as that! Eliminates need to continuously adjust the scope vertical sensitivity, horizontal time and trigger settings V level time V/Div Time/Div Trigger

Oscilloscope Isolation The ScopeMeter input connectors are insulated to prevent against exposure to electrical voltages The input power adapter is isolated from earth ground, allowing for floating measurements A typical bench oscilloscope uses metal BNC connectors and metal chassis components, potentially exposing the user to hazardous voltages. To protect against electric shock the bench oscilloscope is connected directly to earth ground via wall outlet. Isolated adapter DC Out AC to DC Power Adapter, specially designed to meet CAT II 1000V/ CAT III 600V Safety rating Ref ARef B

Channel Isolation Bench oscilloscope with exposed metal BNC connectors and common input references, for safety reasons are tied to earth ground Fluke 190 series portable oscilloscope with insulated BNC input connectors isolated from earth ground with isolated input references CH A Signal Input CH B Signal Input CH A Referen ce Input CH B Referen ce Input CAT II 1000 V/ CAT III 600V Isolation Common reference tied to earth ground CH A Signal Input CH B Signal Input The Fluke ScopeMeter test tools provide a safe means to measure floating differential voltages

Using the Oscilloscope Input Connections –BNC Connectors are 300V CAT IV –Fluke 10:1 Probes provide 1000V CAT III 600V CAT IV

Using the Oscilloscope Resetting the to factory settings

Using the Oscilloscope Hiding Labels and Key Illumination meaning

Using the Oscilloscope Probe Settings

Using the Oscilloscope Selecting Input Channels

Using the Oscilloscope Connect-and-View™

Using the Oscilloscope Automatic Measurements

Using the Oscilloscope Average, Persistance, and Glitch Capture

Using the Oscilloscope Displaying Glitches and suppressing High Frequency Noise

Using the Oscilloscope Acquisition Rate

Using the Oscilloscope AC/DC Coupling

Using the Oscilloscope Bandwidth and Noisy Waveforms

Using the Oscilloscope Mathematics (FFT)

Using the Oscilloscope Reference Trace

Using the Oscilloscope Meter Mode

Using the Oscilloscope Trend Plot Meter

Using the Oscilloscope ZOOM Button

Using the Oscilloscope CURSOR Button

Using the Oscilloscope Record Waveforms in Deep Memory

Using the Oscilloscope Scope Record in Single Sweep Mode

Using the Oscilloscope REPLAY Button

Using the Oscilloscope Trigger Level

Using the Oscilloscope Saving and Recalling

Using the Oscilloscope FlukeView Scope Software Demonstration

Conclusion Questions?