Tektronix TDS 500C, TDS 600B, TDS 700C FFT Windows

Using Features for Advanced Applications

3–206 TDS 500C, TDS 600B, & TDS 700C User Manual

You specify the phase suppression level in dB with respect to 1 VRMS. If the

magnitude of the frequency is greater than this threshold, then its phase angle

will be displayed. However, if it is less than this threshold, then the phase angle

will be set to zero and be displayed as zero degrees or radians. (The waveform

reference indicator at the left side of the graticule indicates the level where phase

is zero for phase FFTs.)

It is easier to determine the level of phase suppression you need if you first

create a frequency FFT math waveform of the source and then create a phase

FFT waveform of the same source. Do the following steps to use a cursor

measurement to determine the suppression level:

1. Do steps 1 through 7 of To Create an FFT that begins on page 3–193. Select

dBV RMS (side) for the Set FFT Vert Scale to (side).

2. Press CURSOR ➞ Mode (main) ➞ Independent (side) ➞ Func-

tion (main) ➞ H Bars (side). Use the general purpose knob to align the

selected cursor to a level that places the tops of the magnitudes of frequen-

cies of interest above the cursor but places other magnitudes completely

below the cursor.

3. Read the level in dB from the @: readout. Note the level for use in step 5.

4. Press MORE (main) ➞ Change Waveform Definition menu (side). Press

Set FFT Vert Scale to (side) repeatedly to choose either Phase (rad) or

Phase (deg).

5. Press Suppress Phase at Amplitudes (side). Use the general purpose knob

to set phase suppression to the value obtained using the H Bar cursor. Do not

change the window selection or you will invalidate the results obtained using

the cursor.

To learn how to optimize your display of FFT data, read about how the FFT

windows data before computing the FFT math waveform. Understanding FFT

windowing can help you get more useful displays.

Windowing Process. The oscilloscope multiplies the FFT time domain record by

one of four FFT windows before it inputs the record to the FFT function. Figure

3–99 shows how the time domain record is processed.

FFT Windows

Contents

Main Page WARRANTY Page Table of Contents Getting Started Operating Basics Reference Appendices Glossary Index List of Figures Page Page Page List of Tables Page General Safety Summary To Avoid Fire or Personal Injury Symbols and Terms Preface Related Manuals Default Model Model References Conventions Page Page Page Product Description Product Description 12 TDS 500C, TDS 600B, & TDS 700C User Manual Differences by Model Page Page Start Up Preparation Probe Usage Signal Path Compensation Recommended Probes Putting into Service Input Coupling Installation Front Cover Removal Power On Self Test Power Off Page Overview Page Operating Interface Maps Front Panel Map Left Side 24 TDS 500C, TDS 600B, & TDS 700C User Manual Front Panel Map Right Side TDS 500C, TDS 600B, & TDS 700C User Manual 25 Rear Panel Map 26 TDS 500C, TDS 600B, & TDS 700C User Manual Display Map To Operate a Menu To Operate a Pop-Up Menu Tutorial Setting Up for the Examples Connect the Input Signal Reset the Oscilloscope Page Examine the Display Elements Example 1: Displaying a Waveform Adjust the Waveform Display Autoset the Oscilloscope Page Example 2: Displaying Multiple Waveforms Add a Waveform Page Page Assign Controls to Another Channel Remove a Waveform Example 3: Taking Automated Measurements Display Measurements Automatically Page Page Page Page Displaying a Snapshot of Automated Measurements Example 4: Saving Setups Save a Setup Page Recall a Setup Page Page Overview Acquiring and Displaying Waveforms Triggering on Waveforms Measuring Waveforms Saving Waveforms and Setups Page Page Acquiring and Displaying Waveforms Coupling Waveforms to the Oscilloscope To Compensate Passive Probes Input Impedance Considerations Setting up Automatically: Autoset and Reset To Autoset the Oscilloscope List of Autoset Defaults 310 TDS 500C, TDS 600B, & TDS 700C User Manual Table 31: Autoset defaults (Cont.) Selecting Channels Page Waveform Priority Scaling and Positioning Waveforms To Check Position To Check the Vertical Scale To Change Vertical Scale and Position Page To Change Vertical Parameters To Set External Attenuation (TDS 500C and TDS 700C Only) To Check the Horizontal Status To Change Horizontal Scale and Position To Change Horizontal Parameters Page To Select the Delayed Time Base Extended Acquisition Length (Option 2M Only) Page Page Choosing an Acquisition Mode Sampling and Digitizing Real-time Sampling Equivalent-Time Sampling Interpolation Interleaving The Acquisition Modes Page TDS 500C, TDS 600B, & TDS 700C User Manual 331 Multiple Waveform Acquisitions Figure 315: How the Acquisition Modes Work Single Waveform Acquisition Page Page Selecting Repetitive Sampling Stop After Page Preventing Aliasing Customizing the Display Change Display Settings Select the Display Style Page Page Select Interpolation Filter Select the Graticule Type Select the Format Customizing the Display Color Change the Display Color Choose a Palette Change the Palette Colors Set Math Waveform Color Set Reference Waveform Color Select Options Restore Colors Zooming on Waveforms Using with Waveforms Interpolation and Zoom Checking the Zoom Factor Zoom a Waveform Set Interpolation Reset Zoom Using Dual Window Mode Page Dual Zoom a Waveform To Set Dual Zoom Offset Using InstaVu Acquisition Mode Waveform Capture Rate To Use InstaVu Mode TDS 500C, TDS 600B, & TDS 700C User Manual 357 Normal DSO Mode Figure 329: Normal DSO Acquisition and Display Mode Versus InstaVu Mode InstaVu Mode To Set the InstaVu Style To Set the InstaVu Readout Options Incompatible Modes Using FastFrame Page Page Page Triggering on Waveforms Triggering Concepts The Trigger Event Trigger Sources Trigger Types Trigger Modes Trigger Holdoff Trigger Coupling Trigger Position Triggering from the Front Panel Slope and Level To set MAIN LEVEL Delayed Trigger System To Set to 50% To Force a Trigger To Single Trigger To Check Trigger Status Page Triggering on a Waveform Edge Trigger Menu To Check Edge Trigger Status To Select Edge Triggering To Select a Source To Specify Coupling To Set Mode & Holdoff To Set Slope Triggering Based on Logic To Set Level Pattern and State Classes Setup and Hold Class To Check Logic Trigger Status 380 TDS 500C, TDS 600B, & TDS 700C User Manual Figure 340: Violation Zones for Setup/Hold Triggering To Trigger on a Pattern Page To Define a Time Qualified Pattern Trigger Page To State Trigger To Trigger on Setup/ Hold Time Violations Page Page Triggering on Pulses 390 TDS 500C, TDS 600B, & TDS 700C User Manual Figure 345: Pulse Trigger Readouts Table 37: Pulse trigger definitions To Trigger on a Glitch Page To Trigger on a Runt Pulse Page Page Trigger Based on Pulse Width To Trigger Based on Slew Rate Page Page Page Trigger Based on Pulse Timeout Page Communications Triggering To Select Comm Triggering To Select a Source To Specify Code To Set Mode & Holdoff Page Delayed Triggering To Set Level or Threshold Page To Run After Delay To Trigger After Delay TDS 500C, TDS 600B, & TDS 700C User Manual 3109 Delayed Triggerable By Events Figure 352: How the Delayed Triggers Work Delayed Triggerable By Time Delayed Runs After Main Page Page Page Measuring Waveforms Taking Automated Measurements Measurement List TDS 500C, TDS 600B, & TDS 700C User Manual 3115 Table 310: Measurement definitions (cont.) Measurement Readouts Display Measurements Remove Measurements Gate Measurements Page Define High-Low Setup Define Reference Levels Page Take a Delay Measurement Take a Snapshot of Page Display Measurement Statistics (TDS 500C and TDS 700C Only) Taking Cursor Measurements Cursor Types Cursor Modes Cursor Readouts Select the Cursor Function Set Mode and Adjust the Cursors Select Cursor Speed Select Time Units Select Amplitude Units Taking Graticule Measurements Measure Waveform Amplitude Displaying Histograms (TDS 500C and TDS 700C Only) Measure Waveform Time Start Histogram Counting Reset Histogram Counting Display a Histogram Setting Histogram Box Size Histogram Measurement List Measurement Readouts Display Histogram Mask Testing (Option 2C Only) Remove Measurements Setting Mask Options Selecting a Mask Page Adjusting Time Base Position Counting Masks Editing a Mask Page Page TDS 500C, TDS 600B, & TDS 700C User Manual 3141 Table 312: Standard masks Optimizing Measurement Accuracy: SPC and Probe Cal Signal Path Compensation Channel/Probe Deskew Probe Cal Page Page Page Page Page Page 3150 TDS 500C, TDS 600B, & TDS 700C User Manual Table 313: Probe cal status Saving Waveforms and Setups Saving and Recalling Setups To Save a Setup To Recall a Setup To Recall the Factory Setup To Delete All Setups and Waveforms Tek Secure Saving and Recalling Waveforms and Acquisitions To Run the File Utilities To Save a Waveform To Save an Acquisition (Option 2M Only) To Change Format To Delete Waveforms Page To Recall an Acquisition From Disk (TDS 500C and TDS700C Only) To Enable Autosave Managing the File System To Run the File Utilities To Access the File Utilities Page To Delete To Rename To Copy To Print To Create a Directory To Set Confirm Delete Printing a Hardcopy To Set Overwrite Lock To Select a Drive To Format Supported Formats To Set Up for Making Hardcopies Page Page To Print Directly to a Hardcopy Device Page To Save to a Disk To Print Using a Controller Page Communicating with Remote Instruments To Prepare for Remote Operation Page To Set Up for Remote Operation Page Page Determining Status and Accessing Help Displaying Status Page Page Page Using Features for Advanced Applications Limit Testing To Create Limit Test Template Page To Select a Limit Test Source To Specify the Limit Test Response Single Waveform Comparisons Waveform Math Multiple Waveform Comparisons To Use Single Wfm Math To Use Dual Wfm Math Fast Fourier Transforms To Average a Math S To Create an FFT Page Page To Take Cursor Measurements of an FFT Page To Take Automated Measurements of an FFT The FFT Frequency Domain Record Page Page Record Length Acquisition Mode Zoom and Interpolation Undersampling (Aliasing) Considerations for Phase Displays Page FFT Windows Page Page Page Waveform Differentiation To Create a Derivative of a Page Page Using Zoom Waveform Integration To Create a Integral Math To Take Cursor Page To Take Automated DC Offset Using Zoom Page Appendix A: Options and Accessories Options A2 TDS 500C, TDS 600B, & TDS 700C User Manual Table A1: Options (cont.) TDS 500C, TDS 600B, & TDS 700C User Manual A3 Table A1: Options (cont.) Standard Accessories A4 TDS 500C, TDS 600B, & TDS 700C User Manual Table A2: Standard Accessories (Cont.) Optional Accessories You can also order the optional accessories listed in Table A3. Table A3: Optional Accessories Accessory Probes Page Accessory Software Warranty Information Service Assurance Page Appendix B: Algorithms Measurement Variables High, Low HighRef, MidRef, LowRef, Mid2Ref Other Variables MCross Calculations Page Measurement Algorithms Amplitude Area Cycle Area Burst Width Cycle RMS Delay Extinction Ratio Extinction % Extinction dB Fall Time Frequency High Low Maximum Mean Mean dBm Minimum Negative Duty Cycle Negative Overshoot Negative Width Optical Power Peak to Peak Period Phase Positive Duty Cycle Positive Overshoot Positive Width Rise Time RMS: Integration Algorithm Measurements on Envelope Waveforms Missing or Out-of-Range Samples Page Appendix C: Packaging for Shipment Page Appendix D: Probe Selection Passive Voltage Probes General Purpose (High Input Resistance) Probes Low Impedance (ZO) Probes High Voltage Probes Active Voltage Probes Current Probes High Speed Active Probes Differential Probes Fixtured Active Probes Optical Probes Page Appendix E: Inspection and Cleaning General Care Inspection and Cleaning Procedures Page Appendix F: Programmer Disk Loading the Programs Running the Help Program Page Page Glossary Page Page The ratio of High optical power to Low optical power. Page Page Page Page Page Page Page Page Page Page Page TDS 500C, TDS 600B, & TDS 700C User Manual Index1 Index Numbers A Index2 TDS 500C, TDS 600B, & TDS 700C User Manual B C TDS 500C, TDS 600B, & TDS 700C User Manual Index3 Index4 TDS 500C, TDS 600B, & TDS 700C User Manual D TDS 500C, TDS 600B, & TDS 700C User Manual Index5 E F Index6 TDS 500C, TDS 600B, & TDS 700C User Manual G H TDS 500C, TDS 600B, & TDS 700C User Manual Index7 I K L Index8 TDS 500C, TDS 600B, & TDS 700C User Manual M TDS 500C, TDS 600B, & TDS 700C User Manual Index9 Index10 TDS 500C, TDS 600B, & TDS 700C User Manual N O TDS 500C, TDS 600B, & TDS 700C User Manual Index11 P Q R Index12 TDS 500C, TDS 600B, & TDS 700C User Manual S TDS 500C, TDS 600B, & TDS 700C User Manual Index13 Index14 TDS 500C, TDS 600B, & TDS 700C User Manual T TDS 500C, TDS 600B, & TDS 700C User Manual Index15 U V W Index16 TDS 500C, TDS 600B, & TDS 700C User Manual X Y Z