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Agilent Technologies Agilent 35670A manual Averaging to Reduce Measurement Variance

Models: Agilent 35670A

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AGILENT 35670A

Supplemental Operator’s Guide

If continuous real-time measurements over a long duration are required, and absolutely no overload conditions are desired, then a fixed input range can be set that is greater than any signal expected. During periods of low signal level, dynamic range will not be optimal, however the entire measurement can be completed without overloads. To set up a fixed range of 1 volt:

•Press the [Input] hardkey.

•Select the [CHANNEL 1 RANGE] softkey (F3), enter 1, then press the [Vpk] softkey (F1).

If engineering units are turned on ([XDCR UNIT ON OFF]) then the range can be specified in EU. For example, if an accelerometer is connected to channel 1 with XDCR UNIT turned on and XDCR UNIT LABEL specified as [g], then the input range can be specified as 4 “g” as per the following:

•Press the [Input] hardkey.

•Select the [CHANNEL 1 RANGE] softkey (F3)

•Enter 4, then press the [EU] softkey (F8).

Averaging to Reduce Measurement Variance

Spectral measurements of steady signals give results which have a statistical variation over time. Averaging several results will help reduce this variation. The AGILENT 35670A has several averaging techniques available. For general spectrum measurements, RMS or power averaging is commonly used. To average a series of ten spectrum measurements using RMS averaging, follow these steps:

•Press the [Avg] hardkey.

•Press the [NUMBER AVERAGES] softkey (F2), enter 10, then press the

[ENTER] softkey (F1).

•Press the [AVERAGE TYPE] softkey (F3)

•Press the [RMS] softkey (F1)

•Press the [Avg] hardkey.

•Turn on averaging by pressing the [AVERAGE ON OFF] softkey (F1) until ON is highlighted.

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Agilent Technologies Agilent 35670A manual Averaging to Reduce Measurement Variance

Contents

Supplemental Operator’s Guide for the Agilent 35670A Dynamic Signal AnalyzerAGILENT 35670A Supplemental Operator’s Guide SECTION 13 ORDER DOMAIN RESULTS IN LIST MODE SECTION 24 PLOTTING AND PRINTING TRACE DATA Section 1 Turning On the AGILENT 35670A Meas Data Inst ModeTrac Coord Coord A FreqUsing Transducers with External Preamplifiers Using ICP-TypeTransducers with the AGILENT 35670ASection 3 Measuring with Transducers Specifying Transducer Sensitivity and Units Selecting Single Channel Operation Setting Up Transducer Units for DisplacementSelecting Frequency Span Frequency Spans Available for the AGILENT 35670A Quantifying Power Spectrum Results Maximizing Dynamic Range Frequency Zooming to Increase ResolutionSection 5 Improving Measurement Results Averaging to Reduce Measurement Variance AGILENT 35670A Supplemental Operator’s Guide Selecting Single Channel Operation AGILENT 35670A Supplemental Operator’s GuideDisplaying Time Waveforms Selecting Time Record LengthEvent Triggering Quantifying Time Trace Results Selecting Dual Channel Operation Presetting the AnalyzerSection 7 Measuring Dual Channel Spectra Selecting Frequency SpanUsing Markers with Dual Channel Measurements Coupled Markers with Peak Tracking Coupled MarkersMaximizing Dynamic Range Dual Channel AveragingAGILENT 35670A Supplemental Operator’s Guide Section 9 Measuring Dual Channel Time Waveforms Displaying Dual Time WaveformsSelecting Dual Channel Operation Selecting Time Record LengthTriggering a Dual-ChannelTime Measurement Arming Dual Channel Time MeasurementsTrigger Delay Using Markers with Dual Channel Time Measurements AGILENT 35670A Supplemental Operator’s Guide Setting Up the Transducer Parameters Choosing a Preliminary Frequency Span Setting Up Input RangeSpecifying Trigger Parameters WAITING FOR CH 1 TRIGGER Setting Up Time DisplaysUsing Force/Response Windows Averaging Displaying Hammer Test ResultsAGILENT 35670A Supplemental Operator’s Guide Delay = 01.T ForceWidth = T ExponentialDecay = T Changing Frequency SpanAGILENT 35670A Supplemental Operator’s Guide Section 13 Order Domain Results in List Mode AGILENT 35670A Supplemental Operator’s GuidePrepare the order display as follows Prepare the order results list as followsTo start taking measurements AGILENT 35670A Supplemental Operator’s GuideSelecting Measurement Parameters Recalling the Spectra from Non-VolatileRAM Recalling the Spectra from DiskScaling the Displays Using Markers to Compare Section 15 Waterfall Spectra at Time Intervals Setting Up the Waterfall DisplaySelecting Single Channel Operation Selecting Measurement ParametersUsing Slice Markers with Waterfall Data Setting Up Time Step ArmAGILENT 35670A Supplemental Operator’s Guide Specifying the Start RPM Setting Up the TachometerSection 16 Waterfall Spectra at RPM Intervals Scaling the Display Starting and Pausing a MeasurementAGILENT 35670A Supplemental Operator’s Guide Accelerometer Polarity AGILENT 35670A Supplemental Operator’s Guide Set up triggering on Channel 1 to 5% of rangeAGILENT 35670A Supplemental Operator’s Guide Set up the AGILENT 35670AFor accelerometers with the same polarity For accelerometers with opposite polaritySet up trace coordinates as peak-to-peakmil Set up displayAGILENT 35670A Supplemental Operator’s Guide AGILENT 35670A Supplemental Operator’s Guide AGILENT 35670A Supplemental Operator’s Guide AGILENT 35670A Supplemental Operator’s Guide Preset the AGILENT 35670AConnect the transducers Enter Channel 1 input parametersAGILENT 35670A Supplemental Operator’s Guide Set up display parametersChoose measurement parameters AGILENT 35670A Supplemental Operator’s Guide AGILENT 35670A Supplemental Operator’s Guide Viewing Results Using Real and Imaginary TracesAssessing Measurement Quality Set up Trace B to measure velocity in inch/s 0-pk Preset the AGILENT 35670AAGILENT 35670A Supplemental Operator’s Guide Press the Trace Coord hardkey AGILENT 35670A Supplemental Operator’s GuidePress the Y UNITS softkey F8 Press the XDCR UNIT CONVERT softkey F4AGILENT 35670A Supplemental Operator’s Guide AGILENT 35670A Supplemental Operator’s Guide When the run-upand run-downis completedCharacterizing the External Trigger Specify User Levels for TriggeringAcquire and Display the Trigger Signal Setting Up External TriggerCharacterize the Trigger Signal Set up a non-TTLtrigger as followsAGILENT 35670A Supplemental Operator’s Guide Set up measurement parametersSaving Trace to 3.5” Disk Confirming Contents of 3.5” Disk FileSaving Trace to Non-VolatileRAM NV-RAM Confirming Contents of NV-RAMAGILENT 35670A Supplemental Operator’s Guide To return to the Trace viewRecall Trace Data from Non-VolatileRAM NV-RAM Recall Trace From 3.5” DiskAGILENT 35670A Supplemental Operator’s Guide Plotting the Display Generating Output with the AGILENT 35670ASection 24 Plotting and Printing Trace Data AGILENT 35670A Supplemental Operator’s Guide Printing the DisplayCheck the Plot/Print Destination Plot the TraceSection 25 Importing Plots into Microsoft Word Plot to a File Using the AGILENT 35670A Section 28 Precautions to Prevent Loss of Data Measuring Acceleration, Displaying Displacement Converting Frequency Response Units to Compliance Math Functions and XDCR UNIT CONVERTNow display the function F1 on Trace B AGILENT 35670A Supplemental Operator’s GuideAGILENT 35670A Supplemental Operator’s Guide above the track number AGILENT 35670A Supplemental Operator’s GuideSection Section