Composite Measurements

RFmx WCDMA 19.1 Help

Edition Date: October 2019

Part Number: 375421H-01

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RFmx WCDMA 19.1 Help
RFmx WCDMA 20.0 Help

Composite measurement is a technique which allows multiple measurements to be performed in parallel on the same acquired data. This technique leads to faster measurement times since all the measurements in a composite set are based on the same acquired data, and are processed in parallel threads on the CPU. Although the same data set is used for each measurement in a composite set, RFmx allows different configuration settings for each measurement, enabling multifaceted signal analysis.
The following code snippets show the difference between serial measurements and composite measurements:
Serial measurement:

C#

instrSession = new RFmxInstrMX(resourceName, "");
specAn = instrSession.GetSpecAnSignalConfiguration()
specAn.ConfigureRF("", centerFrequency, referenceLevel, externalAttenuation);
specAn.Txp.Configuration.ConfigureRbwFilter("", rbw, rbwFilterType, rrcAlpha);
specAn.Acp.Configuration.ConfigureCarrierAndOffsets("", integrationBandwidth, NumberOfOffsetChannels,channelSpacing);
specAn.Acp.Results.Read("", timeout, out carrierAbsolutePower, out offCh0LowerRelativePower, out offCh0UpperRelativePower,
                        out offCh1LowerRelativePower, out offCh1UpperRelativePower);
specAn.Txp.Results.Read("", timeout, out averageMeanPower, out peakToAverageRatio, out maximumPower, out minimumPower);
instrSession.Close();

VB

instrSession = New RFmxInstrMX(resourceName, "")
specAn = instrSession.GetSpecAnSignalConfiguration()
specAn.ConfigureRF("", centerFrequency, referenceLevel, externalAttenuation)
specAn.Txp.Configuration.ConfigureRbwFilter("", rbw, rbwFilterType, rrcAlpha)
specAn.Acp.Configuration.ConfigureCarrierAndOffsets("", integrationBandwidth, NumberOfOffsetChannels, channelSpacing)
specAn.Acp.Results.Read("", timeout, carrierAbsolutePower, offCh0LowerRelativePower, offCh0UpperRelativePower,
                        offCh1LowerRelativePower, offCh1UpperRelativePower)
specAn.Txp.Results.Read("", timeout, averageMeanPower, peakToAverageRatio, maximumPower, minimumPower)
instrSession.Close()

 

Composite measurement:

C#

instrSession = new RFmxInstrMX(resourceName, "");
specAn = instrSession.GetSpecAnSignalConfiguration()
specAn.ConfigureRF("", centerFrequency, referenceLevel, externalAttenuation);
specAn.Txp.Configuration.ConfigureRbwFilter("", rbw, rbwFilterType, rrcAlpha);
specAn.Acp.Configuration.ConfigureCarrierAndOffsets("", integrationBandwidth, NumberOfOffsetChannels, channelSpacing);
specAn.SelectMeasurements("", RFmxSpecAnMXMeasurementTypes.Acp | RFmxSpecAnMXMeasurementTypes.Txp, enableAllTraces);
specAn.Initiate("", "");
specAn.Acp.Results.FetchOffsetMeasurementArray("", timeout, ref lowerRelativePowerArr, ref upperRelativePowerArr,
ref lowerAbsolutePowerArr, ref upperAbsolutePowerArr);
specAn.Txp.Results.FetchMeasurement("", timeout, out averageMeanPower, out peakToAverageRatio,
out maximumPower, out minimumPower);
instrSession.Close();

 

VB:

instrSession = New RFmxInstrMX(resourceName, "")
specAn = instrSession.GetSpecAnSignalConfiguration()
specAn.ConfigureRF("", centerFrequency, referenceLevel, externalAttenuation)
specAn.Txp.Configuration.ConfigureRbwFilter("", rbw, rbwFilterType, rrcAlpha)
specAn.Acp.Configuration.ConfigureCarrierAndOffsets("", integrationBandwidth, NumberOfOffsetChannels, channelSpacing)
specAn.SelectMeasurements("", RFmxSpecAnMXMeasurementTypes.Acp Or RFmxSpecAnMXMeasurementTypes.Txp, enableAllTraces)
specAn.Initiate("", "")
specAn.Acp.Results.FetchOffsetMeasurementArray("", timeout, lowerRelativePowerArr, upperRelativePowerArr,
                                               lowerAbsolutePowerArr, upperAbsolutePowerArr)
specAn.Txp.Results.FetchMeasurement("", timeout, averageMeanPower, peakToAverageRatio, maximumPower, minimumPower)

instrSession.Close()


When the composite measurements are performed, only a single acquisition is made and each measurement in the composite set is performed on the same acquired data. Internally, RFmx merges the acquisition settings from all the measurements in a composite set to provide the acquisition settings that satisfy the needs of all the measurements being performed. However, not all measurements can be performed as composite measurements. For example, a harmonics measurement cannot be performed in composite with an ACP measurement, since a harmonics measurement requires multi-segment acquisitions for different harmonics.
To perform multiple measurements as composite measurements, use the RFmxSpecAnMX.SelectMeasurements  method, and pass the measurement types you want to perform together to the parameter measurement using bit-wise OR operator.
Besides faster test execution times, composite measurements also allow you to see different measurements on the same DUT signal enabling you to debug difficult issues. For example, you can see if a bad ACP result is correlated to a bad EVM result.

 

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