Fetches the mean chip rate error, mean frequency error, mean RMS EVM, maximum peak EVM, mean magnitude error, and mean phase error of the complex chips of the corrected signal for the QEVM measurement.

Syntax

Namespace: NationalInstruments.RFmx.WcdmaMX

public int FetchEvm(string selectorString, double timeout, out double meanRmsEvm, out double maximumPeakEvm, out double meanFrequencyError, out double meanMagnitudeError, out double meanPhaseError, out double meanChipRateError)

Parameters

NameTypeDescription
selectorStringstring

Specifies a selector string comprising of the result name. If you do not specify the result name, the default result instance is used. Example:
""
"result::r1"
You can use the BuildResultString(string) method to build the selector string.

timeoutdouble

Specifies the time for which the method waits for the measurement to complete. This value is expressed in seconds. A value of -1 specifies that the method waits until the measurement is complete.

meanRmsEvmout double

Upon return, contains the mean of the RMS EVM values for a QPSK signal. This value is obtained by averaging the RMS EVMs over all averaging iterations. The number of acquisitions is specified by the value of the SetAveragingCount(string, int) method. This value is expressed as a percentage.
The EVM of a chip is the magnitude of the vector difference between the received chip and the ideal chip. The RMS EVM is obtained from all the chips in the measurement interval.

maximumPeakEvmout double

Upon return, contains the maximum value of the peak EVMs for a QPSK signal. This value is expressed as a percentage. This value is obtained over all averaging iterations. The number of acquisitions is specified by the value of the SetAveragingCount(string, int) method.
The EVM of a chip is the magnitude of the vector difference between the received chip and the ideal chip. The peak EVM is obtained from all the chips in the measurement interval.

meanFrequencyErrorout double

Upon return, contains the mean of the frequency errors for a QPSK signal. This value is expressed in Hz. This value is obtained by the mean of frequency errors obtained over all averaging acquisitions. The number of acquisitions is specified by the value of the SetAveragingCount(string, int) method.
The frequency error is the estimated difference between the carrier frequency of the received signal and the ideal signal.

meanMagnitudeErrorout double

Upon return, contains the mean of RMS magnitude errors for a QPSK signal. This value is expressed as a percentage. This value is obtained by averaging the RMS magnitude errors over all averaging acquisitions. The number of acquisitions is specified by the value of the SetAveragingCount(string, int) method.
The magnitude error of a chip is the difference in the magnitudes of the received chip and the ideal chip. The RMS magnitude error is obtained from all the chips in the measurement interval.

meanPhaseErrorout double

Upon return, contains the mean of the RMS phase error values for a QPSK signal. This value is expressed as a percentage. This value is obtained by averaging the RMS phase errors obtained over all averaging acquisitions. The number of acquisitions is specified by the value of the SetAveragingCount(string, int) method.
The phase error of a chip is the difference in the phases of the received chip and the ideal chip. The RMS phase error is obtained from all the chips in the measurement interval.

meanChipRateErrorout double

Upon return, contains the mean of the chip rate errors for a QPSK signal. This value is expressed in ppm. This value is obtained by averaging the chip rate errors over all averaging acquisitions. The number of acquisitions is specified by the value of the SetAveragingCount(string, int) method.
The chip rate error is the estimated error between the chip clock rate of the transmitted signal and the chip clock rate at the receiver.

Returns

Returns the status code of this method. The status code either indicates success or describes a warning condition.